IMPROVEMENT OF STONE FRUITS

F. P. CULLINAN, Senior Pomologist, Division of Fruit and Vegetable Crops and Diseases, Bureau of Plant Industry1


[ABSTRACT.] THE kind of search in which the breeder of peaches is engaged may be illustrated by the Elberta. This is the leading commercial peach in the United States today. It originated in Marshallville, Ga., in 1870, and in the 67 years since that time no better peach has been found, when all characteristics are considered. Yet in quality the Elberta does not rank as high as some other peaches, and the tree and the blossom buds are not sufficiently resistant to low winter temperatures. By suitable crosses, varieties have been developed that have better quality and more cold resistance in the bud; but these in turn are not adapted to so many different growing regions as the Elberta. Again, seedlings of Elberta have been found that ripen earlier than the parent variety and are better in quality and more attractive. It would seem possible, then, to develop a variety that would be a distinct improvement over Elberta, yet possess the valuable characteristics that have given the Elberta preeminence. Such an achievement would be a major contribution to fruit culture in the United States.

The beautiful and delicious varieties of peaches, plums, cherries, and apricots that make up the group of stone fruits as we know them today are undoubtedly vastly different from their early progenitors. Down through the centuries many wild species and varieties have been selected by man in his search for new food supplies and a better diet. Just how long this slow process of improvement of the various kinds of wild fruit has been going on, history does not relate. As civilization progressed we know that many of these wild fruits were taken from their native homes and distributed to new locations where there were new soils and new climatic conditions. In these new environments certain modifications occurred in size of tree and in size, shape, color, and flavor of fruit. Many trees perished in the new environments. Perhaps only a few survived the vicissitudes of climate in some of the regions into which they were taken. Through these early chance selections, however, a beginning was made in the improvement of the stone fruits.

Stone fruits are now grown in all parts of the Temperate Zone in the Northern Hemisphere. In the United States the culture, production, and sale of these fruits constitute a great industry. In 1931, the peak year of peach production, the commercial crop was over 76% million bushels. According to the census of 1935, the country produced in the previous year about 45 million bushels of peaches, over 23 million bushels of plums, and 5 million bushels of cherries. Peaches, plums, and apricots in the fresh, canned, and dried state are consumed in large quantities in this country and abroad. About 200,000 tons of peaches are dried in the United States annually. California alone produces about 75 percent of the world output of dried prunes. Cherries are commercially important as fresh, canned, and frozen products. There is little wonder that such a great industry should demonstrate weaknesses in many of our long-cherished varieties of home-grown fruits. We might imagine that after all these years of selection and discovery of new sorts, we would have reached perfection. Unfortunately, this is not the case; in fact, it may be said that the work of improvement has just begun. We must continue the search for superior fruits, locating and studying the best raw materials, and then using the methods available to the plant breeder to combine desirable characters in a superior progeny.

BOTANY OF THE STONE FRUITS

Before attempting to consider the progress made in improving the varieties of stone fruits, a few words should be said about the botany of these fruits in general.

Botanists have classified the stone fruits into several species. While there has not been entire agreement as to the number of these species, most botanists place them in the great genus Prunus in the rose family (Rosaceae); others, however, separate the peach and its close relatives as the genus Amygdalus. The fruit develops from a one-celled ovary: the wall of which ripens with a fleshy, juicy exterior, making up the edible part of the fruit, and a hard interior, called the stone or pit. The seed is contained in the stony portion.

But while these fruits have enough in common to be grouped in the same genus, they are quite different in many fruit, flower, and tree characters. When the fruits are ripe the flesh of some varieties parts readily from the pit. Such fruits are spoken of as freestones. Other varieties and species, for example, the canning cling type of peaches, are clingstones; that is, the flesh adheres to the stone. The individual fruits may be smooth, as in the apricot, nectarine, plum, and cherry, or hairy, as in the peach. They vary in size, color, and shape with varieties and species. The flesh may be yellow, green, white, or red, or show various combinations of these colors. The stones or pits of the peach are rough and grooved, those of the plum and cherry relatively smooth, those of the apricot somewhat intermediate.

The flowers of the different stone fruits are quite characteristic for the respective groups. In the peach and the apricot they are borne singly, arising from one to three separate buds at a node. They are practically without stems in the peach, and nearly so in the apricot. They are on long stems in the cherry and on only moderately long ones in the plum, but in both these fruits the flowers are borne in clusters. The flowers of the edible plums are white or nearly so, while those of the peach and the apricot may be white, pink, or reddish.

As will be pointed out later, hybridization between some of the species of stone fruits is practically impossible.

METHODS OF BREEDING

The technique of stone-fruit breeding is not greatly different from that employed with other deciduous fruits. The essential operations are (1) collecting pollen to be used in the crosses, (2) emasculation of the flowers, (3) pollination, or the actual transfer of pollen to the stigmas of the pistil, (4) bagging, or protecting flowers from foreign pollen, (5) protecting fruit that has set, and (6) growing the seedlings for testing and study of the progeny.

Much of the breeding work with stone fruits is carried on with trees growing in the orchard. This has its drawbacks as well as many advantages. Blossom buds, flowers, or young developing fruits may be killed by cold. Under such conditions the continuity of breeding work is interrupted and a year’s time is frequently lost. To avoid this difficulty, particularly in the regions of unfavorable climate, it has been found satisfactory to grow the trees in tubs or pots in the greenhouse. Emasculation and pollination can thus be carried on under controlled temperature. Since it is necessary for most stone fruits to have sufficient cold to bring them out of the rest period, the trees in tubs must be removed from the greenhouse in late summer or fall and placed out of doors or in a cool storage place. "They may be brought back to the warm greenhouse by the middle of January, and the trees should then bloom in 3 or 4 weeks. While greenhouse trees do not reach the large size of those growing in the field and consequently do not produce as many blossoms, sufficient material can usually be obtained for certain crosses and for genetic and cytological study. In some cases it may be the only way blossoms can be produced for breeding work.

In obtaining pollen to be used in breeding it is usually necessary to collect shoots of the male parents desired and force the blossoms in a greenhouse or warm room in order to have the pollen available when the flowers on the tree are ready for pollination. Care should be taken, of course, that no foreign pollen is introduced by bees or other insects. When the flowers have opened, the anthers may be plucked off by running the filaments through a comb or some similar instrument that will lift off the anthers, which may then be placed in suitable containers to dry at room temperature of 65° to 70° F. When dry they break open and the pollen can be easily crushed out. The pollen should be stored in a dry, cool place in vials or small boxes, from which it may be used directly when the crosses are made. It is convenient to leave a small camel’s-hair brush in each container to use in the transfer of pollen.

The structure of the flowers of the peach and other stone fruits permits rapid emasculation. The stamens and the single pistil are enclosed under the folded petals. As the blossom expands from the bud scales, the calyx pushes up, carrying the nonexpanded leafy floral structures, forming a cup around the ovary. The long style of the pistil grows up through the stamens and under certain conditions may even push through between the petals before they expand (fig. 1). In the technique of emasculating, the calyx cup is easily cut with the nails of the thumb and first finger, and the entire corolla with its three rows of stamens attached may be lifted from the flower, leaving the pistil undisturbed. Early workers used sharp-pointed tweezers or scissors to cut the calyx cup, but the fingernail method is more rapid. With varieties of peach that are pollen-sterile, or varieties of plums and cherries that are self-unfruitful, emasculation is unnecessary in ordinary hybridization. A small percentage (0.5-0.8) of set is sometimes obtained in selfing self-unfruitful varieties. While this is a negligible amount in variety breeding, it should not be overlooked in cytological studies.

Register, vote, organize!
Figure 1.—Section through a peach flower showing arrangement of floral parts. By pinching through the calyx cup at a with the thumb and first finger, sepals, petals, and stamens are all removed in one operation, leaving the single pistil.

If emasculation is done just before the petals open (fig. 2)—which is just before any pollen that might cause selfing has been shed—the pollen of the parent to be used in the cross may be applied to the stigmas at once. Where a large number of pollinations are made on a single tree, it is frequently convenient to emasculate all the blossoms before pollinating. With the aid of the camel’s-hair brush, from the pollen container a large number of flowers can be pollinated in a short time. Some workers prefer to use the tip of the finger, to which the pollen will adhere, and apply the pollen by touching the stigmas. Care should be taken to remove all pollen grains of one variety or strain from the finger before dipping into a container of another variety. The individual blossoms, single shoots, or entire branches that have been pollinated with a single pollen variety should be carefully labeled with full data on a tag or label that will remain until the fruit is harvested.


Figure 2.—Flower buds of peach (left) showing ideal stage for emasculation. Within 24 hours with temperatures of 70° to 75° F. the flowers will open as shown on right.

Protecting flowers after pollination is important. The method generally used is to tie a glassine or paper bag over the end of the branch bearing the pollinated flowers (fig. 3). Sometimes two or three flowers may be enclosed in a single bag. With some of the stone fruits, particularly the peach, this method has not been entirely satisfactory, especially where the breeding work is done in the orchard. The relatively long style or stalk of the pistil is easily broken if the bag blows against it (fig. 4) causing loss in bagged flowers. It is necessary, however, to use some method of protection where only a few flowers on a tree are pollinated. A very heavy grade of paper bag with sufficiently sturdy basal folds to hold the sides out from the flower when the bag is inverted over the branch and tied is desirable to reduce the injury to a minimum. When large numbers of crosses are made, and when no special genetic or cytological studies are undertaken, it is doubtful whether peach flowers need to be protected, particularly if an entire branch or tree has been emasculated. Bees or other insects in visiting the emasculated flowers rarely touch the stigmas and thus do not introduce foreign pollen. If an entire tree is emasculated for a large number of crosses, a tent built over the tree will prove satisfactory not only as a means of protection for the emasculated flowers but for insuring a large set of fruit under unfavorable weather conditions.

Figure 3.—When only a few blossoms on the tree are to be pollinated it is necessary to protect the flower from foreign pollen. A heavy paper bag or some cover not easily collapsed by the weather is necessary to prevent injury to the pistil.

Figure 4.—A peach flower after fertilization, showing the pistil with its long style and the enlarging hairy basal portion, the ovary, which becomes the fruit. In the cherry, plum, apricot, and nectarine the fruit develops similarly from a single hairless ovary.

After fertilization of the ovules has taken place (fig. 5) and the style begins to darken and wither, the protecting paper bag is removed and an open-mesh bag of coarse cheesecloth or heavy net is placed over the end of the branch to protect the developing fruit. If the fruit drops off at maturity it will be held in the bag. Where the entire tree has been emasculated and tented, or where a number of branches on the tree have been pollinated without bagging, it is necessary to harvest the fruits before they fall.

Figure 5.—Peach flowers after emasculation and fertilization. The single pistil (A) is normal, but occasionally, in some varieties and under certain nutritional conditions, two (B) or more pistils (C) may develop in a single flower.

