ANALYSIS OF GENETIC VARIABILITY AND CHARACTER ASSOCIATION IN F 2 SEGREGATING POPULATION OF TOMATO (Solanum lycopersicum L.)

Abstract

An experiment was conducted at the experimental farm of Sher-e-Bangla Agricultural University, Dhaka, during the period from September 2021 to February 2022 using twenty-eight genotypes of tomatoes (Solanum lycopersicum L.) to analyze the genetic variability and character association in F population of tomato in a randomized complete block design with three replications. The analysis of variance revealed significant differences for various traits among the genotypes. For all of the characters, phenotypic variance was greater than the genotypic variance. The GCV values were lower than that of PCV values, indicating that the environment had an important role on the expression genes controlling these characters. The number of cluster per plant (35.033), number of fruits per cluster (47.347), number of fruits per plant (81.5), fruit diameter (41.008), single fruit weight (66.156), total soluble solid (53.131) and yield per plant (41.691) all had high genotypic co-efficient of variation (GCV). It indicated that selection may be effective based on these characters. High heritability with high genetic advance in percent of mean was observed in number of fruits per cluster (73.667 and 83.714 respectively), number of fruits per plant (85.669 and 89.897 respectively), fruit diameter (93.326 and 81.609 respectively), single fruit weight (96.603 and 79.649 respectively) and total soluble solid (72.553 and 93.227 respectively) indicating the most suitable condition for selection. It also indicates the presence of additive genes in these traits and reliable crop improvement through selection of such traits is possible. High heritability with low genetic advance in percent of mean was observed in plant height (87.719 and 30.99 respectively), days to 1 2 st fruiting (81.845 and 26.508 respectively), fruit length (88.531and 57.068 respectively) and shelf life (81.168 and 44.243, respectively) suggesting nonadditive

gene action for the expressions of these characters. The result revealed a highly significant positive correlation with days to 1 st fruiting (rg = 0.224, rp = 0.227), number of branches per plant (rg = 0.422, rp = 0.498), number of cluster per plant (rg = 0.231,rp = 0.244), number of flowers per plant (rg = 0.242,rp = 0.366), number of fruits per plant (rg = 0.418,rp = 0.447), fruit diameter (rg = 0.553,rp = 0.367), single fruit weight (rg = 0.734,rp = 0.524) and total soluble solid (rg = 0.332,rp = 0.266) indicating that a possible increase in these traits tends to increase in fruit yield per plant. In path analysis data on various parameters viz. plant height (0.183), days to 1 st flowering (0.764), days to maturity (0.305), number of cluster per plant (0.892), number of flowers per cluster (0.684), number of fruits per cluster (0.936), fruit length (0.753), fruit diameter (0.575), single fruit weight (0.75) and total soluble solid (0.178) had revealed positive direct effect on yield. Among these, number of cluster per plant, number of fruits per cluster, number of fruits per plant, fruit diameter, single fruit weight and total soluble solid had also significant positive correlation with yield per plant at genotypic level, indicating direct selection may be executed considering these traits as the main selection criteria to reduce indirect effect of the other characters during the development of high yielding tomato variety. Therefore, considering the agronomic and genetic performance the G genotype for high yield, and G 9 ×G genotype for short durated ripen fruits might be suggested for further selection in next generation.