Analysis of Difference QTLs for Oil Content Between Two Environments in Brassica napus L.

Based on the established genetic linkage maps of Brassica napus L., QTLs for difference in oil content between high latitude (Wanzhou, Chongqing, China) and low latitude (Beibei, Chongqing, China) environments were detected using the composite interval mapping model. The mapping populations, SWU-1 and SWU-2, contained 188 and 219 recombinant inbred lines, respectively. In the SWU-1 population, the oil content differences ranged from 0 to 18.66% between the 2 environments, and 2 difference QTLs were located in the linkage groups 6 and 7 with the phenotypic contributions of 10.3% and 12.4%, respectively. In the SWU-2 population, the oil content differences ranged from 0.43% to 17.17% between the 2 environments. Three difference QTLs were located in linkage groups 8 and 14, which explained 6.6–10.6% of the phenotypic variation each. The oil content difference was significantly correlated with growing environment (P < 0.01), and the coefficient of variation was 58.24%. This indicates the presence of environment-insensitive QTLs associated with oil content in rapeseed genotypes. In both environments, no visible linkage relationship was observed between QTLs for oil content difference and QTLs for oil content. Therefore, it is inferred that sensitive and insensitive genes to environment might have a different expression system to oil synthesis genes in Brassica napus L.