The stones are removed from the harvested fruit and are allowed to dry in a place free from molds and fungus contamination. Seeds of stone fruits require an after-ripening period of 2 to 3 months at low temperatures before they will grow. They are usually soaked for several hours and then placed in moist sand out of doors during the winter, or, preferably, they may be held for 2 or 3 months in a refrigerator or cold storage at about 40° F.

To insure a high percentage of seedlings in the case of valuable material, the best method is to remove the pits from the cold box, crack them, and remove the seeds. The seed coats are then removed and the young embryos sterilized in hypochlorite solution or some similar disinfectant and placed in small bottles on sterile nutrient agar to grow. When the young seedlings are rooted and a few inches tall, they may be transplanted from the culture bottles to pots in the greenhouse and later removed to the field or nursery row. The more common method of growing the seed is not to remove the seed coat but to plant the seed directly in pots in the greenhouse or in the nursery. Sometimes the pits are not cracked but are planted directly in the field in the fall when out-of-door temperatures will bring about the proper chilling required to insure growth of the seeds in the spring.

A great obstacle in stone-fruit breeding is the difficulty in getting the seeds of some crosses to resume growth. Many hundreds of seeds of crosses of sweet cherry, early-ripening varieties of peach, and other stone fruits have been planted, but no seedlings grew from apparently normal seeds. It is believed that planting the seeds on sterile nutrient agar will be helpful. At the present time, however, there are stubborn seeds of early-ripening varieties of peach and cherry that will not grow even though given the agar-culture treatment. Many such varieties possess desirable characteristics, but they cannot be used as female parents until some method is found to obtain germination of the apparently normal seed they produce.

To economize space the young seedlings are usually planted in test blocks in rows 10 feet apart, with the trees 5 feet apart in the row, which is about as close as cultural operations will permit. At least 3 or possibly 4 years must elapse before fruit characters can be studied. If it is decided to hasten the fruiting of the progeny, buds or scions can be taken from the seedlings when they are large enough and grafted into branches of bearing trees. In general, budding has proved a more satisfactory method for top-working peach than grafting. In California, however, grafting has proved very satisfactory in the hands of experienced men when dormant scions were placed early in the spring in the cut-back branches of trees 4 to 8 years old. Fruit may be obtained in 2 years from budding, and sometimes in 1 year from grafts. Where tree characters of the seedlings are to be studied, this information is best obtained by leaving them in the field for some years after first fruiting.

Under the most favorable conditions it requires about 5 years from the time the cross is made until a preliminary reading is obtained from the seedling and trees can be propagated for testing in the orchard. If we assume the average life of a peach tree to be about 15 years, then it will be about 20 years before full evaluation can be made of the lifetime merits of a variety. Frequently a much longer time elapses before the value is determined, because of the fact that new varieties are not tested promptly under widely varying soil and climatic conditions.

EARLY HISTORY

THE ORIGINAL home of the peach (Amygdalus persica L. or Prunus persica Batsch.) was thought to be Persia, since this fruit was doubtless introduced into Greece from that country shortly after the beginning of the Christian Era. De Candolle concludes, however, that the peach has never been truly wild in Persia. Botanists agree that the peach is wild in China. The late Frank N. Meyer, explorer of the United States Department of Agriculture, reported finding many wild peaches in China, the fruits of which are inedible, being small and hairy, hard, and with a sourish flesh (17). The peach has also long been cultivated in China. It was written about some 2,000 years before its introduction to the Roman world. Reference to the "tao", meaning peach, has been found in the writings of Confucius in the fifth century B. C. and in the Ritual in the tenth century B. C.

There is evidence that the peach reached France and possibly Spain at about the time it was introduced into Greece. From southern Europe it spread to northern Europe, possibly the greatest spread taking place from France. In more recent times France has been an important nursery center, and in the fifteenth and sixteenth centuries nursery trees were sent from France and disseminated through England, Belgium, the Netherlands, and Germany.

Few other fruits are grown under such varied conditions and over such extended areas as the peach. Once a wild inhabitant of China, it is now cultivated in every part of that vast country. Extensive plantings of the peach occur in Turkistan and Persia. It is not surprising, therefore, that early writers regarded Persia as the original home of the peach, as is suggested by the species name persica later given it. Peaches thrive in all parts of southern Europe and are grown in sheltered places in the northern latitudes. In the United States the peach found such congenial surroundings that it spread rapidly and widely, leading botanists three centuries later to believe it was native to this country. Today peach varieties are found growing in practically every State of the Union. While the fruit is not grown commercially in regions that are subject to low winter temperatures, some varieties or seedlings are able to withstand the winter temperatures in the colder parts of the country.

Because of the general distribution of the peach in Europe, Asia, South Africa, Australia, South America, and the United States, there has been a general selection of varieties best adapted to the various regions and climatic conditions, as well as to the preferences of consumers. Through this process of selection and hybridization peach varieties with widely differing characteristics have been developed and propagated. Some of the wide differences are so marked that botanists have been inclined to separate the peach into races and, in a few instances, species.

American pomologists (25) in the past century tried to divide peaches into four groups or races: (1) The Persian race, brought to North America by the early settlers, best represented by varieties of the Crawford group; (2) the north China or Chinese Cling race, characterized by large fruits with tender skin and flesh, vigorous tree growth, and abundant and regular bearing, and including such Chinese varieties as Chinese Cling, Chinese Free, and later descendants Belle and Elberta; (3) the south China race, sometimes called the Honey, represented by varieties that bear small, oval to pointed, white-fleshed fruits with a peculiar honey-sweet flavor, and adapted in the United States only to some subtropical sections; (4) the Peento race, a warm-climate type with trees inclined to be evergreen and to bear fruits that are much flattened endwise, white-skinned and white- fleshed, and sweet to very sweet. However, all varieties hybridize freely, and there has been so much crossing between the groups that it is practically impossible to classify many of our present yellow- and white-fleshed varieties on this basis (16) (fig. 6).

Figure 6.—Shapes of different types of peaches that may be used in breeding: A, Peento, or so-called saucer peach of the Gulf States; B, the honey peach of Florida and Texas, represented by varieties such as Imperial and Honey; C, peach of the Chinese Cling type, representing most of our present-day commercial freestone and canning cling varieties.

The nectarine was formerly thought to be a different species from the peach. It is now known that the nectarine is simply a smooth- skin peach. The trees differ in no respect from the peach, and it is impossible to tell a peach tree from a nectarine tree. The leaves are the same. The fruits and seeds have essential characteristics in common. In short, the only difference between the peach and the nectarine is the absence of hairs in the latter. Nectarines are known to have come from peach seeds, and vice versa.
  [That nectarines could arise from peach seed is unsurprising, but I'm not sure the author is correct in saying "vice-versa". The nectarine trait (gg) is simply inherited and recessive, so without invoking some major modifier genes that negate the "simply-inherited" part, it's not possible to get peaches from nectarine seeds. My guesses include a poorly-defined phenotype somewhere, or some peach pollen pollinized the nectarine such that a heterozygous fuzzy offspring was generated. There are modifier genes affecting the density of fruit trichomes, for instance, so some peaches are less fuzzy than others, but they still have fuzz. At the time of writing, the GG gene has not been characterized molecularly, but it is conceivable that there are weak alleles that confer a fuzzless gg phenotype in some backgrounds and permit some fuzz in others. -ASC]

COMMERCIAL PEACH GROWING AND ITS STIMULUS TO VARIETY IMPROVEMENT

Commercial peach growing in the United States began early in the nineteenth century (fig. 7). Large orchards were planted in Maryland, Delaware, and New Jersey. Prior to this time thousands of peach trees, all seedlings, were planted by growers. Many of the varieties grown in those early years were apparently better suited for making brandy than for general consumption as canned or fresh fruit. While the art of budding and grafting had been known for a long time, it was not until early in the nineteenth century that large commercial orchards of varieties propagated from cions were used.

Figure 7.—The beginning of commercial peach growing. The early settlers planted fruit trees near the homestead. The home orchard frequently gave place to large commercial plantings.

