Mapping boron efficiency gene(s) in Brassica napus using RFLP and AFLP markers

Soil boron (B) deficiency, a world‐wide problem in agriculture, exists for more than 33 million hectares of cultivated land in China. Genetic variation exists for B‐efficiency among different Brassica napus germplasms. To identify genes controlling B efficiency, an F₂ population of B. napus was constructed from a cross between a high B‐efficiency cultivar, ‘Qingyou 10’, and a low B‐efficiency cultivar, ‘Bakow’, and then evaluated for seed yield, bolting date and maturity date under B‐deficient conditions. The ratio of high B‐efficiency to low B‐efficiency individuals fitted the expected ratio of 3:1, indicating a major gene controlling the B‐efficiency trait. The major gene was mapped in the ninth linkage group of B. napus. Genome‐wide quantitative trait loci (QTL) analyses detected one major locus near the major gene, which explained 64.0% of the phenotypic variance. At the same time, three minor loci in three linkage groups were also detected, and these minor loci individually explained 39.2%, 32.5% and 36.9%, respectively, of the phenotypic variance. A total of 11 QTLs were detected for bolting date and maturity date, some of which were associated with B‐efficiency.