Abstract:

Seed and pod traits are important factors affecting soybean yield, which are controlled by polygenes. The previous studies have identified many QTLs associated with yield and its component. The previous genetic analysis also pointed out that improving the seed and pod traits was an efficient way to increase soybean yield, but there was little QTL analysis on seed and pod traits. In order to find out steady and repeatable QTLs of these traits, 255 recombinant inbred lines (RILs) derived from the cross between Zhongdou 29 and Zhongdou 32 were used to map QTLs of seed and pod traits in two years. ANOVA analysis showed that the characters of one-seed pod, four-seed pod, and number of seeds per pod had significant year-line interaction in two years, while number of pods and number of seeds had not. A genetic linkage map of soybean genome was constructed, which consisted of 23 linkage groups with 98 SSR markers. The Interval Mapping method(IM) and Composite Interval Mapping method(CIM) were used to identify QTL associated with one-seed pod, four-seed pod, number of pod, number of seeds, and number of seeds per pod. A total of 51 QTLs for these traits were identified in two years using different statistic methods. Among them, 24 QTLs explained the phenotypic variance ranging from 5% to 80% by using interval mapping method, and 27 QTLs accounted for 4% to 73% of the variance for the 5 traits using CIM. Tow QTLs of four-seed pod and tow QTLs of number of seeds per pod were found in tow years with different methods. These results can be used for the further fine mapping and marker assisted selection of these traits.

Key words: Soybean, Seed and pod traits, Four-seed pod, Number of seeds per pod, QTL analysis