Abstract:

To identify quantitative trait loci (QTL) related to oil, protein and glucosinolate content and elucidate the relations among them, we analyzed several traits of two F₂ populations derived from the original cross and a reciprocal cross betw een high-oilcontent lines 8908B and R1 in Brassica napus. Oil and protein content showed a significant correlation in both populations (r = -0.68 and r = -0.81, respectively; P<0.01). Protein and glucosinolate content showed a significant correlation (r = -0.45; P<0.01) in the F₂ population of the reciprocal cross but not in the F₂ population of the original cross. We constructed a genetic linkage map on the basis of 118 F₂ plants of the original cross. The map was made up of 21 linkage groups, including 121 markers, covering 1 298.7 cM. A composite interval mapping method was used to map QTL related to the three quality traits. Two QTLs related to oil content were detected on LG8 and LG10 and accounted for 4.8% and 13.7%, respectively, of the phenotypic variation, and R1 had a positive effect on both loci. Two QTLs related to protein content, pro1 and pro2, were identified on LG1 and LG3 and accounted for 15.2% and 14.1%, respectively, of the phenotypic variation. 8908B had a positive effect on pro1 loci, and R1 had a positive effect on pro2 loci. Four QTLs related to glucosinolate content were detected. Among these, glu1 and glu2 located on LG20, glu3 located on LG4, and glu4 located on LG8 accounted for 1.9%-25.4% of the phenotypic variation. R1 had a positive effect on glu1, and 8908B had a positive effect on the other three loci.