Abstract:

Oilseed rape is one of the most important oil crops in China, and its oil content is a very important quantitative trait, which is easily affected by environment. Oil content in seeds of oilseed rape is mainly controlled by genes and affected by the interaction of genotype and environment. In the present research, a low oil content line APL01 (Brassica napus L.) was crossed with a high oil content line M083 (B. napus L.) to develop six basic populations (P₁, P₂, F₁, B₁, B₂ and F₂) for analysis of the genetic model. Results showed that seed oil content in this cross was controlled by an additive-dominance major gene plus additive-dominance-epistasis polygene. The heritabilities of major gene were 38.37%–47.16%, while those of the polygene were 24.29%-38.28%. A genetic linkage map of Brassica napus L. was constructed by BC₁F₁ and 251 molecular markers, which contained 19 linkage groups. Five QTLs, qOC1, qOC8, qOC10, qOC13-1 and qOC13-2, related to seed oil content were identified from this cross by WinQtlCart 2.0. qOC1 was located in the region of m19e21c–A0214Ra142 on linkage group N1, which could explain 5.21% of the oil content variation in the population. qOC8 was located in the region of A0216Gb206-m5e42 on N8, and accounted for 6.34% of phenotypic variation. qOC10 was located between m15e48 and A0228Bb437 on linkage group N10 and explained 9.45% of phenotypic variation. qOC13-1 was located in the region of A0224Rb157–A0301Gb399 on linkage group N13, and accounted for 18.12% of phenotypic variation. qOC13-2 was located in the region of A0226Ba377–A0226Ba367 on linkage group N13, and accounted for 10.17% of phenotypic variation. Among these five QTLs, the positive effects of qOC10 and qOC13-2 loci for oil content were from APL01, while those of qOC1, qOC8 and qOC13-1 loci from M083. The qOC13-1 with larger phenotypic effect could be regarded as major gene locus, and other four QTLs with relative smaller effects could be regarded as polygene loci.

Key words: Oilseed rape, Oil content, Inheritance, QTLs