Variability of grain productivity and energy profile of maize (Zea mays L.) genotypes

The goal of the present work was to test if there is genetic variability between precocious and superprecocious cycle maize genotypes in terms of grain productivity and energy profile. Data from two separate experiments were used. An experiment was conducted with 36 precocious cycle genotypes and another experiment was conducted with 22 superprecocious cycle genotypes. The following variables were measured: grain productivity (PROD), ethereal extract (EE), starch (ST), amylose (AML), and nitrogen-corrected apparent metabolizable energy (AMEn). For all variables, basic statistics and analysis of variance was performed. For each experiment, the genotypic correlation matrix was calculated and the multicollinearity was evaluated. Then, the Mahalanobis generalized distance matrix was calculated, the clustering of the genotypes was performed and the averages of the groups formed were compared, separately for each experiment. There was genetic divergence between precocious genotypes, as well as between superprecocious genotypes, especially in terms of grain PROD, EE concentration, and AML concentration. Groups of more productive genotypes presented lower EE and higher AML grain concentrations. The results of the present study indicated that it is possible to plan crossings between groups of genotypes in terms of PROD, EE and AML, with the goal of maximizing heterosis. (C) 2014 Elsevier Ltd. All rights reserved.