Table 1.—Fifty varieties of peach grown commercially in the United States during the past 25 years
VarietyPlace of originDate of originOriginator or introducerColor of fleshFirmness of flesh1Stone: free or clingRipening date2Quality
Admiral DeweyVineyard, Ga.1899J.D. HustedYellowSoft-meltingSemifreeJuly 15-23Good
AltonDenison, Tex.1899T.V. MunsonWhiteSoft-meltingSemifreeAug. 3-10Good
ArpArp, Tex.1897C.P. OrrYellowSoft-meltingSemiclingEarlyVery good
BelleMarshallville, Ga.1870L.A. RumphWhiteMeltingFreeAug. 16-20Good
BrackettAugusta, Ga.1912J.P. BerckmansYellowMeltingFreeAug. 29-Sept. 1Good
CarmanMexia, Tex.1889J.W. SteubenrauchWhiteSoft-meltingSemifreeJuly 31-Aug. 5Good
ChairsAnne Arundel county, Maryland1880Franklin ChairsYellowMeltingFreeLate midseasonExcellent
ChampionNokomis, Ill.1880I.G. HubbardWhiteSoft-meltingFreeAug. 17-22Excellent
ChiliChili, N.Y.1845 (?)Pitman WilcoxYellowMeltingFreeSept. 8-12Fair
Chinese ClingShanghai, China1850Imported by Charles DowningWhiteMeltingClingAug. 25-29Good
ClimaxFlorida1886G.L. TaberWhiteSoft-meltingSemifreeLateGood
CrosbyBillerica, Mass.1876Mr. CrosbyYellowMeltingFreeLate midseasonGood
Early CrawfordMiddletown, N. J.1820 (?)William CrawfordYellowMeltingFreeAug. 17-20Very good
Early ElbertaKaysville, Utah1908Sumner Gleason, Stark Bros. NurseryYellowMeltingFreeMidseasonGood
Early WheelerMcKinney, Tex.1906E. W. KirkpatrickWhiteNonmeltingClingJuly 11-20Fair
ElbertaMarshallville, Ga1870S. H. RumphYellowMeltingFreeAug. 21-27Good
EnglePaw Paw, Mich.1875C. C. EngleYellowMeltingFreeAug. 24-Sept. 3Good
EurekaLouisiana1870UnknownWhiteSoft-meltingSemifreeJuly 27—Aug. 5Good
FosterMedford, Mass.1857J. T. FosterYellowMeltingFreeLate midseasonVery good
FrancesTexas1895L. T. SandersYellowMeltingFreeSept. 3-8Good
GaumeLive Oak, Cal.1913Louis GaumeYellowNonmeltingClingLate midseasonGood
Gold DropMichiganUnknownGeorge W. GriffinYellowMeltingFreeSept. 8-10Good
GreensboroGreensboro, NC1891W. G. BalseyWhiteSoft-meltingClingJuly 13-18Good
Hale EarlyOhio1850Mr. Moas. Introduced by Hale and Jewett NurseryWhiteSoft-meltingSemifreeJuly 23-28Good
Heath ClingUnknown1760-70(?)UnknownWhiteMeltingClingSept. 22-27Good
HileyMarshallville, GA1886Eugene HileyWhiteMeltingFreeAug. 8-14Very good
IllinoisNorth Alton, Ill.1910E. H. RiehlWhiteMeltingFreeAug. 17-25Very good
Iron MountainNew Jersey1890UnknownWhiteMeltingFreeSept. 21-25Fair to good
J.H. HaleSouth Glastonbury, Conn.1912J.H. Hale, W. P. StarkYellowFirm-meltingFreeAug. 23-30Good
KalamazooKalamazoo, Mich.1869J.N. StearnsYellowMeltingFreeAug. 8-Sept. 3Good
KrummelSt. Louis, Mo.1895Mr. KrummelYellowMeltingFreeSept. 23-27Good
Late CrawfordMiddletown, N. J.1815(?)William CrawfordYellowMeltingFreeSept. 5-9Very good
Lemon FreeOhio1885UnknownYellowMeltingFreeSept. 12-19Good
LolaMexia, Tex.1876J. W. SteuberWhiteMeltingSemifreeMedium earlyGood
LovellWinters, Cali.1882G. W. ThissellYellowMeltingFreeLate-midseasonGood
MayflowerNorth CarolinaUnknownUnknownWhiteSoft-meltingClingJune 19-30Fair
Mountain RoseMorristown, N. J.1851Dr. MarvinWhiteMeltingFreeAug. 16-19Good
Oldmixon FreeUnknown1835Sir John OldmixonWhiteMeltingFreeSept. 3-8Good
MuirJohn Muir farm, Silveyville, CA1890G. W. ThissellWhiteMeltingFreeAug. 19-25Good
PallasAugusta, GA1878L.E. BerckmansWhiteMeltingFreeAug. 22-26Good
PeentoChina1828William PrinceWhiteMeltingFreeMedium earlyGood
PhillipsSutter County, CA1880Joseph PhillipsYellowNonmeltingClingSept. 12-19Good
PaloroGridley, CA1912Frank DixonYellowNonmeltingFreeAug 22-26Good
ProlificMichigan1890Greening Bros.YellowMeltingFreeAug. 25-Sept. 1Good
RochesterRochester, N.Y.1900Heberle Bros.YellowMeltingFreeJuly 30-Aug. 5Excellent
St. JohnUnknown1860(?)UnknownYellowMeltingFreeAug. 5-10Excellent
SalweySurrey, England1844Colonel SalweyYellowMeltingFreeLateGood
StumpNew Jersey1825UnknownWhiteMeltingFreeSept. 3-8Very good
TriumphVineyard, GA1895J. T. HustedYellowMeltingSemifreeJuly 15-27Good
Tuskena (Tuscan)Mississippi1873UnknownYellowNonmeltingClingEarly midseasonGood

1The terms "melting” and "nonmelting" are used to denote the degree of softness of the flesh of ripe fruits. All freestones have either firm- or soft-melting flesh, and some early-ripening clingstones (Greensboro) have soft, watery, melting flesh, while the flesh of clingstone varieties of the commercial canning type, such as Phillips, have firm nonmelting flesh.
2The ripening dates are those for the U. S. Department of Agriculture orchard at Beltsville, Md., in 1936, a normal season. Where the variety listed did not fruit, the general season is indicated as early or midseason.

As the commercial industry spread, there was always a demand for varieties that would succeed best under various soil, climatic, and other environmental conditions occurring in the different peach- growing sections. In northern regions growers were interested in varieties hardy in wood and bud to withstand low winter temperatures, while in the more southern latitudes they were interested in varieties that would stand summer droughts and high temperatures and with fruit that would retain its firmness during shipment to distant markets. Then came the scourge of disease and insect troubles—peach yellows, leaf curl, brown rot, curculio, and the peach-tree borer. What varieties, if any, would prove most resistant to these troubles?

During the period 1850 to 1900 a large number of varieties were selected from seedlings as worthy of introduction. The list of 50 varieties given in table 1 contains the names of many that still have an important place in the peach sections of the country. They also served as parents for varieties introduced during the last 20 years. The dates of origin of these varieties cannot be accurately obtained in all cases. They are approximately correct and are given to show the length of time the variety has been under orchard test.

It will be noted that the geographical origins of these varieties include nearly all of the States east of the Mississippi between the Great Lakes and the Gulf. Peach growing as an industry was truly widespread in the United States by the end of the nineteenth century. The need for new varieties to replace those that had been under trial was apparent during the period from 1900 to 1910. This was principally due to the fact that peach growing was rapidly developing into an industry for specialists. When the business of peach growing had developed to a point where it was necessary to ship the crop to consuming markets several hundred miles from the orchards, varieties had to be chosen that would stand up in transit and compete successfully with varieties from other sections on the market at the same time. The freeze of 1899 had wiped out many orchards in the North and emphasized the need for varieties that would withstand cold for the commercial orchards of the future. More recent freezes of the winters of 1917-18, 1933-34, and 1935-36 have reemphasized the importance of developing varieties for the North that are more cold-resistant than many now being grown.

WORK OF PRIVATE BREEDERS IN THE UNITED STATES

During the last 30 years there has been an increasing recognition by peach growers of the need of originating new varieties better adapted to meet local requirements in various regions. This is well illustrated by the more recent work of J. W. Steubenrauch, of Mexia, Tex., who developed the Carman variety from pits planted in 1889. It is one of many important commercial peach varieties originated in Texas during the period 1850-1900. Mr. Steubenrauch, now 84 years old, summarized his work in a letter on May 13, 1936.

He planted his first orchard of peaches in central Texas in 1879. There were many kinds available to the growers, mostly what were then called Indian peaches, some good, but not very suitable for general markets. Recognizing the need for varieties of the best quality ripening from early to late season, he bought many trees of new varieties from various parts of the country. In the course of a few years he had 100 or more distinct varieties growing in his orchard.  Feom this number there were not more than about 10 that would be called good varieties for that period, mostly suitable for home use. Among a lot of Elberta trees planted in 1884, he found one tree that he considered superior to all the rest, producing finer fruit more regularly. Having a fine later peach that was part Indian stock, named Belle October, he decided, to bud from the fine Elberta and Belle October parents on a single stock away from all other peach trees. From the two varieties blooming together with bees as pollinating agents, he obtained fruit and seeds of the early and late varieties.

Planting the seeds from the best peaches of both varieties, he produced some fine new seedlings in season from the time of Elberta till late in October. One of the leading ones is the Frank, which was named for Frank P. Holland, publisher of Farm and Ranch. This peach bore a heavy crop again in 1936, making 32 years of continuous annual production. Mr. Steubenrauch describes this variety as a fine yellow-red cling, ripening in the middle of August in central Texas.

In addition to the Frank he produced six others that he considers fully as good. These are Tena, Lizzie, Liberty, Anne, Barbara, and Katie.

These varieties, which have been tested in southern latitudes as well as in some of the Northern States, have demonstrated superior germplasm and are worthy of note for possible use by breeders of peaches.

The man who discovered and introduced the variety that took the lead in commercial peach production in this country from 1910 up to the present was the late S. H. Rumph. He produced the Elberta from a seed of Chinese Cling planted at Marshallville, Ga., in 1870. Curiously enough, another seed reported to have come from the same Chinese Cling tree, planted in the same year by S. H. Rumph’s brother, L. A. Rumph, also of Marshallville, Ga., gave rise to the variety called Belle of Georgia. Today these two are still among the leading commercial varieties. They are of particular genetic interest because the Elberta, a yellow, and the Belle, a white, are reported to have come from seeds of the white-flesh Chinese Cling, and because they are promising varieties for use as parents in breeding work.

Hiley, a probable seedling of Belle, originated with Eugene Hiley, also of Marshallville, Ga., in 1886. Today the Hiley variety ranks second to Elberta as the leading peach of the Southeastern States. It has demonstrated its value as a possible parent in peach improvement because of its high quality and its ability to produce fruits in those southern latitudes where warm winters may be a factor in delaying spring growth and blossoming (fig. 8).

Ditch MoscowMitch!

Figure 8.—In southern peach-growing latitudes and in regions with warm winters some varieties are much slower than others in coming out of the rest period after mild winters. On the left is a row of Hiley in full bloom, and on the right a row of Early Rose still dormant. Photographed at Marshallville, Ga., April 12, 1932, a year of marked prolonged dormancy for this region. This is about 5 weeks later than average full bloom.

One of the most important varieties that became prominent in the period 1900-1920 is J.H. Hale. This variety was discovered by J. H. Hale as a single tree in a lot of Early Rivers peaches shipped to him by David Baird, of Manalapan, N. J., and planted on his farm at South Glastonbury, Conn. Buds from this tree were taken later to Hale’s farm at Fort Valley, Ga. Here the variety also showed great promise as a commercial peach, and it was introduced by Hale through the W. P. Stark Nursery in 1912. By 1925 it ranked fourth among the freestone varieties grown for fresh fruit in the United States. Present opinions differ as to its value as a commercial variety. It has most of the essential fruit characters of a good commercial peach, but the trees are somewhat dwarfish on some sites and locations, not particularly hardy in wood and bud, and not highly productive. The flowers are pollen-sterile, a serious fault that affects productivity when the variety is planted in solid blocks. By and large, the variety is not as widely adapted nor as productive as one of its probable parents, the Elberta, and it has not displaced that variety from the position of America’s no. 1 commercial peach. However, certain characteristics of the J.H. Hale make it of particular interest to the peach breeder and cytologist. Some genetic features of this variety are discussed later in this article.

Hale introduced another variety, the Early Rose, which proved its commercial importance as an early shipping peach for the Southern States. This soft-flesh cling of fair quality and good color was discovered as a chance seedling growing at Fort Valley, Ga., by John H. Baird, of the Hale farm.

Controlled crossing has been carried on by J. E. Markham, of Xenia, Ill., who, beginning in 1925, developed and introduced to the trade Vivid Globe (Yellow Globe x J.H. Hale) [this heritage may be written incorrectly. It shows J.H. Hale as the pollen parent, which is impossible, unless one of the J.H. Hale variants was used. -ASC], Canadian Queen (Canadian Banner X Early Elberta), Markberta (Halberta X Canadian Queen), Markham Cling (Golden Cling 𝕩 Jap Cling), Mark Late (Canadian Queen X Markberta), Globe Haven (South Haven X Vivid Globe), Markham Jewel (Imperial Elberta X Canadian Queen), and Halberta (J.H. Hale X yellow seedling). Most of these varieties have not been widely tested.

