Identification of disease resistant bmr sorghum recombinant inbred lines derived from diverse donor and recurrent parents

Brown midrib mutants discovered in maize, sorghum and pearl millet through mutagenesis constitute an important genetic resource. Studies indicated that the discovered bmr mutants not only have lower lignin content than their wild -type counterparts, but they are also associated with an improved fodder digestibility and improved process yield in biofuel production. There is need to combine this novel trait with disease resistance to enhance the commercial utilisation of sorghum cultivars by end users. We have assessed reaction of a random set of F2:4 generations that represented progenies from 46 unique cross combinations involving 12 recurrent parents and 5 donor parents against anthracnose, leaf blight, and charcoal rot diseases. The genotypes were artificially inoculated with the pure cultures of the disease -causing organisms in separate experiments. There were significant genotypic differences for the disease severity and area under disease progress curve (AUDPC) in leaf blight and anthracnose, and number of nodes crossed and lesion length in charcoal rot disease. Progeny expressing bmr12 and bmr6bmr12 were generally superior in resistance to foliar diseases and charcoal rot than bmr6. The reaction of most of the bmr lines against the diseases was similar to their corresponding wild -type parents. Principle component and hierarchical cluster analysis identified sets of genotypes with bmr6, bmr12, and bmr6bmr12 loci that combine desirable levels of resistance to two or all the three diseases. These sets of bmr derived lines could be the potential sources to develop disease resistant bmr hybrids and pure line varieties, and improved breeding populations in sorghum.