HORTSCIENCE 48(6):681–691. 2013. fruit maturation; and drought, salt, cold, and disease tolerance (Mirzaev, 2000; Mirzaev and Kuznetsov, 1984; Ribakov and Ostroukhova, Genetic Resources of Apricots (Prunus 1972). Despite this rich genetic diversity, geographical and political isolation—in con- armeniaca L.) in Central Asia junction with recent plant quarantine and 1 importation restrictions—have limited access David E. Zaurov and Thomas J. Molnar to Central Asian germplasm in Western re- Department of Plant Biology and Pathology, School of Environmental and search and genetic improvement efforts. This Biological Sciences, Rutgers University, 59 Dudley Road, New Brunswick, limited access is unfortunate, because germ- NJ 08901-8520 plasmfromCentralAsiacanbeusedtoim- prove many aspects of apricot culture, as shown Sasha W. Eisenman in the work of Ledbetter (2009) and Ledbetter Department of Landscape Architecture and Horticulture, School of et al. (2006) regarding sugar profiles of the Environmental Design, Temple University, 580 Meetinghouse Road, Ambler, fruit. More extensive use of these genetic re- sources could lead to enhanced adaptation and, PA 19002-3923 ultimately, the expansion of regions where Timothy M. Ford this high-value, sustainable, and healthy crop could be grown. Improving Perennial Plants for Food and Bio-energy, Inc., 400 North 1000 Two apricot species, P. armeniaca and East, Hyde Park, UT 84318 P. dasycarpa Ehrh., can be found naturally occurring in Central Asia (Mirzaev, 2000). Ravza F. Mavlyanova Prunus armeniaca [synonyms: Armeniaca Uzbek Scientific Research Institute of Plant Industry, 702133, P.O. Botanika, armeniaca (L.) Huth, A. vulgaris Lam., Kibray District, Tashkent Province, Uzbekistan P. tiliifolia Salisb.], referred to as the common apricot, is a deciduous, temperate tree ranging John M. Capik from 5 to 15 m tall. It produces the well- Department of Plant Biology and Pathology, School of Environmental and known apricot fruits, some with edible ker- Biological Sciences, Rutgers University, 59 Dudley Road, New Brunswick, nels, that vary tremendously in size, shape, NJ 08901-8520 color, and flavor. It can be found growing up to 3000 m above sea level in natural stands as C. Reed Funk well as cultivated plantings across Central Department of Plant Biology and Pathology, School of Environmental and Asia, northwest China, Afghanistan, Kashmir, parts of Iran, Dagestan (Russia), Turkey, and Biological Sciences, Rutgers University, 59 Dudley Road, New Brunswick, the Caucasus region. NJ 08901-8520; and Improving Perennial Plants for Food and Bio-energy, Prunus dasycarpa [synonyms: A. atropur- Inc., 400 North 1000 East, Hyde Park, UT 84318 purea Loisel., A. dasycarpa (Ehrh.) Borkh., A. fusca Turpin & Poit., P. armeniaca var. Joseph C. Goffreda dasycarpa (Ehrh.) K.Koch, P. nigra Desf.], Department of Plant Biology and Pathology, School of Environmental and commonly referred to as the black apricot, is Biological Sciences, Rutgers University, 59 Dudley Road, New Brunswick, reported to be a hybrid of P. armeniaca and NJ 08901-8520 P. cerasifera Ehrh. (cherry plum) (Zhukovsky, 1971). It grows as a small tree and is typically Additional index words. Armeniaca armeniaca, fruit crops, germplasm collection, Prunus found in regions where the two species are dasycarpa, tree breeding sympatric. It is cultivated in Central Asia, the state of Jammu and Kashmir in India, the Abstract. Central Asia is a center of diversity for many important fruit and nut tree Beluchistan region of Pakistan, and in the species, including wild and cultivated apricots (Prunus armeniaca L.). A wealth of apricot Xinjiang Province of China. Its fruits differ germplasm that expresses novel and valuable characteristics such as fruits with high from that of P. armeniaca by being generally soluble solids, edible kernels, glabrous skin, and diverse colors and flavors, as well as small with purple skin and yellow flesh. later-blooming flowers, late-maturing fruit, and drought, cold, and salt tolerance, can be The focus of this article is on the genetic found growing across this region. Since the dissolution of the Soviet Union, Central Asia resources of wild and cultivated P. armeniaca has become more accessible for reciprocal germplasm exchange and scientific collabo- in Central Asia, a region Vavilov (1931, 1951) rations. Thus, opportunities now exist to obtain, study, and use a much wider diversity of considered to be one of the centers of origin of Central Asian apricot germplasm in breeding efforts, which can lead to improved crop the species. It should be noted, however, that traits and ultimately an expansion of the regions where this high-value crop can be in Vavilov’s system of describing the centers grown. To bring attention to the valuable P. armeniaca genetic resources found in of origin of crop plants, the ‘‘Central Asiatic Central Asia and to promote its better use, management, and preservation, a description Center of Origin’’ included Northwest India and history of the species from a Central Asian perspective, along with recent and [Punjab, the northwestern frontier prov- ongoing activities, are discussed in this article. inces (current-day Pakistan), and Kashmir], Afghanistan, Tajikistan, Uzbekistan, and the western Tian Shan Mountains (Kyrgyzstan Central Asia is a center of origin for many the world (356,000 t in 2011) behind Turkey and Xinjiang, China). The highlands of important fruit and nut tree species, including and Iran [Food and Agriculture Organization Turkmenistan were part of the ‘‘Near-Eastern wild and cultivated apricots (Prunus arme- of the United Nations (FAO), 2013] (Table 1). Center of Origin.’’ This article covers only niaca) (Vavilov, 1931, 1951). Apricots, con- A wealth of cultivated and wild apricots can Uzbekistan, Tajikistan, Turkmenistan, Kyrgyzstan, sideredbymanytobeoneofthemostdelicious be found growing across Central Asia. Much and part of southern Kazakhstan (Fig. 1). tree fruits, have been produced and appreci- of this germplasm exhibits valuable charac- Across this vast region exist native popula- ated in the region for millennia and are in- teristics such as fruits with high soluble solids; tions and locally derived cultivars that are tertwined with the culture. Today, Uzbekistan glabrous skin; diverse colors, shapes, textures, adapted to a wide variety of climatic condi- is the third largest producer of apricots in and flavors; edible kernels; later flowering and tions and soil types. The climate and soils of
HORTSCIENCE VOL. 48(6) JUNE 2013 681 Table 1. Top 20 apricot (Prunus armeniaca) producing countries and Central Asian countries (in bold). Asian, Irano-Caucasian, European, and Total estimated production in 2011 from greatest to least, and area harvested (FAO, 2013). Dzhungar-Zaili. An overview of Kostina’s Country Production (t) Area harvested (ha) Avg harvest per hectare (t·ha–1) ecogeographical groups and discussion on Turkey 676,138 59,696 11.3 the migration and domestication of apricot Iran (Islamic Republic of) 452,988 50,177 9.0 germplasm from its centers of origin can be Uzbekistan 356,000 36,500 9.8 found in Zhebentyayeva et al. (2012). Of these Italy 263,132 19,595 13.4 groups, the Central Asian group is considered Algeria 205,000 32,000 6.4 to be the largest and most diverse. Apricot Pakistan 189,420 29,634 6.4 cultivars in Central Asia largely originate France 154,980 13,902 11.1 Morocco 132,523 12,678 10.5 from wild plants found in the region with the Ukraine 119,900 9,300 12.9 total number of cultivars recorded exceeding Japan 106,900 16,600 6.4 500 (Andrienko, 1997; Esenbaev et al., 1981; Egypt 96,643 6,247 15.5 Kostina, 1978; Mirzaev, 2000; Mirzaev and China 88,010 24,000 3.7 Kuznetsov, 1984). Spain 86,889 18,727 4.6 When compared with the other ecogeo- Greece 82,800 6,000 13.8 graphical groups, the Central Asian group has Syrian Arab Republic 75,919 13,746 5.5 been reported to possess the most heat- and United States of America 60,509 4,917 12.3 cold-resistant and salt-tolerant forms of the Russian Federation 60,000 11,000 5.5 South Africa 57,421 6,300 9.1 speciesaswellasformsexpressingawide Afghanistan 