Diallel analyses and estimation of genetic parameters of hot pepper (Capsicum chinense Jacq.)

Abstract

The degree of heterosis in the genus Capsicum spp. is considered high; however, most of the studies refer to the species Capsicum annuum L. In spite of the potential use of F1 hybrids in pungent peppers of the species Capsicum chinense, few studies are available which assess the magnitude of heterosis in this species . This study was carried out to assess heterosis and its components in F1 hybrids from a diallel cross between hot pepper lines (Capsicum chinense) and to obtain data on the allelic interaction between the parents involved in the crosses. Trials were made in Rio Branco-Acre, Brazil, from March through October 1997. A randomized complete block design with fifteen treatments and three replications was used. The treatments were five C. chinense accessions (from the Vegetable Germplasm Bank of the Universidade Federal de Viçosa - BGH/UFV) and 10 F1 hybrids derived from single crosses between them (reciprocals excluded). Diallel analyses were performed for total yield, fruit length/diameter ratio, fruit dry matter per plant, Xanthomonas campestris pv. vesicatoria incidence, capsaicin yield per plant and number of seeds per fruit. Non-additive genetic effects were larger than additive effects for all the traits assessed. Epistasis was detected for fruit dry matter per plant, capsaicin yield per plant and number of seeds per fruit. In these cases, epistasis seemed to be largely responsible for heterosis expression. Dominant gene action, ranging from incomplete dominance to probable overdominance, was responsible for heterosis in those traits where no epistatic genetic action was detected.