America as the double-flowered However they are pollen and graft ornamental form of P. glandulosa called also known as “sandkings.” Some have compatible with plums and not cherries flowering almond. These shrubs grow as suggested Nanking cherry may be closer in and have been misclassified as cherries. multiple stems, and are easy to affinity to the wild shrubby almonds. It is The Apple Industry in China China has A few cultivars of the pure species have propagate using rooted cuttings or root usually propagated by seed, sometimes approximately 10 been named, but there are many hybrid sprouts. As a result they are frequent fruiting in the second year from seed and so cultivars available. These are some of the relics around old homestead sites. The has been spread widely particularly in 1 2 million apple growers only plums that are hardy enough for the flowers are borne singly or in pairs, and northern regions. Prunus tomentosa has been Stephen A. Hoying , David A. Rosenberger , northern US and Canada. Sand cherry come in pink or white, single or double. hybridized with P. besseyi, P. cerasifera and P. 3 with 5 million acres. was used extensively by Hansen in Fruit are red to dark red, about 1 cm japonica. and George Lamont In 2004 China became South Dakota to develop cold-hardy diameter on a 1 cm stem, edible raw but 1Cornell Cooperative Extension, Newark, NY the number one fresh plums, with more than a million often cooked due to their acidity. P. Desert Species 2Department of Plant Pathology, NYSAES, Cornell University, Highland, NY seedlings grown (Hansen, 1937). ‘Sapa’, japonica accessions from China are quite 3 apple exporter in the his most important release, was a hybrid prolific and have crossed readily with New York State Horticultural Society, Geneva, NY Six Prunus species native to desert of sand cherry Sultan (Japanese plum) plum to produce a range of fruitful world and its exports regions from Texas to California have and has been used as a parent of many hybrids. This species appears to have pubescent fruit and unclear taxonomic other hybrids and for rootstock some resistance to plum curculio, but could double in the affinities. Most are not well-adapted to development. Sand-cherry hybrids with whether or not this is true resistance that eastern conditions. The most utilized may next few years. Even plums are often called “cherry plums”, can be transferred and utilized remains uring July of 2005, the three of us be Prunus texana, which is endemic to the production on the world apple market. though much of this a term also used to refer to P. cerasifera. to be seen (Yonce et al., 1995). It also has traveled to the major apple In California, ‘Hiawatha’ (a seedling of Rio Grande Plains and Edwards Plateau of Even though we weren’t able to fully been crossed with plum in Japan, as well growing regions in Shandong fruit is second class ‘Sapa’) is looking promising as a semi- as used as a dwarfing rootstock (actually Texas, preferring poor or disturbed soil. It D grasp the complexity of Chinese society and Shaanxi Province in China as part dwarfing rootstock for peaches. interstem) for peach. In China there is at is a bushy shrub with grayish, very irregular and apple production, we certainly of the International Fruit Tree quality and is destined least one breeding program forP. humilis, branches. Young branches are covered with uncovered many interesting facts about Association summer tour. Apple Prunus besseyi may have been more with large-fruit selections up to 3 cm. short, stiff hairs. Peach bush has white or the Chinese apple industry along the for Mongolia and rarely pink blossoms that develop into small production in Shandong and Shaanxi widely hybridized than any otherPrunus , Meador from New Hampshire also has way. pubescent fruit with fair fruit quality. As a account for approximately 50% of the Russia, China also has partly due to its wide compatibility. All the released ‘Jan’, ‘Joy’ and ‘Joel’, hybrids of Background breeding work appears to have been done P. japonica and P. jacquemontii, a similar seedling it can be highly precocious, fruiting country’s production (Table 1). The trip high quality apples China’s land mass is approximately with western forms of P. besseyi, as they species from the Himalayas. These in Florida in 12 months from seed. It was organized by Dr. Bruce Barritt, going to the EU and had better fruit quality and larger fruit, hybrids are providing cold-hardy tart hybridizes readily with other plums, and Washington State University and Dr. 3.7 million square miles, about the same plus that region of the country was too cherries on a small bush. ‘Joy’ is self- natural hybrids have been reported and Yuan Yongbing, Director of Graduate as the United States (Figure 2), and other quality driven cold to grow most other Prunus. fruitful but the others require cross- grown for fruit. It is sometimes used to make Administration at Laiyang Agricultural China lies at approximately the same Unfortunately, these western forms have pollination. Hybrids of P. japonica P. jellies and preserves. Two other species have University in Qingdao, China. Eighty- latitude as the U.S. We visited the two markets. We expect high sensitivity to blossom and twig blight salicina produced in Japan are vigorous useful characters. Not surprisingly, P. one individuals from the United States, most important apple-growing regions that China will have a caused by Monilinia sp., making them but unfruitful (Kataoka et al., 1988), but andersonii, native to the desert areas of Canada, Australia, Mexico, France, Great in China, Shandong and Shaanxi short-lived in humid climates. P. besseyi hybrids with Japanese plum at Byron California, has high levels of drought Britain, and Chile participated. (Figure Province. Shandong Province at north huge impact on the US o also is native to the shores of Lake have been highly productive. tolerance (Rieger and Duemmel, 1992), but 1). latitude 36-37 (equivalent to that of apple industry over the Michigan as well as to the inland sandy it does not grow well in our climate. Prunus Virginia) has a temperate continental barrens of central Michigan. The species Nanking Cherry Prunus minutiflora, is one of the few dioecious (male The group from IFTA was invited to climate characterized by moist summers next decade. also ranges into the Northeastern United tomentosa is a common trade and female flowers on different plants) tour some of China’s apple growing and dry, cold winters. The average o States and south to Virginia. These eastern ornamental/fruiting shrub which is Prunus species. As its name indicates, it has regions. While there, we observed the temperatures are 20-30 F in January and 75-82oF in July with a frost-free season forms of the species may be useful in native to North and West China from the extremely small flowers. F hybrids with horticultural and pest management 1 of approximately 200 days. Average breeding plums and rootstocks better Himalayas to Korea. It is extremely cold- commercial plums have been fully fertile at practices followed in China, and tried to occurs mostly during summer and fall annual precipitation is 25–35 inches and adapted to the humid regions. They are hardy but suffers from dieback in Byron, with an intermediate, shrubby assess the future impact of China’s apple monsoons. Fruit is grown on valley much smaller-statured plants than warmer climates. In northern China and growth habit. Since this species occurs on floors and hillside terraces in the coastal western accessions even in good soil, Korea the fruit was the first to ripen, and calcareous soils, it may be useful in