Genetic Improvement of Yield and Yield Contributing Characters of Chickpea (Cicer arietinum L.) through Mutation Breeding

Abstract

The whole work of the present investigation was carried out in three separate heads, such as study of genetic control, study of genotype-environment interaction and study of variability, correlation, path-coefficients and selection index. Eight chickpea lines were studied for eleven yield and yield contributing characters viz. days to maximum flower (DMF), number of primary branches at maximum flower (NPBMF), number of secondary branches at maximum flower (NSBMF), plant height at maximum flower (PHMF), plant weight after fully dry (PWFD), root weight after fully dry (RWFD), number of pods per plant (NPPP), pod weight per plant (PdWPP), number of seeds per plant (NSPP), 1000-seed weight (1000-SW) and seed weight per plant (SWPP). In part I, in the study of genetic control five single crosses were used. In the analysis using generation means, the additive-dominance model, gene effects, degree of dominance, heritability, genetic advance, effective factors, heterosis and inbreeding depression were evaluated. The findings of this part I was first for the development of pure lines and the second for utilization of hybrid vigour commercially. It has been found from the analyses that the additive dominance model was found to be adequate as the r..2 values were non-significant supported by ABC scaling test for the characters viz, NSBMF, PHMF, NPPP and PdWPP in cross I {IA x 3A); DMF, PHMF, NPPP and NSPP in cross II (2C x 4C); NSBMF, PHMF, NPPP and NSPP in cross III ( 4C x 3C); DMF and NPBMF in cross IV ( 4A x 78). These crosses for those characters also indicated high narrow sense heritability and high genetic advance. Therefore these crosses for those characters would likely be good materials for the development of prospective pure lines for further breeding works. The second line of fruitful research would likely be with the crosses for the exploitation of hybrid vigour commercially. In this regard, the characters viz, NSPP and SWPP in cross I (1A )( 3A); NPBMF, 1000-SW and SWPP in cross II (2C x 4C); DMF and PdWPP in cross III (4C x 3C); RWFD and 1000-SW in cross The whole work of the present investigation was carried out in three separate heads, such as study of genetic control, study of genotype-environment interaction and study of variability, correlation, path-coefficients and selection index. Eight chickpea lines were studied for eleven yield and yield contributing characters viz. days to maximum flower (DMF), number of primary branches at maximum flower (NPBMF), number of secondary branches at maximum flower (NSBMF), plant height at maximum flower (PHMF), plant weight after fully dry (PWFD), root weight after fully dry (RWFD), number of pods per plant (NPPP), pod weight per plant (PdWPP), number of seeds per plant (NSPP), 1000-seed weight (1000-SW) and seed weight per plant (SWPP). In part I, in the study of genetic control five single crosses were used. In the analysis using generation means, the additive-dominance model, gene effects, degree of dominance, heritability, genetic advance, effective factors, heterosis and inbreeding depression were evaluated. The findings of this part I was first for the development of pure lines and the second for utilization of hybrid vigour commercially. It has been found from the analyses that the additive dominance model was found to be adequate as the r..2 values were non-significant supported by ABC scaling test for the characters viz, NSBMF, PHMF, NPPP and PdWPP in cross I {IA x 3A); DMF, PHMF, NPPP and NSPP in cross II (2C x 4C); NSBMF, PHMF, NPPP and NSPP in cross III ( 4C x 3C); DMF and NPBMF in cross IV ( 4A x 78). These crosses for those characters also indicated high narrow sense heritability and high genetic advance. Therefore these crosses for those characters would likely be good materials for the development of prospective pure lines for further breeding works. The second line of fruitful research would likely be with the crosses for the exploitation of hybrid vigour commercially. In this regard, the characters viz, NSPP and SWPP in cross I (1A )( 3A); NPBMF, 1000-SW and SWPP in cross II (2C x 4C); DMF and PdWPP in cross III (4C x 3C); RWFD and 1000-SW in cross V (4A x 7B) and