Development of seed cuticular waxes on bloomless mutants of Sorghum bicolor L. Moench

Development of seed cuticular waxes on wild-type Sorghum bicolor and isogenic bloomless (bm) mutants was analyzed using gas chromatography and mass spectrometry. The amount of cuticular waxes per seed dry weight of wildtype increased significantly between the soft dough and hard dough stage, and then decreased after the hard dough stage. Analysis of seeds from wildtype and two sorghum leaf wax mutants allowed identification of the first gene mutations that alter cuticular waxes of seeds. Total cuticular wax quantities on bm2 and bm4 seed surfaces varied between 37% and 75% of wild-type levels during development. Interestingly, bm4 had much higher proportions of short chain length wax constituents than wildtype and bm2 throughout development. These new mutant resources and knowledge about wax development presented here may prove useful for future studies to elucidate the role of cuticular waxes in pest resistance of grain.