Genetic Relationships Among Peanut Cultivars and Breeding Lines in Shandong Province, PRC H.Q
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HYDROLASE ACTIVITY IN TRANSGENIC PEANUT 95 Genetic Relationships Among Peanut Cultivars and Breeding Lines in Shandong Province, PRC H.Q. Xue* and T.G. Isleib' ABSTRACT Zhan Yang from which 67, 28, 27 and 19 lines were Shandong province is the leading peanut-producing derived, respectively. Among the 20 dominant cultivars province in China which in turn is the leading peanut of Shandong province, recently released cultivars Lu producing country in the world. Shandong Peanut Hua14and Lu Hua 15have the lowestaverage coancestry Research Institute (SPRI), an institute ofthe Shandong with the others which means those two new cultivars' Academy of Agricultural Science, has had an ongoing have the high genetic divergence. In contrast, the very breeding program for more than 40 yr and is the source popular cultivars Fu Hua Sheng, Baisha 1016, Xuzhou of the peanut cultivars that dominate production in 68-4, Lu Hua 9, and the new cultivar 8130 were closely Shandong province and northern China. About 75 related to the other cultivars. The results suggest that peanut cultivars and breeding lines have been released the genetic base of Shandong peanut cultivars released in Shandongby SPRI and otherinstitutions. The genetic before 1990 is narrow, but that cultivars released after base of Shandongpeanutcultivars has beendescribed as 1990 have broadened the genetic base due to introduc narrow. The objective of this studywas to (a) determine tion and use of new germplasm in the pedigrees. This the geneticcontribution of main ancestors to the genetic information will be used as a guide for peanut breeders base of Shandong peanut cultivars and (b) study the in choosingparents and avoiding geneticvulnerabilityto genetic relationships among the peanut cultivars re pests. For new cross combinations, parents with low leasedin Shandongprovinceduring 1950-1999. Twenty coefficients of coancestry should be chosen in order to six ancestors were identified in the pedigrees of 69 keep enlarging the gene pool of the new cultivars. improved lines, 24 ancestors of Chinese origin contrib uted 96.1% of the Shandong peanut genetic base, and two exotic introductions contributed only 3.6%. The Key Words: Arachis hypogaea L., coefficient of four most important ancestors based on average coancestrywith the69 improvedlines are Fu HuaSheng coancestry, genetic base, genetic vulnerability. (PI 436545), Shi Tou Qi (PI 430227 and PI 461435), Jianggezhuang Ban Man (PI 433351), and Shuyang Da Shandong is the leading peanut-producing province in 'Res. Asst. and Prof., Dept. of Crop Science, North Carolina State China, which in turn is the leading peanut-producing coun Univ., Raleigh, NC 27695-7629. try in the world. Shandong's annual area under peanut *Corresponding author (email: [email protected]). (Arachis hypogaea L.) is 23% ofthe total for China, and the Peanut Science (2002) 29:95-10IPeanut Science (2002) 29: 95-101 96 PEANUT SCIENCE province's production is 31% of the national total (He, parents to initiate new breeding populations to serve as 1996). Shandong is the central province in the northern sources ofnew cultivars (Manjarrez-Sandoval et al., 1997). Chinese peanut-producing area which includes Shandong, The objectives of this study were to (a) determine the Henan, Hebei, Liaoning, northern Jiangsu, and southern genetic contribution ofmain ancestors to the genetic base of Shanxi provinces and lies between latitudes 32°N and 42°N Shandong peanut cultivars and (b) study the genetic rela and east of longitude 107°E. Peanut is grown in several tionships among peanut cultivars and breeding lines in different production systems in Shandong, either as a full Shandongprovince. This informationwillbe usedas a guide season sole crop or as a rotation crop with wheat (Triticum for peanut breeders in choosing parents and avoiding ge aestivum L.), watermelon (Citrullis lanatus L.), or veg netic vulnerability to diseases and pests. etables. About 60% of the Chinese peanut crop is crushed for oil and the meal fed to animals, and the remaining 40% is used for direct human consumption or for export. Peanut Materials and Methods stover is commonly dried as hay and used as winter feed for The 75 peanutcultivars and breedinglines in the analysis ruminant livestock. (Table 1) included officially released cultivars, lines not ShandongPeanutResearch Institute (SPRI), an institute officially released but distributed to and widely grown by ofthe Shandong Academy ofAgricultural Science, has had farmers, breeding lines heavily used as parents in cultivar an ongoing breeding program for more than 40 yr. SPRI is development, and breedinglines releasedas germplasm. Of the source of the peanut