Repeatability estimates of genetic, phenotypic and environmental correlations in oats with and without fungicide application

Abstract

1 ABSTRACT - Estimates of associations among traits are not very precise when based on annual data since the year factor influence the phenotype strongly. Therefore, objective of this work was to estimate the repeatability coefficients and number of years needed for an accurate prediction of genetic, phenotypic and environmental correlations among six important traits in oat with and without fungicide application (treatments). Nine oat cultivars were evaluated for four years (2000, 2001, 2002, and 2003) with and without fungicide, in a random block design with three replications. In the absence of fungicide, two years of trial evaluation were enough to provide reliable phenotypic and genetic correlation estimates; the same was not true for the experiments with fungicide application where at least seven (phenotypic) and 21 (genetic) years were required. In both treatments the environmental correlation estimates were little predictable.