breeding mountains as well as on the coastal and sometimes growing as a ground cover so it was made into a compote to rootstocks tolerant to high pH, allowing inland plains. Apples are grown from rather than an upright shrub, and plant celebrate the “5 peaches and plums to be grown on such sea level to 1500 feet above sea level. health at Byron seems good so far. The late- th th sites. blooming characteristic of P. besseyi is at day of the 5 moon”, the longest day of the year. The species Shaanxi Province has a continental least partly due to higher post-rest heat monsoonal climate with an annual accumulation, enabling them to fruit well name describes the most distinctive Plumcots precipitation of 20-30 inches deposited in lower-chilling zones than would be feature, the heavily pubescent leaves by monsoons in summer and fall. It has expected (Werner et al., 1988). Use of this and young stems. Leaves are irregularly Natural plumcots have been grown a very dry winter and spring. Shaanxi is species to develop cold-hardy plums toothed, thick and about 5-7 cm long. for generations in regions of the world continues in the USA only at the Flowers are white, 1.5-2 cm in diameter where both cots and myrobalan plums were colder in the winter and hotter in University of Wisconsin-River Falls in and in 1-2 per bud. Fruit is 1 cm across, grown such as in Southwest Asia. These summer than Shandong. January Wisconsin. sometimes slightly hairy, and with a were common enough to merit their own temperatures ranged from -12 to -38 °F flavor that ranges from mild to tart. Fruit species name, P. dasycarpa. Several local and July temperatures from 78-88 °F. Chinese Bush Cherries A second is usually bright red, but rarely dark red varieties have made it to the US, including Fruit is grown on highly erodable loess or white. It has been crossed to some soil plateaus located North Latitude 35- misclassified “cherry” is P. japonica and ‘Irani Olju’, ‘Tlor Csiran’, and ‘Mirocais’. o and approximately 3,000 ft above sea extent to other bush cherries such asP. 37 relatives P. glandulosa and P. humilis, which These plumcots are mostly red or purple level. The soils are extremely deep (>150 are from China (Ingram, 1948). This group besseyi but little to true cherries. Some skinned with some light fuzz. Typical of the nurseries sell “black Nanking cherry,” ft) and uniform. The Province is bisected is best known in Europe and North plum parent they tend to be acidic and Figure 1. IFTA Group and Chinese hosts at Laiyang Agricultural University in Quingdao China, which may be hybrids with sand-cherry, by the Yellow River, the color and name small. July 11, 2005 of which comes from the eroded soils 36 NEW YORK STATE HORTICULTURAL SOCIETY NEW YORK FRUIT QUARTERLY • VOLUME 14 NUMBER 1 • 2006 13 TABLE 1 50° Plum species with germplasm worthy of exploitation. Bolded species are represented in NRSP-5/IR-2 or NPGR-Davis collections. Varieties italicized are hybrids with P. salicina. 48° Species Common name Origin Subspecies/synonyms Varieties extant P. alleghaniensis Allegheny plum, sloe Northeastern U.S. davisii P. americana American plum, wild goose plum, hog plum Central + eastern U.S. lanata, mollis Anderson’s Early, Ember, 40° 42° Goff, Hazel, Kahinta, Monitor, Red Coat, Bejing Underwood, Wolf

P. andersonii Desert peach California, Nevada 36° Figure 2. (left) A comparison of land mass and P. angustifolia Chickasaw plum, sand plum, sandhill plum Southern U.S. varians, watsonii Bruce, Six Weeks latitude of China and the United States. The P. besseyi Sand cherry Canada, northern U.S. cuneata, depressa, Alace, Black Beauty, Convoy, major apple growing Provinces in China are pumila, susquehanae Deep Purple, Hiawatha, 30° highlighted. Manor, Mansan, Sapa, Sioux 30° Figure 3. (above) Chinese farmers stopped P. fasciculata Desert almond, desert peach brush Southwestern U.S. what they were doing to watch our group as P. fremontii Wild apricot, desert apricot Southern California we toured orchards in Shandong. P. geniculata Scrub plum Florida 24° P. glandulosa Chinese bush cherry China, Japan 20° P. havardii Havard wild almond Texas, Mexico 0 1000 “Capitalistic Communism” (economic K freedom and growth while still P. hortulana Wild goose plum, hortulan plum Central U.S. mineri Miner, Wayland 0 600 18° M maintaining political control of the P. humilis Manchurian dwarf cherry Northern China people). Apple growers were among the P. japonica Flowering almond, Japanese bush cherry Eastern Asia first to be allowed to freely market their P. maritima Beach plum, shore plum Coastal northeastern U.S. gravesii Hancock, Jersey, Patricia, crop. Under this system, growth in GNP Raribank, Squibnocket that the river carries. According to our incomes are four to six times greater than has leap from 3% annually in the early P. mexicana Big tree plum, Mexican plum South central U.S., Mexico local guide, the river is sometimes also in rural areas. China is attempting to 1970s to 8% in the 80s and 9% in the 90s. This is a fantastic growth rate compared P. minutiflora Texas wild almond, small flower peach bush Texas, Mexico called “The Mother River” since its color control the migration to cities by is the same as Chinese skin color. to the U.S., which has averaged 3% P. munsoniana Wild goose plum South central U.S. Late Goose, Whitaker requiring residence permits for city dwellers without which people cannot annual growth in GNP in recent years. P. nigra Black plum, Canada plum Northern U.S., Canada Aitken, Assiniboine, Bounty, China is a united multiethnic nation access government jobs, schools, or While the overall GNP per capita of Grenville, Norther, Pembina with a population of 1.3 billion people health services. Despite this, cities have China is a fraction of that in the U.S., the P. salicina Japanese plum China bokhariensis, Abundance, Burbank, Kelsey, or 20% of the world’s population. Sixty- large numbers of “illegals” who operate high level of growth in China, if gymnodonta Satsuma four percent of the population is still an underground economy of sorts. maintained, will cause them to surpass P. subcordata Pacific plum, sierra plum Northwestern U.S. kelloggii, oregana G.M. Clark, Kelly Sierra #2 rural, but there is a constant shift of the U.S. about 2037. However, as China P. texana Texas almond cherry, Texas peachbrush Texas people away from agriculture to the For 27 years, since the death of Mao struggles with infrastructure, pollution, cities where better employment and foreign exchange rates, it is doubtful P. umbellata Flatwoods plum, hog plum, sloe Southeastern U.S. injucunda, mitis, tarda and the beginning of the reign of Deng opportunities exist and where average Xiaoping, China has practiced that they will maintain this 9% growth rate. due to high heat requirement rather than American Plum Prunus americana, little if any of this germplasm came from strictly to high chilling requirement. Late the third Southeastern US species, is wide- southern sources. Hence most surviving bloom, but with a low chilling require- spread across the eastern states, and is the cultivars (Table 1) as well as seedlings ment, would be a desirable addition to common roadside plum in more northern from commercial seed sources are better our commercial fruit types, as plum flow- regions. In the far north it intergrades into adapted to more northern areas. Ameri- ers are often killed by frost in the South- P. nigra, which has produced some of the can plum has large leaves with a coarse east. The species probably also tolerates most cold-hardy plums. In the west it margin. Older trees may have grey, scaly salt and