QTL Mapping Of Important Yield Traits In Soybean Population

Genetic linkage map provides plant genetists with a powerful tool for the analysis of plant genome structure and function in soybean.A cross of Liaodou14 and Tiedou46 was made,and then self-pollinated for 6 generation by single seed descent method to construct a RIL population containing 138 lines.A SSR markers-based genetic map of this population was constructed and QTL analyses of some important agronomic traits were also carried out at five locations in two years.Results of these studies were as follows:1.A genetic map based on SSR markers was constructs with this population.It covered 20 linkage groups and contained 149 SSR loci.The total length of the map was 1433.52 c M and the average distance was 9.04 c M.The number of markers on each group ranged from 4 to 15,and the length of each group ranged from 25.45 to 133.27 c M.This map fitted the public integrated genetic map well both in the sequences and the distances of markers.2.Complete interval mapping method of Ici Mapping were used to detect QTL concerning plant height,nodes of main stem,podding height,pods of main stem,one-seed pod number,two-seed pod number,four-seed pod number,100-seed weight and seed weight per plant.When LOD >2.5,a total number of 42 QTL were found on 12 groups of consensus soybean map.Most of the QTL were clustered,especially on group D1 a,D1b,I and N.Some QTL were mapped to the same loci,it means that QTLs were reliable in different environments.3.Two QTLs of plant height were detected on group D1 a and O and explained more than 20% of phenotypic variation.The one on group O named q Ph-O-1 was detected in two environments.Two QTLs of nodes of main stem were detected on group A1 and O,the one on group O was detected in four environments.Three podding height were detected on group D1 b and explained from 3.46% to 29.54% of phenotypic variation.Four QTLs of pods of main stem were detected on the group D1 b,O and J.Two QTLs on the group J were located on the same interval.Seven QTLs of one-seed pod number were detected on group D1 b,N and I.The main effect QTL named q Ospn-D1b-3 was located in two environments and explained more than 30% of total variation.Seven QTLs of two-seed pod number were detected on group D1 b,F,G N and I.The main effect QTL named q Tspn-D1b-3 could explain 45.31% of total variation.Seven QTLs of four-seed pod number were detected on group D1 a,D1b,N and I.Three QTLs of 100-seed weight were detected on group A2,D2 and D1 a and explained less than 10% of total variation.Five QTLs of seed weight per plant were detected on group D1 b,N,I and J and could explain the total variation from 9.82% to 28.74%.4.The gene of resistance to continuous cropping also were detected in this study on group H and I and could explain less than 10% of total variation.