Khanna, V. K.Vedulla, Usha Tejaswini2023-04-112023-04-112019https://krishikosh.egranth.ac.in/handle/1/5810196288The productivity of blackgram (Vigna mungo (L.) Hepper) has become a limiting factor since the crop is adversely affected by various biotic and abiotic factors. As it is a self-pollinated crop having narrow genetic base, breeding is however difficult. Hence, immediate attention is required to improve the crop through transgenic technologies. In this study, a regeneration protocol was standardized using plant growth hormones such as cytokinins (BAP) and auxins (NAA and IBA) in three accessions namely KU-16-41, GP-115-IC-10703 and PANT-U-40. A total of 20 different MS media were used, of which MS media containing BAP 1.0 mg/l took less number of days for explant establishment in all the accessions with an average of 5.8, 5.8 and 6.6 days in KU-16-41, GP-115-IC-10703 and PANT-U-40, respectively. MS media containing BAP 4.0 mg/l showed best average percent of responding explants with 97.1% in KU-16-41, 98.4% in GP-115-IC-10703 and 95.8% in PANT-U-40. Shoot number was highest in media containing BAP 4.0 mg/l with an average of 9.8, 14.2 and 9.6 in KU-16-41, GP-115-IC-10703 and PANT-U-40, respectively. Length of the shoot was highest in media with BAP 1.0 mg/l and NAA 1.5 mg/l and this media was considered as the best since subsequent shooting and rooting was observed with an average root number of 10.4, 14.5 and 10.4 and average root length 5.4, 5.8 and 5.4 cm in KU-16-41, GP-115-IC-10703 and PANT-U-40, respectively. Those explants which did not show rooting were then transferred to rooting medium (BAP + IBA) where media with BAP 1.0 mg/l and IBA 1.0 mg/l was regarded as best since highest no. of roots and root length was recorded. The major limitation for low productivity in blackgram is lack of genetic variability. Hence, diversity analysis was carried out with 20 RAPD markers in 31 accessions of blackgram. All the 20 RAPD primers showed polymorphism by generating 271 polymorphic bands among a total of 278 bands with band size ranging from 0.13 to 3.0 Kb. The percent polymorphism was found to be 97.48%. PIC value ranged from 0.504 (OPG-04) to 0.861 (OPG-03). The primers OPG-03 and OPH-04 were found to be more informative as they generated highest PIC value. The dissimilarity coefficient generated among the 31 accesions ranged from 0.162 to 0.399. The dissimilarity value was found to be the highest (0.399) among the genotypes PANT-U-6 and GP-52-NO-5/31. Hence these two accessions are more diverse as they were genetically less similar. Least dissimilarity value (0.162) was found among the genotypes KU-34 and GP-46-99-213. In accordance with dissimilarity values, clustering was done using neighbor-joining UPGMA and three major clusters (I, II and III) were obtained with 13, 12 and 6 genotypes, respectively.EnglishThesis