56,043 8,320 6.7 variety of fruit characteristics (Ivanov and Turkmenistan (21st) 36,091 2,353 15.3 Ivanova, 1981; Kostina, 1936; Mirzaev, 2000; Tajikistan (25th) 25,000 11,000 2.3 Mirzaev and Kuznetsov, 1984; Ribakov and Kyrgyzstan (32nd) 18,200 8,000 2.3 Ostroukhova, 1972; Zhebentyayeva et al., 2003; Kazakhstan (37th) 13,000 2,632 4.9 Zhukovsky, 1971). For example, studies were performed in Tajikistan with 68 apricot culti- vars from different ecogeographical groups, the Central Asian region vary considerably dark). These soils are typically non-saline including European cultivars. Results showed depending on geographic location, altitude, [total salts less than 0.25% and chlorine less the Central Asian cultivars were the most and exposure. The majority of the region has than 0.01% of absolute dry weight (ADS) of coldhardy, led by Mirsandjali #2, Khurmai, a sharp continental climate and displays dis- soil] or slightly saline (total salts less than Novot, Kandak, Gulyangi-52, Ubileini Navoi, tinct seasonal changes with occasional wide 0.25% to 0.5% and chlorine less than 0.01% to Iskandari, and others (Usmanov, 1983). Re- daily temperature fluctuations. The average 0.04% of ADS) with organic matter content searchers in the Ukraine conducted a similar monthly air temperature across Central Asia ranging from 1% to 4%. To a lesser degree, study over a 5-year period (2004–08). They varies from 24.0 to 27.7 °CinJulyto–0.3to apricots are also cultivated on the brown and looked at cold tolerance of 60 cultivars from 3.5 °C in January. The maximum air tempera- light brown carbonated soils found in the Armenia, Bulgaria, Hungary, China, the ture in some locations can reach as high as foothill and mountain areas (Pankov, 1965). United States, Moldova, Romania, Uzbeki- 48 °C with low temperatures to –40 °C. In The growing range of apricot in Central stan, Czech Republic, and others, and again November and December as well as in February Asia reaches its northern limit at 45 °Nlatitude showed that the most cold-hardy apricot and March, air temperature may fluctuate from (Zhukovsky, 1971). In mountain forests, wild cultivars were of Central Asian origin (Korzin –25 to 25 °C within a 24-h period (Mirzaev, trees can be found with small, sweet fruits and Gorina, 2009). A third study in Uzbekistan 2000). Precipitation is also variable, from 87 to that often have small leaves and bitter kernels also demonstrated that Central Asian apricot 366 mm in the valleys (apricot cultivation in (Kudryashov, 1950; Lomakin, 1971; Zhukovsky, cultivars have greater overall heat and cold these areas requires irrigation) to over 1000 mm 1971). They occur up to 1500 m above sea resistance in comparison with other ecogeo- in areas of higher elevation (Mirzaev, 2000). levelinthewesternTianShanMountain graphical groups when tested in Uzbekistan The major soils found in the valley regions System, on the south slopes of the Chatkal (Mirzaev, 2000; Mirzaev and Kuznetsov, are generally of the sierozem type (from light (Fig.1,no.1),Uzun-Akhmat(Fig.1,no.2), 1984). to dark, typically with a pH of 8.1 to 8.2) and and Susamir Mountain Ranges (Fig. 1, no. 3); Central Asian cultivars were also reported in the higher elevations soils range from a on the northwest slopes of the Ferghana to have higher fruit yields and sugar content dark sierozem to brown soil type with a pH Range (Fig. 1, no. 4); and on the Zailiysky and were considered to have superior flavor of 7.8 to 8.0 at 1100 m above sea level and 7.6 and Dzhungarsky Alatau Mountains (Fig. 1, and fruit coloring compared with many other to 8.0 at 1600 m above sea level (Mirzaev, nos. 5 and 6, respectively). Native trees can also cultivars (Ribakov and Ostroukhova, 1972; 1982). Most apricot cultivation occurs in be found in the Kotur-Bulak Gorge, in Almaty Usmanov, 1983). regions where the soils are classified as the Province, Kazakhstan (Bailey and Hough, Trees from within the Central Asian group various types of sierozem (light, typical, 1975; Kalmikov, 1973; Mehlenbacher et al., are generally characterized as being self- 1991; Mirzaev, 2000; Mirzaev and Kuznetsov, incompatible and are adapted to a wide array 1984; Zhukovsky, 1971). In addition, wild and of soil types (Mirzaev, 2000). Zhebentyayeva cultivated apricots can be found in the Pamir et al. (2003) suggested that the great di- Received for publication 19 Feb. 2013. Accepted for publication 2 May 2013. Mountains (Fig. 1, no. 7) at elevations of more versity of apricots found in the region is We acknowledge the New Jersey Agricultural than 3000 m (Pulatov, 1976). likely the result of domestication occurring Experiment Station and the Rutgers Center for In the 1980s, apricot orchards covered more over millennia through the natural associa- Turfgrass Science for their support. We are also than 83,000 ha in Central Asia: 43,600 ha in tion of wild and partly domesticated forms grateful to the late Prof. Uri M. Djavacynce Uzbekistan, 22,600 ha in Tajikistan, 10,300 ha and their intercrossing with cultivated germ- (Schroeder Institute, Uzbekistan), Academician in Kyrgyzstan, and 6,500 ha in Turkmenistan plasm that originated in the Ferghana Valley. Djamin Akimaliev (Kyrgyz Agricultural Institute), (Mirzaev and Kuznetsov, 1984). Today, the Maghuly et al. (2005) included a number of Professor Ishembay Sodembekov (Kyrgyz Agrar- total production area reported has decreased Central Asian cultivars in their simple se- ian University named after K.I. Skryabin), Dr. to 60,500 ha, although 36,500 ha can now be quence repeat (SSR) study and confirmed Arstanbek Kuliev, and Mrs. Aisha Turbatova (Gareev Botanical Garden, Kyrgyzstan) for their found in Uzbekistan (Table 1) (FAO, 2013). that they represent a basal lineage. They also manuscript contributions and/or assistance in the Kostina (1936, 1941, 1964) divided the exhibited high variability in a number of differ- collection of apricot germplasm. world’s apricot germplasm into four ecogeo- ent alleles, further supporting the increased level 1To whom reprint requests should be addressed; graphical groups based on geographic origin of genetic diversity present in the Central e-mail [email protected]. and morphological characteristics: Central Asian germplasm. The highly mountainous,
682 HORTSCIENCE VOL. 48(6) JUNE 2013 Fig. 1. Map of Central Asia including reference to locations mentioned in the text in the order they are mentioned. Country names are abbreviated: Uzbekistan (Uzb.), Tajikistan (Taj.), Kyrgyzstan (Kyr.), Turkmenistan (Tur.). (1) Chatkal Mountain Range; (2) Uzun-Akhmat Mountain Range; (3) Susamir Mountain Range; (4) Ferghana Mountain Range; (5) Zailiysky Mountain Range; (6) Dzhungarsky Alatau Mountains; (7)PamirMountains;(8) Ferghana Province, Uzb.; (9) Namangan Province, Uzb.; (10) Andijan Province, Uzb.; (11) Isfara, Taj.; (12) Khudjan, Taj.; (13) Kanibadam, Taj.; (14) Osh Province, Kyrgyzstan; (15–16) Zarafshan River Valley (Samarqand Province and the upper and lower reaches of the Zarafshan River in Bukhara Province, Uzb. and adjacent western Taj.); (17) Shakhrisabz region, Uzb.; (18) Kitab region, Uzb.; (19) Khorezm Province, Uzb.; (20)Dasxoguz (Tashauz) Province, Tur.; (21) Kopet-Dag Range, Tur.; (22) Xinjiang region, China; (23) Issyk Kul region, Kyr.; (24) Dinau, Surkhandaryo Province, Uzb.; and (25) Chimbay, Karakalpakstan Autonomous Republic. isolated terrain, the self-incompatible nature and Kanibadam regions (Fig. 1, nos. 11, 12, sandy-loam areas. Irrigation water comes of the apricots found there, the ancient trade and 13, respectively)], and a small region in the from the Sokh and Shakhimardan Rivers. routes through Central Asia, and the early pro- Osh Province of Kyrgyzstan (Fig. 1, no. 14). Apricot production in Namangan Prov- pagation of orchards through seed (not through Apricot cultivation in Ferghana Province, ince, Uzbekistan, occurs at an elevation of clonal means) all support this hypothesis. Uzbekistan, occurs in the Kokand and Fer- 400 to 800 m above sea level. This is the one Kostina further divided the Central Asia ghana regions. The Kokand production re- of the warmest locations in Uzbekistan and ecogeographical