Tuesday, September 11, 2007 - 1:15 PM

QTL Analysis of resistance to verticillium wilt  using Gossypium hirsutum´G. barbadense backcross populations

Dr. Baocai Zhang, Mr. Junwen Li, Mrs. Aiying Liu, Ms. Yuzhen Shi, Ms. Yanhua Shao, Mr. Jianhong Zhang, Ms. Liang Jia, and Prof. Youlu Yuan. Cotton Research Institute, CAAS; Key Laboratory of Cotton Genetic Improvement, Ministry of Agriculture, P R China, yellow river road,development district, anyang, henan, 455004, China

In order to introgress elite alleles of Gossypium barbadense L. for resistance to verticillium wilt into G. hirsutum L, the elite G. hirsutum cultivar ‘CCRI36’ and G. barbadense ‘Hai1’ were used as recurrent and donor parent, respectively, to produce BC1, BC1S1 and BC2F1 populations. After screening the two parents and F1, 226 SSR primer pairs were used to screen the BC1F1 population. Linkage test indicated that 220 loci could be mapped to 32 linkage groups and covered a total genetic distance of 2408 cM. Twenty three QTLs for verticillium wilt were identified in the BC2F1 and BC1S1 generations, 17 for disease index, and 6 for the ratio of susceptibility. Each QTL could explain 6.4%  to 24.5% of the phenotypic variance. One QTL for disease index on linkage LG17 was detected in the BC2F1 verticillium wilt nursery and in the BC2F1 and BC1S1 field populations, which could explain 24.5% of the phenotypic variance, suggesting stable genetic effects for resistance to verticillium wilt. This QTL should by useful in marker assisted breeding.