Private breeders played a very important part in the work of selecting peach varieties of promise not only from a commercial standpoint but also from that of further improvement of the peach by systematic breeding. Space does not permit listing the many individuals who have been constantly on the watch for the appearance of superior sorts originating as chance seedlings and who subjected the seedlings to careful test. The names of many of these men are given in table 1, together with the description of the varieties they introduced.

PEACH BREEDING AT PUBLIC INSTITUTIONS IN THE UNITED STATES

Breeding work with peaches was started at the New York (State) Agricultural Experiment Station at Geneva, N. Y., in 1895, when open-pollinated seeds of the Elberta were planted. No crosses were made until 1910. Work was also begun at the Iowa Agricultural Experiment Station in 1905, when the late S. A. Beach planted some selfed seeds of the Chili in an attempt to develop hardy varieties that would prove resistant to cold. Crandall, at the Illinois station, began work on the development of new varieties about 1907. At the same time work was started at the California station on the development of peach varieties that would be satisfactory for growing in the warm climate of southern California. By 1914 several States had provided funds for peach breeding at a number of State institutions. Peach-breeding studies were begun at the New Jersey station in 1914. The present peach-breeding work in Michigan started at the South Haven Horticultural Experiment Station in 1924. The United States Department of Agriculture began cooperation in peach breeding with this State in 1919 and later cooperated in the work in California. By 1930 there was considerable interest in developing new varieties of peaches by systematic breeding, and variety improvement work has recently been started in a number of other States.

The first promising varieties that resulted from this early station work for replacement of unsatisfactory kinds were introduced in 1925 by the New Jersey station and also by the Horticultural Experiment Station at Vineland, Ontario, Canada. A list of new varieties introduced as a result of systematic breeding and selection work by State and Federal agencies and by the Ontario station for the period 1900-36 is given in table 2.

Work is now being carried on at the various State experiment stations to meet special requirements of the peach industry in the several States. Following table 2 is a summary of the crosses being made and the progeny obtained, beginning with States in which the work has been in progress for the longest time.

Table 2.—Peach varieties developed and introduced by public institutions
State or ProvinceVariety introducedParentageBreederWhen crossedYear named and introduced
CaliforniaBabcockStrawberry X PeentoCitrus Experiment Station, E. B. Babcock and C. O. Smith19071933
IowaPollyChili (selfed, F2 open-pollinated)Iowa Agricultural Experiment Station1915 1932
MichiganHalehavenJ.H. Hale X South HavenSouth Haven Horticultural Experiment Station1924 1932
New JerseyAmbergemBelle (selfed)New Jersey Agricultural Experiment Station1914 1934
CumberlandBelle X Greensboro19141925
ButtercupLola X Arp19161925
DeliciousBelle X Greensboro19141925
EclipseBelle (selfed)19141925
GoldfinchSlappey X Admiral Dewey1916 1926
Golden JubileeElberta 𝕏 Greensboro (open-pollinated hybrid)1914 1925
MarigoldLola X Arp1916 1925
MassasoitSlappey X Admiral Dewey1916 1925
MeteorBelle(selfed)1914 1925
OrioleSlappey Х Admiral Dewey19161925
PioneerBelle X Greensboro1915 1925
PrimroseBelle X Elberta19151925
RadianceBelle X Greensboro1914 1925
RosebudCarman X Slappey19161925
SunbeamSlappey X Admiral Dewey19161925
White HaleJ.H. Hale X Belle or Ray----------
Garden StateSeedling nectarine (self-pollinated)
U.S. Department of AgricultureMaxineNo. 1 Early seedling X Lemon FreeW. F. Wight19191935
LeetonLeader (open-pollinated)19241935
StanfordHauss X Phillips19241935
EllisPhillips X Linden19241935
Ontario, CanadaVaughanLeamington (selfed)Ontario Horticultural Experiment Station19131925
VedetteElberta (open-pollinated)19151925
VeteranVaughan X Early Elberta19191928
ValiantElberta (open-pollinated)19171925
VimyElberta X Arp19161925
ViceroyVaughan X Early Elberta19191930

New York

To date 65 varieties, 8 seedlings, and 5 P. I.3 numbers have been used in breeding work at the Agricultural Experiment Station at Geneva. Champion was used 8 times, Crosby 8, Elberta 27, Greensboro 13, Chili 11, Hunter (nectarine) 19, J.H. Hale 11, Krummel 8, Livingston 12, Rivers Orange (nectarine) 10, Rochester 10, South Haven 10, Sure Crop (nectarine) 31, and Veteran 9. There were in all 333 crosses, 24 selfs, and 13 open pollinations. Of the 400 seedlings set in the orchard, 307 have originated from crosses made since 1922. Many of the seedlings are just beginning to fruit, and therefore their full history is unknown.

New Jersey

From the work started in 1914, 20 new varieties had been introduced up to the spring of 1936. In addition to these there are 17 unnamed but specially selected peach seedlings showing considerable promise that are now being grown in State-wide commercial tests During the period 1923 to 1936, 6,257 seedlings had been obtained by crossing, selfing, and open-pollinating varieties of peach and nectarine possessing desirable characteristics. Of this number 1,064 have been retained for further study. Approximately two-thirds of this number are of J.H. Hale parentage.

Iowa

One of the objectives of the breeding work at the Iowa Agricultural Experiment Station is to test the feasibility of making interspecific crosses with stone fruits. About 100 potted trees grown in the greenhouse are being utilized in this work. Varieties of Amygdalus persica, including nectarines of A. davidiana (Carr.) Zabel as well as hybrids between these two species, are being grown. From the crosses made, approximately 75 promising seedlings are now being studied in the field. These include Chili (fourth generation) open-pollinated, Chili (third generation), Bailey X A. davidiana, J.H. Hale X A. davidiana, and Chili (third generation) A. davidiana.

Illinois

Of the first series of crosses made by Crandall at the Illinois station all have been discarded except Illinois 146, 148, and 101. These are being propagated for further testing under semicommercial conditions. The quality of all three of these is high, but they probably are somewhat lacking in the firmness of flesh that a commercial peach must possess.

Michigan

From the peach-breeding work begun at the Michigan station in 1924, one promising commercial variety, Hale Haven, a cross of J.H. Hale X South Haven, was introduced in 1932. This is a large yellow freestone maturing 17 days before Elberta and about the same time as South Haven. It is considered to be an improvement over the latter variety because of its higher color, thicker skin, and perfect freestone condition. The number of seedlings being grown at the present time from the crosses made during the period 1924-36 is 2,076. During the period 1924-30, 700 seedlings were obtained from crosses of J.H. Hale with a number of commercial varieties important in Michigan, such as Banner, Kalamazoo, Elberta, South Haven, and New Prolific. Of this list only 15 had superior horticultural value.
   Work is now under way in an attempt to develop some clingstone varieties of canning types suitable for Michigan conditions. At the present time there are under observation 359 seedlings from crosses where one parent is freestone and the other cling, or where both parents are cling.

California

The work on peach breeding at the California Agricultural Experiment Station at Davis has been confined in recent years (1930-36) largely to developing a satisfactory type of nectarine for canning. A large number of seedlings are now being grown on the station grounds from about 1,310 crosses of nectarine X nectarine and nectarine X peach. Among the varieties of nectarines used as seed and pollen parents are Stanwick, Ansenne, Diamond Jubilee, Sure Crop, Quetta, Boston, Dixie, New Boy, Goldmine, and Lippiatt. Peach varieties used. either as seed or pollen parents in crosses with these nectarine varieties are Lovell, Muir, Late Champion, Red Cling, Elberta, Late Crawford, J.H. Hale, Fay Elberta, and Rochester. In addition there is a very excellent collection of over 300 named and P. I. numbered varieties of peach and nectarine as a source of breeding material.
   Breeding work with peaches was begun in 1907 at the University of California Citrus Experiment Station, Riverside, to develop varieties for growing in southern California. In this section many of the older varieties of cling and freestone types do not start growth sufficiently early in the spring to secure normal development, and shedding of blossom buds is common following warm winters. The Babcock peach, which was introduced in 1933 by G. P. Weldon, of the Chaffee Junior College, and by the University of California, was the result of the early work started by E. B. Babcock and C. O. Smith and continued by J. W. Lesley. The special value of the Babcock peach lies in its easily broken dormancy. It is an early white freestone of fair size and good quality. In recent years other crosses have been made, using as seed parents various cling and freestone varieties, and pollen from Honey and Peento types and varieties in which dormancy is easily broken. The Babcock is also being used in these crosses. From this work about 12 seedlings have shown promise and are being carried for further testing. Sims pollinated by P. I. 32374 has given a very promising yellow cling. Sims is a variety characterized by a short rest period.

Massachusetts

Breeding work at the Massachusetts station was begun in 1918. The progeny from most of the crosses made in 1925 and 1926, using as female parents varieties that showed considerable hardiness, has been discarded as unsatisfactory for growth under Massachusetts climatic conditions. There are 2,460 seedlings now receiving special study, mostly of a genetic rather than an immediately practical nature. However, a number of promising seedlings have been selected for further testing. In 1931 and 1932 over 2,000 seedlings were obtained in crosses with Belle, Champion, and Gold Drop in studying the problem of linkage between flesh adherence to stone and flesh texture. Some crosses have also been made in a study of the inheritance of bark color.

Virginia

In recent years studies have been made on the progeny of a smooth- skinned Crawford seedling obtained by selfing, when it was crossed with such varieties as J.H. Hale, South Haven, Rochester, Oriole, Golden Jubilee, Elberta, and Gold Drop. The object of the crosses is to obtain a variety of high quality possessing bud hardiness. Orchard and potted trees are being used. From this work, as well as that previously done with open-pollinated and. selfed Elberta, about 15 seedlings of horticultural value have been obtained.

Texas

Breeding studies were begun at the Texas Agricultural Experiment Station, College Station, Tex., in 1935. This work has for its purpose the development of varieties suited to peach-growing districts of Texas where the winter temperatures may not be low enough to give the proper amount of chilling required for best development of varieties that do better in more northern latitudes. Hiley, Pallas, Belle, Early Elberta, Anna, Indian Free, Slappey, and Florida Gem have been used in the crosses.

