Inheritance and molecular markers for the seed coat color in Brassica juncea

To elucidate the inheritance of seed coat color in Brassica juncea, Sichuan Yellow inbred (PY) was crossed with the Ziyejie inbred, and their F₁, F₂ and BC₁ and BC₂ progenies, derived from backcrossing to PY, were phenotyped for seed coat color. Results showed that the yellow seed coat was controlled by two independent recessive loci. Seven brown-seeded near-isogenic lines were developed by successive backcrosses to PY and by selfing. One of the BC₆F₂ populations segregated for a single locus controlling seed coat color was used for mapping. Using the 88 primer pairs from sequence-related amplified polymorphism and the 500 random primers, two markers were found to be linked to the gene for brown seed coat, which were designated as SCM57 and SCM1078. The crossover between these markers and the brown seed coat loci was 2.35% and 7.06%, respectively. A sequence characterized amplified region (SCAR) marker according to Negi et al. (2000), designated as SZ1-331, was found to be linked to the gene for brown seed coat, with a crossover estimate of 2.35%. The markers were located on the same side of the brown seed coat loci and 2.41, 7.51 and 2.41 cM away from the brown seed coat locus. The seven brown-seeded near-isogenic lines were classified into two groups by three DNA markers. They were located at the same linkage group of the marker RA2-A11 previously published by Padmaja et al. (2005).