An innovative way of developing an improved variety utilizing both gamma rays induced and recombinational variability in Blackgram (Vigna mungo L.(Hepper))

Mutagenesis in association with recombination breeding offers a viable option to improve locally adapted varieties and release the variability hidden in the conserved gene blocks. An attempt was made to compare variability generated through different mating schemes and combination of mating and irradiation in Vigna mungo L. (Hepper) to improve productivity of recommended varieties. Four genotypes viz., Manikya and TAU-1 two locally adapted varieties, which lack optimum seed size and number of pods per, plant respectively. And two selected complimentary donor lines viz., No.169, a line for high pod number (50-55) and No. 216 for seed mass (6.5g) were crossed to generate four single crosses, two three way and one double crosses. Four single crosses were further irradiated with 20 Kr gamma rays and advanced to F2M2 and F2 generation for evaluation based on seven agronomic traits. Irradiated progenies of single crosses exhibited higher PCV and GCV values for clusters per plant and pods per plant. Variability generated by irradiation was more compared to recombination variability for clusters per plant and pod length traits. Irradiated single cross (F2M2) progenies produced higher frequency of superior progenies for pods per plant, 100 seed weight and seed yield per plant compared to other hybridized progenies involving two or more than two parents. Nature of association between pod length and number of pods per plant under irradiation was improved favorably and even it was changed from non significant negative to positive significant in F2M2 progenies of a cross TAU-1x169.Selected superior progenies isolated in F2 and F2M2 (112) and in F3M3 and F3 generation (135) which were advanced separately from F2, F2M2 to F3, F3M3 by following three different selection methods and all these selected individual progenies were advanced to F5 generation and were evaluated in progeny row trial with two replications, Based on their seed yield, which yielded more than mean + two standard deviation values, we found that 29 advance breeding lines were superior. It is interesting to note that when pedigree of 29 advance breeding lines was traced back, we found that 18 lines originated from irradiated single crosses and five lines from single crosses without irradiation and six lines from hybridized populations involving more than two parents revealing the importance of irradiation in creation of desirable variability. We found that based on stability analysis involving 29 advance breeding lines, the stable performance of DBS-14, DBS-16, DBS-24 and DBS-26 genotypes over environments with better mean performance for seed yield. The seed protein content across environments, ranged from 17.9 to 27.2 per cent when grown at Dharwad location. Genotype DBS-15 (27.20%) had highest seed protein content, which was followed by DBS-12 (26%) compared to high yielding check TAU-1 (19.68%). We found that two genotypes DBS-7 and DBS-21 had low seed sugar content across three test environments and these can be considered as low flatulence causing lines upon consumption by human beings. We found that based on results of large scale trials in different agro climatic conditions, genotype DBS-14 was most promising genotype with superior seed yield (22.0%) and seed mass apart from its tolerance to stem fly damage compared to adaptive cultivar TAU-1. Based on the merits, genotype was identified for commercial cultivation in the name of DU-1 in Karnataka provenance and also registered with NBPGR New Delhi for its novel agronomic traits. (author)