STUDY OF INDUCED GENETIC VARIABILITY, CORRELATION CO-EFFICIENT ANALYSIS IN MUNGBEAN (VIGNA RADIATA) (L.) WILCZEK

The mutability induced with different gamma irradiation frequencies viz. 10, 20, 30, 4o and 50 K-rad doses in some agronomic and morphological traits of five divergent cultivars of mungbean namely, M-29-37, M-38-54, M-22-24, M-19-19 and M-133-100 was studied in M1, M2 and M3 generation stages under irrigated and M1 under rainfed conditions. These investigations were carried out in the Research Area of Department of Plant Breeding and Genetics, Faculty of Agriculture, Gomal University, Dera Ismail Khan. The characters included in these studies were days to germination, days to 50% flowering, days to maturity, plant height, number of branches, number of pods number of clusters, pod length, seeds per pod, 1000 seed weight, dry matter yield, grain yield and harvest index. The crop was sown in kharif season during all the years of studies i.e. 1990, 1991 and 1992. The experiments were laid out in R.C.B.D.having four replications with split plot arrangement with varieties in main plots and gamma rays in sub-plots. All the cultural operations were kept constant and uniform in all the treatments during all the years. The data were recorded from ten randomly selected plants from each treatment. The data were can analyzed statistically to establish the level of significance among the treatments. The relatl0nship of grain yield and nine agronomic traits through correlation and path co-efficient analysis was also studied in present investigations. Besides, M1' M2' and M3 (irrigated) and M1 (rainfed), twenty divergent genotypes mungbean studied under irrigated and rainfed conditions were also included in correlation an path coefficient analysis. All the twenty genotypes were sown in R.C.B.D. wlth four repeats. All the above mentioned characters excluding days to germination, pod length and seeds per pod were included in this analysis. The results of the analysis showed that a wide range of variability/mutability exists in almost all the characters due to the effect of genotypes/gamma rays and their interaction. The main varietal and doses effects showed that a non-significant variation was only observed for harvest index percentage in all the experiments. It was only significant due to genotypic-cum-doses interaction in M2 population. Rest of the characters were found to be significant and highly significant in one or other experiment. Stimulating effect on grain yield in various generations was found with 30, 40 and 50 K-rad doses of gamma rays. It was, therefore, suggested that these doses might be beneficial if utilized for grain yield enhancement. The 50% flowering showed a strong positive association r with grain yield in all the experiments except M3 and varietal (irrigated), where it was non-significant. Days to maturity was -negatively associated with grain yield in all the experiments except M1 (irrigated) where it showed a strong positive association with yield. A positive and significant correlation between plant height and grain yield in M1 (irrigated), M3 and varietal experiment (irrigated) was observed. It showed negative relationship with grain yield in M2'M1 (rainfed) and varietal experiment (rainfed). Number of branches showed positive relationship with grain yield in-all the experiments except Ml (irrigated) where it showed negative association with grain yield. Number of pods has positive -correlation with grain yield in majority of the cases except M1 (irrigated) and M3 generation. Number of clusters were negatively associated with grain yield in all the mutants under irrigated conditions. Whereas under rained condition and varietal experiment (irrigated) it showed positive correlation with grain yield. The 1000 seed weight showed positive association with grain yield in all the experiments except varietal (irrigated). The dry matter yield showed a strong positive relationship with grain yield in all the experiments except M1 (irrigated). The harvest index was positive and significantly correlated with grain yield in all the experiments except M1 and M2. Path co-efficient analysis revealed that the traits like days to 50% flowering, number of pods, 1000 seed weight, dry matter I yield and harvest index exerted positive effect on grain yield. While days to maturity, plant height and number of branches were not important for determining the grain yield in these studies. The estimates of coefficient of variability revealed that PCV were r higher in magnitude than GCV for all the characters in all the experiments. The largest heritability in M1 (irrigated) was found for days to flowering followed by days to maturity. In case of M2, M1 (rainfed) and varietal (irrigated and rainfed, the highest magnitude of h2 was exhibited for days to maturity. Among the estimates of heritable characters it was observed that high h2 was associated with high genetic advance for days to maturity in M1 generation (irrigated and rainfed) and plant height in varietal experiment (irrigated). Similarly, high h2 coupled with low genetic advance for days to 50% flowering and number of clusters in M1 (irrigated), dry matter yield and grain yield in M1 and days to 50%, flowering and maturity in varietal experiment (irrigated). The association of high h2 with high genetic advance is considered due to the additive gene effect. While high h2 with low genetic advance happens in the presence of non-additive genes (epistasis and dominant)