Molecular marker analysis of the linkage drag around the FAE1 loci of Brassica juncea during conventional backcross breeding

A post-transfer investigation was carried out to analyze the process of gene introgression in a conventional backcross-breeding program taking low erucic acid as target trait in Brassica juncea. FAE1 locus is involved in the elongation of oleic acid (C18:1) to erucic acid (C22:1). A high concentration of erucic acid in the seeds of Brassica species has been reported to be nutritionally undesirable. Molecular markers like AFLP markers, microsatellite markers, and gene-based SNP markers were used to determine the size of the donor parent chromosomal segments retained around the FAE1 genes in the individuals selected from different backcross generations. The genotype of the individuals was inferred from the genotype of the markers and the graphical genotypes were constructed using GGT software. Molecular marker analysis led to the identification of rare recombinants near the target locus with reduced size of introgressed segment from the donor parent. Based on the present study, we propose that marker-assisted backcross breeding in B. juncea could prove to be a promising tool for the transfer of many quality traits from unadapted East European germplasm to Indian cultivars.