ANURADHA, CHGEETHANJALI, K2016-12-282016-12-282015http://krishikosh.egranth.ac.in/handle/1/93496In the present investigation,fifty two genotypes of black gram (Vigna mungo (L.) Hepper) were evaluated to study these genotypes against Mungbean Yellow Mosaic Virus (MYMV) and to study the genetic diversity based on morphological characters and molecular markers. The genetic diversity studies were carried out during rabi 2014-15 at experimental field of college farm in Professor Jayashankar Telangana State Agriculture University (PJTSAU) with fifty two genotypes to find out the information on Disease incidence and nature and extent of the genetic variability, heritability, genetic advance, character association, path analysis and genetic divergence. For molecular diversity studies 52 genotypes employing 50 SSR primers are carried out. Fifty two blackgram genotypes were screened for disease screening based on disease severity index by using 0-5 scale. Based on their reaction no genotype was found to be highly resistant, LBG-752 was resistant and MBG-1050 was observed highly susceptible. Observations were recorded on 12 characters, viz., plant height, number of branches per plant, number of clusters per plant, number of pods per plant, number of seeds per pod, pod length, days to initial flowering, days to 50% flowering, days to full maturity, percent disease incidence , seed yield pre plant and 100 seed weight. The analysis of variance revealed significant differences among the genotypes for all the characters studied indicating that the genotypes represented wide variability. The estimates of phenotypic coefficient of variation (PCV) were higher than the estimates of genotypic coefficient of variation (GCV) for all the traits under study indicating the environmental influence over the traits. High heritability along with high genetic advance as percent of mean was observed for plant height. The association of high heritability with high genetic advance was indicative of additive gene effects and could be improved through selection of these traits. Days to initial flowering, Days to 50% flowering, Days to full maturity and Disease incidence % were recorded high heritability with low genetic advance as percent mean, these characters are not inherited to generations hence these traits cannot used for selection. Based on the relative magnitude of D2 values, the genotypes were grouped into ten clusters. The cluster I was the largest comprising of twenty four genotypes followed by cluster II and III with eight genotypes, cluster IV with six genotypes and cluster V,VI,VII, VIII, IX and X with one genotype each. The highest divergence occurred between cluster IX and X (15.02), followed by cluster III and IV (14.07), cluster IV and VII(13.07) and cluster III and IX (12.96). Based on the inter cluster distances, hybridization between the genotypes from two divergent clusters could produce desirable recombination in yield. Among the characters studied relative contribution of days to initial flowering (22%) showed maximum towards divergence followed by percent disease incidence ( 21%), days to full maturity (19%), plant height (17%), 100 seed weight (5.58%), number of pods per plant (4.9%), days to 50% flowering (4.45%), number of clusters per plant (2.79%), number of branches per plant (0.83%), pod length (0.30%) and seed yield per plant (0%). From the correlation studies, it is observed that plant height, number of branches per plant, number of clusters per plant, number of pods per plant, pod length, 100 seed weight, days to initial flowering, days to 50% flowering and days to full maturity showed positive correlation with seed yield per plant and improvement of these characters might contribute to high yields in blackgram. Path analysis revealed that highest positive direct effects on seed yield were exerted by number of pods per plant, number of seeds per pod, 100 seed weight, pod length, disease incidence percentage, days to initial flowering, number of branches per plant and plant height they would directly increase the seed yield. Molecular diversity analysis was carried out using fifty SSR primers employed of which 18 showed polymorphism and remaining primers were monomorphic. The PIC value ranged from 0.71 to -0.45 with an average value of 0.49. The highest PIC value was recorded in VR040 and lowest in VR-357. A dendrogram based on unweighted pair group method with arithmetic average (UPGMA) grouped 52 blackgram genotypes into 2 clusters. Among these there is distinct variation recorded with the genotypes MBG-223, MBG-1034 and LBG-685 with less similarity coefficient of 55 to 65 (%). So it is recommended to go for intra specific variation within the genotypes based on multivariate analysis. Both morphological traits and SSR markers were highly effective in estimating genetic diversity and distinguishing genotypes in blackgram. Direct selection for yield improvement through traits such as number of branches per plant, number of pods per plant, number of seeds per pod, days to 50% flowering and 100 seed weight would be rewarding. Lowest diseased genotypes T9, LBG-752, LBG-685, LBG-402, LBG-17, BG-7, KU-12-06, RU-13-108 and RU 12-05 can be used to breed for resistance to MYMV. Sufficient variability exists in urdbean genotypes which are potential to be used in selection of suitable parents for breeding, genetic mapping studies and QTL analysis.enVARIABILITY, CHARACTERIZATION, BLACK GRAM, YELLOW MOSAIC, VIRUS RESISTANCEThesis