INHERITANCE OF QUANTITATIVE CHARACTERS IN CHILLI (Capsicum annuum L.)

Abstract

The present research program was undertaken to study the inheritance of quantitative characters related to yield in chilli (Capsicum annuum L.). The experiment was conducted at R & D Farm, Lal Teer Seed Limited, Gazipur, Bangladesh. Detailed gene actions in association with combining ability, heterosis, heritability and path analysis were studied. Based on the degree of divergence among genotypes, the 20 accessions, CCA 1, CCA 2, CCA 3, CCA 4, CCA 5, CCA 6, CCA 7, BARI Morich 1, CCA 9, CCA 10, CCA 11, CCA 12, CCA 13, CCA 14, CCA 15, CCA 16, CCA 17, CCA 18, CCA 19 and CCA 20 could be grouped into six clusters. Six different homozygous divergent parents CCA 2, CCA 5, BARI Morich 1, CCA 11, CCA 15 and CCA 19 were selected for 6X6 diallel cross excluding reciprocals from six different clusters using ranking among genotypes within cluster. Yield per plant, at phenotypic and genotypic level, was significantly and positively correlated with fruit length, fruit weight and number of fruits per plant and days to fruit maturity (green). The direct effect of number of fruits per plant was very close to correlation value at phenotypic and genotypic level. Selection should be done through number of fruits per plant. GCA variance was significant for all the traits and significant SCA variance was observed for all the measured variables except fruit width. Both additive and non-additive effects influence the performance of the hybrid in all the traits. The non-additive effects played a more important role than additive effects. The parents CCA 5, BARI Morich 1 and CCA 19 were found good general combiners. Considering the SCA effects and mean performance, hybrids 36 and 23 were best and showed better performance in average and standard heterosis. Top two yield per plant were obtained in hybrids 36 (898.87g) and 23 (833.63g). Indigenous X exotic crosses showed significant heterobeltiosis. Broad sense heritability of all the 11 characters was above 90% indicating highly heritable. Narrow sense heritability of days to 50% flowering, fruit length, fruit width, fruit weight, days to fruit maturity (green), days to maturity (ripe), plant height, plant canopy width were high and number of seeds per plant, number of fruits per plant, yield per plant were medium according to classification of Robinson (1965). Estimates of heritability by mid parent-offspring regression indicated that all the characters were highly heritable. Gene action for yield and yield contributing traits were studied in four selected crosses, involving five parents including their F;'s, F's and first back crosses generations in this work. The significant scaling tests (one or more scales in A, B and C) and joint scaling test indicated the presence of digenic epistasis for all the traits studied. Number of fruits per plant and yield per plant were controlled by additive, dominance and epistatic gene action. Determination of transgressive segregation and more comprehensive understanding of generation means can be visually gained by developing boxplot. Desirable transgressive segregants were found in all traits except days to flowering. The number of effective gene was one in all the eleven traits in all four crosses, which was underestimated in presence of epistasis. In general, the modified bulk method, reciprocal recurrent selection, diallel selective mating system, biparental mating system and heterosis breeding are recommended for yield improvement in chilli.