cultivars that dominate production the 75, 47 were developed at SPRI; 16 were developed at in Shandong province and the rest of the northern Chinese otherinstitutes of Shandong province; andtwo, Xuzhou 68 peanut production area. About 75 peanut cultivars and 4 and Baisha 1016,weredevelopedinJiangsu and Guangdong breedinglines have been releasedin Shandongby SPRI and provinces and introduced to Shandong where they eventu other institutions. Among these, Fu Hua Sheng, Hua 17, ally became very important cultivars. Hua 28, Hua 37, Xuzhou 68-4, Baisha 1016, Hai Hua 1, and The 75lines includethree Chineseplanttypes-virginia Lu Hua 9 are the most important in terms ofthe extent of type (alternate-branching forms typical of subsp. hypogaea their cumulative cultivated areas. Lu Hua 14 and 8130 are vars. hypogaea andhirsuta Kohler); spanish-type (typical of new cultivars that show promise ofsimilar broadacceptance subsp.fastigiata Waldron var. vulgaris Harz); and middle by Shandong's peanut growers. type, a type intermediate to virginia and spanish based on Genetic vulnerability and its converse, genetic diversity growth habit and pod characteristics. Among the 75 lines, of crop species, have become global issues. Lack ofgenetic one was alandrace (Fu HuaSheng), four were selectedfrom diversity among the cultivars ofa crop makes it vulnerable to unidentified landraces (Qun Xuan .5, Xie Kang Qing, Zhong epiphytotics and widespread depredation by insect pests. Xuan 48, and Zhong Xuan 65), and one was a line for which Genetic diversity in crop species is generally assessed using there was no further pedigree information (Chang Da 6). some measure of distance or similarity among cultivars The remaining 69 were improved lines including seven based on one or more ofthree main types ofdata-pheno selected as naturally occurring variants within landraces (Xi typic data, genetic markers, andpedigree-basedmeasures of Xuan 7,ZhongXuan62) orcultivars (ShuangJi2, LuHua10, degree of relatedness. Thefirst two methods require that all Lu Hua6, PengXuan 2, and QiXuan2); three were selected pertinent cultivars be assembled and data collected. In the following mutagenesis (ChangHua4, Lu Hua7, and Lu Hua case ofphenotypic traits, testing must be sufficiently exten 12); and 59 were selected following hybridization. sive to provide confidence in the results. In the case of Details of pedigree information for most cultivars have marker data, there must be a large number of markers been published (SPRI, 1983; Gu and Xue, 1997). Some exhibiting polymorphism within the population. Either pedigree and related data information are from crop regis methodis resource intensive. In contrast, pedigree dataare trationinformationand personalcommunications. Ancestry widely accessible and generallyaccurate, andits use does not was traced back until no further information was available. require that the cultivars themselves be in hand for analysis, Each line was assigned to a "breeding level" depending on Following thesoutherncomleafblight [Bipolarismaydis how manycyclesofcrossingand selectionthe linewasremoved (Nisikado & Miyake) Shoemaker] epiphytotic of1970 in the from the ancestral lines. In this system, ancestral lines were United States, the U.S. government sponsored studies on assigned to Level 0, lines selectedfrom Level 0 ancestors, or the level ofgenetic vulnerability ofmajor U.S. crops. Most from crosses between Level 0 lines were assigned to Level were found to have fairly narrow genetic bases, including 1, and so on. Each line was assigned to the level one above peanut (Hammons, 1972, 1976). Knauft and Gorbet (1989) that of the higher ofits parents. The genetic contribution of found that use ofmore diverse parentage in development of an ancestor to a modem cultivar or line was determined as new runner- and virgina-type cultivars after 1976 had some the fraction of genes in the modem cultivar that could be what broadenedthe genetic base ofpeanuts in the U.S., but traced to an ancestor through pedigree analysis (Gizlice et that the average coancestry among seven of eight runner al., 1996). Coefficientof parentage (e) was usedto make this type cultivars released after 1976 was 0.32, between the determination and is defined as the probability that a ran values for half- and full-sibs. Similar studies have not been dom allele at any locus in one cultivar is identical by descent performed on most crops in China, soybean beingan excep to a random allele at the same locus in the second cultivar tion (Cui et al., 2000a,b). Such studies provide breederswith (Malecot, 1948; Kempthorne, 1969). Techniques for the useful information regarding the risks inherent in the re calculation ofeare widely known. Ifthe parents oflines X lease of new cultivars closely related to existing ones. They are A and B, and the parents