United States Department of Agriculture

Peach-breeding work in the Department was started in 1919. The early crosses were made at the branch experiment station of the Michigan Agricultural College at South Haven, Mich. Later, crosses were made at the United States Plant Introduction Garden at Chico, Calif. Since 1922 the work has been carried on in the Santa Clara Valley, principally in the experimental orchard at Leland Stanford Junior University, Palo Alto, Calif. Work has recently been undertaken at the United States Horticultural Station at the National Agricultural Research Center, Beltsville, Md., where some 150 varieties are available for study. During the past year 79 separate crosses were made, usually high-quality cold-resistant varieties.
   New varieties that have been introduced as a result of the work in California are Leeton, Maxine, Stanford, and Ellis. The Leeton is a selected seedling of Leader grown at Palo Alto from pits imported by Frank Dixon from Leeton, Australia. Maxine is the product of a cross made at South Haven, Mich., between Lemon Free and an unnamed early-ripening seedling of noticeable bud hardiness. The Stanford, a Hauss x Phillips hybrid, is a canning cling peach ripening in season with Phillips. The Ellis, a cross of Phillips x Linden, is also a canning cling type ripening about a week ahead of Stanford. The introduction of these varieties has been based largely upon their behavior under California conditions. The two freestone varieties are worthy of testing under eastern conditions. The Leeton ripens about in season with Triumph and shows promise of being a better early peach than the latter variety. The Maxine is a yellow-flesh variety of high quality, ripening just after Rochester. It has proved to be quite cold-resistant in bud during two recent severe winters (1934-35 and 1935-36) at Beltsville, Md.
   A large number of hybrids have been produced since 1922, and these are under test in the experimental orchard at Palo Alto, Calif. Some of the more promising of these hybrids are being tested at other places in California and, in a limited way, in a number of orchards in the eastern United States. Nearly all of the imported freestone varieties produced in this California breeding work are being tested at Beltsville, Md. The seed parents are given in the following list, together with the number of hybrids developed from each parent: Elberta 11, Hauss 5, Horton Rivers Chili 8, J.H. Hale 11, Illinois 2, Leader 5, Libbee 8, Lovell 7, Maxine 3, Miller Late 2, Mira 1, Muir 15, Newhall 3, Ontario 4, Paloro 18, Phillips 5, Pratt-Low 10, Salwey 44, Selma 3, St. John 2, Tuskena 14, Uneeda 1, Yellow Free 2, Yellow Transvaal 18.
   In addition to the more common commercial varieties, a large number of Department introductions having desirable characteristics and showing considerable promise for breeding have been used. Among these are a Chinese introduction (P. I. 43289) and a Spanish cling (P. I. 43570T2). The varieties listed above as female parents have also been used as pollen parents in a good many reciprocal crosses. Backcrosses and intercrosses have also been made with first-generation hybrids. Studies are being made on the progeny of 234 separate and distinct crosses of named varieties and hybrids. From this group of hybrids a number of promising freestone varieties have been obtained that have characteristics superior to a number of the present commercial varieties. Some are promising canning clings, while others show marked resistance to delayed foliation and are adapted for growing in warmer climates where the present commercial varieties do not produce satisfactory annual crops. Combinations have been made between important commercial varieties subject to delay in foliation and such introduced varieties as Yellow Transvaal and St. Helena, which have less prolonged dormancy, in the hope of transmitting this desirable character to the progeny.
   In 1909 Shamel and associates (29) noted some striking limb variations in studies of freestone varieties in California, and more recently he has discovered some early- and late-ripening strains among peach varieties. Weldon (31) has also reported finding several limb variations in orchards in the same State. It appears that some varieties of peach are less stable than others. While very few color sports of peach have been found to date, it would not be surprising if more should be found when careful search is made.

PEACH BREEDING IN OTHER COUNTRIES

Canada

Since 1914 peach breeding has been carried on at the Ontario Horticultural Experiment Station, Vineland, Ontario, to meet the needs of the market and climatic conditions of southern Canada, especially to secure varieties giving a seasonal succession of ripening. Open-pollinated seedlings have been grown in considerable numbers. Some hybridizing has also been done. Earlier ripening Elberta types with attractive fruit of high quality were sought. In all, 13,106 seedlings were grown during the period 1911-36. Of these, 144 have horticultural value. Six varieties were introduced during the period 1925-30. Two of the most promising, Valiant and Vedette, are Elberta seedlings.
   From 1918 to 1922 approximately 2,200 open-pollinated seedlings of Elberta were fruited. A second lot of 1,000 Elberta seedlings bore a marked resemblance to the parent tree in growth characteristics and in fruit. Probably 15 to 20 percent could have been propagated and distributed as Elberta, while approximately 3 percent had white flesh, and 15 percent were semiclings or clings. A fair number were moderately good, none exceptional, the majority being of Elberta quality or poorer. The variation in season from Elberta was slight, ranging from a week earlier to a week later. Five hundred and fifty open-pollinated seedlings of Lemon Free were almost identical with the parent. Only a very occasional tree bore fruit with even a suggestion of color other than the yellow. Seedlings of New Prolific, Reeves, and Early Crawford were very much like their parents. The fact that open-pollinated seedlings of peach came so true to type when the pits were taken from an orchard in which there were upward of 150 varieties, thus affording every opportunity for natural crossing, suggests that the peach is usually self-pollinated under orchard conditions.

England

Experiments with peaches and nectarines were begun at the John Innes Horticultural Institution, Merton, England, in 1911. The object was to investigate the genetic composition of fruit trees by raising selfed offspring. The varieties used were Royal George, Blood Leaf, and Lord Napier nectarine. The results: obtained will be considered later under the discussion of genetic relationships in the peach.

Australia

The work on production of improved varieties of dessert peaches in New South Wales is located at Hawkesbury Agricultural College, Richmond, while that on improved varieties of canning peaches is at the Yanco Experiment Farm, Yanco. Breeding at the Yanco Farm with peaches was begun in 1928. One of the principal objectives was the development of better varieties for canning that would possess high quality, large size, good yield, and freedom from red around the pit. There is a need for early canning varieties to come in immediately after the late apricots are harvested. Table freestone types are also sought in New South Wales, though not specifically in the breeding program at Yanco. The following varieties have been used in crosses as sources of open-pollinated seeds: Golden Queen, Leader, Paloro, Pullars, Sims, Tuskena, Goodman Choice, Locksley Perfection, and Phillips (Victorian strain). Of these the greatest promise as parents has been shown by Golden Queen, Phillips, Tuskena, and Sims (Victorian). Goodman Choice has desirable habits, and Pullars excels in yield but is red around the pit. Leader, a freestone, is one of the best parents. Dessert types that are being planted for orchard trial are Phillips X Triumph, Tuskena X Leader, and La France x Elberta.
At the Hawkesbury Agricultural College, seedlings of Goldmine (nectarine) X Triumph (peach), Blackburn X Triumph, and Elberta X Wiggins have produced fruit of some promise as freestone dessert peaches. With nectarines, work is under way to improve on the standard variety Goldmine. The varieties used as pollen parents are Mrs. Chisholm, W. C. Frip, and Irrewarra.

Morocco

A fruit and vegetable experimental laboratory was established in 1933 for the study of horticultural genetics. Its activities extend to the six experiment stations of the Lacarelle group, distributed in the different fruit-producing regions of Morocco, as well as to the official experimental gardens of the protectorate. The peach-breeding work has a definite objective, the production of new varieties of high quality adapted to local climatic and soil conditions, as well as stocks resistant to certain diseases, such as gummosis. The work to date has been concerned principally with the study of the hereditary characters of varieties that would appear to be the best parents. A number of hybrids have been produced and are under test. Four forms of the Atlas peach are being used as stocks.

SOME OBJECTIVES IN IMPROVEMENT OF PEACH VARIETIES BY BREEDING

In surveying the long list of peach varieties available for planting, many are found with very desirable characteristics but for one reason or another not entirely satisfactory from the standpoint of the commercial grower or the home fruit gardener. The fault is often determined by the fruit-growing region in which the particular variety is grown. In one region it may be lack of resistance to winter cold, in another it may be unproductiveness; in still another a peach may prove to be a good bearer with satisfactory cold resistance but lack fruit size and quality. If-suitability for canning is the principal requirement in a section, a variety must be judged entirely from this standpoint. Varieties poorly suited for one region or purpose may be entirely suitable for other conditions.

In this article the Elberta has been mentioned as our most important commercial variety, but it lacks some desirable characteristics. It is adapted to a wide range of soil and climatic conditions and is an excellent shipping peach, but it does not have the high fruit quality nor the desired degree of resistance of the tree and blossom buds to low winter temperatures. Where the characteristics of this variety have been combined by breeding with those of a variety more hardy in bud, the results have been promising. A few varieties have been obtained that are of higher quality and more cold resistant in bud than Elberta, but they are not so widely adapted to the fruit-growing regions of this country. Seedlings of the Elberta have been found that ripen ahead of the parent and have fruit of higher quality and more attractive in appearance. So far, when all characteristics are considered, a peach truly better than Elberta has not been found; but if by proper combination of characters a superior variety that is as widely adapted can be produced, it will be a major contribution to American fruit culture. To secure a hardy commercial variety for the colder peach-growing sections of the United States is another most important objective in fruit improvement.

It has long been known that varieties of the so-called Crawford type are of very high quality but not especially productive, and very tender in bud. Varieties of this type have passed out of commercial production because they possessed these unprofitable characters. Attempts should be made to introduce Crawford-type fruit quality or its equal into other varieties, or to combine the hardiness and productive qualities of other varieties with those of the Crawford type.  Progress has been made in this direction by using St. John, a Crawford type of high quality but not particularly strong in tree character and cold resistance in bud, in crosses with Admiral Dewey, an old variety that is particularly hardy in bud, with small, fuzzy, unattractive fruits. A very promising hybrid has been thus developed in the . breeding work of the Department of Agriculture.

The J.H. Hale variety has many outstanding fruit characteristics, but it is lacking in vigor of tree, hardiness, and productivity. A cross of J.H. Hale X South Haven at the Michigan Agricultural Experiment Station has resulted in a hybrid showing decided improvement over the South Haven variety. Considerable breeding is under way, using the J.H. Hale variety as a parent. Accomplishments to date, while not entirely satisfactory, give promise for the future.

The raw material represented by varieties of peach in this country needs further reworking through breeding methods in order to obtain the desired combination of characters. In this material there are still many important characters lacking that may be found in varieties now growing in other parts of the world. The need of continuing to import material is apparent. An example is the quest for a variety that is not subject to delayed foliation. In climates with warmer winters than those of the fruit regions of this country, varieties are to be found adapted to such conditions. Such varieties should be introduced into this country for combination with our own. Progress has been made in California in recent years on this aspect of breeding work by the Department of Agriculture. Varieties of the peach of the St. Helena and Transvaal types, introduced respectively from the Island of St. Helena and from South Africa and crossed with our native varieties, have given results that would indicate that the problem of delayed foliation can be overcome at least to some extent through breeding.

There is need for more knowledge about the heritable characteristics of rootstocks for peaches. It has been observed that some varieties of a particular parentage are more susceptible than others to cold injury or to root disease. It is important to know which seedlings may be used as stocks to insure longevity, productiveness, and disease resistance. Work is now under way in the Department of Agriculture to determine the merits of seedlings of known varieties of peach and plum suitable for understocks (fig. 9).


Figure 9.—Peach rootstock effects. Early Hiley variety, fourth year in the orchard. The row on the right is on plum (Prunus hortulana), and the one on the left is on the widely used Tennessee “natural” peach stock. The dwarfing influence on the hortulana stock is apparent.

