Divergência fenotípica entre acessos de uvas de mesa no Semi-Árido brasileiro

Abstract

Resumo -O objetivo deste trabalho foi avaliar a divergência fenotípica em uvas da Coleção da Embrapa Semi-Árido, com base em oito variáveis morfoagronômicas avaliadas nos anos 2005 e 2006. Nas uvas com sementes, a análise por componentes principais identifi cou oito grupos contrastantes. As variáveis mais relevantes, quanto à divergência genética, foram peso e comprimento de bagas. Em uvas sem sementes, formouse apenas um grupo, e as variáveis mais relevantes foram peso de bagas e produção. A distância euclidiana média padronizada no grupo com sementes mostrou que 41% dos acessos apresentaram estimativas acima da média geral. No grupo sem sementes, o percentual foi de 47%. Foi observada concordância de resultados com os componentes principais. Pelo UPGMA, formaram-se três grandes grupos das uvas com sementes: o primeiro, com 14 acessos; o segundo, com seis acessos e similaridade de 56%; e o terceiro, com 19 acessos e similaridade de 73%. Das uvas sem sementes, formaram-se três grupos: um, com 11 acessos e similaridade de 59%; outro, com sete acessos e similaridade de 58%; e o terceiro com apenas um acesso. Sugere-se que os acessos com maior divergência quanto aos caracteres estudados sejam utilizados para a obtenção de híbridos de videira.Termos para indexação: Vitis vinifera, descritores de videira, divergência genética, melhoramento genético. Phenotypic divergence among table grapes accesses in the Brazilian Semi-AridAbstract -The aim of this work was to evaluate the phenotypic divergence in grapes from the Collection of Embrapa Semi-Árido, in 2005/2006, based on eight morphoagronomic variables. In seeded grapes, the analysis by main components identifi ed eight contrasting groups. The most important variables for genetic divergence were weight and length of berries. In seedless grapes, only one group was found, with berry weight and yield as the most important variables. The standardized mean Euclidean distance in the seeded grapes showed that 41% accesses had estimative higher than the general mean; in the seedless grapes, it was 47%. Agreement with the principal components was observed. Through UPGMA, three big groups with seeds were formed: the fi rst with 14 accesses; the second with six accesses and 56% similarity; the third with 19 accesses and 73% similarity. In the seedless group, two groups were formed: one with 11 accesses and 59% similarity; another with seven accesses and 58% similarity; and the third with one access. It is suggested that accesses with higher divergence for the studied characters be used to obtain grape hybrids.

Genetic diversity of a brazilian wine grape germplasm collection based on morphoagronomic traits

“…However, the highest score in the last eigenvector was higher than 0.70, associated with the characteristic bunches weight, indicating that no trait can be discarded. Borges et al (2008) obtained eight groups of seeded grape cultivars and one group of seedless grape cultivars by principal componentes in the same germplasm collection. They observed an agreement between the most divergent accessions of seeded and seedless table grapes cultivars by two multivariate methods: principal components and the mean Euclidean distance.…”

“…The multivariate techniques in the analysis of quantitative and qualitative characteristics have been applied in viticulture in the evaluation of the diversity of genotypes for resistance to diseases (NASCIMENTO et al, 2006) and for morphological, agronomic and biochemical descriptors (MICHELI et al, 1993;CRAVERO et al, 1994, MATHEOU et al, 1995a, 1995bBOSELLI et al, 2000;COELHO et al, 2004;BORGES et al, 2008). The molecular characterization of 81% of the accessions of the Embrapa Semi Arid grapevine germplasma bank was performed by Leão et al (2009), using seven microsatellite markers.…”

“…The allelic profiles were compared with international databases, allowing the identification of many duplicate accessions, synonyms and name errors, generating a robust database for grape cultivars identification. Borges et al (2008) analyzed a group of table grapes cultivars of the same germplasma bank by principal components and UPGMA.…”

Phenotypic divergence among wine grap accessions in the semi-arid region of Brazil

“…Studies of morphological characters contribute to demonstrate the diversity in germplasm of Vitis vinifera (Martinez and Martinez 2007). A similar study was conducted by Borges et al (2008) with grapes for The dissimilarity measures were determined by analysis of the mean Euclidean distance, where, for white grapes, the minimum and maximum dissimilarities were 0.28 in the accessions Moscato Canelli and Seara Nova, and 2.41 in Altesse and Colombard, respectively, with an overall mean estimate of 1.35. These results indicate that the last two accessions in this analysis are the most divergent.…”

“…The characterization of the accessions of the grapevine genebank has been studied since the eighties, however, the genotypic and phenotypic divergence of grape accessions has only recently been assessed (Borges et al 2008, Leão et al 2008. The study of 73 wine grape accessions and cultivars in the valley of the lower course of the São Francisco river, Brazil, that make up the genebank was only intensified in recent years, due to the implementation of six wineries in the region.…”