Evaluation of Top-Cross Popcorn Hybrids Using Mixed Linear Model Methodology

Abstract

The market for popcorn (Zea mays L.) has been continuously growing in Brazil fact has required the development of cultivars adapted to local environmental conditions. For this reason, the analytical objectives of this study were to evaluate top-cross popcorn hybrids in relation to popping expansion and grain yield in three different ecogeographic regions of Brazil, in order to estimate variance components using Restricted Maximum Likelihood (REML) and predict breeding values using Best Linear Unbiased Prediction (BLUP). Genetic evaluation considered a linear model with heterogeneous residual (environmental) variances. The Restricted Likelihood Ratio Test (RLRT) evidenced significant differences (p < 0.01) for the genotypic effect. Grain yield showed a moderate heritable trait (h2 = 0.26-0.39). A higher additive genetic control was evidenced for popping expansion (h2 = 0.58-0.85). Genetic correlations and Spearman coefficient between both traits were negative, indicating that selection based on grain yield would have a negative effect on popping expansion. The top-cross hybrids showed an adequate grain yield, whereas the quality of the popcorn was lower than commercial standards.