Assessment of genetic parameters in periwinkle through diallel analysis

Estimation of genetic variability assists in determining the contribution of various plant parameters inexhibiting the improvement of genotypes under a specific set of environmental factors. Genetic analysis allows us to clearly understand various morphological, physiological, and genetic traits, in addition to the type and extent of their role in the advancement of cultivars. The present investigation was carried out to evaluate six inbred lines of periwinkle (Vi-15-1, Vi-13-2, Vi-16, Vi-15-2, Vi-29, Vi-14-3), and their cross combinations in the full diallel fashion for ornamentally important characters. Analysis of variance revealed highly significant variations for all the parameters in all the inbred lines utilized in the study. The highest broad sense heritability estimates were observed for the number of seeds/follicles (H= 97.77 %) in the parents, whereas plant height had the highest heritability in the cross combinations (H= 98.73%). The high values of phenotypic and genotypic coefficient of variation in parents (PCV=34.41; GCV=34.02) and crosses (PCV=25.49; GCV=24.93) were recorded for thenumber of seeds/follicles. In the present study, moderate to high heritability together with a high percentage of genetic advance was recorded for seeds/follicle, follicle length, primary branches/plant, plant height, internode length and plant spread, suggesting that the additive gene action controlled these characters. Therefore, the results suggested the existence of variability for studied traits in these periwinkle inbred lines, which should be improved in future breeding.