waterlogging, given its preferred blends into P. mexicana. In the deep south bark. Flowers are also large, 2-3 cm across habitat in the sand dunes along the ocean. down to Florida, where P. americana is and in groups of 2-5. Fruit is usually 2-3 Efforts to utilize this species for fruit, jelly, typically found in river bottoms, it is now cm in size, with sometimes dry, but usu- wildlife food, and ornamental use have rare, possibly as a result of extensive rogu- ally palatable flesh and bright red color. recently been revived in the Northeast by ing of wild plums by the government over Fruit usage is similar to Chickasaw plum, Richard Uva and others (Uva and Whit- the last 40 years to reduce inoculum of being consumed fresh and processed, of- low, 1997). Several named varieties exist, peach phony disease caused by Xylella ten from wild plants. some appearing to be hybrids with P. fastidiosa. The inability of P. Americana to americana. After numerous attempts, we re-colonize may relate to limited root Prunus nigra is the northernmost have a few seedlings that appear to be suckering, to erratic cropping, or to its plum species in North America, with a hybrids of P. maritima with commercial being at the limits of its natural distribu- range extending into Canada. It was also plums. tion. Although superior fruit types of this selected by local farmers, and the better Figure 4. Mao is still revered in China. This large portrait hangs on the Figure 5. Apple orchards in Shandong Province are located on terraces carved from the hillsides. species were selected by early settlers, varieties crossed with Japanese plums to outer wall of the forbidden city in China. 34 NEW YORK STATE HORTICULTURAL SOCIETY NEW YORK FRUIT QUARTERLY • VOLUME 14 NUMBER 1 • 2006 15 1.8 of G2-3. Local efforts to preserve it are of more northern accessions of P. left the species completely unused by According to our hosts, China has coordinated by Bok Tower Gardens in umbellata. Because of its poor fruit qual- breeders. Curiously, there is a remnant approximately 10 million apple growers Acres Production 1.6 Lake Wales, Fla. Young plants seem rare ity, P. umbellata has not been used by population in central Michigan, which with 5 million acres. Some of these in the wild, suggesting that natural re- breeders; at Byron, Georgia, fruit of F was described long ago and presumed growers are organized for research, 1.4 1 colonization is difficult. The small fruit are hybrids with Japanese plums retain the extinct until “rediscovered” in the last demonstration and marketing purposes palatable and are borne in profusion on bitter flavor and small size. Leaves are decade by Sylvia Taylor of the Michigan into village cooperatives such as the 1.2 bushes with a minimum of foliage. The elliptic to lanceolate, 4-7 cm long. Some Department of Natural Resources (Taylor, villages of Gou Dong, Feng Jia Yuan, Le, 1.0 scrub plum is not hardy at Byron, having trees have very hairy leaves and twigs, 1990). Scattered trees are seen along road- and Fangxiang that we visited. Land is only a minimal chilling requirement. We others have no hair. Flowers are similar sides, with a few spots of local abundance. owned by the government and leased to 0.8 do have a few plants that appear to be to P. angustifolia, but borne in clusters (um- The most curious collection is at the “Big the grower with 50-70 year contracts successful hybrids with commercial bels) of 2-6 from a bud. Fruit is small and Frost Pocket” where dozens of diverse

Million Bushells 0.6 depending on the way the land will be plums but they have not yet fruited. The usually bitter, 1 cm in diameter on a long trees are assembled on a hillside overlook- used. In 2004, Shandong, the leading 0.4 scrub plum is not hardy at Byron, Geor- stem, so it resembles a blueberry. Fruit ing a sandy plain reputed to have had a apple producing province, had gia, having only a minimal chilling re- color ranges from black to purple to red single daily temperature extreme of 24° approximately 790,000 acres, down from 0.2 quirement. Locally it is occasionally used to yellow. Because of the resemblance to to 104° F, with occasional lows of -26° F. its peak of just over 1.6 million acres in for jelly as the fruit is surprisingly edible. P. spinosa, the species is frequently called This Michigan subspecies has been placed 0.0 1998 (Figure 6). “sloe plum”. Trees are vigorous, but less on some endangered species lists. Prunus 1980 1985 1990 1995 2000 2005 Hog Plum Prunus umbellata is an prone to recolonize than Chickasaw alleghaniensis is marginal in chilling at Even though acreage has fallen Figure 6. Change in apple acreage and production in Shandong from 1980 to 2004. obscure southeastern plum that is notice- plum. As a scion it is not consistently com- Byron but several hybrids with commer- sharply, production continues to rise as able primarily during bloom, which oc- patible with peach rootstock, which re- cial plums have been obtained. It is col- new plantings made in the 1990’s begin curs several weeks after that of P. duces its value in rootstock breeding, de- lected locally for jellies. to bear and horticultural practices TABLE 1 angustifolia. This plum grows with a single spite local adaptability. Hog plum has bit- continue to improve. Production in 2004 trunk, in contrast to the tendency of P. ter or tart fruit so must be processed, as Beach Plum The beach plum, P. Shandong and Shaanxi provinces make up 75% of China’s Production. in Shandong reached an all time high of angustifolia to form thickets along the jelly for instance, for human consump- maritima, occurs along the Eastern U.S. 350 million bushels (443 bushels/acre) Chinese Apple Acreage and Production by Province 1991 & 2000 roadside. Apparent natural hybrids be- tion, such as in jellies. coast from Maine to Maryland and once most for the fresh market (Figure 6). Acreage (1000 acres) Production (million bushels) tween these two species are common, and formed the basis for numerous cottage Province 1991 2000 % change 1991 2000 % change have intermediate leaf, bloom and fruit Alleghany Plum Prunus industries (Bailey, 1944; Uva and Whitlow, Shaanxi produced about 288 million characters. At the southern fringe of its alleghaniensis is mainly restricted to the 1997). This species is the latest to bloom bushels in 2004 on 989,000 acres (291 Shandong 1030 1110 8% 85 339 299% range, there appears to be some introgres- mountains from Connecticut to Pennsyl- at Byron, often nearly two months after leads Shaanxi 545 990 82% 26 204 685% bushels/acre).the nation in production This province of apple now juice Henan 328 518 58% 20 125 525% sion of P. geniculata, as the leaves resemble vania to Virginia and resembles P. commercial plums. Its ability to fruit at concentrate. Together Shandong and Hebei 538 820 52% 28 95 239% that species and are distinct from those umbellata. Again, the small bitter fruit has Byron suggests the late bloom is partly Liaoning 550 488 -11% 30 65 117% Shaanxi produced approximately Shanxi 268 445 66% 9 85 844% 560,000 metric tons of concentrate in the Gansu 285 420 47% 10 36 260% 2004/5 season. China’s export of juice All other 613 845 38% 30 122 307% concentrate comprised 46% of the Total 4,157 5,636 36% 238 1,071 350% world’s total. Source: China State Statistics Bureau, Adapted from World Apple Report A Typical Orchard

