Identification of two major QTL for yellow seed color in two crosses of resynthesized Brassica napus line No. 2127-17.

Yellow seed color, which results from a thinner seed coat, is associated with improved feed quality of rapeseed ( Brassica napus L.) meal and increased oil and protein content. As this trait follows various genetic models under different genetic backgrounds, a study was performed in two genetic backgrounds to gain a better understanding of the genetic mechanisms underlying yellow seed color. The quantitative trait locus (QTL) analysis was undertaken using two crosses, Quantum ×No. 2127-17 (HZ-1) and No. 2127-17 × 94,570 (HZ-2). In the HZ-1 population, three putative QTL were detected in linkage groups N18, N5, and N3, respectively. For all of them, yellow seed color arose from the No. 2127-17 alleles. Of these QTL, the one in linkage group N18 ( Bnsc- 18a) explained more than half of the phenotypic variation. In the HZ-2 population, three QTL were found in linkage groups N9, N18, and N8, respectively. Of these QTL, that in linkage group N9 ( Bnsc- 9a) explained more than half of the phenotypic variation, whereas the QTL Bnsc- 18a had a low seed color value and explained only 9.03-11.72% of the phenotypic variation. Bulked segregant analysis (BSA) of the extremes of a BC1 population derived from the cross of No. 2127-17 × 94,570 (HZ-3) identified one major gene that was identical with the QTL Bnsc- 9a detected in the HZ-2 population. The QTL Bnsc- 18a was common in the HZ-1 and HZ-2 populations, and the others were population-specific. These results suggested that different black-seeded forms had different seed color genes. [ABSTRACT FROM AUTHOR]