Genetic control of the Growth of Root Nodules and their Relation with yield in Black Gram (Vigna mungo L. Hepper)

Abstract

For the ease of study the present work was carried out in three separate sections. Section I: 1t contains the analysis of variance, components of variation, heritability and genetic advance for nine lines in black gram. The twelve quantitative characters such as, date of first flower (DFF), date of maximum flower (DMF), plant height at first flower (PHFF), plant height at maximum flower (PMFF), plant weight at harvest (PWtH), dry plant weight (DPWt), number of false pod per plant (NFPdPP), number of pod per plant (NPdPP), pod weight per plant (PdWtPP), number of seeds per plant (NSPP), seed weight per plant (SWtPP) and 100-seed weight ( I 00-SWt). The collected lines were distinctly different from each other for these characters that justifies their inclusion in the present investigation. The highest phenotypic variation and co-efficient of variability were found for NSPP. The genotypic variation and co-efficient of variability were observed for D50%F and PHFF respectively. The highest heritability and genetic advance as a percentage of mean (GA%) with a value of 42.717 and 16.0939 respectively, were recorded for PHFF. High error component of variation causes a low estimation of heritability. Low heritability as well as low values of genetic advance and genetic advance as a percentage of mean were noted for NSPP. Section II: It deals with the analysis of variance with factorial analysis and correlation co-efficient of root length (RL), shoot length (SL), fresh plant weight (FPWt), fresh root weight (rRWt), root volume (RV), nodule number (NN), nodule weight (NWt), number of pod per plant (NPdPP), fresh pod weight (FPdWt), dry pod weight (DPdWt), number of seeds per plant (NSPP), yield per plant (YPP) and I 00-seed weight ( 100-SWt). Analysis of variance indicated that all lines were significant. Factorial analysis indicated that the individual effect of fertilizers is more important for root and shoot characters than yield, while yield itself showed increase response with combined fertilizer dose instead of single dose particularly nitrogen. However, all the root and shoot characters and yield per ii plant except NPdPP and 100-SWt showed the importance of combined dose ie. NPK in black gram. Correlation study indicated that RL showed positive significant correlation with NPdPP and FPdWt. SL exhibited positive significant correlation with FPWt, FRWt and NN. The correlation of FPWt was found to be positively significant with FR Wt, NN, RV and NWt. FRWt showed positively significant correlation with RV. A significant positive correlation was exhibited by NN with NWt, NPdPP, YPP and 100-SWt. The correlation co-efficient of RV was found to be positively significant with NPdPP and FPdWt. NWt showed positively significant correlation with NPdPP, FPdWt, YPP and 100-SWt and negatively significant correlation with NSPP. Section lll: Factorial analysis and analyses of variance, variability, heritability, genetic advance and genetic advance as a percentage of mean for the six characters like moisture, dry-matter, protein, free sugar, reducing sugar and vitamin C of root nodules were done in this section. In the analysis of variance for the chemical characters of root nodules the lines (L) were found to be significant in different from each other and dose (D) effects were not found at each stage (S), except reducing sugar for dose and free sugar and reducing sugar for stage. Application of the individual dose, N, K, P and combined dose, NP, PK, NK and NPK have no effect in most of the stages for all the characters. Protein showed the highest PCV and GCV among these chemical characters. All the chemical characters, except moisture and dry-matter for root nodules exhibited high heritability and genetic advance as a percentage of mean. ln the calculation of molecular weight of protein and its bands it was found that lines L20, L11, L14 and L 15 contained mostly similar types of protein in seeds and root nodules. While, similarity in regard of molecular weight of protein and its band for nodule and seeds was found in least number of cases in L1R- Regarding the 18 amino acids detected, in maximum two cases all the nine lines were found to be different. However, glycine, methionine, leucine, phenylalanine, lysine and arginine were common for root nodules in all the lines. The concentration of bacterial colonies all the nine lines were different. The highest concentration was found for L20 followed by Lis, L15 and L19. With these results lines L20 and L15 may be considered for further breeding research for high yield in black gram.