Estimation of genetic components in F1 hybrids and their parents in determinate tomato (Solanum lycopersicum L.)

Genetic analysis of yield and its contributing traits was studied in parents and their F1 hybrids in determinate tomato. The experiment was laid out in randomized block design with two replications under Vegetable Program at Horticultural Research Institute NARC, Islamabad, Pakistan in spring 2011. The study was comprised 15 new crosses (determinate), their parental lines along with international hybrids for primary evaluation. Significant differences were observed for the characters viz. number of fruits per plant, number of clusters per plant, number of fruits per cluster, number of flowers per plant, fruit length (cm), fruit width (cm), plant height (cm) and fruit yield (t/ha). Data was analyzed for genotypic variance, phenotypic variance, genetic advance, broad sense heritability (h2bs), phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV). The highest PCV and GCV magnitude was observed for yield (56.78 and 56.71 t/ha) followed by plant height (44.86, 44.84) and fruits per plant (43.26, 43.23). The heritability (h2bs) is ranged from 0.93 to 1.00. For all the characters studied the highest heritability was observed in fruit per plant, fruit yield (t/ha) and plant height (1.00). The GA as percentage of mean at 5% and 1% level ranged from 33.96 to 116.68 and 43.53 to 149.53, respectively. The highest estimates of genetic gain were obtained for fruit yield (116. 68, 149.53), plant height (92.33%, 118.33%) and number of fruits per plant (89.00, 114.06). The characters with high values of GCV and h2bs, accompanied by high GA % suggest that improvement of these characters would be effective through phenotypic selection. Four principal components were taken out having Eigen value equal to 1. These added 86% of the variability amongst the genotypes studied. All the four principal components exhibited high commonalities for plant height, fruit length, clusters per plant, fruits per plant, fruit weight (g), fruits per cluster, fruit yield (t/ha), flowers per cluster, clusters per plant. Cluster analysis based on Euclidean distances showed high level of genetic diversity among parents, hybrids and checks.