Inheritance Of Resistance To SMV, Cellular Ultrastructure Analysis And Resistant Gene Mapping In Soybean

Soybean mosaic virus(SMV)is a worldwide disease and occurs in different regions of China, resulting in the loss of yield and seed-quality. Using resistant varieties is the most economic and effective method to control SMV. Northeastern China is the main soybean production region in the country, but the germplasm with the resistance to SMV are rare. Therefore, it's very important to identify new resistant germplasm and study genetic relationship of resistant germplasm. Molelcular breeding is becoming more and more practical technology for plant breeding. The use of markers in plant breeding for indirect selection of resistance can favorably enhance breeding efficiency. In this study, we have demonstrated the inheritance of leaf resistance in Zhongxuan95-5117 to N3 strain of SMV and of leaf and seed coat resistance in Dongnong93-046 to N1 strain of SMV, as well as the correlation of resistance with agronomic traits. We analyzed the impact of SMV N1 and N3 on ultrastructure of leaf cells in different resistant varieties. We identified SSR markers closely linked to SMV resistant gene by the method of BSA and mapped them on soybean molecular linkage groups. Two genetic linkage maps were constructed using the crosses with resistant parents based on SSR markers. 70 soybean germplasm were screened for SMV resistance by the inoculation of SMV N1 and N3 strains, and the coincident rate of plant resistance to SMV and relevant molecular markers were evaluated using soybean germplasm and F3 progenies. The main results are summarized as followings:1. A cross of Zhongxuan95-5117(RN3)×HB1(S N3)was made and selfed to construct F5 and F6 populations with 117 RILs. The RIL populations were used to determine the inheritance for resistance to SMV N3. The segregation ratio of resistance and susceptivenese was 1︰1 , indicating that Zhongxuan95-5117 carried a single resistant gene for SMV N3 strain.A soybean line(Dongnong93-046)highly resistant to SMV N1 strian was crossed with susceptible variety(Hefeng25). Their F1,F2 and F2﹕3 individuals were identified for plant resistance by inoculation with SMV N1. The results showed that F1 was resistant to SMV N1. F2 population segregated in a ratio of 3 (resistant and necrosis)︰1 (susceptible ), and F2﹕3 population segregated in a ratio of 1 (resistant)︰ 2 (heterozygous)︰ 1 (susceptible), indicating that Dongnong93-046 carried a single dominant gene that confered plant resistance to SMV N1.A reciprocal crosses were made with Dongnong93-046 and Conrad to investigate the...