Genetic variability and association of characters in Ethiopian hot pepper (Capsicum annum L.) landraces

Abstract

Forty nine hot pepper accessions collected from different agroecologies were compared in a 7x7 simple lattice design to estimate genetic variability and understand the association of characters. Plant characters and yield components were evaluated and analyzed accordingly. The values of genotypic correlation coefficients were higher in magnitude than phenotypic values in most instances in which fruit yield per plant showed high positive significant genotypic correlation value with pericarp thickness (r = 0.91) and number of fruits per plant (r = 0.61). On the other hand, significant negative associations were registered with days to flowering (r = -0.73) and 50% fruiting period (r = -0.75). The phenotypic correlation coefficient of most characters with yield was not significant except for flowering period, fruit length and number of fruits per plant. The path coefficient analysis indicated that pericarp thickness (mm) (5.5), fruit diameter (mm) (1.4), number of fruits per plant (0.8), number of branches (0.33) and flowering period (0.2) had the highest direct positive effect. However, fruit weight (-2.8), number of internodes (-1.66), leaf area index (-1.6) and plant height (-0.4) had a high negative direct effect on yield. The genetic component analysis indicated that phenotypic coefficient of variation (PCV) was higher in magnitude than genotypic coefficient of variation (GCV) for most characters except pericarp thickness and leaf area index. Higher magnitude of GCV was observed in leaf area index (67%) followed by pericarp thickness (34%), number of branches, internode length (23%) and plant height. Close estimates of GCV and PCV were recorded from fruit and internode length, pericarp thickness and fruiting period. Very high PCV and very low GCV estimates were obtained from fruit weight and number of fruits, fruit yield, plant height and canopy width. Broad sense heritability was high for fruiting date, fruit length, plant height, internode length and fruit diameter. However, genetic advance as percent of the mean (GAM) was high to moderate for length and number of internodes, number of branches, fruit diameter and weight, pericarp thickness and leaf area index. Therefore, from this study, fruit diameter, pericarp thickness, leaf area index and internode length exhibited high to moderate genotypic and phenotypic coefficients of variation along with medium to high heritability and genetic advance and can be used as a selection criterion for pepper improvement program.