Environmental stratification for evaluation cotton genotypes in Mato Grosso State, Brazil. / Estratificação ambiental para avaliação de genótipos de algodoeiro no estado de Mato Grosso.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Data of yield were obtained from Regional Yield Trials of cotton (Gossypium hirsutum) genotypes carried out in Mato Grosso State, Brazil in 1998/99, 1999/00 and 2000/01, was used in this study on environmental stratification and evaluation of the minimum number of environments required for cotton genotypes assessments. Eight genotypes were evaluated in 1998/99, fourteen in 1999/00 and fifteen in 2000/01. The genotypes were planted in the following eight locations: Campo Novo dos Parecis, Sorriso, Primavera do Leste, Rondonópolis, Campo Verde, Sapezal, Pedra Preta e Lucas do Rio Verde. From the analysis of variance and the environmental means, two techniques were applied based on AMMI analysis (Additive Main effects and Multiplicative Interactions) analysis. The first method was based on an interaction distance between locations estimated by AMMI analysis. The second method was based on the winning genotypes approach, throught the interactions estimates from models AMMI1 and AMMI2. The methodologies were efficient to provide an environmental stratification at every years of evaluation. The results of the matrix of coincidences over the three years of this study suggested the formed strata have a predictive property, since their identification was based on a different set of genotypes in each year and they remained the same over the years. Then, the method based on an interaction distance between locations estimated by AMMI analysis permited to constitute one stratum involving Campo Verde and Lucas do Rio Verde. However, the method based on the winning genotypes approach has formed a two strata involving four locations; the first group was constitute by Sorriso and Lucas do Rio Verde and the second involved the locations Primavera do Leste and Lucas do Rio Verde. The methodology based on the winning genotypes approach to made possible the formation of environmental strata based on statistical criteria of easy understanding and showing graphic display. This method to allowed the demarcation of strata in a mathematical way through the performance winning genotypes; it provided an integrated understanding about the recommendation of genotypes with specific adaptation for each environmental stratum.

ASSUNTO(S)

environmental stratification melhoramento genótipo vegetal cotton zoneamento ecológico plant breeding genótipos algodão ammi analysis

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