Data/hora: 19/06/2024 13:41:35

Biblioteca(s): | Embrapa Arroz e Feijão; Embrapa Hortaliças.
Data corrente: | 25/11/2003
Data da última atualização: | 15/03/2011
Autoria: | REGO, E. R. do; RÊGO, M. M. do; CRUZ, C. D.; CECON, P. R.; AMARAL, D. S. S. L.; FINGER, F. L.
Título: | Genetic diversity analysis of peppers: a comparison of discarding variable methods.
Ano de publicação: | 2003
Fonte/Imprenta: | Crop Breeding and Applied Biotechnology, Londrina, v. 3, n. 1, p. 19-25, Mar. 2003.
Idioma: | Inglês
Conteúdo: | There are a lot of variables in genetic diversity studies, and it is nevessary to know whether or not they are all important and which ones can be discarded. There are often little changes in clutering patterns if a subset of these variables is used, becaurse the discarded variables are redundant or of little contribution to the variability. This study aimed at comparing two discards of variables methods - the Singh method and the principal components method - as well as evaluating the effect of the discards on the cluster analysis. In this analysis data of six ripe fruits traits were used. Other characters with previously know variability or collinearity were added to the analysis. The method considered being the most efficient was the one, which indicated variables that did not after the initial clustering pattern when discarded. The Singh method did not detect variation differences when standardized data were used. When the distanced was obtained by the non-standardized data, the pericarp thickness (0.018%), total soluble solids (0.1668%) and minimum width (2.99%) had the lowest contirbution to the divergence. The principal components pointed out that the characteristics fruit length, total soluble solids and seeds yield fruit were considered as dispensable variables. There were no changes in the initial clustering pattern when fruit length was discarded. The data showed that the two compared methods different, since Singh's and principal component methods showed different variables to be discarded. The Singh method was not efficient in detecting multicollinearity among variables. The principal component method was more efficient in pointing out the variables that can be discarded. It is advisable that the genetic divergence is calculated based on the scores of the principal components. In future studies, when there is no replicated data, the genetic divergence and the pinpoint of characters should be calculated  based on the principal component scores to avoid discarding some important variables when determining divergence. However, if the variable values differ independently, the Singh method based on Euclidean distance is appropriate.
Palavras-Chave: | Análise multivariada; Diversidade genética; Metodologia.
Thesagro: | Biodiversidade; Pimenta.
Thesaurus Nal: | Capsicum.
Categoria do assunto: | --
Registro original: | Embrapa Arroz e Feijão (CNPAF)

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CNPAF - (21793-1) - ADD - AP - -- - 631.05 - C - 200400141 - DIS
CNPH - (26653-1) - ADD - AP - -- - 631.53 -  -  - DIS