Youlu Yuan
Institute of Cotton Research- CAAS, China
Title: Genome wide QTL mapping for resistance to Verticillium wilt, fiber quality and yield traits in cotton chromosome segment substitution lines
Biography
Biography: Youlu Yuan
Abstract
The development of chromosome segment substitution lines (CSSLs) from Gossypium barbadense in G. hirsutum background provided ideal materials for further genome research and crop improvement through MAS. We had developed BC5F3:5 populations with the donor parent Hai1 and the recurrent parent CCRI36. In this study 300 CSSLs and their two parents were planted in a randomized complete block design with 2 replications in two ecological locations (Anyang and Xinjiang) in 2015 and 2016, respectively. Verticillium wilt resistance was collected at the time of July and August in the field. A total of 597 pairs simple sequence repeat (SSR) markers screened from 2292 pairs of markers in the high density map from a BC2F1 population of G. hirsutum × G. barbadense were used to identify the polymorphisms among the BC5F3:5 lines. A total of 56 quantitative trait locus (QTLs) for Verticillium wilt resistance were detected, 30 of them are stable, and 38 QTLs (68%) had negative additive effects, which indicate that the G. barbadense alleles increased Verticillium wilt resistance and decrease DI by about 2.64 to 13.23. By meta-analysis, 30 QTL hotspot regions for VW resistance were identified and 13 of them were new hotspot regions. 191 QTLs were detected for fiber yield and fiber quality, 98 for the fiber quality traits and 93 for the yield related traits, 54 of them are stable. Three chromosomes of Chr05, Chr10 and Chr20 contained more QTLs. 30 clusters with disease index and fiber related traits were identified on 16 chromosomes. Most of the fiber traits were clustered with the disease index stable QTLs. We found 6 clusters namely, C01-cluster-1, C05-cluster-4, C07-cluster-1, C19-cluster-2, C22-cluster-1 and C22-cluster-2, which had positive correlation between VW resistance and fiber quality traits. Two clusters, C10-cluster-1 and C25-cluster-1 had also positive correlation between VW resistance and yield related traits (boll weight and lint percentage). One cluster, C20-cluster-1 is important for VW resistance, fiber quality and fiber yield. So, these clusters and related QTLs are very important for breeding improvement of fiber quality and yield, VW disease resistance