NSBMF in cross V (SA x 6A) showing high heterosis both for mid parent and better parent and also showing overwhehning dominance and duplicate type of epistasis suggesting that these crosses for those characters be utilized for the commercial utilization of hybrid vigour. ln part II, investigation on genotypic x environment interaction was done. The same eleven quantitative characters as in part l eight lines were studied. In this part four irradiation doses namely no irradiation (Do), 20Kr (DA), 30Kr (D8) and 40Kr (De) and three consecutive years (2007-08, 2008-09 and 2009-10) were considered as the twelve environments in this investigation. The range of variation was wide and pronounced in the genotypic means for all the characters indicated that genotypic differences among the chickpea lines. Here environmental means also indicated that different environments had different effects on all the traits. Joint regression analysis revealed that genotypic x environment interaction accounted for by both linear and non-linear functions of environment. A non­significant greater portion was accounted for by the linear function of environments. From the estimation of stability parameters the genotypes, like line-2, line-4, line-6 and line-8 for DMF; line-1, line-4, line-7 and line-8 for NPBMF; line-I, line-2, line-5 and Line-7 for NSBMF; line-2, line-3, line-4, line-5, line-6 and line-7 for PHMF; line-I for PWFD; line-3 and line-6 for RWFD; line-4 for PdWPP; line-2 for NSPP and line-4 for SWPP were predicted to show the stable performances i.e., adaptable to all environments and could be used for further breeding research. Besides, line-3 and line-5 for NPBMF; line-4 for NSBMF; line­I for PHMF; line-I, line-7 and line-8 for RWFD; line-2 and line-6 for PdWPP, line-4 for 1000-SW and line-2 and line-6 for SWPP were adaptable for favourable environment. On the other hand, line-5 and line-6 for DMF; line-2 and line-6 for NPBMF; line-3, line-6 and line-8 for NSBMF; line-8 for PHMF; line-2, line-4 and line-5 for RWFD; line-I and line-8 for PdWPP; line-I, line-3 and line-8 for SWPP showed stable performances for unfavourable environments. V (4A x 7B) and NSBMF in cross V (SA x 6A) showing high heterosis both for mid parent and better parent and also showing overwhehning dominance and duplicate type of epistasis suggesting that these crosses for those characters be utilized for the commercial utilization of hybrid vigour. ln part II, investigation on genotypic x environment interaction was done. The same eleven quantitative characters as in part l eight lines were studied. In this part four irradiation doses namely no irradiation (Do), 20Kr (DA), 30Kr (D8) and 40Kr (De) and three consecutive years (2007-08, 2008-09 and 2009-10) were considered as the twelve environments in this investigation. The range of variation was wide and pronounced in the genotypic means for all the characters indicated that genotypic differences among the chickpea lines. Here environmental means also indicated that different environments had different effects on all the traits. Joint regression analysis revealed that genotypic x environment interaction accounted for by both linear and non-linear functions of environment. A non­significant greater portion was accounted for by the linear function of environments. From the estimation of stability parameters the genotypes, like line-2, line-4, line-6 and line-8 for DMF; line-1, line-4, line-7 and line-8 for NPBMF; line-I, line-2, line-5 and Line-7 for NSBMF; line-2, line-3, line-4, line-5, line-6 and line-7 for PHMF; line-I for PWFD; line-3 and line-6 for RWFD; line-4 for PdWPP; line-2 for NSPP and line-4 for SWPP were predicted to show the stable performances i.e., adaptable to all environments and could be used for further breeding research. Besides, line-3 and line-5 for NPBMF; line-4 for NSBMF; line­I for PHMF; line-I, line-7 and line-8 for RWFD; line-2 and line-6 for PdWPP, line-4 for 1000-SW and line-2 and line-6 for SWPP were adaptable for favourable environment. On the other hand, line-5 and line-6 for DMF; line-2 and line-6 for NPBMF; line-3, line-6 and line-8 for NSBMF; line-8 for PHMF; line-2, line-4 and line-5 for RWFD; line-I and line-8 for PdWPP; line-I, line-3 and line-8 for SWPP showed stable performances for unfavourable environments.