Improvement of Genetic Nature of Yield Components for High Yield Through Irradiation in Lentil (Lens Culinaris Medic.)

Abstract

The whole work of the present investigation was carried out under two separate parts, such as variability and diversity estimate and genotype-environment interaction. Under two parts the eight yield and yield contributing characters studied, were plant height at first flowering (PHFF), number of branches per plant at maximum flowering (NBPMF), plant area per plant (PAPP), number of pods per plant (NPdPP), pod weight per plant (Pd WPP), number of seeds per plant (NSPP), seed weight per plant (SWPP) and plant weight per plant (PWPP) of six lentil (Lens culinaris Medic.) lines for the analysis. In part-I, variability and diversity estimates (components of variation, coefficient of variability, heritability, genetic advance) were studied at four irradiation doses namely no irradiation (DI), 20kr (D2), 25kr (D3) and 30kr (D4) in two consecutive years i.e., 2005-2006 and 2006-2007. In the analyses the presence of wide range of variation of all the characters indicated that they are quantitative in nature and are under polygenic control. The lines were genetically well differentiated as indicated by the analysis of variance. Significant differences among the doses for most of the characters showed that the four doses included in the analysis were different from each other. Significant year and dose and respective interaction items with lines for most of the characters indicated that the environments (in respect of year and dose) were different and they interacted with the genotypes (lines) differently. Significant interaction of LxDxY showed that lines, year and dose were interacted among themselves. The different components of variation and coefficient of variabilities calculated were more or less high for PAPP, NSPP, NPdPP, NBPMF and PHFF which indicated a wide scope of improvement of this trait through selection. Heritability and genetic advance were estimated to be low for all the characters. In part-II, investigation on genotype x environment interaction was done. The same eight quantitative characters as in part-I of six lentil lines were studied. The same four irradiation doses in two years were considered as the environments in this investigation. Joint regression analysis revealed that genotype-environment interaction accounted for by both the linear and non-linear functions of environments. A significantly greater portion was accounted for by the linear function of environments. From the estimation of stability parameter, the genotypes like line-6 for SWPP; line-11 for NPdPP, PdWPP and PWPP; Bm2 for NPdPP and PdWPP; line Bm3 for PHFF and PdWPP and line Bm4 for PdWPP; were predicted to show the stable performances, i.e. adaptable to all environments and could be used for the future lentil research. On the other hand, line-6 for PHFF and NSPP; line- 11 and line Bml for SWPP were adaptable for favourable environment. Besides, line-6 for NBPMF and PdWPP; line Bm2 for PHFF and SWPP; line Bm3 for SWPP and line Bm4 for PHFF, SWPP and PWPP showed stable performances for unfavourable environment.