group into five subgroups gion occurs at an elevation of 400 to 500 m it has an average yearly precipitation of 170 (Ferghana, Zarafshan, Shakhrisabz, Khorezm, above sea level and is typically very windy. to 180 mm with 229 frost-free days. The soils and Kopet-Dag) with the Ferghana and Zar- Its average yearly precipitation is 80 to 130 mm are non-saline or slightly saline and are afshan subgroups being the most significant in and it has 205 to 209 frost-free days. Soils in categorized as a typical sierozem and high- size and diversity of germplasm. Much more the region are alluvial and are classified as clay, light-meadow type. The Syr Darya recently, this division was supported by SSR being light-sierozem (stony clay-loam, 0.8% River and other small rivers from the Chatkal analysis performed on a wide collection of to 1.2% organic matter) to light-meadow Range are the primary sources of irrigation P. armeniaca held at the Nikita Botanical (2.5% to 4% organic matter) types and are water. Apricots are also grown in this prov- Gardens in Yalta, Ukraine (Zhebentyayeva non-saline or slightly saline. Irrigation water ince at higher elevations (700–1000 m above et al., 2003). for production comes from the Syr Darya, sea level) where an average of 135 to 350 mm To provide examples of the diversity of Sokh, and Isfara Rivers. Like the Kokand of annual precipitation and 219 frost-free days locally derived apricot germplasm and the production region, the Ferghana region also occur. The soils are typically of the sierozem sometimes extreme environment in which it occurs at an elevation of 400 to 500 m above type (Mirzaev, 2000; Mirzaev and Kuznetsov, is grown, the geographic and climatic condi- sea level, but it has a higher yearly precip- 1984; Pankov, 1965). tions of Kostina’s Central Asian ecogeograph- itation (140–180 mm) and more frost-free Apricot production in Andijan Province, ical subgroups are discussed subsequently. An days (typically 212 d). Soils in the Ferghana Uzbekistan, occurs at an elevation 400 to overview of the apricot germplasm found in region are classified as non-saline sierozem, 1200 m above sea level. This production area each group is provided as well. slightly saline meadow-type, and stony light- has an average of 200 to 400 mm of yearly Ferghana subgroup. The Ferghana eco- sierozem soils. Orchards are irrigated from precipitation and 193 to 217 frost-free days. geographical subgroup is the largest, most the Syr Darya River and a number of other The soils are non-saline, of the typical sier- diverse, and well studied of the Central Asian small rivers originating in the Alai Mountain ozem and light-meadow type, or are stony, subgroups, in part because more than 65% of Range. The Kokand and Ferghana regions also shallow, slightly saline, dark-sierozem with the apricot orchards in Central Asia are located have higher elevation growing zones (700– the organic matter content ranging from 2.5% in the Ferghana Valley (Mirzaev, 2000). The 1700 m above sea level), which have similar to 4% (Babushkin, 1963; Kolosova, 1981; Valley spans the Ferghana, Namangan, and yearly precipitation (180–350 mm) and frost- Mirzaev, 2000; Mirzaev and Kuznetsov, Andijan Provinces of Uzbekistan (Fig. 1, nos. free days (196–206). The main soil type in the 1984; Pankov, 1965). 8, 9, and 10, respectively), part of northern higher elevation growing zone is sierozem Apricot production in northern Tajikistan Tajikistan [area surrounding the Isfara, Khudjan, (1.5% to 2.5% organic matter) with clay and occurs in the regions surrounding Isfara,
HORTSCIENCE VOL. 48(6) JUNE 2013 683 Khudjan, and Kanibadam (part of the Ferghana when compared with Hurmai (Mirzaev, 2000; and the lower reaches of the mountains), Valley), where the mean yearly temperature is Mirzaev and Kuznetsov, 1984; Smirnova, Zarafshanskiy pozdniy (recommended for 13.6 °C. Hot summers occur in this region with 1980). a broad testing in the all regions), Novvot a mean temperature in July of 27.6 °C with Another notable cultivar is the very late- (resistant to frost and disease; recommen- days occasionally reaching as high as 43 °C. maturing Kech Pishar, which does not fall ded for the foothill and mountain zones), The average yearly precipitation varies from into a specific sortotype. The fruits mature Oleg Koshevoy (Table 2; recommended 200 mm in the valleys to greater than 600 mm around the end of August to mid-September. for the backyards in the southwest part of in the foothills. The relative air humidity in the Other notable cultivars that do not fit into a Uzbekistan), and Samarqandskiy ranniy #117 summer is 27% to 30%. The winter is mild sortotype classification include the glabrous, (used for multiple end uses) (Mirzaev, 2000). with a mean January temperature of –1.3 °C. white-fleshed Ak uryuk (Table 2), Dzhaupazak, After extensive testing of cultivars from The soils are light brown and have low organic and Lyuchak, which are grown mostly for this subgroup, the Schroeder Uzbek Research matter content (Dzhuraev and Pulatov, 1988; fresh fruit. Institute of Fruit Growing, Viticulture, and Wine Usmanov, 1983). Zarafshan subgroup. This subgroup is Production (formerly known as the Schroeder Apricot cultivars and accessions from the found in the Zarafshan River Valley located Institute), Tashkent Provence, Uzbekistan, Ferghana subgroup are generally character- in Uzbekistan (Samarqand Province and the recommended Kursadik and Rukhi djuvanon ized as producing fruits with an elongated upper and lower reaches of the Zarafshan miona for cultivation in the Ferhgana valley shape that are slightly or moderately pubes- River in Bukhara Province) and in adja- and other regions of Central Asia (Mirzaev, cent. Externally, the fruits are orange or cent western Tajikistan (Fig. 1, nos. 15 and 2000; Mirzaev et al., 2004). creamy yellow and sometimes have a slight 16, respectively). In Samarqand Province, Shakhrisabz subgroup. This subgroup spans reddish blush. The flesh is dense and has a Uzbekistan, apricot cultivation occurs at an the foothills and mountainous areas of the high total sugar content and low acidity. The elevation of 200 to 1000 m above sea level. Kashka Darya River Valley in the Shakhrisabz major end use of apricots from this subgroup This area has an average annual precipitation of and Kitab regions of Uzbekistan (Fig. 1, nos. is dried fruit with only 5% used for fresh 200 to 400 mm and 170 to 216 frost-free days. 17 and 18, respectively). In these areas, apri- consumption. The cultivars that are used for Orchards are generally irrigated and the soils cots are grown at elevations up to 2000 m fresh fruit consumption are specifically early- are classified as sierozem and can be clay or above sea level. In the lower elevation of the or late-maturing. Rare glabrous, white-fleshed, sandy-loam. In Bukhara Province, Uzbeki- valleys, precipitation averages 200 to 300 mm juicy forms can also be found in this subgroup stan, apricot cultivation occurs at 200 to 500 m per year. At 1000 to 2000 m above sea level, (Mirzaev, 2000; Mirzaev and Kuznetsov, above sea level. This area has an average the annual precipitation is 400 to 800 mm 1984). annual precipitation of only 110 to 120 mm (Babushkin, 1963). In the valley, soils are typ- It should be mentioned, although cultivars and 217 frost-free days. The soils are of the ically of the light sierozem type, although with are typically propagated clonally in this re- sierozem and meadow-type with moderate increasing elevation, soils become light brown gion, seed propagation has occurred, which adds salinity. The Zarafshan River is the source of to brown soil types. some confusion regarding cultivar names and water for irrigation in both Provinces (Mirzaev In general, the apricots of this subgroup identities. To help organize the wide diversity and Kuznetsov, 1984). In the upper Zarafshan are characterized as having small or midsized of apricot germplasm in the region, cultivars Valley region of Tajikistan, apricots are grown fruit with light-colored flesh and a large seed have been grouped according to common from 600 to 2000 m above sea level (Pulatov, with a