To study the QTL mapping of seed weight per plant,which is beneficial to increase the yield of soybean.In this study,the BC3 F3 population is a chromosome segment substitution lines which constituted by 161 lines,with the wild soybean ZYD00006 as donor parent and the cultivar Suinong 14 as recurrent parent,selfing and backcross continuously for several years.The genetic background of this population relatively consistent,which reducing the interference greatly and improving the accuracy of QTL mapping.The QTL mapping was combined by ANOVA Method and T-test for independent samples.A total of 9 QTLs underlying seed weight per plant were detected which distributed on 7 linkage groups.Three QTLs were detected by both methods,including QSW-J-1,QSW-J-2,QSW-G-1.2 QTL were in accord with known results.Another 7 ones were the new discovery QTL,which should be specific loci in our materias.The fragment length of QSW-J-1 was 7.0 cM,and the additive effects of it is-2.7 g,which could be used as the first choice loci for further study.

A soybean backcross population was constructed using Suinong 14(recurrent parent)and wild soy-bean ZYD00006(donor parent). 23 QTLs(4 with positive effects,19 with negative effects)for oil content on 11 linkage groups were detected by One - way ANOVA at 0. 01 level. Compared with recurrent parent Suinong 14,13 BC3 F3 lines had higher oil contents and 20 BC3 F3 lines had lower oil contents. These 33 lines were selected to con-struct a selective population. Based on this selective population and random population(control),25 QTLs for oil content on 15 linkage groups were found by Chi - square on genetic hitchhiking,among them 11 QTLs had positive effects,and 14 QTLs had negative effects. Total 34 QTLs were found by these 2 methods. Among them,14 were detected in both methods,and 11 were newly found.

The hitchhiking effects in the advanced wild soybean chromosome segment substitution lines with selection under100-seed weight conditions were analyzed by scanning multiple molecular loci. The lociare connected with 100-seed weight and their response in selection condition were analysized. 28. 10% of the loci in random population were detected with segregation distortion( P 0. 05),after selection in view of 100-seed weight,the segregation distortion of allelic genes was reduced but the degree of segregation distortion increased. The segregation distortion ratio reduced to 4. 13% and 23. 14%,the variation of chi-square reduced to 0-166. 67 and 0. 01-81. 30. Twelve putative 100-seed weight related loci were obtained using chi-square test( P 0. 05) by comparison of the introgressive frequency of alleles between random population and selected population.