Powdery mildew of sorghum (Erysiphe pisi var. pisi) is of worldwide occurrence and causes substantial yield losses. As far as resistance against powdery mildew is concerned, the presence of powdery mildew-resistance gene O (Mlo) plays a key role. The Mlo gene was first identified in barley, and the Mlo protein was found to be an integral plasma membrane-localized protein that possesses seven transmembrane regions. In the present work a total of 12 well reported Mlo genes from Oryza sativa, 15 well characterized Mlo genes from Arabidopsis thaliana genome were taken for comparative studies in sorghum (Sorghum bicolor). Comparative analysis of Mlo proteins from S. bicolor genome revealed the presence of 13 hypothetical genes within the genome. Map viewer analysis indicates that the predicted S. bicolor SbMlo genes are distributed on eight of the ten chromosomes. Sorghum chromosome 9 has 3 genes; chromosome 10 and chromosome 1 have 2 genes each, while chromosomes 2, 3, 4 and 5 have 1 gene each. Sub-cellular localization of identified Mlo proteins encoded by genes SbMlo1, SbMlo2, SbMlo4, SbMlo5, SbMlo6, SbMlo9, SbMlo10, SbMlo11, SbMlo12 and SbMlo13 are present in plasma membrane; SbMlo3 product is located in endoplasmic reticulum, SbMlo7encoded protein is located in vacuolar membrane and SbMlo8 product is present in the nuclear region. In silico characterization (using phylogenetic classification, motif analysis and cis-acting elements studies) suggested its diverse function associated with disease resistance based on specific expression containing fungal elicitor responsive elements. Gene specific primers, expression primers and universal primer were designed to check the expression and availability of SbMlo genes through wet lab experimentation.

Genetic improvement for higher production and better quality has remained pivotal to agriculture. Lack of sufficient genetic variability for economically important traits is one of the reasons attributed for slow advancement in chickpea. Improvement in either single or few economic traits and quality characters can be achieved with the help of induced mutations within the shortest possible time. An experiment was conducted to evaluate the extent of biological damage in M1 and M2 generations along with genetic variability for yield and yield contributing traits in M3 and M4 generations of chickpea following mutagenesis with EMS and SA. The breeding behavior of the mutants was studied through M1-M4 generations. All the mutagenic treatments brought about dose dependent diminution in seed germination, pollen fertility and seedling growth in M1 and M2 generations. The reduction was more prominent in M1 than in M2 generation, indicating that some sort of recovery mechanism must be operating in the superseding period. A significant increase in mean values for pod bearing branches per plant, pods per plant, 100-seed weight (g) and total plant yield (g) was noticed in both M3 and M4 generations. Moreover, the magnitude of genotypic coefficient of variation, heritability and genetic advance for yield and its contributing components were recorded to be higher in the mutagenized population. Increase in mean values in conjunction with an augment in genetic variability advocate further possibilities of selecting more promising lines with high yield and genetic potential. The mutants isolated can be utilized in future as suitable genetic source material in breeding, genetic and functional genomics research.

Sodium azide (SA) - a respiratory inhibitor has long been considered as a potential chemical mutagen for inducing variability in crop plants. The induction of biological damage in terms of instantaneous effects on seed germination, pollen fertility and seedling growth was envisaged by treating the seeds of two wheat (Triticum aestivum L.) varieties viz., HD-2285 and HUW-234 with 0.01%, 0.02%, 0.03% and 0.04% of SA. All the mutagenic treatments bring about dose dependent decline in seed germination, pollen fertility and seedling growth in M1 and M2 generations. The reduction was more prominent in M1 than M2 generation. For all the traits under study, var. HUW-234 was found to be more responsive than the var. HD-2285 to various doses of SA. The direction of shift in mean values for plant height indicated that negative micro- mutations outweighed the positive ones, while the reverse was true for number of tillers per plant, number of grains per spike, 100-grain weight and grain yield per plant. Coefficient of variation (CV) was recorded to be elevated in the mutagen treated population in both the generations for both the varieties, providing greater scope for attaining the favored selections. In M2 generation, the mean seed protein content of the mutants displayed no considerable variation from the controls. However, the coefficient of variation was of lesser magnitude, representing that the further improvement in this particular trait is pretty difficult to accomplish.