The average Chinese “orchard garden” is 4 mu which is equivalent to Good inventory 2/3 of an acre. This results from government policy that allocates 1-2 mu selection available per family member. Tree spacing is very tight with tree canopies utilizing all for immediate available space. Typical spacings were approximately 9ft X 9ft in a square to slightly rectangular arrangement with delvery! no apparent rows or row direction (Figure 7). Tree densities are 450–680 trees/acre with approximately 450 trees per family of four. An entire family must make their living on an orchard as small as 290ft X 100ft. Mr. Yan Junjie, Village Head of Gou Dong Village in the Muping District of Shandong Province, explained the economics of fruit production in his village. The village is comprised of 210 households, with 180 households managing orchards on a total of 161 acres. They grow 102 acres of apples, 17 acres of grapes, 17 acres of Figure 7. Apple orchard densities are approximately 600 trees per acre and are tightly spaced jujube, and 25 acres of sweet cherries. He with no apparent rows or row direction. 16 NEW YORK STATE HORTICULTURAL SOCIETY NEW YORK FRUIT QUARTERLY • VOLUME 14 NUMBER 1 • 2006 33 but fruit size is small. Breeding programs intermittent efforts in Florida, Texas, and Chickasaw Plum Prunus TABLE 2 in the Southern Hemisphere include recently, Wisconsin (Okie and Ramming, angustifolia is the most common roadside Production costs for Gou Dong Village in the Muping District of Shadong Province, South Africa and Australia. Their goals 1999). and fence-row plum in the Southeastern according to Mr. Jan Junjie, Village Head. are development of large fruited, high United States, where it is often found on quality plums with resistance to bacterial sandy soils. The original range is Values expressed in US dollars Plums can have quite an allure for Expenses per acre of apples (1 Chinese RMB = 0.12379 $US) spot and bacterial canker, and the ability the breeder, for several reasons. They unknown, but likely was smaller than the to store without internal breakdown. have great potential as a commercial crop current range from Texas, across Kansas Hired labor $668.47 Fertilizer 371.37 Storageability of four weeks is crucial to in regions outside of California. Cultural to Maryland and New Jersey, and as far Chemicals 185.69 exporting the fruit by ship. management is similar to peaches, which south as central Florida. It grows as a Irrigation 37.14 are already widely grown, and consumers small twiggy tree or in a thicket, since it Bags to cover fruit on trees 817.01 Japanese plum breeding in Europe are familiar with the fruit. Fruit quality produces root suckers readily. Leaves are Reflective film placed in orchard to omprove color 111.41 is relatively new, but will be important as exceeding that commonly available in the lance shaped, often rolling slightly at the Machinery 59.42 Miscellaneous 51.99 demand continues to increase for the large supermarket would make locally grown margins to form a trough-like shape. Fruit fruited Japanese plums. Breeders at Rome fruit readily marketable. The wide range is 1-2 cm across, usually red or yellow Total expenses/A $2,302.49 and Forli are seeking smaller trees to of native species provides an untapped with yellow flesh. Most plants have fruit Income per acre from apple sales $3,416.60 that is edible, with watery flesh ranging reduce production costs in combination source of genetic material, albeit in a Net income per acre $1,114.11 with large size, dark skin, and good eating “collect-your-own” format, as few from sweet to tart. It is easily propagated quality. At Florence, goals are to develop accessions are currently available in by root sprouts, budding or seed. Birds self fertile, late blooming plums with high collections. Results from hybridizations and animals likely spread it initially, but quality, particularly yellow skinned types. are very unpredictable. The current its survival relates to its ability to re- Figure 8. Fuji is the most common variety in Recently a breeding program has begun varietal arrays for most regions outside sprout profusely when the above-ground China with over 60% of the production. near Avignon in Southern France where California are sorely lacking, which part of the plant is destroyed. Native poor weather during pollination is a makes potential progress by the breeder Americans, and later European settlers, major problem. Sharka resistance is also easy to visualize and appreciate. The selected larger, more palatable types said that last year they produced 1,155 important. remainder of this paper describes some particularly from the western range of the bushels of apples per acre, with 90% of this intriguing germplasm maintained species. Some of these are still grown in qualifying for fresh fruit. Table 2 lists Genetic Resources at Byron, GA., and summarizes our efforts the Midwestern USA for jelly. In many production costs (exclusive of the labor to collect it and use it in scion and areas local people eat the fruit fresh. provided by the orchardists themselves). Much native United States plum rootstock development. Hybrids with Japanese plum, such as germplasm exists (Little, 1976; Little, 1977; ‘Bruce’, had better size but only slightly Apple Varieties Okie, 2001). No native fruit was as Plum species and relatives better fruit quality, and became the extensively collected and selected by early predominant plums in the region because The tremendous growth of the apple settlers in the United States as plums, The Prunus described here can be they were able to survive local disease industry in China has occurred prima- primarily because of the wide range of loosely grouped into three sections: pressure. Unfortunately, disease rily through the planting of the Fuji va- native species readily at hand and the wild plum species, mainly in North resistance and tree vigor appear closely riety (Figure 8). This hard and long-stor- shortage of suitable alternative fruits. America (Table 1); bush cherries, most linked with small fruit size and poor fruit ing variety has been an ideal fit with Wight (1915b) lists 623 named plum of which might be better called “bush quality. This hybrid material has China’s lack of refrigerated storage and continued to be used to breed adapted cultivars derived solely from American plums” and desert species. Where both transportation facilities. The Fuji apple plums, such as ‘Robusto’ and ‘Byrongold’ species. Most arose in Iowa, Texas, parents have the same number of is the most widely grown variety in Figure 9. Impressive displays of fruit including apples were common everywhere in China. developed at USDA, Byron, Georgia. In Minnesota, Nebraska, and South Dakota chromosomes, plum interspecific China. We were told that strains in- Alabama and Georgia, there is a market from P. americana, P. hortulana, P. hybridization is generally successful. cluded the Nagafu series (1, 3, and 6), for “green plums” which are local angustifolia, P. munsoniana, or a Many hybrids have been made, Red Fuji, and Red General (also called tion distribution systems) that will be varieties picked while green and prized combination thereof. Unfortunately for particularly with P. cerasifera, salicina, Red Star which is a new large early va- necessary if their industry is to convert modern plum breeders, only a handful of simonii, besseyi, americana, angustifolia, for their sour flavor. Perhaps this market rapidly to other apple varieties and pro- reflects the childhood experience of locals riety probably Beni Shogun). Fuji ac- these native cultivars are still available, hortulana, munsoniana, and nigra. counted for 50 % of total production in duce export-quality fruit. In Shaanxi, for since cultivation of native plums is now Hybrids between these nine species are eating the wild plums green, before the example, the orchard margins along “worms” got them. 2000 and is