Enhancement of in Vitro Digestibility of Sorghum (Sorghum bicolor (L) Moench) in Brown Midrib (bmr) Mutant Derivatives of bmr1 and bmr7

Ten sorghum derivatives with brown midrib alleles (bmr1 and bmr7) were investigated for stover fodder quality traits, grain yield and the relationships between these productive traits. Potential fodder quality was assessed by laboratory analysis. Significant differences were observed among the tested derivatives of bmr1 allele for stover nitrogen (N) content, in vitro organic matter digestibility (IVOMD), and acid detergent lignin (ADL) content. In contrast, no significant genotypic differences were observed among bmr7derivatives. In the bmr1gene derivatives stover N content ranged from 0.63 to 0.81%, ADL content varied from 2.6 to 3.2% and IVOMD ranged from 52.9 to 55.4%. Two lines have recorded over 55% IVOMD and higher grain yield than the bmr1 source. In bmr7 derivatives IVOMD ranged between 52.9 and 54.4%. The enhanced IVOMD coupled with improved grain and biomass yield in bmr1 and bmr7 derivatives will increase overall benefits from sorghum in mixed crop livestock systems. This is the first study on utilization of bmr1and bmr7mutants in improving the forage quality of tropical sorghums with perceptible genetic enhancement of candidate biomass and grain yield traits.