Pod And Seed Traits QTL Analysis Of Offspring Gained By Crossing Glycine Max With Glycine Soja

Pod and seed traits are important components of soybean production; more flowers and pods are important factors in soybean fertility. With more flowers and pods, high reproductive coefficient and abundant genetic diversity, Glycine soja, which is the near relative wild species of Glycine max, can be used for exploring superior pod and seed traits QTLs by molecular marker analysis and assist high-yielding breeding. In this study, F2 mapping population was gained by hybridization with U.S. cultivar 06-17 as paternal and Nanjing local wild species Jiangpu wild soybean-5 as maternal. F2 genetic map of soybean was constructed by mapping software Joinmap 3.0. On this basis, pod and seed traits, such as NBP, NEP, TNP, WPPS, and WPHS, were Located and analyzed by software WinQTLCart 2.5 in F2 and F2:3 families, respectively. The main results are as follows:1,507 pairs of polymorphic primers were obtained by polymorphism inter-screening of parents from total of 1007 pairs of SSR primers gained from Soybase’ website and 300 pairs of EST-SSR primers provided by Wang Yufeng, respectively. It showed high polymorphism with 38.8% of total primers. Polymorphic analysis of the 222 SSR marker loci in F2 population showed that the paternal type, maternal type and hybrid-type banks, respectively, with 24.2%,24.7% and 48.5% of total number, fitted for the regularity of 1:2:1 separation inχ2 testing. But for each marker locus,77 loci,34.7% of the total number segregation distorted in population, showing a more high percentage of segregation distortion.2, A genetic map of soybean was constructed by 222 SSR markers results. It contained 26 linkage groups and 205 SSR markers, with an average distance of 11.45cM between adjacent markers and spanning 2222.05cM of Kosambi map distance across 26 linkage groups. The linkage group lengths were ranged from 24.39 cM (E-a) to 183.08cM (Dlb). It contained 2 to 18 markers and an average of 8.5 markers in each linkage group. Compared with the "public map",26 linkage groups can be most marked with the order of the map, but the linkage group E, F, L and M were both divided into two parts; most linkage groups appeared gaps of longer than 20cM. There were 3 gaps in linkage group C2 and one gap of 42.92cM in Satt659-Satt425 interval of linkage group F-a. In order to obtain dense and accurate genetic map, further encryption study is needed.3,27 pod and seed traits QTLs were detected in generations of F2 and F2:3 families with a threshold of 3.0, distributing on linkage group A2, B1, B2, C1, E-a, F-b, H, I, L-b, N, and all showing dominance effects. By analysis, it indicates that:(1) Additive effects of QTLs detected in two generations showed a certain degree of regularity. Additive effects of NBP and WPHS QTLs were positive, and the value of two NBP QTLs were 2.27,2.39, higher than that of 0.24-0.63 in WPHS, while additive effects of NEP, TNP and WPPS QTLs were negative. Except NBP, it reflects the nearly conclusion with comparison of pod and seed traits’mean between F2, F2:3 families and parents. (2) Many traits QTLs with the phenomenon of concentrated distribution, mainly distributed on the linkage group I, L-b and H. It shows well corresponding results with pod and seed traits correlation analysis results. (3) 3 QTLs, qNEP-l-1, qTNP-l-1, qWPPS-l-1, detected in two generations, were both in the vicinity of Satt678 located in linkage group L-b, with higher LOD values (3.82-7.34), contribution rate(5.35-12.32).They may be the stabilize expression main effect QTLs. In addition, QTLs, qNEP-h-1, qTNP-h-1 and qWPHS-h-1, were detected in F2:3 families both distributed on linkage group H, respectively, with contribution rates of 17.71%,17.71% and 17.25%, LOD values of 8.62,8.47 and 8.25. qWPHS-h-1 showed tiny synergistic effect of 0.46 from 06-17 (paternal) allele, and qNEP-h-1, qTNP-h-1 showed efficient synergistic effect of-36.86,-38.48 from Jiangpu-5 wild soybean(maternal) allele. QTLs, qNEP-l-1,qTNP-l-1,qNEP-h-1,qTNP-h-1,qNEP-e-1,qNEP-f-1,and qTNP-f-1, existed in nearly the same corresponding marker interval, with high contribution rate, high LOD, synergistic effects of maternal, or detected in the two generations, indicates that they are the probably superior pod and seed traits QTLs worthy further studying.