probably 60% today. rare. The National Research Support mostly fertile and productive. Hybrids Shandong’s production is 70% Fuji with major highways are lined with 4-ft deep Project (NRSP-5; formerly IR-2) has about have also been made with P. japonica, the remainder Gala, Jonagold, Golden earthen pits where apples are stored for five species and some hybrid varieties, Chinese bush cherry. The plums and Scrub Plum One of the rarest as Delicious and Red Delicious. Other va- several months after harvest until they while the NCGR has about 13 American bush cherries are mostly inter- well as most southern-ranging plum rieties mentioned were Qinguan, can be sold and transported to juice plum species, mostly as one or two compatible. Successful hybrids between species is P. geniculata, which is localized Granny Smith, Lujia, and Fuyan. plants. accessions each (Table 1). These small the plums or bush cherries and the true in central Florida on very sandy areas numbers are surprising considering there cherry species are extremely rare, known as scrub. This unique ecosystem Cultural Practices Most apples are still consumed fresh are about 20-25 native North American suggesting that those in Table 1 are follows a relict sand ridge, which is very in China (Figure 9). While Fuji has been plum species, depending on the better thought of as plums than cherries. inhospitable for plants, with sand to a Young orchards are interplanted a boon to the industry, it will also be- taxonomic treatment (Mason, 1913; Several of the diploid plum species have depth 1.5-4 m. Prunus geniculata was with two or three other income produc- come a disadvantage as China tries to Wight, 1915a; there is no comprehensive been hybridized with peach, but the widespread in the area when originally ing crops such as peanuts, soybeans, gain a larger share of the world market. reference for North American Prunus offspring are usually sterile. Prunus described by Harper in 1911. corn, peppers, apple nursery trees, taro, To be successful in the world market, species). The recent retirement of Joe cerasifera has also been hybridized with and/or a variety of species of ornamen- Since that time much of the origi- China will need to broaden its apple Norton at Auburn University leaves the several almond species. Others of the tal nursery stock before they fill the nal habitat has been turned into citrus portfolio by adding other tart and semi- USDA-ARS/Byron program as the last species listed in Table 1 have apparently available space (Figure 10). Mature or- Figure 10. Young orchards were commonly groves or housing developments, result- tart varieties. The Chinese currently lack major plum breeding program outside of never been used in hybridization chards often had clover or other nitro- interplanted with peanuts, soybeans, taro, ing in a federal endangered plant status the infrastructure (storage, packing, California, with modest, sometimes programs. gen-fixing groundcover planted. and other crops. transportation, research, and informa- 32 NEW YORK STATE HORTICULTURAL SOCIETY NEW YORK FRUIT QUARTERLY • VOLUME 14 NUMBER 1 • 2006 17 leaf scald). Most of our selections are black skin with red flesh, very tasty. Less cultivars were released before 1950, highly resistant to the first two but only vigorous tree and very atttractive to deer. especially from South Dakota and tolerant of the last, which is the disease Minnesota Agriculture Experiment that finally kills them. Combined with a Spring Satin. Parentage: BY4-601 (= Stations, using the most cold hardy plum disease-resistant tree we need fruit that Queen Ann x Santa Rosa) x Frontier. Early species: P. nigra, P. besseyi, and P. salicina is large, firm and of good flavor and ripening plumcot. Red-black skin with (from Manchuria) (Kadir and Proebsting, texture. Late blooming is needed to yellow-red flesh, good quality when soft, 1994). ‘Sapa’ (=P. besseyi x Sultan) and its ensure a crop every year. Although we light fuzz. Productive. many hybrid offspring, although poor in have a few good plums with most of these quality, are widely adapted (Anderson characteristics, we do not yet have good Advanced Plum Selections from and Weir, 1967; Hansen, 1937). These ones for the entire season, especially the Byron, GA hybrids are often called “cherry plums”; extremes. As new improved selections are the same terms used for P. cerasifera, and made, many of the older selections once are now used more for rootstock BY8154-58. Parentage: BY69-123 op thought to be fairly good are perceived development than for fruit production. (=Mariposa x Methley). Ripens 1 1/2 weeks to be sub-standard by the latest standards. The University of Minnesota breeding before Santa Rosa, about with Methley. In plums, the current desired target program, long inactive, recently released Large, reddish-bronze skin with red flesh. requires excellent fruit similar to those an old selection as ‘Alderman’. Very good quality, sticky wax bloom. from California, but with more flavor. In Consistent production not certain. Very recent years we have planted many New York and Ontario, Canada Figure 12. Girdling and limb tieing is used extensively on mature good tree. seedlings of ‘Spring Satin’ and various trees to control excess vigor. have also had Japanese plum breeding as other parents in an effort to produce a a minor adjunct to European plum BY8158-50. Parentage: BY69-409 op range of freestone plumcots. breeding. ‘Vanier’, was released by (=Mariposa x Morris). Ripens a few days Ontario in 1984. Neither program has before Santa Rosa. Attractive red color Named Plum Varieties from continued much Japanese plum breeding. and firm flesh. Tends to overbear, The most important northern variety has Byron. GA dwarfing the tree. been ‘Early Golden’, a chance seedling found in Ontario over 50 years ago but Robusto. Parentage: BY4-1537 (=Queen BY91M937. Parentage: BY8154-242 = still widely grown. Other programs Ann x Barstow) x BY7-335 (=Ozark Premier Mariposa x Methley. Ripe slightly after developing cold hardy stone fruit were x P. angustifolia). Very vigorous tree. Eaten Methley. Red black skin with red flesh. the Horticultural Experiment Station, green like Bruce. Quality is fair when ripe Productive. Good flavor for early but Brooks, Alberta; Dominion Experiment Figure 11. All apples were bagged to protect developing fruit from but fruit is too soft and juicy for shipping. slightly sour skin. insects, diseases, and russet. Station, Morden, Manitoba; USDA Northern Great Plains Field Station, Segundo. Parentage: BY4-1236(=Queen BY91M961. Parentage: BY8304-27 op. Mandan, North Dakota; and the Ann x Santa Rosa) x BY7-335). Similar to Ripe two months after Methley. Dark red University of Saskatchewan, Saskatoon, Enclosing fruit in paper bags is a Robusto - a “green” plum eaten firm. Ripe skin with red flesh. Productive. Mild Saskatchewan (Okie and Weinberger, universal practice in the provinces of quality mild and watery. Very big tree. flavor. China that we visited (Figure 11). Bags 1996). In general these hardy plums lack size, firmness and quality necessary for protected fruit from insects, diseases, Byrongold. Parentage: BY68-87 op BY95M1094. Parentage: BY8334-16 x and corrosive sprays, and bagged fruit (=Gaviota op x BY7-335). Vigorous tree more than local use. Modest efforts to BY8327-65. Ripe with Methley. Dark red improve northern plums have been develop an attractive pink blush with an Figure 13. Metal S-shaped clips were used to bend upright branches with golden fruit. Good eating quality if skin with whitish-red flesh. Good fully ripe. Colors early so don’t pick too continued by private