bitter kernel. Glabrous types can also morphological and phenological characteris- 1976). Yearly precipitation ranges from 110 be found in this subgroup. Typical cultivars tics and geographic origins, although not every to 400 mm and soils in this area are generally of the subgroup are generally described as cultivar fits into a specific group. These group- classified as sierozem with those above 1600 m having exceptional flavor (good sugar to acid ings are referred to as sortotypes, or conculta, classified as brown soils. ratio) and can be used both fresh and dried of which more than 30 have been described Although smaller in size compared with (Mirzaev, 2000). It should be noted that with each sortotype containing many cultivars. the Ferghana subgroup, the Zarafshan sub- orchard production has been based on seed- Despite the wide phenotypic diversity, the most group is considered more variable in fruit size, ling trees here more so than in the other commonly grown cultivars fall into a small color, and flavor (Mirzaev, 2000; Mirzaev and subgroups (Mirzaev and Kuznetsov, 1984). number of sortotypes across the region. In Kuznetsov, 1984). Achkinazi (1933) divided Khorezm subgroup. This subgroup is found many instances, the most important cultivar all of the cultivars of this subgroup into six in the northern part of Uzbekistan [Khorezm of the sortotype shares its name with the categories depending on time of maturation, Province (Fig. 1, no. 19) and the Karakalpak- sortotype with the other cultivars in the group fruit size, and the ability of the fruit to dry on stan Autonomous Republic] and the Dasxoguz containing some derivation of the sortotypes the tree. These include ‘Dzhaupazak’ (early- (Tashauz) Province of Turkmenistan (Fig. 1, name. For example, the most commonly grown maturing), ‘Makhtoba’ (light-colored fruit), no. 20). The climate of this area is sharply cultivars of the Ferghana subgroup are Babai, ‘Rukhi djuvanon miona’ (late-blooming), continental and is characterized by having an Isfarak, Kandak, Hurmai, Mirsandjali, and ‘Arzami’ (intense exterior color with carmine- average annual precipitation of less than 100 mm Supkhani, which are described in Table 2. red blush), ‘Gulyangi’ (fruits are persistent and along with relative air humidity levels that can The Babai sortotype holds 20 cultivars, dry on the tree; this type is found around the occasionally drop to 1% to 2%. The dry season which are known for retaining fruit in windy upper Zarafshan River), and ‘Kandak’ (high typically lasts from the end of May to October. conditions and have high sugar content. The sugar content). In general, fruits from this The yearly number of frost-free days in this Isfarak sortotype holds 25 cultivars and is subgroup are used for producing dried apri- region fluctuates from 180 to 195 (Babushkin, known for dried fruit production. The Kan- cots as well as for fresh consumption and 1963). Summer temperatures can reach 45 °C, dak sortotype holds 17 cultivars and is noted canning. Some cultivars within this subgroup, whereas winter temperatures often drop below for some retention of fruits in windy condi- particularly those grown near the city of Samar- –30 °C with a mean yearly temperature of 10 tions. The Hurmai sortotype holds more than qand, are glabrous with white or light-colored to 12 °C. Winter typically lasts nearly 5 months 40 cultivars characterized as having large flesh and relatively high acidity. These include (Akhmedov, 1993). The main soil type in this size fruit and tolerance to a wide variety of ‘Arzami pozdniy’, ‘Gulungi luchak’, and region is an alluvial meadow-type soil that is soil conditions. The Mirsandjali sortotype ‘Makhtobi samarqandsky’. The most widely highly saline (total salt content greater than holds 16 cultivars and is used for dried and grown cultivars in this subgroup include 1.0%, chlorine greater than 0.20% of ADS). canned end-use purposes. The Supkhani sor- Kursadik (Table 2), Arzami (Table 2), Ahrori, The groundwater is also salty, and the water totype holds 15 cultivars that typically pro- Rukhi djuvanon miona, Gulungi luchak, Lu- table is located 1 to 2 m below the surface duce large fruits and are widely distributed in chak zolotistyi, Badaminskiy krupnoplodniy, (Pankov, 1965). Central Asia. Cultivars in the Isfarak and and Mokhtobi samarqandskiy. More recently Apricots of this subgroup are character- Supkhani sortotypes are also known for hav- developed cultivars include Ubileini Navoi ized by superior salt, cold, and heat tolerance ing higher soil and management requirements (Table 2; recommended for irrigated valleys when compared with other subgroups, but in
684 HORTSCIENCE VOL. 48(6) JUNE 2013 H
ORT Table 2. Characteristics of commonly planted Central Asian apricot (Prunus armeniaca) cultivars including those with unique attributes (Mirzaev, 2000; Mirzaev et al., 1983; Mirzaev and Kuznetsov, 1984).
S Percent sugar CIENCE Ecogeographical Avg fruit Relative bloom content of Percent acidity Other Cultivar subgroup wt (g) Fruit color time fresh fruit of fresh fruit Ripening time Primary end use characteristics Ak uryuk Ferghana 30–40 Creamy white End of March 11–16 0.6–0.7 10 June Fresh High quality of fruits V
OL Gulistan Ferghana 33 Yellow with red Early April 17 0.88 1–10 June Dried/fresh/canned/ Frost-resistant
86 J 48(6) . blush preserves Isfarak Ferghana 20–30 Yellow–orange or End of March 15–20 0.7–1.0 15–30 July Dried Wind and disease creamy orange, resistant sometimes with UNE red blush
2013 Kandak Ferghana 20–25 Yellow–orange End of March 14–17 0.4–0.6 15–30 June Mostly dried (small High yield, poor portion canned) resistance to frost Hurmai Ferghana 30–35 Bright yellow Late March to early 14–16 0.6–1.1 End of June/early Dried/fresh/canned/ High quality of fruits, April July preserves high-yielding Kich Pishar Ferghana 25–30 Creamy yellow March–April — — End of August to Canned Frost- and disease- mid-September resistant Mirsandjali Ferghana 25–30 Yellow with pink– End of March to early 13–21 0.6–1.2 Beginning 20 June Dried and fresh Frost-resistant carmine blush April Supkhani Ferghana 35–50 Light orange with End of March 14–18 0.6–1.2 In valleys, end of Dried High quality of fruits, occasional June to early July; poor resistance to greenish hue in mountains end frost July to early August Vimpel Ferghana 3 50–60 (to 105) Slightly shiny End of March 15.8 1.96 Mid-June Dried/fresh/canned/ Frost- and disease- European type yellowish creamy preserves resistant with pinkish red blush Kursadik Zarafshan Up to 40 Yellow with bright End of March to early 14–16 0.9–1.1 Early July Dried High quality of fruits, carmine blush April poor resistance to when exposed frost to sun Rukhi djuvanon Zarafshan 35–40 Orange–yellow with End of March to early 14–16 0.8 After mid-June Fresh/canned/juice Frost- and drought- miona bright carmine April resistant blush Zarafshansky Zarafshan 45 Yellow with red End of March to early 15–16 0.85 Mid-July Dried Frost-resistant pozdniy blush on lower April half Navruz Zarafshan 3 40 Yellow with dark First half of April 13 0.84 Starting early July Dried/preserves Late-blooming, Shakrisabs red blush frost-resistant Ubileini Navoi Zarafshan 45 Shiny, golden End of March 14–16 1.0–1.2 End of June to early Dried/fresh/canned/ Wind-resistant, yellow with bright July preserves average frost blush resistance Arzami Zarafshan 40–70 Light creamy yellow End of March 11–13 0.8 Second half of June Fresh and canned Frost-, drought-, and with carmine red disease-resistant blush Oleg Koshevoy Zarafshan Up to 90 Half yellow and half End of March 12 1.0 First half of June Fresh and canned Frost-resistant red Babai Ferghana 10–20 Yellow–reddish, Late March to early 13 0.6 Mid-June to Dried with seeds and Resistant to winds sometimes with April mid-July canned carmine red blush Ak nurul Khorezm 22–25 Light yellow with 1–10 Apr. 16 0.5 End of June Fresh and dried Drought-, frost-, and orange blush salt-resistant Kizil palvan Khorezm 45–50 Yellow–green with 1–10 Apr. 14–16 0.8–1.0 End of June Fresh and dried Drought-, frost-, and
