Potencial de híbridos comerciais de milho para obtenção de linhagens em programas de melhoramento

Abstract

With the objective of identifying the best commercial hybrids to extract maize lines, a top cross scheme of 49 endogamic partial lines (S3) was carried out with the IA33 tester. The resultant hybrids were evaluated for grain yield, in Campinas, Mococa, and Palmital (São Paulo State Brazil), in two agricultural years (2005/2006 and 2006/2007), in a randomized block design, with three replications, in two experiments (TC1 and TC2). Individual and group variance analysis and a grouped analysis of the experiments with common treatments were carried out, for each place. The top cross hybrids were grouped according to the line origins. Afterwards, orthogonal contrasts were carried out by using the Student's t test, in order to compare the hybrid groups. It was verified that the use of commercial hybrids to extract lines is an interesting strategy. In general, it was also verified that the top cross hybrid groups, whose lines originated from the AG1051, Master, and XL357 hybrids, obtained high yield, with a higher potential for lines extraction.