individuals and outstanding finish which is important horizontal to contain vigor and promote fruitfulness. cropper. Sweet when soft. for their fresh markets. We saw only a soon. Mixed consumer acceptance for Brian Smith at the University of yellow plums. Wisconsin at River Falls. small number of unbagged fruit in all the BY98Z1204. Parentage: Spring Satin x cots. orchards we saw and visited. Shandong are kept shorter than those in Pest Management Ripe with Methley. Dark red fuzzy skin Unfortunately for modern Rubysweet. Parentage: Mariposa x Shaanxi by using more intensive prun- with yellow-orange flesh. Tastes good breeders, only a few of the improved Methley. Bronze skin color is less attractive Chinese apple growers still use full- ing (Figure 14). Growers appeared to be Chinese officials and at least some firm, freestone. Resembles apricot tree. native American selections are still but eating quality of red flesh is excellent. vigor seedlings of the common apple trying to keep tree heights down so that apple growers are emphasizing “green” available, since cultivation of native Skin slightly bitter. Locally popular in species Malus pumila as a rootstock. They ladders are not needed for pruning, thin- production systems. However, the American plums is obsolete. These Southeast U.S. BY98Z1281. Parentage: Spring Satin x self. have experimented with the Malling ning, bagging, picking or for applying “green” system in China is much differ- Ripe four weeks after Methley. Black species are discussed later. stocks but reported to us that these pesticides over the top of the continu- ent than in Europe. At several stops, of- fuzzy skin with red flesh. Tastes Ok firm, Explorer. Parentage: Queen Ann x Santa rootstocks were not successful under ous tree canopy. Consequently, trees in ficials emphasized that they were using Plum Breeding - Foreign Rosa. Attractive black plum but has not mostly freestone. their conditions. As is expected when Shandong appeared greener, more vig- “green” systems that required elimina- The been a reliable cropper most years. Not Although P. cerasifera is likely an seedling rootstocks are used, Chinese orous, and had a denser canopy. tion of chemical fertilizers and use of BY98M1698. Parentage: BY8327-65 x drier environment in Shaanxi, combined grown commercially. ancestor of European plums, it is a diploid apple farmers must use extreme mea- only those pesticides that do not dam- Black Ruby. Ripe 21 days after Methley. with less pruning, seemed to limit tree species cross-fertile with Asian and sures to keep trees within the 64-100 age the environment. They substituted Red black skin with red flesh. Good vigor in that province. Their orchards suf- Black Ruby. Parentage: BY4-95 op American plum species. These “cherry square feet allotted for each tree. Young animal manures for chemical fertilizers. cropper. Medium size. Can eat firm. fer from the same maladies common to (=Queen Ann x Santa Rosa). Large, firm plums” have not been used much in trees are managed by limb bending and Both factors were important for reduc- orchards on seedling rootstocks in the black fruit on healthy upright tree. modern breeding outside Eastern Europe tying plus pruning. Mature trees are held ing water pollution and making produc- Plum Breeding - Northeast United States - excessive vigor and lack Slightly sour skin. and the former USSR, although chance to their spaces via multiple prunings tion systems more sustainable. It was not of precocity. These factors contribute to hybrids with P. cerasifera produced during the growing season, intensive clear how many apple farmers are actu- the difficulty their industry will face Ruby Queen. Parentage: BY7607-10 op None of the historic public ‘Methley’ in South Africa and ‘Wilson’ in girdling of trunk and limbs (Figure 12), ally adopting green production strate- when changing to new varieties. =Frontier x Redroy. Latest good plum, ripe breeding programs developing cold- Australia. This species provides earliness, and continued shoot bending using spe- gies but each “Experimental Farm” we about three weeks after Santa Rosa. Red- hardy plum hybrids are still active. Many cold-hardiness and probably self-fertility, cial clips (Figure 13). Orchards in visited indicated they had implemented 18 NEW YORK STATE HORTICULTURAL SOCIETY NEW YORK FRUIT QUARTERLY • VOLUME 14 NUMBER 1 • 2006 31 perimeter. The sprayers were mounted ‘Burbank’ and ‘Satsuma’. He then Superior Farms) have named ‘Black (1989). While most have improved disease in the bed of a tricycle truck about the intercrossed these and other imports with Diamond,’ ‘Black Flame,’ ‘Black Gold,’ resistance, only ‘AU-Rubrum’ has size P. simonii and North American species, ‘Black Torch’ and ‘Sweet Rosa.’ Their and firmness adequate for commercial size of a John Deere Gator, and spray resulting in ‘Beauty,’ ‘Duarte,’ ‘Eldorado,’ program is the largest of the private shipping. ‘AU-Amber’ is very sweet for tanks usually consisted of a 30-gal or 50- ‘Formosa,’ ‘Gaviota,’ ‘Santa Rosa,’ ‘Shiro,’ breeders, and as with most private an early plum, but crops erratically. gal drum (Figure 17). and ‘Wickson’ (Howard, 1945). These programs, the releases are patented (Okie Breeding has been discontinued with the plums formed the basis for the world’s and Ramming, 1999). retirement of Norton. The predominant pest problems shipping plum industry, and some are still varied by location, but apple scab (black widely grown. Pure P. salicina and related With the advent of Burbank’s Plum Breeding – USDA-Byron spot), rust diseases, and Alternaria leaf species have been little used as parents improved plums which were large and spot (red spot) were the major diseases since Burbank’s early hybridizations and firm enough to ship long distances, a new The United States Department of mentioned as requiring fungicide few pure P. salicina clones are available industry developed in California where Agriculture (USDA) stone fruit breeding treatment. The latter disease is similar outside of China. Most of Burbank’s local industries in other states mostly died in Georgia began in 1937 at the to the Alternaria leaf spot disease that hybrid plums are thought to descend out. As local industries declined, breeding Horticultural Fruit Laboratory in Fort can defoliate Red Delicious and Fuji in from crosses of—P. salicina, P. simonii and programs were closed. California-bred Valley, which is located in the center of North Carolina, but it is not widespread P. americana. In general, P. salicina plum cultivars were tried around the the main peach production area. John in the U.S. In China, it is controlled by contributed size, flavor, color and keeping world, but with the exception of a few Weinberger was the peach breeder from using copper sprays during summer, a ability; P. simonii contributed firmness and places like Chile and some parts of Italy, 1937-1954, when he transferred to Fresno, practice that explains at least part of the acidity; whereas the American species they have not thrived as well as they did California to begin the peach breeding reason for bagging fruits on the trees. gave disease resistance, tough skin and in California. program there. Victor E. Prince continued Figure 14. Dr. Predo Yotic from Tasmania, Figure 16. Furnace for the production of home- Insect pests can include cutworms, aromatic quality. the breeding in 1954. In 1964, the program Australia in a typical tree in Shaanxi. made fungicides aphids, tarnished plant bugs, mealy Plum Breeding - Southeast was moved 20 miles east from Fort Valley bugs, leaf rollers, leaf miners, and trunk After Burbank, breeding was to the newly