The Sorghum Epicuticular Wax Deposition Genes Bm2 and Blmc Are Allelic.

Epicuticular waxes (EW or bloom) play a prominent role in protecting plants against abiotic and biotic stresses. Sorghum has visible EW that coats the aerial surfaces of the plant and can protect a plant from drought and pest attack. Bm2, a bloomless locus in sorghum is well characterized and mutants of this locus, bm2-1 to bm2-6 lack EW with inhibited synthesis of the cuticle. At the same time, the sorghum mutant bloom-cuticle (blmc), also exhibited absence of EW and inhibited synthesis of the cuticle and many other pleiotropic effects. An allelism study was conducted to see if blmc is an allele of Bm2 locus. F₁ and F₂ seeds were obtained from the cross of bm2-3 X blmc to visually evaluate for EW. F₁ plants were evaluated in greenhouse and selfed F₂ progeny seeds were visually evaluated for EW in the field along with their parents and wild type plants. Our result confirmed that blmc is an allele of the Bm2 locus and was further designated as bm2-7. This finding will allow us to merge previous results independently generated from these loci and facilitate in fine mapping of Bm2 locus using just one mutant from this series.