Genetic Divergence and Character Association Studies for Forage Yield and Its Component Traits in Oat (Avena Sativa L.)

Abstract

Advisor: Dr. S. A. Kerkhi, Professor. Department of Genetics and Plant Breeding Degree Awarding Uriiversity: Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut (Uttar Pradesh) The present investigation entitled "Genetic diver·gence and character association studies for forage yield and its component tr·aits in oat (Avena sativa L.)" was carried out during rabi 2014- 15 at Crop Research Centre of Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut (Uttar Pradesh) with 37 diverse genotypes of oats to drive the information on genetic variability, heritability, genetic advance, character association (correlation coefficient), path coefficient analysis and genetic diversity (02 analysis) for eleven characters viz; days to 50% flowering, number of leaves per plant, flag leaf area, plant height, number of tillers per plant, stem girth/thickness, number of green pods per spike, length of spike, leaf stem - ratio, green fodder yield per plant and dry fodder yield per plant and that were subjected to various statistical and biometrical analyses. In the present study thirty seven genotypes of oat have been screened for green fodder yield and its compone11t characters. Analysis of variance (ANOVA) showed highly significant variances among the genotypes for all the characters and wide spectrum of variability were also observed among all the genotypes. In the study highest phenotypic coefficient of variance (PCV) and genotypic coefficient of variance (GCV) were observed for flag leaf area followed by leaf stem - ratio, number of green pods per spike, green fodder yield per plant, dry fodder yield per plant, number of leaves per plant, number of tillers per plant, length of spike, stem girth I thickness, plant height at complete heading and days to 50% flowering. High estimates of heritability were observed for two traits namely flag leaf area and number of green pods per spike, however, moderate heritability was observed for leaf stem - ratio, number of leaves per plant, dry fodder yield per plant, green fodder yield per plant and length of spike while low estimates of heritability were also observed for days to 50% flowering, stem girth, number of tillers per plant and plant height at complete heading. High genetic advance expressed as percent of mean (>20%) were observed for flag leaf area, number of green pods per spike, leaf stem-ratio, dry fodder yield per plant, green fodder yield per plant, number of leaves per plant and length of spike while moderate to low estimates of genetic advance were also observed for number of tillers per plant. stem girth, plant height and days to 50% flowering. In the character association studies, highly significant positive correlation was observed between green fodder yield per plant with dry fodder yield per plant, stem girth /thickness and plant height at complete heading; days to 50% flowering with length of spike and flag leaf area; dry fodder yield per plant with plant height at complete heading and stem girth I thickness; plant height with stem girth and number of green pods per spike; number of tillers per plant with number of leaves per plant; stem girth with number of green pods per spike and flag leaf area; flag leaf area with length of spike and number of green pods per spike; length of spike with number of green pods per spike while negative and significant correlation were also observed between green fodder yield per plant with number of tillers per plant; days to 50% flowering with number of tillers per plant and number of leaves per plant; number of tillers per plant with length of spike; number of leaves per plant with number of green pods per spike and length of spike. At genotypic level, the direct effect of independent variable on green fodder yield indicated that, the length of spike had very high positive direct effect on green fodder yield followed by number of tillers per plant and stem girth but the direct effect of remaining characters on green fodder yield were negative and of low magnitude. Path coefficient analyses indicated that, the length of spike had the highest positive direct effect on dry fodder yield per plant followed by plant height, number of tillers per plant and days to 50% flowering but the direct effect of remaining characters on dry fodder yield were negative and of low magnitude. 0 2 analysis was done by using multivariate statistical tools given by Mahalanobis (1936), Rao (1952) and Ward's Method (1963). By 0 2 analysis, 37 oats genotypes were grouped into seven clusters. A total of ten genotypes fell into cluster I, seven genotypes in cluster II, six in cluster Ill, one each in cluster IV & V respectively, nine in cluster VI, and three genotypes in cluster VII. The cluster mean analysis indicated that the, highest cluster mean value for days to 50% flowering was observed in case of cluster V, genotypes of cluster IV had highest cluster mean for green fodder yield per plant; while the genotypes with dry fodder yield per plant were concentrated with high mean in cluster VII. The highest cluster mean for plant height at complete heading was recorded in cluster VI; for number of tillers per plant in case of cluster. The highest cluster mean value for number of leaves per plant was observed in case of cluster IV; for flag leaf area was recorded in case of cluster VI for cluster VI; for number of green pods per spike cluster VI, The genotypes of cluster V were having highest cluster mean for leaf stem- ratio. On the basis of 0 2 analysis, the maximum intra cluster 0 2 value was observed in cluster VII followed by cluster VI, cluster II, cluster I while cluster Ill exhibited the most lowest 0 2 value. Whereas the maximum average inter cluster 0 2 value was recorded between cluster V and VI while the minimum average inter cluster 0 2 value was recorded between cluster I and m. However, the percent contribution and expression of characters towards the genetic divergence was observed in this way; number of green pod per spike had maximum contribution (%) towards the genetic divergence followed by flag leaf area. dry fodder yield per plant, leaf stem - ratio, green fodder yield per plant, number of leaves per plant, days to 50% flowering, number of tillers plant, stem girth I thickness and length of spike while lower contribution (%) was made by plant height towards the genetic divergence. Based on the genetic diversity and Superiority with respect to any of the traits that were identified in various genotypes, would be involved in hybridization programme for the improvement of oats. Consequent upon the present overall results, it may be concluded that the genotypes taken for the present study were having high range of genetic variability which may be used in hybridization programme for obtaining superior and desired recombinants for particular character. High heritability with high genetic advance may be used as a tool for desired traits in relation to direct selection of superior genotypes from diverse population. Significant positive correlation coefficient and positive direct and indirect effect of independent variables on dependent variable mostly used for indirect selection of desired genotypes. Both the direct and indirect selection parameters were found to have potential for. improving the traits of interest through selection breeding programme. The hybridization programme could be taken between the genotypes of cluster V and cluster VI then between cluster I and cluster Ill for obtaining desirable recombinants for the various characters of present study that were most important for the improvement of fodder yield in oats crop. And hybrids can also be developed by involving divergent genotypes in oats. Therefore, crosses between the genotypes of above mentioned clusters would produce the better recombinants or segregants, for desirable traits in improvement of fodder yield in oats.