685 carmine red blush salt-resistant general, they have small fruits and less vari- The cultivars of the Irano-Caucasian group the cultivar, the average yield is generally 10 ation in fruit characteristics like shape and in Central Asia were shown to be very early- to 15 t·ha–1 (Mavlyanova et al., 2005; Mirzaev color. Old orchards of this subgroup include flowering and have low frost resistance. As et al., 2004). The average productivity of a a high percentage of trees grown from seed. such, they can only be found in collections of cultivated apricot is 80 to 100 kg per tree, but The best, most widely grown cultivars of the the various scientific organizations in Central exceptional trees can yield 500 to 600 kg with subgroup are Kizil nukul, Ak nukul, Kizil Asia (Mirzaev, 2000). The Dzhungar-Zaili some reports of up 1100 kg per tree (Pulatov, palvan, Kuzgi, Khorezmi, and Paivandi subgroup is comprised of landraces and lo- 1976). turtkulsky (Kuznetsov, 1970; Mirzaev, 2000; cally cultivated forms and has undergone very According to research conducted at the Mirzaev and Kuznetsov, 1984). limited controlled breeding. This subgroup is Schroeder Institute, apricot has a high light Kopet-Dag subgroup. This small subgroup characterized by its cold-hardiness, neces- requirement and as a result requires open is found in the upper Sumbar River Basin at sary in a region where the winter tempera- spacing in cultivation with minimum accu- an elevation of 500 to 700 m above sea level tures reach as low as –30 °C (Kostina, 1970). mulation of 2500 degree-days to mature in the west part of the Kopet-Dag Range, The Dzhungar-Zaili subgroup is grown in the crops (Mirzaev, 2000). When trees are not Turkmenistan (Fig. 1, no. 21). The climate is Almaty Province of Kazakhstan and into the spaced properly, there is a higher occurrence sharply continental and the relative air humid- Xinjiang region of northwestern China (Fig. 1, of fungal diseases as well as a decrease in ity is very low as a result of its close proximity nos. 6 and 22). yield and fruit quality. In the wild, disease to the deserts of Central Asia and Iran. The Production in the Issyk Kul Basin. Al- occurs more frequently on trees growing in yearly precipitation ranges from 120 to 150 mm though apricots are cultivated in the southern depressions and wet areas. Apricot requires in the foothills and below and up to 500 to portion of Kyrgyzstan (Osh Province), the well-aerated soils and will not thrive in heavy 550 mm in the higher elevations. Soil is northern parts of the country have harsher soils with high clay content (Smykov et al., classified as typical sierozem with 1.5% to climatic conditions, limiting their cultivation 1985). However, they are considered to be 2.5% organic matter and is non-saline to potential. However, extensive trials have been highly tolerant of drought and low relative air slightly saline (Fet and Atamuradov, 1994; conducted in the moderated Issyk Kul region humidity (Torrecillas et al., 1999). Gvozdetskiy and Mikhailov, 1978; Pankov, (Fig. 1, no. 23). Within the Issyk Kul Basin Across Central Asia, flowering time fluc- 1965). (elevation of 1600 to 1800 m), there is very tuates from year to year and by geographic The trees of this subgroup are large and low precipitation, 158 frost-free days, and an region. For example, in southern Uzbekistan relatively long-lived and share traits (general average yearly temperature of 7 °C. With the [Dinau, Surkhandaryo Province (Fig. 1, no. shape of the tree and fruits) in common with addition of irrigation, apricot production has 24)], flowering starts 6 Mar., whereas in the the Armenian, semidomesticated apricots been successful in this area using cultivars north [Chimbay, Karakalpakstan Autono- known as ‘‘Khardzhi’’ of the Irano-Caucasian originating from a variety of Central Asia mous Republic (Fig. 1, no. 25)], flowering group (Kostina, 1964). In general, the fruits subgroups and the European ecogeographical begins 10 Apr. (Mirzaev and Kuznetsov, are large with bitter kernels and are produced group (Arakelyan and Bashmakov, 1981). 1984). Lomakin (1977) reported that, in for fresh consumption. general, Central Asian cultivars had a higher Other ecogeographical groups cultivated Morphology and Biology of P. armeniaca chilling requirement compared with Euro- in Central Asia. Apricot germplasm from the in Central Asia pean cultivars. They also required a higher European ecogeographical group was intro- temperature to initiate blooming in the spring duced into Central Asia in the mid-19th In Central Asia, cultivated apricot trees in addition to having slower flower devel- century for the purpose of producing fruits have a mature height of 6 to 14 m (occasion- opment, typically resulting in an extended for canning. This group is considered to have ally up to 23 m) with trunk diameters of 30 to period of bloom. Lomakin (1977) also reported the least genetic diversity and be the most 60 cm or greater. The crowns are generally that the Central Asian cultivars nearly stopped recent evolutionary derivation of the groups rounded or gently spreading, and root systems flower development and progression when (Kostina, 1970). This group originated from consist of a deep tap root with many lateral temperatures dropped to 8 °C, whereas the germplasm brought to Europe from Iran, branches. Interestingly, some cultivars of the European cultivars kept progressing, which Armenia, and the Middle East and was de- Central Asian ecogeographical group (in par- made the European cultivars more prone to veloped in areas of southern Europe that have ticular those of the Hurmai and Mirsandjali frost damage. The Central Asian cultivars also more moderate conditions and higher air sortotypes) have been shown to have greater tended to better resist dormancy interruption humidity than Central Asia. The trees in this total leaf surface area per tree than the when exposed to warm days during the winter group are mostly self-compatible and, when European and Irano-Caucasian groups (Mirzaev period. compared with the Central Asian group, are and Kuznetsov, 1984). Fruits can reach 2.5 to Because the Central Asian group is known less vigorous, have thicker branches and a 5 cm in length, and the weight of cultivated to be mostly self-incompatible, studies have shorter life expectancy, and are generally less fruits can vary from 5.5 to 80 g. The color of been conducted to determine the best cultivars tolerant of wind, heat, drought, and cold. They the fruit varies from white or yellow to orange to serve as pollinators for well-known pro- also have better resistance to fungal diseases, or orange–red and the kernels can be bitter duction cultivars. Nearly all cultivars tested ripen earlier, have a shorter dormancy period, (inedible) or sweet (edible). Skin of the fruit exhibited good fruit production when polli- and break bud faster in the spring. The fruits can vary from pubescent to glabrous with nated by ‘Arzami’ and ‘Kursadik’, whereas of the European group are generally large various shades and degrees of orange to red ‘Supkhani’ and ‘Isfarak’ successfully polli- (from 40 to 100 g), yellow to orange in color, overcolor. nated approximately half of the cultivars and have bitter kernels. They tend to have a Apricot trees typically have a life span of studied (Mirzaev, 2000; Mirzaev and Kuznetsov, lower sugar content (6% to 12%), are more 30 to 40 years, although some may reach up 1984). The Schroeder Institute has recommen- acidic, and ripen earlier than those of the Central to 200 years. The average life expectancy of ded a planting regime of 3- to 10-ha blocks Asian group (Layne et al., 1996; Maghuly et al., Central Asian cultivars growing on the plains composed of six to 10 rows of the main cultivar 2005; Mirzaev, 2000; Mirzaev and Kuznetsov, and lower foothills is 50 to 70 years. In the alternating with one to two rows of a pollinator 1984; Mirzaev et al., 1983). The widely grown upper foothills and in the mountain zone, the cultivar. cultivars Vengersky luchshiy, Krasnoshcheky, trees tend to be larger and have bigger leaves Korolevsky, Vimpel, and Komsomolets (the than those growing at lower elevations. In Plum Pox Virus latter two were developed by Kostina) are used the mountains of the Chatkal Range, the primarily for canning. ‘Zaraya Vostoka’, also cultivar Hurmai can often live to an age of Sharka disease caused by the Plum pox developed by Kostina, is reported by Mirzaev 100 to 150 years (Mirzaev and Kuznetsov, virus (PPV) is a major limiting factor of et al. (1983) to have the most flavorful fruits 1984). In general, apricot trees start produc- apricot production in a number of countries in the European group. It is commonly culti- ing fruit at 3 to 4 years when grafted and 4 to and quarantine regulations are necessary to vated in Turkmenistan (Vazhov et al., 1989). 5 years when grown from seed. Depending on prevent its spread to new regions (Levy et al.,
