Mapping QTL Governing Seed-Related Traits By Associated Recombinant Inbred Line Population

Seed related traits are controlled by multiple genes and affected by environment s in soybean, which make the selection by phenotype more difficult in improving seed traits. So mapping QTL controlling seed related traits is of importance for yield breeding in soybean. With the objective of detecting stable QTL across to various environment, three parents with significant difference in seed related traits were applied to mate two crosses, ie. Dongnong L13 × Heihe36 and Dongnong L13×Henong60, by which two recombinant inbred line(RIL) population, i.e. RIL3613 and RIL 6013, were derived include 134 and 156 lines, respectively. The two RIL were planted in three environment, i.e. Harbin in 2014 and 2015, and Keshan in 2015, to collect phenotypic data of seed length(L), seed width(W), seed thickness(T) and 100 seed weight(SW). QTL analysis were conducted under modle with additive, epstatistic and genotype by environment interation effects implemented by inclusive interval mapping(ICIM) method and mixed model composite interval mapping(MCIM) method. The results are listed as following.(1)By inclusive interval mapping(ICIM) method, 40 QTL underlying seed related-traits were detected in two RIL, which include 10 L QTLs, 12 W QTLs, 9 T QTLs and 9 SW QTLs. In RIL3613 21 QTLs distributed on linkage B1、B2、C1、D1a、D1b、F、I、J、L、O, and in RIL6013 19 QTL distributed on linkage A1、A2、B1、B2、C2、D1b、E、J、K、N、O. LOD arranged from 2.50 to 8.64, phenotypic variation rate of explanation(PVE) ranged from 8.86% to 67.54%. Among all the QTLs, 6 L QTLs, 4 W QTLs, 6 T QTLs and 6 SW QTLs could be detected repeatedly. There were totally 87 epstatistic QTLs were detected which include 39 epstatistic QTLs controlling L, 4 epstatistic QTLs controlling W, 17 epstatistic QTLs controlling T, 27 QTLs controlling SW with LOD of 5.00~7.95 and PVE of 16.53%~79.44%. Among the whole QTLs, 24 L QTLs,1 H QTL and 10 SW QTLs were identified repeatedly.(2)By mixed model composite interval mapping(MCIM) method, 5 QTLs governing seed-related traits were detected from linkage C1、D1a、L in RIL3613 which include 1 L QTLs, 2 T QTLs and 2 SW QTLs with main effect PVE of 4.92%~7.07% and genotype by environment interaction PVE of 0.09%~0.73%. Among all QTLs, 1 T QTLs could be detected repeatedly. There were totally 23 paires of epstatistic QTLs were detected which include 4 epstatistic QTLs controlling L, 10 epstatistic QTLs controlling W, 2 epstatistic QTLs controlling T, 5 epstatistic QTLs controlling SW with main effect PVE of 0.13%~11.65% and genotype by environment interaction PVE of 0.13%~11.65%. Among the whole QTLs, 1 T QTLs and 4 SW QTLs were detected repeatedly.