Genetic diversity in a structured family of six generations of ornamental chili peppers (capsicum annuum)

Abstract

The genus Capsicum has been used as an ornamental plant, but there are only a few commercial cultivars for this purpose available in Brazil. The aim of this study was to analyze the genetic diversity in a structured family of six generations of ornamental pepper based on quantitative and qualitative data, separately and integrated in the same analysis. These studies are part of the Capsicum breeding program developed at Universidade Federal da Paraíba and Universidade Federal de Viçosa. Six generations (P1, P2, F1, F2, BC1, and BC2) of ornamental pepper, belonging to the germplasm bank of Universidade Federal da Paraíba, were evaluated. Two accessions of ornamental pepper plants belonging to the germplasm bank of UFPB (01 and 132) were chosen based on an earlier diallel study. Ten plants of each parent and F1, 72 plants of backcross 1 (BC1), 75 plants of backcross 2 (BC2), and 147 plants of the segregating F2 generation were studied. Analysis of genetic diversity was performed for all generations. Quantitative data were subjected to cluster analysis by Tocher’s method. Multi-traits were analyzed based on the arithmetic complement of the index of coincidence. The matrices of quantitative and multi-categorical traits were summed, and data were subjected to cluster analysis by Tocher’s optimized method. The relative importance of the traits was evaluated by Singh (1981)’s method. High genetic variability was determined in F2 and backcrosses by three cluster analyses, showing that parents 01 and 132 differ for the evaluated traits. According to the relative importance of traits, those that most contributed to genetic divergence were number of seeds per fruit, number of fruits per plant, days to flowering and days to fruiting.