Genetic Dissection of Isoleucine and Leucine Contents in the Embryo and Maternal Plant of Rapeseed Meal Under Different Environments

The genetic basis controlling the content of two essential amino acids (isoleucine and leucine) in rapeseed meal was investigated through a replicated trial of the two BC1F1 populations from a two-way backcross between 202 TN DH population strains and their parents (‘Tapidor’ and ‘Ningyou7′). Given the impact of rapeseed embryos and maternal plants on seed qualities, a multi-genetic-system QTL mapping method was employed, incorporating both genetic main effects and environmental interaction effects. The results demonstrated the presence of nine QTLs associated with isoleucine and leucine content in the A1, A4, A5, A7, A9, and C2 linkage groups. These included six QTLs controlling isoleucine content and three QTLs controlling leucine content, which collectively explained 55.49% and 56.06% of the phenotypic variation, respectively. Of these, four QTLs were identified as the main QTL, which collectively explained over 10% of the phenotypic variation. All of the identified QTLs exhibited a highly significant additive and dominant effects on seed embryos. Additionally, one of the QTLs demonstrated had a particularly significant additive effect derived from the maternal genome. QTLs controlling isoleucine and leucine were identified in the A1, A4, and C2 linkage groups. Moreover, two QTL clusters influencing these essential amino acid contents were identified in the A4 and C2 linkage groups, situated between molecular markers HS-K02-2 and HBR094 and between EM18ME6-220 and NA12C03, respectively.