opened Southeastern Fruit borers. They do not have plum curculio (Provado), and Bt, as well as other mod- carried on by the University of California As a result of the poor adaptability and Tree Nut Research Laboratory in or apple maggot. They apparently use ern chemistries. During one orchard and USDA. In California, past emphasis of these improved California plums, they Byron. Prince began testing plums in 1958 some miticides, but also indicated that visit, empty foil packets that had con- of breeders has been on size and firmness were crossed with local plums in other and started making crosses in 1964 after they use biological controls. Ladybugs tained pesticides were present in the for shipping, with a mild flavor preferred. parts of the country and world. In the moving to Byron. Much of the early seed and lacewing larvae and adults were roadside litter and confirmed common Black skin color became very popular Southeastern U.S., the Japanese plums for evaluating came from Weinberger in prevalent in at least one orchard that we use of many of the above-listed with the introduction of ‘Friar’ because it were crossed with the local P. angustifolia Fresno, who was also breeding plums at visited. Foliage in many of the orchards agrichemicals (Figure 15). In addition, did not show bruises and was very resulting in plums such as ‘Bruce’ and ‘Six that time. This California plum showed symptoms of apple mosaic some materials (probably Lime Sulfur) productive. However, large, firm, highly Weeks.’ Current breeding objectives in germplasm was crossed with southern virus, but tour participants from were homemade with “cookers” in the colored fruit can be harvested the Southeast United States (Georgia, varieties such as ‘Morris’, ‘Methley’, Washington State and Australia dooryard. (Figure 16). prematurely resulting in reduced Alabama, Texas, and Florida) are the same ‘Bruce’ and the native wild plum, Prunus indicated that the strain of Fuji being Since trees are spaced so tightly, consumer quality. Plums showing some as those of California plus additional angustifolia. Unfortunately the large grown in China is widely known to be ground color may be easier to pick at the orchards have no drive-rows. Pesticides disease resistance. Fruit firmness is attractive California plums would not infected with apple mosaic virus (Figure proper stage of maturity. Low prices and are applied with a handgun using a long somewhat less important because many survive in the humid climate of Georgia. 18). The virus does not cause visible over production of black plums have hose connected to a small motorized local markets are available. Resistance is In 1972 J. M. Thompson took over the damage to fruit, but it may reduce increased interest in other colors. Current sprayer that is left on the orchard required to three primary diseases: plum breeding. Before he retired in 1986, Figure 15. Foil packet containing mixed productivity. objectives include a wider range of skin bacterial leaf and fruit spot and twig Thompson released four plums – pesticides with pictures of cutworms, aphids, color and better eating quality. Red or canker, bacterial canker, and plum leaf ‘Robusto’, ‘Segundo’, ‘Byrongold’ and plant bugs, and leafrollers on the label. black skin color and yellow or red flesh scald. The first two diseases are problems ‘Explorer’ - plus BY69-1637P plumcot. color appear to be most acceptable in many other countries that are trying to Three more plums, ‘Rubysweet’, ‘Black although green skinned plums are grow Japanese plums, such as Australia, Ruby’ and ‘Ruby Queen’ have been shipped to Asian markets. Storage ability, New Zealand, Italy, and South Africa. released since then, along with ‘Spring the “organic food” apple production particularly at the end of the season, is Leaf scald is also a serious problem in Satin’ plumcot. technology and had obtained certifica- also important. Private breeders and Argentina and Brazil, and could be a tion by various agencies. The Canadian growers in California have selected many problem in California in the future if the Since 1964 we have grown over Food Inspection Agency was mentioned important commercial plums (Table 2). glassy-winged sharpshooter vector 56,000 plum seedlings and named eight specifically as one of the certifying agen- Many of the commercial cultivars grown continues to spread. In general, later varieties, or one variety per 7,000 cies (CFIA - http://www.inspection.gc. in California were found as chance or bloom is more desirable but regions such seedlings. This ratio is higher for plums ca/english/toce.shtml). open-pollinated seedlings or mutations, as Florida and parts of Texas, Australia, than peaches because a greater percentage rather than the result of hybridizations. and Brazil require even lower chilling of plum seedlings regress back to a weak Modern pesticides were readily Fred Anderson released ‘Red Beaut,’ requirements than those common in tree or wild-type poor fruit quality. Some available and widely used. Except for ‘Black Beaut,’ and ‘Grand Rosa.’ John Japanese plums. of the current plum selections are very occasional abandoned blocks visible Garabedian developed ‘Angeleno,’ still promising if they stay alive, and should through the bus windows, we did not the major late plum. Floyd Zaiger has A long-term breeding program has result in several named varieties. Our see any orchards that had insect, mite, released ‘Joanna Red,’ ‘Betty Anne,’ been conducted at Auburn University in current goals in both plum breeding are or disease problems that could have ‘Hiromi Red,’ and ‘Autumn Beaut,’ as Alabama, where Joe Norton began in to combine good quality, large, firm fruit been prevented with pesticides. Our well as ‘Citation’ rootstock, an 1955. Releases are ‘Crimson’ (1973), with consistent production on a healthy hosts told us that they commonly used interspecific hybrid, and numerous plum- ‘Purple’ (1973), ‘Homeside’ (1975), ‘AU long-lived tree. Resistance is needed to copper sprays, sulfur, mancozeb, apricot hybrids under the trademarked Producer’ (1977), ‘AU Roadside’ (1984), Pseudomonas syringae (bacterial canker), thiophanate-methyl (Topsin M), Figure 17. Three-wheeled hydraulic sprayer with 50 gallon tanks. Hoses were dragged into terms “pluot” and “aprium.” Breeders at ‘AU Cherry’ (1989), ‘AU Amber’ (1989), Xanthomonas pruni (bacterial leafspot and kresoxim-methyl (Sovran), pyrethroids, the orchard from access roads. Sunworld International (formerly ‘AU Rosa’ (1989) and ‘AU Rubrum’ twig canker) and Xyella fastidiosa (plum methomyl (Lannate), imidicloprid 30 NEW YORK STATE HORTICULTURAL SOCIETY NEW YORK FRUIT QUARTERLY • VOLUME 14 NUMBER 1 • 2006 19 Introgression of Prunus Plums have great potential as a species in Plum commercial crop in regions outside of W. R. Okie California. The wide United States Department of Agriculture - Agricultural Research range of native plum Service, Southeastern Fruit and Tree Nut Research Laboratory, species provides an 21 Dunbar Road, Byron, GA untapped source of genetic material. Results from hybridizations are “ ntrogression” is a big word meaning Origin introduction of the genes of one very unpredictable. This Ispecies into the gene pool of another. The ancestors of what we call paper describes some of This transfer can be a one-time thing, or Japanese plums actually originated in Figure 18. Apple mosaic virus is common on the Fuji variety. Figure 19. Bridge grafting is used to overcome if one parent is much better than the other, China. The term “Japanese plum” this intriguing girdling caused by Valsa mali cankers. it may involve repeated backcrossing of originally