As already indicated, methods must be devised whereby the seeds of early-ripening varieties of stone fruits can be made to germinate after crosses have been made.

Another important objective in stone-fruit breeding work is the development of superior varieties for canning and for drying. In California at the present time varieties of apricots suitable for canning are very much sought for. Varieties of peaches of the canning cling type that have been used for a number of years are not entirely satisfactory because of one weakness or another. Some otherwise satisfactory varieties develop red color in the flesh, especially about the pit, which renders them undesirable for canning. Pit splitting and gumming are other faults. Some of the canning varieties used at the present time are susceptible to mildew through the inheritance of glandlessness. Good types lacking such objectionable characteristics are needed for canning.

The method of approach to the problem of developing better varieties will involve basic studies in the inheritance and transmission of characters. An important part of the work, therefore, will be growing and studying progenies to determine the transmission of desirable as well as undesirable characteristics.

Very little work has been done from the standpoint of securing desirable characteristics through induced mutations. Polyploidy, or increase in the number of chromosomes, which has proved of special interest with other crops, has received little attention from workers in stone-fruit breeding. Some work has been done at the New York Agricultural Experiment Station at Geneva in an attempt to induce polyploidy in stone fruits through the selection of large pollen grains. This method has not yet yielded satisfactory results, but the studies need to be continued, with many other attacks on the general problem. No results have been obtained so far in attempts to cause mutations through heat treatments, a method that seems promising in corn breeding.

SOME GENETIC FACTS ESTABLISHED IN PEACH BREEDING

In a collection of 100 or more peach varieties selected at random, the casual observer of the trees might think that they are all one variety. Among peach varieties in general there are no very marked differences in general tree characters. There are, however, distinct differences in size, shape, and color of leaves, in time of blossoming, in color and size of flower, in time of ripening, and in fruit characters. Genetic studies show these characters to be inherited, and in hybridization many of them appear in the normal Mendelian ratios. Cytological studies to date have not revealed how the factors governing these characters are linked, nor where they are.located on the chromosomes, nor what the behavior is in the reduction division of the sex cells.

Connors (4, 6, 7), of New Jersey, was one of the first workers in this country to investigate some of the genetic relationships in peaches. He made crosses between some of the important commercial varieties in an attempt to gather information on inheritance of characters.

Inheritance of Flesh Characters

Flesh color.—The parents used by Connors in one series of crosses were Elberta and Early Crawford as yellow-flesh varieties, and Belle and Greensboro as white-flesh varieties. Early Crawford has small blossoms, Elberta medium, and Greensboro large. All are freestone except Greensboro, which is a soft semicling. An analysis of the progeny in the F1 generation showed some interesting facts. All of the varieties used in the crosses were of unknown parentage, having originated as chance seedlings. Belle, a white, and Elberta, a yellow, are supposed to be F1 descendants of Chinese Cling, with the pollen parent unknown. Greensboro behaved as a pure white in crosses, but when selfed no progeny was obtained because of the failure of the seeds to grow. St. John (yellow) X Early Wheeler (white) gave all white in the F1, and St. John X Greensboro likewise gave all white F1, seedlings. White flesh is dominant over yellow flesh. Crosses or self-pollinations of homozygous white-flesh varieties have yielded all white-flesh seedlings. Heterozygous whites have yielded three whites to one yellow. Yellows have given all yellow.
   This work makes the supposed parentage of Elberta somewhat open to question. Elberta is a seedling of Chinese Cling, and the pollen parent is thought to be some variety like Early Crawford. If Chinese Cling were pure white, as might be suspected from its early history, then in a cross with a yellow variety the first generation seedlings should all be white. However, Elberta as the F1 in this probable cross is yellow, while Belle, a seedling of the same variety (Chinese Cling) is white. The Chinese Cling parent of Elberta may not have been a pure white. The work at Vineland, Ontario, Canada, reported by Palmer (26), confirms that of Connors in showing that when a homozygous white-flesh peach has been used as one of the parents, all of the progeny will have white flesh. Yellow flesh behaved as a pure recessive. It is perhaps more significant in considering the parentage of Elberta that from 2,200 open-pollinated and selfed seedlings of that variety, there has been none with fruit resembling Early Crawford, the supposed pollen parent. Palmer has ventured the opinion that Elberta is a natural selfed seedling of Chinese Cling, a recessive yellow breeding true for that color.

Texture of flesh.—In the work of Connors, Elberta self-pollinated seedlings showed a high percentage of firm fruit. Wherever Elberta was used as a parent the result was a high percentage of firm-flesh seedlings. Belle X Early Crawford gave a relatively high percentage of firm-flesh seedlings. Soft flesh appears to be dominant over non- melting flesh. The character for producing the tough flesh so desirable for commercial canning is present in Belle, Carman, and Early Crawford. Seedlings of these varieties, however, show red coloring of the flesh about the stone, an undesirable character from a canning standpoint.

Adhesion of flesh to stone—Connors noted that freestone appears to be dominant over clingstone. In crosses between freestone varieties the progeny has been about two freestones to one cling or semicling. There are some varieties that are classed as semicling in which the adhesion of flesh to stone is not very great. In some of these groups such as Greensboro and Carman, the fruits in some seasons may be nearly free. Frequently, if the fruits are allowed to remain on the tree until well ripened, the flesh will almost completely separate from the stone. The true clingstone type of peach is that represented by varieties like White Heath and Red Bird, and the canning cling by types like Phillips and Paloro. Freestones crossed with freestones always gave a high percentage of freestones, the degree depending on the variety. Belle and Elberta carry a factor for adhesion of flesh to stone of about 33 percent. When freestones are crossed with clingstones a higher proportion of freestones than clingstones is obtained.

Inheritance of Other Characters

Foliar glands or nectaries:—The foliar nectaries of the peach are of interest because it has been shown that glandless varieties are more susceptible to some leaf diseases, particularly mildew, than varieties with glands. Some commercial canning cling varieties now grown in California, such as Paloro and Hauss, are glandless. These are quite subject to mildew in some seasons and in some locations. Rivers (27) reports that in crossing varieties having reniform glands with glandless varieties, he obtained an intermediate type, which was round or globose. Connors, in crossing some of our common American varieties, such as Belle, Carman, Elberta, and Greensboro, which are reniform, obtained seedlings all of which were reniform. When these varieties were crossed with varieties with globose leaf glands, the progeny was about 50-50 reniform and glandless. No glandless varieties were selfed, but Bailey and French (2) report all the progeny of a selfed glandless seedling were glandless. The F1 hybrids of a cross between reniform and glandless varieties all have glands that are globose (fig. 10). The character is apparently incompletely dominant.

Ditch MoscowMitch!
Figure 10.—Types of foliar nectaries in the peach and the nectarine: A, Reniform or kidney-shaped glands of Elberta peach; B, globose glands of Fitzgerald peach; C, eglandular leaf of Lippiatts nectarine.

Tree habit.—In crosses at the New Jersey station between Greensboro, spreading type, and Early Crawford, upright type, the seedlings were all intermediate, none being the same as either parent. Seedlings of Early Crawford, self-pollinated, were all upright. Seedlings of Lola and Carman, which are spreading, were all spreading. The progeny from selfed Elberta gave ratios of 1 upright : 2 intermediate : 1 spreading. No dwarfs have appeared among the progeny of these varieties.

Size of blossoms.—With blossoms the blending type of inheritance is usually shown, with sometimes a slight apparent dominance of the small-blossom type. In all cases studied by Connors, the large blossoms and small blossoms were homozygous. Large crossed with small gave all medium, and the medium split up in a ratio of 1:2:1 in the F2 generation. Large blossoms appear to be dominant in varieties bearing them, while varieties with small blossoms give small blossoms in selfing. In crosses of large-petal types with small-petal types all the seedlings had medium-size blossoms. This appears to be a case of incomplete dominance.

Blooming date-——The majority of seedlings bloomed at practically the same season as the parents, but a few individuals bloomed earlier or later. Elberta and Belle, self-pollinated, gave some seedlings that commenced blooming as much as a week after the parents. Slappey is a late bloomer, and all of its progeny were late.

Ripening date—The hybrids usually ripened about midway between the parents, and it is rarely the case that a seedling ripens earlier than the early parent or later than the late parent. The deduction is that the best chance to secure a new individual ripening its fruit at a certain date would be by crossing two varieties the mean of whose ripening dates would fall at the desired time. No marked differences in ripening dates were observed. The majority of the seedlings of the varieties used ripened about in season with the parents, with some slightly earlier and some later than either parent.

Size of fruit—Parents with small-size fruit are to be avoided. Belle transmitted its character for good fruit size. Elberta seedlings are practically all large-fruited.

Beginning in 1921, Connors used the J.H. Hale variety in a number of crosses. During the period 1923-28, 42 crosses were made with this variety. Blake and Connors (4), reporting on the results of these crosses, state that the collection of characters in the J.H. Hale variety was as a group recessive to the characters in varieties such as Chili, Iron Mountain, Chinese Blood, and varieties with nonmelting type of flesh. In the case of J. H. Hale X Chili the progeny of the cross so closely resembled Chili in every way that it was impossible to distinguish many of them from the pollen parent. In summarizing the evidence of inheritance of characteristics in the progeny of these J.H. Hale crosses, Blake and Connors drew the following conclusions: (1) Red flesh color about the pits is apparently dominant over absence of red at the pit; (2) watery melting flesh texture is apparently dominant over firm-melting flesh texture; (3) nonmelting flesh is recessive to both watery melting and firm-melting flesh texture; (4) blood red flesh was dominant over the absence of red; (5) heavy pubescence is apparently dominant over short or light pubescence; (6) oval-conic, oval-oblong, and round-pointed forms in Chili, Iron Mountain, Chinese Blood, Japan Dwarf Blood, and others were dominant over round; (7) full-dwarf and semidwarf growth habit was recessive to standard tree size; (8) early blooming, characteristic of Amygdalus kansuensis (Rehd.) Skeels, was dominant over the late blooming of J. H. Hale; (9) vigorous sucker development from the trunk and main branches characteristic of A. kansuensis was dominant over the slight sucker development of J.H. Hale.

Characters Transmitted by Certain Varieties

Elberta transmits large fruit size, yellow color, and firmness of flesh, freestone character, an extended period of ripening, and a slight tendency to sterility. The self-pollinated seedlings show better quality than that of the variety itself.

Belle is a heterozygous white and is able to transmit white and yellow flesh, a fair degree of firmness of flesh, a fair degree of freestone condition, variability in period of ripening and blooming, and a tendency to sterility.

Early Crawford transmits small fruit size, yellow flesh, a good degree of firm or tough flesh, a fairly high degree of freestone character, tender pubescent skin, and rather high acidity.

Greensboro transmits white flesh, good fruit size and color, hardiness in bud, softness of flesh, and a clingstone character.