686 HORTSCIENCE VOL. 48(6) JUNE 2013 2000). It is vital that new introductions of Vostoka, Komsomolets, Spitak kremovii, Hur- local cultivars in terms of yield, fruit quality, germplasm are free of this virus. Primarily as mai rannii, Gevandi, and Oranjevii pozdnii level of soluble solids, and cropping consistency a result of the potential import of PPV, the 263 (Mavlyanova et al., 2005). ‘Vimpel’ con- (Usmanov, 1983). The most recent reports U.S. Department of Agriculture has listed tinues to be widely grown in home gardens suggest that 180 cultivars are held in their Prunus as a prohibited genus, which may across suitable growing zones in Central Asia. collection today (Progress Report of National only be imported into the United States after The Schroeder Uzbek Research Institute Coordinators of Plant Genetic Resources in issuance of a written permit by the Plant of Fruit Growing, Viticulture, and Wine Pro- Central Asia and the Caucasus, 2007). Protection and Quarantine Program. Some duction maintains an extensive living collec- In Kyrgyzstan, apricot research is cur- studies on PPV showed that resistant culti- tion of more than 500 accessions of apricots, rently being conducted at the Kyrgyz Agri- vars from North America contained unique including cultivars and wild forms (Esenbaev cultural Research Institute, Bishkek. Apricot alleles attributed to Central Asian ancestry et al., 1981; Mirzaev et al., 2004). In 1930, a research began there in 1937, when it was (Badenes et al., 1996; Hormoza, 2002; Hurtado systematic and comprehensive apricot breed- known as the Kyrgyz Fruit Experiment Sta- et al., 2002a, 2002b). ing program was initiated at the institute. Early tion. Later, this station was incorporated into More recently, Zhebentyayeva et al. (2008) evaluations identified three Uzbek cultivars the Kyrgyz Agriculture Research Institute, conducted extensive amplified fragment length (Kursadik, Arzami, Ruhi dzhuvanon miona) also in Bishkek, where the apricot program polymorphism and SSR studies using plant and two European cultivars (Krasnoshoki and was placed under the direction of S.G. material representing North American, Eu- Korolevski) as being better adapted to the Abdrakhmanov. He crossed cultivars from the ropean, Central Asian, and Asian (Chinese) widely fluctuating climatic conditions com- Ferghana subgroup such as Arzami, Ahrori, apricot germplasm as well as the closely mon in Uzbekistan. These cultivars exhibited Mirsandjali, and Hurmai krasnii, with cultivars related Prunus species from Asia. Their flowers and young fruits that were tolerant of from the European ecogeographical group, in- analyses supported an alternative hypothesis late spring frosts (Kovalev, 1963). Schroeder cluding Korolevsky, Krasnosheky, Ananasnii, for the origin of PPV resistance in North Institute plant breeders subsequently devel- Vengersky luchshiy, Ranniy krasnii, Komsomolets American cultivars. They concluded that re- oped improved cultivars expressing traits of as well as from the Irano-Caucasian eco- sistance came from introgression of Chinese later flowering and frost tolerance combined geographical group, including Abdukhaliki, germplasm as well as possible introgression with high fruit quality by selecting improved Abdutalibi, and others. The most notable of of the Prunus species P. mandshurica (Maxim.) seedlings from hybrids between local land- the 10 cultivars released from the program are Koehne, P. sibirica var. davidiana (Carrie`re) races and the larger-fruited European culti- Frunzensky ananasnii, Hurmai frunzensky, Y.L. Chou, and P. mume Siebold & Zucc. To vars. The cultivars developed and released Hurmai gornii, and Komsomsmolets Kirgizii date, PPV has not been reported in Central include Samarqandski ranniy, Medoviy, (Abdrakhmanov, 1969; Soldatov and Kuliev, Asia with the exception of southeastern Uzbekistansky, Ubileini Navoi, Samarqand- 2010). Kazakhstan. Spiegel et al. (2004) tested trees skiy #117, and Zarafshansky pozdniy (Mirzaev In the 1930s, additional research and including wild apricot (originating from wild et al., 1983; Mirzaev and Kuznetsov, 1984). breeding of apricot was conducted at the populations in Zailiyski Alatou at the north- The cultivar Ubeleini Navoi (Table 2), which Botanical Garden of the National Academy ern edge of the Tian Shan Mountain System) originated from a cross between ‘Arzami’ of Kyrgyzstan, Bishkek, Kyrgyzstan, under and cultivated plum growing in the Pomolog- (Central Asian Zarafshan subgroup) and the direction of Dr. E.Z. Gareev (1959). ical Garden in Talgar, Kazakhstan. Although ‘Falgarsky gulungi’ (from Tajikistan), has He organized the collection and establish- PPV strain D was detected in both plum and a reputation for high fruit quality and yield ment of over 200 seedling accessions from apricot trees there, it was reported that the (Mirzaev et al., 1983). Uzbekistan, Tajikistan, and the European sub- plum displayed severe leaf symptoms, whereas Although many of the first cultivars devel- group. From these plants, he released 16 only a single apricot tree showed obvious oped displayed flower bud resistance to cold, cultivars for use in both the fresh and dried symptoms. Uzbekistan, Tajikistan, Kyrgyzstan, they did not produce consistently acceptable fruit markets (Soldatov and Kuliev, 2010). Dr. and Turkmenistan still appear to be free of the yields. Further breeding work yielded im- Gareev also began hybridization efforts be- virus (S. Kozubaev, Chief of the Uzbek Quar- proved cultivars, including Gulistan (Table 2), tween the Central Asian and European sub- antine Inspection of the Ministry of Agriculture Avicena, Abadi, Nuravshon, and Mohir, which groups, which were continued by Dr. I.V. and Water Resources of the Republic of had higher chilling requirements and were Soldatov. Dr. Soldatov released three culti- Uzbekistan, personal communication). later blooming than previous cultivars (Mirzaev, vars, the most notable being Kirbotsad, a 2000; Mirzaev et al., 2004; Mirzaev and large-fruited, late-flowering, consistent annual Research and Germplasm Holdings of Kuznetsov, 1984; Turakulov, 1993). They fruit producer (Soldatov and Kuliev, 2010). P. armeniaca in Central Asia possessed greater resistance to frost and con- An additional program was developed with sistently acceptable fruit yields with their the goal of producing hybrids between apri- Although the most intensive and pro- first bloom being at least 1 week later than cot and plum (P. domestica) (Soldatov and ductive research and breeding of apricot in ‘Ubeileini Navoi’ and ‘Kursadik’ (Mirzaev, Kostritsina, 2002; Soldatov and Kuliev, 2010). Uzbekistan was done in the past, work is still 2000; Mirzaev et al., 2004). In 2010, the It resulted in the development of 25 promising being conducted at the Uzbek Scientific Re- Uzbek Ministry of Agriculture included the hybrids from diverse germplasm, which were search Institute of Plant Industry, formerly cultivars Vimpel, Komsomolets, Gulistan, found to be well adapted to environmental known as the Uzbekistan branch of the Vavi- Navruz, Sovetsky, and Marokand in their conditions found in Kyrgyzstan. These hy- lov Research Institute of Plant Industry (VIR) recommendations for apricot cultivation in brids are currently maintained in the collection (Tashkent Province, Uzbekistan) and the Uzbekistan. of the Gareev Botanical Garden. As of 2008, Schroeder Uzbek Research Institute of Fruit In Tajikistan, apricot research was primar- five cultivars (Korolevsky, Krasnoshchoky, Growing, Viticulture, and Wine Production ily conducted at the Tajik Scientific Research Nikitsky, Spitak kremovii, and Effect) were (Tashkent Province, Uzbekistan) (Mirzaev Institute of Orchards and Viticulture, named recommended for growers in the northern et al., 2004). Since 1928, the Uzbek Scientific after I.V. Michurin (Khujand Province). The regions of Kyrgyzstan and eight cultivars Research Institute of Plant Industry has institute was renamed and is presently called (Arzami, Isfarak, Kursadik, Krasnoshchoky, maintained a living collection of 650 apricot the Scientific Research Institute of Fruit Grow- Mirsandjali, Sovetsky, Supkhani, and Hurmai) cultivars originating from different geograph- ing, Viticulture, and Vegetable Production of for the southern areas (State Commission for ical regions (Mavlyanova et al., 2005; Smirnova, the Tajik Agricultural Academy of Science. Variety Testing of Crops, 2008). 