Local adjustment method for field experiments. 1. The method and its examination by computer simulation

Abstract

The modification of `the nearest neighbour' method for using various size plots in field trials has been developed and the results of testing its validity by computer simulation are presented . It was found that the Field-S variant of this method using a square pilot area is the best for fields with a low and medium spatial heterogeneity . The Field-L variant using the least quantity of neighbours, offers advantages for fields with a medium and high spatial effect .The optimal values of the controlling coefficients of these variants were computed to allow for the calculation of the environmental indices over a wide interval of spatial heterogeneity with sufficient accuracy . For this reason, this local adjustment method is recommended as an obligatory statistical procedure for a prior data analysis of any field experiments that have fulfilled the necessary requirements . The original Field and CRBSD programs using the local adjustment method developed have been created for IBM-compatible personal computers .

Alternativas experimentais na avaliação de famílias em programas de melhoramento genético do feijoeiro

“…Entre esses métodos, o de Papadakis (1937) e o de médias mó-veis (Townley-Smith & Hurd, 1973). Recentemente, em razão do interesse nesse tipo de análise, novas propostas surgiram (Bartlett, 1978;Wilkinson et al, 1983;Besag & Kempton, 1986;Samra et al, 1990;Vivaldi, 1990;Zimmerman & Harville, 1991;Ball et al, 1993;Brownie et al, 1993;Stroup et al, 1994;Helms et al, 1995;Anoshenko, 1996;Clarke & Baker, 1996). Em todos esses trabalhos foram evidenciadas as vantagens do uso da análise espacial.…”

Ajustes de quadrado médio do erro em ensaios de competição de cultivares de milho pelo método de Papadakis

“…Algumas alternativas de análise espacial, por diversos métodos, têm sido aplicadas objetivando aumentar a precisão experimental (Mendez, 1971;Saez & Magaña, 1990;Vivaldi, 1990;Zimmerman & Harville, 1991;Brownie et al, 1993;Amaro & Cobo, 1994;Stroup et al, 1994;Anoshenko, 1996;Clarke & Baker, 1996;Amaro et al, 1997;Souza et al, 2000). Esses métodos são estudados há várias décadas e atualmente vêm sendo aplicados com maior freqüência, principalmente pela disponibilidade de técnicas computacionais para a resolução do grande volume de cálculos que exigem.…”

“…Porém a abrangência espacial das parcelas vizinhas consideradas no cálculo do índice de produtividade não é consenso entre os pesquisadores, haja vista que diferentes formas de cálculo são consideradas (Mendez, 1971;Saez & Magaña, 1990;Vivaldi, 1990;Brownie et al, 1993;Amaro & Cobo, 1994;Stroup et al, 1994;Clarke & Baker, 1996;Amaro et al, 1997;Souza et al, 2000). Os resultados obtidos apontaram para uma tendência de melhoria da precisão com o método de Papadakis, mas não há uniformidade de idéias quanto à magnitude da eficiência desse méto-do, deixando-o numa posição, no mínimo, de igualdade em comparação com outros métodos (Vivaldi, 1990).…”

Local adjustment method for field experiments. 2. Application in experiments with and without replications

“…The modification of the `nearest neighbour' method for work not only with single plants but also with different size plots in real field trials and the estimation of the optimal values for its controlling coefficients have been made in the previous paper (Anoshenko, 1996) . The Field-method could be used in experiments with single plants, as well as with various size plots .…”

“…Therefore, when using these procedures of local adjustment experiments should meet the following requirements : (i) the random placement of genotypes in field trials is necessary ; (ii) the registration of results from all plots is desirable but obviously defective plots must be excluded from the analysis ; (iii) the number of plots in the experimental field should be sufficiently large ; (iv) the test field must have no drastic artificial heterogeneity. These requirements were discussed in more details in the previous paper (Anoshenko, 1996) .…”