Slappey transmits small fruit size, dry, mealy, yellow flesh, lateness of blooming, and nonadhesion of pulp.

Lola transmits small size, tendency to clingstone condition, and tough flesh.

In tree habit the white-flesh varieties are more vigorous in tree growth than yellow-flesh sorts.

Further genetic studies on the inheritance of characters in the peach may be helpful in tracing the origin of the aforementioned groups or races of peaches. This should be possible if prototypes of our present-day varieties could be located, such as the large-petaled, white-fleshed peaches of China, and the small and medium-petaled, yellow-fleshed types found among varieties more common in western Asia and the Mediterranean countries, and among the varieties now commonly grown in this country.

Genetic Studies in England

Work at the John Innes Horticultural Institution in England with the peach Royal George, having small flowers and small, eglandular, serrate leaves, when selfed gave a progeny of seedlings with small flowers and eglandular, serrate-margined leaves. Royal George and its progeny proved to be susceptible to mildew.

The Purple Leaf variety of peach (Blood Leaf) with large flowers, purple leaves, reniform glands, shallow margin, finely serrate, when selfed gave a small number of progeny, all having large flowers, purple leaves, reniform glands, and leaf margin similar to type.

Selfed nectarine (Lord Napier variety) with large flowers, large leaves, reniform glands, and shallow crenate margin gave seedlings with flowers and leaves similar to the parent. A few of the leaves were almost serrate.

Two seedlings raised from a cross of Purple Leaf peach X Lord Napier nectarine had purple leaves, but the pigment was less intense than in the Purple Leaf parent or its selfed derivatives. This suggests that the purple pigment in the peach behaves as a dominant, but the reduction in the amount of pigment suggests a modifying factor. [There conclusion is borne out by previous work, so they shouldn't be saying anything about a measly two offspring, from which one cannot conclude much of anything. The authors should have known about previous work that is more-convincing. -ASC]

Correlations

Hedrick (17) has pointed out a correlation between color of the inside of the calyx cup and the color of flesh of the fruit. When the calyx cup is greenish the fruit will be white, and when the calyx cup is a deep orange the flesh of the fruit will be yellow. An intermediate type is suggested by Connors in which the calyx cup is yellowish buff, and following this the color of the flesh will be white, but the tree carries a character for yellow flesh. This is true in the case of Belle.
   Another correlation, according to Connors, is that between leaves and the color of the flesh. When the midrib and the veins of the leaves of a variety have a yellowish cast the fruit is yellow, but if the midrib or veins are pale green or whitish the fruit will be white.

Pollen Sterility

Most varieties of peaches are self-fruitful. Occasionally failure to produce crops may be due to pollen sterility, which is exhibited in a few commercial varieties, such as J.H. Hale, Halberta, Candoka, Mikado, and Chinese Cling.

Connors in 1921-22 examined over 330 seedlings in the fruit-breeding plots. J.H. Hale was the only variety that did not produce pollen, and about 50 percent of open-pollinated seedlings of this variety were pollen-sterile individuals. Progeny of some crosses with J. H Hale have also shown about 50 percent of sterile individuals, while in other crosses with this variety the progeny all produced pollen. It is suggested that this type of sterility is recessive to the fully fertile flower form. The failure of pollen-grain development in J. H. Hale has been found to be due to degeneration in the microspores some time previous to blossoming. Apparently there are strains of this variety that produce pollen and are self-fruitful, but whether these have arisen as somatic variations or have distinct ancestry is unknown.

Among seedling peach progenies examined the percentages showing pollen sterility were: Belle selfed 21 percent, Belle X Elberta 17, Elberta X Belle 14, Elberta selfed 13, Elberta X Early Crawford 7, Elberta X Greensboro 5, and Belle X Greensboro 4 percent.

Chromosome Numbers in Peach Varieties

The basic chromosome number in the sex cells in the genus Prunus is 8. The varieties of peach examined cytologically show the diploid (2n) number of chromosomes to be 16. So far as known, no triploid or tetraploid types have been discovered. If these have occurred in the past they have apparently not been propagated or were discarded in the search for new varieties. The fruit characteristics of the J.H. Hale variety might suggest a tetraploid condition, but insofar as is known they are not associated with tetraploidy.
The peach is rather a stable entity. No irregularities in chromosome behavior have been reported. Apparently reduction to the haploid number in the formation of the sex cells prior to fertilization and fruit development proceeds in a normal manner. Likewise in somatic cell divisions no conspicuous irregularities have been reported in chromosome behavior, and few varieties have been propagated as true somatic mutations.
The problem of self-unfruitfulness, which is very important in the case of other stone fruits and of apples, and which has stimulated considerable cytological investigation with these fruits, is relatively unimportant in the peach.
Nearly all of our commercial varieties are self-fruitful, that is, they set fruit with their own pollen. In a few instances varieties are self-unfruitful because of pollen sterility.
Our present-day varieties are largely considered to be chance seedlings, and many of them may have arisen as self-pollinated progeny of various types. Some doubtless are the result of natural hybridization. It is a fact, however, that many of these varieties are homozygous for the genes controlling several of the characters studied.

APPENDIX (PEACH)

Table 3.—Locations of peach-breeding work and names of workers in the United States and Canada
State or Province, institution, and locationYear work was begunEarly workersWorkers actively engaged at present
California:
Agricultural Experiment Station, Davis1925
-------
W. A. Tufts, G. A. Philp
Agricultural Experiment Station, Riverside1907E.B. Babcock, C. O. Smith, H. B. FrostJ. W. Lesley
Chaffee Junior College, Ontario
-------
-------
George P. Weldon
U.S. Department of Agriculture, Palo Alto1922
-------
W. F. Wight, L. A. Thompson
Illinois:  Agricultural Experiment Station, Urbana1907C. S. CrandallJ.C. Blair, M. W. Dorsey, J. C. Whitmire
Iowa:  Agricultural Experiment Station, Ames1900S.A. BeachT. J. Maney
Maryland:
U.S. Department of Agriculture, Beltsville1931
-------
F. P. Cullinan, J. H. Weinberger
Agricultural Experiment Station, College Park1929E.C. Auchter, W.L. KerrA. L. Schrader, S. W. Wentworth
Massachusetts:  Agricultural Experiment Station, Amherst1918
-------
J. S. Bailey
Michigan:  Agricultural Experiment Station, South Haven1924
-------
Stanley Johnston, V. R. Gardner
New York:  Agricultural Experiment Station, Geneva1895S. A. BeachU. P. Hedrick, R. Wellington, Olav Einset
New Jersey:  Agricultural Experiment Station, New Brunswick1914C. H. ConnorsM. A. Blake
Texas:  Agricultural Experiment Station, College Station1935
-------
S. H. Yarnell
Virginia:  Agricultural Experiment Station, Blacksburg1925
-------
Fred W. HofMann
Ontario, Canada:  Horticultural Experiment Station, Vineland1914
-------
E. F. Palmer, G. H. Dickson

Peach and Nectarine Breeding Material at the United States Horticultural Station at the National Agricultural Research Center, Beltsville, Md.5
PEACHESNECTARINES
[A-E][F-I][J-M][N & O][P-R][S-Z]
Admiral DeweyCA,GA,NJFairs BeautyJapanese Giant ClingNewcombP.G.W.St. JohnCA,NJBostonCA
Admiral Dewey X St. JohnFather’s PrideJ.H. HaleCA,GA,NJNewhallCAP.I. 36126SalbertaNJGold MineCA,NJ
AlexanderCAFay ElbertaCAJohn RiversNew Jersey 71P.I. 43137SalweyCA,NJGowerCA,NJ
AltonCA,GAFitzgeraldCA,GA,NJJuly ElbertaNJNew Jersey 73P.I. 68353September MammothGAHunter
Australian SaucerCA,NJFeiCAJuly GoldNJNew Jersey 87P.I. 101655Shalil (P. I. 63852)Lipiatt Late OrangeNJ
BabcockCA,GAFlaming GoldJune ElbertaCA,NJNew ProlificGAP.I. 101663Shippers Late RedNJQuettaCA
BannerCA,GA,NJFoxNJKalamazooNJNiagaraCAP.I. 101665SimsCA,GARivers Orange
BarnardFrancesNJKathrynNJN. J. 12722P.I. 101667SlappeyGA,NJStanwickCA
BelleCA,GAGageKetteGA,NJOldmixon ClingCAP.I. 101668South HavenNJSure CropCA,NJ
Beers SmockGeorge IVCA,NJKrummelCA,GA,NJOldmixon FreeCA,NJP.I. 101669StinsonCA,NJ
Berk FavoriteGiant SnowballLate CrawfordCA,NJOpulentCAP.I. 101675StrawberryCA
Best JuneCA,GA,NJGlobeLeetonNJP.I. 101676StumpCA,NJ
BilyeuCAGold DropNJLemon ClingCA,NJP.I. 101677Sun GloGA,NJ
Blood FleshGoldfinchGA,NJLemon FreeGA,NJP.I. 101680Texan
BrackettCA,GA,NJGolden JubileeCA,GA,NJLevyCAP.I. 101681TriumphCA,NJ
Briggs Red MayGreensboroCA,NJLibbeeCAP.I. 101682Uneeda
Canadian QueenHalbertaNJLinworthP.I. 101687ValiantGA,NJ
CandokaNJHalehavenGA,NJLovellCAP.I. 101688VedetteGA,NJ
Captain EdeCAHale EarlyCA,NJLoving ClingP.I. 101689VeteranGA,NJ
CarmanCAHauss X FosterLuken HoneyCAP.I. 43289 x Early CrawfordViceroy
ChiliNJHeath ClingCA,NJMammoth Heath ClingCAPallasCA,NJVivid Globe
Chinese ClingGA,NJHenriettaMarigoldGA,NJPeacharineNJWhite Cling
ChampionCAHileyNJMarkPeak ClingCAWhite HaleNJ
C. O. SmithHobsonCA,NJMarkham ClingPhillipsCA,NJWilmaCA,GA,NJ
CumberlandCA,GA,NJHoney DewMarquetteGA,NJPickett FavoriteYellow Indian
CurryHope FarmNJMartha FernPioneerGA,NJ
DeliciousGA,NJHorton RiverMathewsPolly (Ames 11)NJ
Duke HaleHyslopMaxineNJPratt LowCA
Early CrawfordCA,NJIllinoisCA,NJMayflowerCA,GA,NJRayNJ
Early ElbertaCA,NJImproved Crawford LateMikadoGARed Indian
Early ImperialCAIndian Blood ClingCA,NJMiller LateCARio Oso GemCA,GA,NJ
Early QueenIron MountainNJMinnie StanfordCARoberta
Early RoseCA,GA,NJMountain RoseCA,GA,NJRochesterCA,GA,NJ
Early Wheeler (Red Bird)CA,NJMuirCA,NJRadianceCA,NJ
EclipseGA,NJ
ElbertaCA,GA,NJ
Elberta X Phillips
Engle Mammoth
EurekaCA,GA,NJ
[Superscripts denote the state collections in which they were also listed as present in this Handbook. Rather than repeat them in the following tables, I just noted the duplication. -ASC]