1980). The internationally recognized breeder From 1932 to 1958, over 250 cultivars from In the 1930s, 42 cultivars were introduced K.F. Kostina worked at this institute in the the western part of the Soviet Union (Euro- to the VIR Central Experiment Station (at late 1920s and early 1930s. Over the past pean ecogeographical group) were evaluated. Kara Kala) in Turkmenistan from the Nikita century, the institute has released a number of Studies showed that the introduced cultivars Botanical Garden, the Uzbekistan VIR, and the apricot cultivars, including Vimpel, Zaraya underperformed when compared with the Maykop, Russia, VIR. This early collection
HORTSCIENCE VOL. 48(6) JUNE 2013 687 also included Uzbekistan, Tajikistan, Azerbaijan, produce glabrous-skinned fruits from their developing trees with beneficial phenological and local Turkmen cultivars. By 1987, the Central Asian donor, all with acceptable fruit traits, the program also selects for increased collection was expanded to include 556 acces- size (Ledbetter, 2009). Commercial produc- fruit quality, size, and sugar content as well as sions introduced from Iran, Syria, Tunisia, tion trials are currently ongoing for several unique skin color, flesh firmness and juici- Spain, Italy, France, and the United States as Central Asian-related selections to determine ness, stone freeness, and extended shelf life. well as from the Ferghana, Zarafshan, and their suitability for release and production. Pollen from Central Asian cultivars was Khorezm Central Asian subgroups and other The USDA presently holds a number of obtained from cooperators in the early 1960s material from the Caucasus, China, Syria, and accessions and cultivars from Central Asia through the early 1970s and was regularly eastern Europe (Nosulchak et al., 1988). From in its Germplasm Resource Information used in crosses. Since the program’s inception, the Turkmenistan program, 17 cultivars were Network (GRIN) National Germplasm Repos- six cultivars have been released, including released with four recommended for growers. itory holding at the University of California– OrangeRedTM (‘Bhart’, tested as NJA32), These cultivars included Zaraya Vostoka and Davis (GRIN, 2013). Many of these were Early BlushTM (‘NJA53’), and Sugar PearlsTM Komsomolets (developed by Kostina), Kon- donated by institutes from the former USSR (‘NJA150’), all of which contain Central servniy pozdniy (selected from seedlings of and from collection trips undertaken by Asian heritage. Today, nearly all of the crosses the local landraces), and Spitak kremovii various apricot breeders, collectors, and sci- made at the NJAES have at least one parent (Vazhov et al., 1989). The current status of entists. Based on apricot germplasm from that was derived, in part, from Central Asian the Turkmenistan program is unknown. Central Asia and other regions, it is clear that germplasm. significant improvements can be made in the From 1997 to 1999, a large-scale germ- Central Asian Apricot in the United States crop, and efforts are already being made. plasm collection effort was initiated at However, public breeding programs for apri- Rutgers University to enhance the existing California is the largest producer of apri- cots in the United States are limited to the apricot breeding program. Authors David cots in the United States, producing 56,744 t USDA at Parlier, CA, and Rutgers University, Zaurov and Joseph Goffreda collected open- in 2011, roughly 94% of the U.S. total crop New Brunswick, NJ. pollinated apricot seeds representing germ- [U.S. Department of Agriculture (USDA) Na- The principal objective of the Rutgers plasm from a wide area of Central Asia with tional Agricultural Statistics Service, 2012a], University/New Jersey Agricultural Experi- a focus on Uzbekistan and Kyrgyzstan. Seeds which was less than 2% of the world crop mental Station (NJAES) apricot breeding were gathered from the germplasm collections [3,834,475 t in 2011 (FAO, 2013)]. Washington program is to develop high-quality cultivars of research institutes (Schroder Institute, Re- is the second largest producer in the United that will be consistently productive in the search Institute of Plant Industry, Experiment States with 3538 t in 2011 and Utah is third northeastern United States. The NJAES apri- Station of Tashkent Agrarian University, Kyrgyz with 181 t. No other states record any appre- cot breeding program was initiated in the mid- Research Agricultural Institute, and Gareev ciable production. Based on the annual pro- 1950s (Hough and Bailey, 1982). Very early Botanical Garden), where the germplasm col- duction reported by the USDA’s Fruit and in the program it was recognized that apricots lections also contained selections from around Tree Nuts Situation and Outlook Yearbook from the European group were poorly adapted Central Asia as well as backyard gardens and 2011 (USDA, 2012b), U.S. apricot produc- to New Jersey conditions. The climate of New local markets. A total of 285 seed lots were tion in 2011(60,460 t) has been reduced by Jersey (and the northeastern United States) can collected with each seed lot consisting of nearly 50% since 1980 (120,000 t). often cause serious difficulties in apricot culture 25 to 100 seeds. Additionally, scion wood of Some efforts in incorporating Central (Table 3). Chilling requirements of some cul- specific cultivars was received from two Asian apricot germplasm into U.S. breeding tivars are often met by the end of December, major germplasm repositories, the tree fruit programs have been made in California by whereas extreme fluctuations in winter weather repository at the Central Asian Experiment USDA breeders. Beginning in the early 1990s, can cause temperatures to rise as high as 20 °C Station of the Institute of Plant Industry when access to the countries of the former and fall as low as –20 °C within a short period (formerly a branch of VIR), and the Schroeder USSR became available, accessions from of time. Exposure to this type of heating and Institute. Both sites are located near Tashkent, across Central Asia were imported to California cooling can cause trees to lose their winter- Uzbekistan. By 2001, the Rutgers University in an effort to improve the sugar profiles and hardiness and often results in severe damage Fruit Research and Extension Center, Cream overall quality and diversity of California to the trunk of the trees. Additionally, late Ridge, NJ, housed a collection of more than apricots (Ledbetter, 2009). On their own, fruits spring frosts commonly occur and can dam- 10,000 Central Asian apricot trees, mostly from the introduced Central Asian germplasm age flower buds, flowers, and even immature derived from open-pollinated seed, in addi- were believed to be too small to be sold directly fruit. Finally, spring in the northeastern United tion to the clonal selections. Over the next in the United States. However, some of the States is often quite humid and rainy, in- 10 years these trees were grown in the field Central Asian varieties and seedling selections creasing disease pressure. To address these at Cream Ridge and were systematically were found to express important