Abstract
Abstract
Indian mustard (
B. juncea
) is a widely cultivated oilseed crop in the tropics. Seed oil of conventional Indian mustard varieties contains a very high proportion of polyunsaturated fatty acids and very long-chain monounsaturated fatty acids (VLCMFA), mainly erucic acid (> 30–40%) of total seed fatty acids. Edible oil with high erucic acid content is considered undesirable for human health due to the perceived role of erucic acid in cardiac lipidosis. Seed coat colour in
Brassica
also influences oil yield and quality. Monoplex-PCR markers for erucic acid contents (low, 30%) and seed coat colour (brown vs. yellow) in Indian mustard have been developed independently. We combined these monoplex-PCR markers into a single duplex-PCR assay and validated it in a panel of 34 Indian mustard genotypes for simultaneous detection of erucic acid content and seed coat colour. Gas Chromatography–Flame Ionization Detection (GC–FID) analysis revealed a wide variation in erucic acid content, which ranged from 0.34% in PM34 to 46.98% in Maya. Accordingly, 25 varieties were classified as high-erucic-acid (HEA), six as low-erucic-acid (LEA) groups and three varieties had intermediate (12.3%-20.42%) level of erucic acid. The duplex-PCR assay successfully amplified distinct targeted fragments in 34 genotypes with phenotypic detection accuracy of 96.96% for erucic acid content and 87.87% for seed coat colour. The per-marker running cost of duplex-PCR was ₹50.15 ($0.522) half the cost (₹100.3; $1.144) required for running the corresponding monoplex-PCR assay separately.. This duplex-PCR assay developed for the first time by combining independently published erucic acid and seed-coat colour markers, is a cost-effective, labour- and time-saving scalable tool for large-scale germplasm characterization for erucic acid content and genetic purity testing of commercial grain and seed lots of low erucic acid biofortified varieties of Indian mustard.