Peach and Nectarine Breeding Material at the California Agricultural Experiment Station, Davis, Calif.
PEACHESNECTARINES
[A-E][F-I][J-M][N & O][P-R][S-Z]
AlFlorida GemGAJapan DwarfNJNationalNJPaloroGA,NJSabichi WinterAdvance
Alpha TuscanFlorenceJewelGANewcastle TuscanParagonNJSea EagleAnsenne
AmsdenFosterNJJ. H. Keith Early MayNew JerseyPatisonSellers**BreckNJ
AngelFrankNJJohnsonNicholsPeentoNJSelmaCardinalNJ
AnnabelGAFrank seedlingKatieNJNoble RedPeregrineShamrockDavis
ArpNJFrederickaNJKlondikeOctober BeautyPerfectionShalil seedlingDiamond JubileeNJ
BarbaraNJGaumeLady LindseyOctober IndianP. I. 24807SharpeDixie
Belle OctoberGeorge IVLady PalmerstonOctobertaP.I. 32374ShermanDownton
Bitterless ElbertaGeorge LateLa GrangeOklahoma BeautyP.I. 35201Shippers ClingNJDryden
BloodGibbon OctoberLate ChampionNJOntarioP.I.36485SmithEarly Newington
Blood FreeGilla Tardiva di MilanoLate ElbertaNJOrange ClingP.I.41395Smith IndianEarly Rivers
Blood Leaf ClingGillinghamLate TuscanOrioleGA,NJP.I.43289SneedFisher Yellow
BokharaGlobeLeaderOspreyP.I.43290StearnsGaylord
Bolivian ClingGold DustLeonaNJP.I.43291Summer HeathGriffith
BrackettGAGoodman ChoiceLibertyP.I. 55563SunbeamGA,NJHardwiche
BresquillaGolden ChineseLippiatt*P.I.55564SullivanHumboldtNJ
Brock BeautyGolden Sweet ClingMassasoitNJP.I. 55813SuberJ. C. Wees
BuckhornGolden QueenMaryP.I. 55835SusquehannaKathryn
Burton’s Hale Early seedlingGrosse MignonneMcDevitt ClingP.I. 61302Sutter CreekLippiatt*
CameoHaight Late FreeMcKevittPicquet LateGATaylorLord NapierNJ
CarotaHale ClingMing TombPinkhamTenaMexican
CarpenterHarrisMississippiPlacer ClingTexasMilton
ChiloroHarris Yellow ClingMonte Vista ClingPomonaThurberMuir
CumberlandNJHalford No. 1MorellonePrince of WalesThurmondNettarino Gilla d’Padova
Cotogna di SienaHalford No. 2Morris WhiteNJPullar ClingNJTogoNew Boy
Crimson ClingHalford No. 3MotherRadiantTosetti Late FreeNew White
Cuban NutHelenMotions ClingNJRaisin ClingTrianaNewton
Currie FreeHome FreestoneMothers FavoriteRunyon Orange ClingTribbles ClingNigh
DahlingHoneyGAMowry Strawberry ClingRed MuirTribbles FreeOzark
Day Late ClingHoney ClingMuir PerfectionNJTribbles PriceP. I. 26503
DeckerIdealNJMunfordTuscan (synonym of Tuskena)GA,NJP. I. 29227
DorothyIjam TuscanUp-to-DateNJP. I. 30648
Duchess of CornwallImperialVainqueurP. I. 65973NJ
EarliestVan EmmonP. I. 65974NJ
Early CharlotteVivid GlobeP. I. 65975NJ
Early JapaneseVictorP. I. 65976NJ
Early RoseWaldoNJP. I. 65977NJ
Elberta ClingWaltonGAP. I. 65978NJ
EstellaNJWard LateP. I. 65979NJ
EverbearingWashingtonP. I. 68178
West Late FreePineappleNJ
WilburRed Cling
Wiley ClingRed RomanGA
Winter FreestoneRobinson
WorthSmith
Yellow HileySpanish
Yellow SwanSpencer
Stanwick Elrudge
Togatch Moneck
Traveller
VictoriaNJ
Violet
Wilkinson
[*Lippiatt is listed both as a peach and a nectarine in this table. Hmmm... mistake or real?
**Link takes you to the 'Sellers Cling' entry, but just below is the entry for 'Sellers Free'. Which was in the NJ collection? I dunno.
Superscripts denote the additional state collections in which they were also listed as present in this Handbook. Rather than repeat them in the following tables, I just noted the duplication. -ASC]


Peach and Nectarine Breeding Material at the Georgia Agricultural Experiment Station, Experiment, Ga.
PEACHESNECTARINES
[A-E][F-I][J-M][N & O][P-R][S-Z]
Best MayFertile HaleNJLuttichauNew Jersey 46-BPaloro No. 2Shipper Big Red
ChilowGage ElbertaManlyPhillips No. 1Weem Hale
Georgia HaleRiverdaleWhite English
Hale seedlingWillow Leaf
Harpole Late YellowNJWoodland Cling
Indian Blood [Cling? Free?]
[Superscripts denote the additional state collections in which they were also listed as present in this Handbook. Rather than repeat them in the following NJ table, I just noted the duplication. -ASC]


Peach and Nectarine Breeding Material at the New Jersey Agricultural Experiment Station, New Brunswick, N.J.
PEACHESNECTARINES
[A-E][F-I][J-M][N & O][P-R][S-Z]
A-1 on Salwey Seedling (43124)F. H. B. (43051)Japan Golden Giant ClingOhio Late CrawfordPomona Majorada (P. I. 57689)Blood Fleshed
Admirable Jaune (P. I. 86168)Gallande (P. I. 66094)Jennie WorthenPrunus davidianaSant Anna (P. I. 102530)Flaming Gold
Agostina (80128)GemmerJ. M. MackP.I. 35201SargentsGarden State
Aicken Cling (P. I. 88543)General LeeKihi Kihi (P. I. 88547)P.I. 36485Sellers OrangeG. O. Breeding
Alberge Jaune (P. I. 101820)Golden Elberta ClingKing SolomonP.I. 55564Semi-Dwarf ElbertaNectarine Peach (P. I.88554)
Amarillo Tardio (P. I. 55835)Golden GemLees Salwey (P. I. 88548)P.I. 55775September MonmouthLittles Yellow
Amarillo Tardio (P. I. 55836)Golden HeathLizzieP.I. 55776Sleepers DwarfYennman
AmbergemGoodman Choice on Salwey (68354)Lippiatt Late RedP.I. 55885Smock
Ames 2GordonMadeleine de Courson (P. I. 66095)P.I. 55886Stevens
AnnaGoshawkMamie RossP.I. 55887Strawberry Free
AugbertGrosse Mignonne (P. I. 76357)Marriages Late (P. I. 88550)P.I. 55888Sungold
Aurora (P. I. 57688)Grosse Mignonne (P. I. 91763)Mexican HoneyP.I. 56920Surprise
Beauty BelleGrosse Mignonne (P. I. 102523)Mitchelson (P. I. 88551)P.I. 61302Tos China (P. I. 77877)
Belle de Vitry (P. I. 102515)Hann AlmondMonkton No. 1 (P. I. 88552)P.I. 63850Tos China on Salwey (P. I. 77878)
Bennetts PerfectionHardeeMonkton No. 2 (P. I. 88553)P.I. 63851Tos China on Salwey seedling (P. I.77876)
BerksHaussP.I. 63852Vanity
BilmeyerIce CreamP.I. 63853Volaric (P. I. 107783)
Bolivian (P. I. 36126)IndianaP.I. 63855Waipawa on Salwey seedling (88556)
Briggs Early May (synonym of Briggs)Indian ClingP.I. 74011Watt Early (P. I. 57917)
BurbankIsquierdo (P. I. 57687)P.I. 76202Winner
Burbank Giant FreestoneP.I. 76361Wm. Kane
ButtercupP.I. 88562Wrights Bountiful (P. I. 88567)
CamelliafloreP.I. 88561Wrights Late Red (P. I. 88558)
Chairs ChoiceP.I. 91762Wrights Midseason (P. I. 88559)
Charles Ingouph (P. I. 101825)P.I. 92159Yellow Greensboro
Chinese BloodPlummer (P. I. 88565)Zelandia Peach (P. I. 88560)
Clam Shell ElbertaPoppa de Venere (P. I. 102527)
ColoraPrimrose
ColumbiaPrunus kansuensis
ConnettPrunus mira
CrosbyPurple Leaf
D. B. Ansac (P. I. 88546)Red A
D’ItaliaRed B
Double PinkRed C
Double Red EarlyRed D
Double WhiteReeves
Duke of YorkReina Eleana (P. I. 57690)
DulceRed Magdelaine (P. I. 57691)
Eagles Beak (P. I. 43289)Rosebud
Early May
Elberta Dwarf
Engle Monmouth [probably a typo & they meant "Mammoth" -ASC]
English Galande
Exquisite


[NOTES]
1  The author wishes to acknowledge his indebtedness to the following workers engaged in stone-fruit breeding in this country and abroad for their kind cooperation in furnishing information on the work in progress in their respective States and in furnishing lists of varietal and species material available for breeding studies: W. A. Alderman, Minnesota; J.S. Bailey, Massachusetts; M. A. Blake, New Jersey; M. J. Dorsey, Illinois; N.E. Hansen, South Dakota; F. W. HofMann, Virginia; Stanley Johnston, Michigan: T.J. Maney, Iowa; W. P. Tufts, G. L. Philp, E.C. Hughes, and J. W. Lesley, California; Richard Wellington, New York; S. H. Yarnell, Texas; A. F. Yeager, North Dakota; W. F. Wight, U. S. Bureau of Plant Industry, Palo Alto, Calif; W. P. Baird, U. S. Northern Great Plains Field Station, Mandan, N. Dak.; E. F. Palmer and G. H. Dickson, Vineland, Ontario, Canada; H. Wenholz, New South Wales Department of Agriculture; and M. Ch. Miedzyrzecki, Ain Taoujdat, Morocco.
2. [I didn't include footnote 2 because it was stupid. -ASC]
3  Trees imported by the Division of Foreign Plant Introduction as well as seedlings grown from seeds brought in are distributed for testing under numbers preceded by the initials P. I.
4. [Also stupid. -ASC]
5.  The variety names in this and the following lists conform so far as practicable to the code of fruit variety nomenclature. However, among them there is a considerable number of introductions from other countries, selected strains of standard varieties tentatively designated, and other names applied temporarily, which cannot be made to conform readily to the code. The publishing of such names in this connection is not to be construed as the acceptance of them by this Department.