traits, like issues, breeding efforts have focused on evaluated for characteristics important to elevated Brix levels, varied sugar profiles, later increasing both chilling requirements and the Rutgers breeding program. Because of maturation dates, and interesting morphologi- post-rest heat requirements necessary to in- the large number of seedlings, the initial cal characteristics that were lacking in current duce blooming and enhancing the level of spacing was restricted to less than 1 m be- U.S. germplasm holdings. disease resistance. To expand the fresh apri- tween each plant in the row. Each year, Breeders were able to produce fruiting cot season, trees exhibiting early and late poor-performing trees were systematically California 3 CentralAsiaF1 hybrids starting maturation were identified and used in con- culled with many others dying on their own in 1997. These hybrid seedlings, as expected, trolled cross hybridizations. In addition to from lack of adaptation and/or disease. As of showed great variability. Unfortunately, fruit size was still not large enough for fresh sale, although many of the offspring showed seg- Table 3. Climate information from weather stations near the Rutgers University Cream Ridge Fruit regation for multiple desired traits. Thus, Research and Extension Center (Freehold, NJ) and the Improving Perennial Plants for Food and Bioenergy, Inc. research farms (Logan, UT) (National Climate Data Center, 2013a, 2013b) in select F1 plants were subsequently inter- crossed or backcrossed to improved California comparison with the Samarqand and Pskem regions of Tashkent Province, Uzbekistan (Mirzaev, cultivars (Ledbetter et al., 2006). Through 1982). these efforts, breeders were able to produce Avg yearly Record air temp (°C) Avg yearly Avg air temp (°C) many progeny expressing desired traits from precipitation (mm) Maximum Minimumtemp (°C) January July both parents. These plants included selec- Freehold, NJ 1187 41.1 –28.9 11.4 –1.1 23.5 tions that ripen over 2 weeks later than Logan, UT 477 39.4 –33.3 7.4 –6.1 22.7 standard Californian cultivars, plants with Samarqand, Uzb. 328 40.0 –30.0 12.9 –2.0 24.0 highly elevated Brix levels, and plants that Pskem, Uzb. 995 41.0 –27.0 8.9 –1.8 23.3
688 HORTSCIENCE VOL. 48(6) JUNE 2013 2013, only 160 trees remain, representing Mormon (a highly variable common Chinese collected in Central Asia and/or through the most disease-resistant and productive landrace), Goldrich, Tilton, Moorpark, Rival, seedlings derived from Central Asian-related trees that produce high-quality fruits. Phe- and Perfection (Utah State University, 2013). advanced selections from Rutgers Univer- nological and fruit characteristics of some The growing regions of the Intermountain sity. The breeding goals in Utah are similar to promising Central Asian apricot selections West are similar to the production regions of those of New Jersey; in addition, the material growing at Cream Ridge are presented in Central Asia in terms of mean annual precip- is screened for resistance to lime-induced Table 4, and images of general fruit diver- itation, temperatures, growing season, and iron chlorosis and tolerance of high pH soils sity are presented in Figure 2. elevation (Table 3). To date, a number of as well as saline soils and irrigation water. Although Utah currently has a small promising apricot selections have been iden- They are also assessed for the presence of amount of commercial apricot production, tified in Dayton, ID, and Richmond and edible kernels, tolerance of cold temperatures spring frosts during flowering can often Thatcher, UT, by breeders at Improving during flowering and drought, and improved damage crops and limit production. Currently, Perennial Plants for Food and Bioenergy, rootstock performance. These characteristics the common cultivars grown in Utah include Inc. These selections are from germplasm have all been observed in the Central Asian material with tree health of a number of seed selections representing a significant improve- Table 4. Fruit characteristics of select Central Asian apricots accessions growing at the Rutgers University ment over current cultivars used in the region. Cream Ridge Fruit Research Station, Cream Ridge, NJ. Furthermore, the most promising Central Asian Avg ripening Avg Avg flesh Avg fruit Avg percent Avg seedlings have been crossed with improved Genotype no. date wt (g) firmnessz qualityz soluble solids crop loadz breeding selections from Rutgers University K22-227-98629 11 July 39.8 3.5 3.8 20.0 3.1 with progeny now undergoing evaluation in D79-51-98635 8 July 32.7 3.0 3.6 18.0 4.9 Thatcher and Hyde Park, UT. The overall goal D80-57-98649 10 July 55.0 3.0 3.0 17.0 3.8 is to improve reliability and consistency of crop D80-50-98649 22 June 56.0 2.8 3.0 11.0 4.3 yields in the region in addition to higher fruit D80-56-98649 6 July 58.5 2.8 3.8 13.0 3.0 quality, which should support an expansion K23-266-98651 18 July 24.0 3.0 3.0 22.0 4.0 of the industry as well as edible landscapes in K23-268-98651 16 July 33.0 3.5 3.0 23.0 3.8 Utah. DW2-100-99992 24 June 29.0 2.5 — 21.0 4.5 DT7-367-98812 5 July 62.0 3.0 3.5 16.0 2.8 zFrom 1 to 5; 5 is the best. Conclusions Apricot germplasm from Central Asia has many unique and useful characteristics such as a diversity of fruit flavors with high sugar content and extreme cold, drought, heat, and salt tolerance. These traits are very valuable to the future genetic improvement and wider use of the species. The breeding value of the Central Asian group has been demonstrated in the work of Ledbetter et al. (2006) with dramatic increases in the sugar content and fruit quality of California-adapted apricot varieties. Furthermore, the last six releases from the Rutgers University NJAES program each contain an appreciable amount of Cen- tral Asian germplasm in their pedigrees. More recently, by making a wide germplasm collection in Central Asian, well-adapted seedlings were identified that produce very high-quality, high sugar content, flavorful fruit of marketable size and yield (Table 4). Continued germplasm exploration and eval- uation would likely lead to the identification of additional improved material, which could ultimately lead to the expanded production of this high-value crop. Although access to Central Asia is increas- ing, loss of habitat and lack of regeneration of native populations resulting from human de- velopment and overgrazing, compounded by challenging economic times, is putting pres- sure on the existing in situ and ex situ pools of apricot genetic resources. Our article aims to shed light on these valuable resources to promote their improved use, management, and preservation. Increased study and intro- duction of P. armeniaca from the genetically diverse wild and cultivated germplasm found in Central Asia will facilitate the development of new cultivars with improved fruit charac- Fig. 2. Example of fruit diversity from Central Asian trees growing at the Rutgers University Fruit teristics. Traits such as high sugar content, Research Station, Cream Ridge, NJ. Accession numbers are as follows, clockwise from upper left: elevated Brix levels, unique flavor and aroma, DT3—348; D85—47; DT4—306; unspecified fruit on tree; DT10—327; DT3—349. edible kernels, and disease resistance will be
HORTSCIENCE VOL. 48(6) JUNE 2013 689 valuable for breeders working to develop Food and Agricultural Organization of the United Kostina, K.F. 1978. Apricot breeding under condi- trees with high quality fruit while helping to Nations. 2013. Agricultural production, crops tions of the U.S.S.R. south. Acta Hort. 85:190– decrease vulnerability to existing and emerg- primary apricots. 22 Jan. 2013.
690 HORTSCIENCE VOL. 48(6) JUNE 2013 National Climate Data Center. 2013a. National plum and apricot], p. 136–141. In: Mat. resp. U.S. Department of Agriculture. 2012b. Fruit and Oceanic and Atmospheric Administration, nauchno-praktich. Konf. ‘‘Botanicheskiye tree nuts situation and outlook yearbook 2011. Freehold–Marlboro, NJ, station. 10 Feb. 2013. issledovaniya v Kirgizstanye’’ [The repub- 20 June 2012.
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