Diversidade genética e estudo de geração em características morfoagronômicas de pimenteiras ornamentais (Capsicum annuum)

• Autor(a) principal: Nascimento, Mayana Ferreira
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4799
• topic: Pimentas; Capsicum annuum; Genética; Plantas ornamentais; Peppers; Capsicum annuum; Genetics; Ornamentals; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::MELHORAMENTO VEGETAL

The Capsicum peppers are grown in a wide variety of types, sizes, colors, flavors and pungencies for various purposes. In addition, more recently, the great diversity of Capsicum has fostered its trade as ornamental plants, but there are few commercial varieties for ornamental purposes. The knowledge about the inheritance of the traits that will be submitted to continuous selections and the diversity generated from crosses are very important for the success of a breeding program of ornamental pepper. This study aimed to analyze the genetic diversity and a generation study in ornamental pepper. The genetic diversity were studied in a family structured in six generations, based on quantitative and qualitative data, separately and integrated in the same analysis. The generations study was done on quantitative traits, identifying the allelic interactions involved in the genetic control of traits. There were estimated the additive, dominance, phenotypic, genetic and environmental variance, the heritability in broad and narrow sense and genetic effects additive, dominant and epistatic (additive x additive, additive x dominance and dominance x dominance). The studies are part of the Capsicum breeding program of Federal University of Paraíba (UFPB) and Federal University of Viçosa (UFV). Two accessions of ornamental pepper plants belonging to the germplasm bank of vegetables UFPB (01, 132) were chosen based on earlier diallel study. Plants of the accessions 01 and 132 were crossed to generate the hybrids (F 1 ). The F1's hybrids were backcrossed to the parental‟s to generate the backcross progenies (BC 1 and BC 2 ) and self pollinated to generate the F 2 generation. There were studied 10 plants of each parent and F 1 , 72 plants of backcross 1 (BC 1 ), 75 plants of backcross 2 ( BC 2 ) and 147 plants of the segregating F 2 generation. All generations were applied for the analysis of genetic diversity. First a matrix was generated about the 22 quantitative characters according to the clustering method of Tocher, and then another matrix with only 19 multicategoric characters based on the arithmetic complement of the index of coincidence simple. The data integration was performed by the sum of the two matrices. The data of all generations were used to study the variances, means and allelic interactions of the 22 quantitative traits evaluated. The crosses between the parents and 01 132 generated variability in the segregating generations (F 2 ) and backcrosses (BC 1 and BC 2 ) according the individual analyzes of quantitative multicategoric and also according the study based on data integration of different kinds of characters. The traits that more contributed to genetic divergence were number of seeds per fruit, number of fruits per plant, days to flowering and days to fruiting, discarding the other variables. The following individuals are liable to selection: 5 of generation F1; 1, 35, 37, 39, 43, 44, 47 and 49 of the segregating F 2 generation in order to obtain higher number of seeds per fruit. The individuals 2, 7, 8, 16, 17, 20, 23, 27 and 44, of the generation F 2 can be selected aiming higher number of fruits per plant. The individuals 28 of F 2, the plants 18, 20, 21 and 22 of BC 1 and 1, 5, 14 and 16 of the BC 2 (F 1 x 132) are useful for the selection for early flowering and early fruit set. The additive part of the phenotypic variance found for plant height, diameter of the petal, anther length, number of fruits per plant and days to flowering and to fruiting lead to the conclusion that the phenotypic selection in the F 2 generation should be efficient to obtain genetic gains. According to the reduced model, the traits crown diameter, fruit diameter and number of seeds per fruit were not influenced by epistatic effects, but only the additive and dominant, what make possible to select superior individuals in segregating generations or improve these traits by means of hybridization, respectively.