Avaliação de cinco estratégias de amostragem para a obtenção da coleção nuclear de soja (Glycine max (L.) Merrill) / Evaluation of five sampling strategies to obtain the soybean (Glycine max, L. Merril) core collection

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

A core collection is a group of accessions selected to represent the genetic variability of the entire germplasm collection of a species with minimum redundancy. Core collection construction is strategic because it allows prioritization of assessment, characterization and resource application in a manageable group of accessions of a species. The main objective of this study was to develop and validate a soybean core collection using five sampling strategies. All the available information was gathered from passport and characterization (qualitative) data and 18 quantitative traits from 15,558 accessions of the Glycine max (L.) Merrill germplasm subcollection from the United States Department of Agriculture (USDA). The sampling intensity for all the strategies was 10.28% resulting in 1,600 accessions for each entire collection obtained. The first core collection was obtained by random sampling (strategy R). The other four core collection were obtained by the combination of two procedures to choose the number of accession in each group (proportion and logarithm) and two procedures to choose the accessions in each group (random sampling and sampling based on multivariate analysis of the quantitative traits) that generated the following strategies: proportional (P), logarithmic (L), proportional multivariate (MVP) and logarithmic multivariate (MVL). The parameter estimates (means, variances and variation amplitudes), the statistical tests and frequency distributions indicated that there were differences among the five core collections compared with the entire collection. But all were considered acceptable to represent the entire collection because more than 70% of the means and amplitudes of the characteristics were not significantly different from the means and amplitudes of the entire collection. The core collection developed by strategy R best represented the genetic structure of the base collection in statistical terms. But this type of sampling may not include the accession whose proportion is small in the entire collection. Strategies P and L, while not maximizing the representativeness of the core collection in statistical terms, were superior in terms of variability preservation for breeding purposes. In this sense, the MVP and MVL strategies produced the two best core collections with the first being slightly superior. The MVP sampling strategy was characterized by maintaining the maximum variability and minimum redundancy of the accessions, and therefore, was chosen to form the soybean core collection consisting of 1,600 accessions.

ASSUNTO(S)

soybean soja genetic variation in plant germoplasma vegetal variação genética de plantas vegetal germplasm

ACESSO AO ARTIGO

Documentos Relacionados