Genetic Analyzing And SSR & ISSR Molecular Tagging Of Gene Conferring Resistance To Race 4 Of Soybean Cyst Nematode (Heterodera Glycines) In Soybean (Glycine Max (L.) Merr.)

The soybean cyst nematode (Heterodera glycines Inchinoe,SCN) is among the mosteconomically desiructive soybean [Glycine mcu~ (L.) MelT.] pest throughout world~de.Race4hemostseriousoneamonganySCNmnChina.1tv~illbeconsidemble significance in the research of disease prevention and breeding in soybean to study resistant genetic mechanism for race 4 of SCN and to make molecular tagging and mapping for resistance gene.The Ymgxianxiaoheidou, a local gennplasm of Shanxi, exhibits good resistance to race 4 of SCN. In this study the resistant evaluation was made in F2 population fromingxianxiaoheodou X fendou 50?by the plastic bags.The same materials were employed as map population for SSR and ISSR molecular tagging with the method of Bulked Segregant Analysis(BSA) The puipose of this study was to realize markers-assisted selection(MAS) in developing resistance cultivars to SCN of soybean.The main results as follows:1. Two method for evaluating the resistance to race 4 of SCN, the standard strain methodand the number of cyst method, are used. The Yingxianxiaoheidou resistance to race 4 of SCN is conirolled under 1 or 2 couples of recessive allele (rhgX) in F2 population from mgxianxiaoheodou X fendou 50 ?The result of this study is consistent with predecessors?Study showed that F2 from mgxianxiaoheodou X fendou 50 an be used for molecular tagging .These resistant genes have been defined as. By analysis of agmnomic character, a morphological marker linked with rhgX~ namely seed coat color marker Qingse, has been acquired.2.Two molecular markers linked with rhgX was sereened by molecular tagging techneque of SSR and ISSR: SattO38 whose lengths are I 8Obp and 1 85bp and Issr8 11 whose length is 350bp.The SattO38 attributed to SSR marker shows codominance whose segregation ratio is 1:2:1 in F2 population; The Issr8ll attributed to ISSR marker shows dominant character whose segregation ratio accords with 1:3 in two F2 populations.Both of the molecular markers follow Mendel laws.3.Genetic analyzing, SattO38, Issr8l I and Qingse, approximately 26.9, 10.2 and 35.2cM distal of rhgX, respectively. When we compare the result of resistance Identification to SCN with molecular markers, SattO38 and Issr, and morphological marker Qingse, the conform ratio is 98%, 900/a and 75% respectively. Study showed that SattO38 and Issr8 11 may be used for molecular marker assistant breeding of resistant gene (rhgX) to SCN.4.The genetic mapping of members of markers whose sequences is StattO38-rhgXIssr8 11 -Qingse localizated on molecular linkage group G of soybean. The rhgX is a new resistant loci to SCN which is different with rhgl.