was applied to Prunus salicina germplasm maintained an interspecific hybrid with one of its imported from Japan in the late 19th parents (generally the one with better century, but now includes all the fresh at Byron, GA., and In Shandong province, we noted We were surprised to see so few some differences of opinion, and many fruit). Within Prunus, plums have had the market plums developed by intercrossing summarizes our efforts that tree trunks and scaffold limbs were pests in the orchards that we visited. It “what if” questions. However, none of most extensive mixing and matching of various diploid species with the original severely affected by Botryosphaeria appears that pest control technology in us would deny that China and Chinese species. Use of exotic species for the other species. Most plums are diploid (two sets to collect it and use it in species, fungi that cause roughened China is far more advanced than the apple producers will have a huge impact main stone fruits – peach, cherry, almond of chromosomes) except for the European scaly bark with superficial blister-like horticultural technologies being on the U.S. apple industry over the next and apricot – has been minimal and plums which are hexaploid (six sets). scion and rootstock pustules in the outer bark. These fungi employed by Chinese apple growers. decade. It will be interesting to see how mostly directed at rootstock develop- These plums were initially improved by development. are also common in some NY orchards. those impacts develop and what ment. So I will primarily address species selection in Japan and later, to a much Their impact on productivity is Marketing and Export directions they will take. mixing as it relates to plums, specifically greater extent, in the United States. unknown. However, the trunk lesions Japanese plums. apparently can produce inoculum that In 2004 China became the number In China, P. salicina may have California cultivars because of its firm can cause fruit infections after bags are one fresh apple exporter in the world. Most of these Japanese plums are originated in the Yangtze River Basin but flesh and strong flavor. Chinese botanists removed prior to harvest. Preharvest The 775,000 metric tons they exported Steve Hoying is an Area Extension Educator consumed as fresh fruit. Production in the now is found across eastern China. The describe it as native to North China, and and postharvest fruit decays caused by just edged out France, and is about 50 % in orchard management for the Lake Ontario United States is concentrated in Califor- history of ‘Zhui Li’ cultivar goes back 2500 occasionally cultivated. It has some Botryosphaeria species cause severe losses above the U.S. fresh apple exports. This Fruit Region of New York State. Dave nia, where they are best adapted. Com- years. Numerous local selections have characters reminiscent of apricot and was thought by some to have descended from in some parts of China amount is still less than 8 % of their total Rosenberger is a research and extension mercial production in California is domi- since been developed, but plum has never a natural hybrid, but more likely is just production, which is a lower percentage professor at Cornell’s Hudson Valley nated by a few major cultivars, and new been as important in China as peach, an upright variant of P. salicina. In Shanxii province, we saw than the U.S., but still is an earth shaking Laboratory and leads Cornell’s research and cultivars become important only slowly. either commercially or culturally. Plums numerous orchards devastated by Valsa number. Even though much of this fruit extension program in plant pathology. There are few breeding programs outside in Southern China are concentrated in Plum stones have been found in mali, a fungal disease of apples that is is second class quality destined for George Lamont is a recently retired California, where the primary goals of seven provinces, but especially in Fujian Japan dating back to the Yayoi Era, about similar, both in terms of the pathogen Mongolia and Russia, China also has increased size, firmness and quality have and Zhejiang, with over 20 million plum Executive Director of the New York State 2300 years ago. Japanese books dating and epidemiology, to our cytospora high quality apples going to the EU and required no further use of primitive trees found there and about 200 cultivars Horticultural Society, and a fruit grower in back 1500 years mention cultivated canker disease on peaches. The canker other quality driven markets. Desmond germplasm. Recent utilization of genetic grown. Truly wild stands are rare but are Orleans County. plums. Plums have been common garden problem in Shanxii has been exacerbated O’Rourke, publisher of the World Apple resources of Japanese plum has been lim- reported to still occur in Hubei and plants in Japan for centuries, but by the severe pruning and regular Report, predicts China’s exports could ited in the United States compared with Yunnan, where some trees in Zhongdian improvement efforts have only taken girdling of the trunk and major scaffolds. that of many other crops. Difficulties in County are over 100 years old. Low double in the next few years. place in the last century. Plum culture in In addition, they have gradually collection, importation and quarantine chilling types of P. salicina are found in Japan and also Korea is very ancient, so removed lower scaffold limbs in this through-put have limited the germplasm Southern China and Taiwan. Cold hardy None of us can predict how world that it is not possible to tell for certain if province as they allowed trees to grow available. Prunus is more difficult to pre- plums in Northern China have been events will unfold over the next decade, the countries were ever part of the native taller in an effort to improve the next year, or even the next day. Those serve because of the large amount of space classified as P. ussuriensis and P. productivity. The severe pruning and needed compared to small fruit crops, and gymnodonta, but are otherwise very range for plums. of us on the IFTA tour had an interesting girdling weakened trees and the removal the shorter life of trees relative to other similar to P. salicina. Modern breeding glimpse of China as an apple producing of lower scaffold limbs provided ideal tree crops because of disease and insect programs, especially in USSR., have Plum Breeding - California country and as an emerging world entry points for Valsa mali. Their solution problems. Lack of suitable rootstocks has utilized this source of hardiness (Okie and power. Nevertheless, it was only a has been to bridge-graft around the also reduced tree life. The trend toward Weinberger, 1996). Trees of improved P. salicina glimpse, and that glimpse was limited cankered areas. Some trees with trunks fewer breeding programs, most of which cultivars ‘Kelsey’ and ‘Abundance’ were 5-8 inches in diameter had four or five to a short time period and a relatively emphasize “short-term” commercial va- Prunus simonii was described based introduced into the United States from bridge grafts of various ages (Figure 19). small area of a huge country. We came riety development to meet immediate in- on cultivated specimens by Western Japan over 100 years ago. Luther Burbank away with some common observations, dustry needs, has also contributed to re- botanists. This species (probably the same himself imported a second lot of Japanese duced use of exotic material. clone each time) was used in developing plum seedlings and from them named 20 NEW YORK STATE HORTICULTURAL SOCIETY NEW YORK FRUIT QUARTERLY • VOLUME 14 NUMBER 1 • 2006 29