Abstract:

【Objective】 Mapping and conforming a major QTL for oil content in linkage group 7 using BC3F1 population in Brassica napus L. 【Method】 QTL-near isogenic lines (NILs) were developed by marker assistant selection on the basis of primary QTL analysis with SG-DH lines. 1700 BC3F1 plants, containing corresponding marker genotypes on A7 and trait phenotypes of oil content, were used for fine mapping oil QTL and association analysis between the marker genotypes and the trait (oil content) performance on A7 by software WinQTLCartographer 2.5 and SPSS11.5. 【Result】 The confidence interval of oil content QTL was located between the markers ZAAS849s and R131, which range about 21.7 cM and the peak value of LOD was 9.71. The distances between QTL and the nearest flanking markers RPSaA3 and ZAAS839 were 0.9 and 2.1 cM, respectively. The additive effect of QTL was 0.75, with Chinese allele increasing oil content. Marker-oil content association analysis (ANOVA) indicated that the oil content showed a significant difference among the three types of marker genotypes in each loci within QTL region (four markers), of which the marker ZAAS839 showed the largest P value (P=1.2×10-10). 【Conclusion】 QTL position identified by mapping analysis using BC3F1 population was overlapped with primary QTL identification using SG-DH lines, however, the confidence interval was clearly decreased. The most probable QTL position is in the region near the markers RPSaA3 and ZAAS839. The genetic distance between RPSaA3 and ZAAS839 is about 3 cM.

Key words: Brassica napus L., oil content, QTL-NILs, QTL-mapping