Genetic Divergence, Selection Index and Genotype – Environment Interaction in Lentil (Lens culinaris Medic)

Abstract

The whole work of the present investigation was carried out for the study of variability, selection indices, for identify of stable genotypes and for identification and characterization of genetic diversity of six lentil (Lens culinaris Medic) varieties under three different heads; such as part-I: genetic variability, correlation, path coefficients and selection index; part-II: genotype- environment interaction and part-III: genetic divergence using morphological and biochemical markers. For this, eleven yield and yield contributing characters viz date of first flower (DFF), plant height at first flower (PHFF), number of primary branches at first flower (NPBFF), plant height at maximum flower (PHMF), number of primary branches at maximum flower (NPBMF), number of secondary branches at maximum flower (NSBMF), plant weight per plant (PWPP), number of pods per plant (NPdPP), pod weight per plant (PdWPP), number of seeds per plant (NSPP) and seed weight per plant (SWPP). In part-I, the mean values were highly significant with their respective standard errors and wide range of variation among the means values were obtained, suggesting that characters studied are quantitative in nature and under polygenic control. The highest values of σ2P, σ2G, σ²Y, σ²GY and σE² components of variation and PCV, GCV and G˜YCV were obtained for NSPP. Moderate h2b were obtained for PHMF and high GA values were noted for NSPP, while high GA% value was recorded for PdWPP. In the present investigation, correlation studies showed that genotypic correlation was higher than the respective phenotypic correlation in most of the cases. SWPP showed positive correlation with PWPP, PdWPP and NSPP both at phenotypic and genotypic levels. NPBFF, PHMF and PdWPP had the high direct effect on SWPP both phenotypic and genotypic levels, but NSPP showed high direct effect on SWPP at genotypic level. Considering selection index, the highest expected genetic gain was observed in NPBFF, NPdPP, PdWPP, NSPP and SWPP and with their combination. When the two yield contributing characters viz. PdWPP and SWPP were included in the indices, the expected genetic gain was increased. In part-II, stability performances of different lines were different for different characters. Joint regression analysis revealed that genotype × environment interaction was accounted for by both linear and non-linear functions of environment. . A good number of lines showed stable performances for different characters in different environments. The genotypes which showed stable performances, i.e., adaptable to all environments are Bm1 for NPBFF, Bm2 for PHMF, NSBMF, NPdPP and NSPP, Bm3 for NPBFF, Bm4 for PHMF and PWPP, Bm5 for NPBFF and PdWPP and Bm6 for PWPP and PdWPP. The genotypes which are adaptable to favorable environment are Bm1 for most of the characters except DFF, PHFF and NPBFF, Bm3 for all of the characters except NPBFF and NPBMF, Bm4 for PHFF and NPBMF, Bm5 for NSBMF and Bm6 for all of the characters except PHMF, NSBMF and NPdPP. In part-III, above six lentil varieties with thirteen lines of F2 generations were analyzed through morphological markers and seed storage protein profiling for comparing the genetic divergence. In case of morphological characters, analysis of variance showed significant values for all the characters which indicating that the lines are significantly different from each other. Based on Euclidian distance, Bm1 was noted to be closely related with Bm4 × Bm3 and showed the highest dissimilarity value 0.99. Dendrogram was constructed based on the dissimilarity values of eleven characters and the lines were grouped in two clusters. In this study, seed storage protein profiling showed 70.37% polymorphism among the bands of all lines. The highest polymorphic bands were recorded in Bm5 × Bm3. Six type of seed storage protein, albumin protein was abundant in quantity in all the varieties and as well as all the varieties were polymorphic for lysozyme protein. In this analysis, close relatedness was found among cultivar Bm1 and the crosses Bm3 × Bm4 and Bm6 × Bm1 based on Jaccard’s similarity coefficient and cluster analysis. The highest genetic distance showed between Bm4×Bm1 and Bm5× Bm3 F2 lines. The results of principal component analysis is supported by the results of dendrogram, In this work, results of morphological and biochemical marker analysis suggested that the F2 cross of Bm5Bm3 showed the highest genetic diversity among all the materials investigated and it should better for further breeding work.