Abstract

The objectives of this research were: (a) to evaluate the strategy of line selection using the general combining ability test (delayed form), and the performance per se of groups of lines with endogamy levels between S4 and S7. (b) to estimate phenotypic correlation between grain yield and other agronomical traits in lines and hybrids, and between lines and their hybrids, for several economically important factors. Two groups of hybrids were formed, one intermediate and one late cycle. The V-385 C3 was used as the common testero The lines were simultaneously multiplied. The lines themselves and the hybrids were planted in Zapo pan and Tlajomulco, Jalisco, Mexico. Use of late testing (S3 or S4 and later), simultaneous evaluation of the lines themselves, and the graphic method developed were important strategies for selecting lines with a high general combining ability and agronomic quality. The study was also use fuI for reducing the number of lines to evaluate, and for selecting in advance the best type of hybrid to produce. Phenotypic correlation for grain yield between lines and test crosses was similar in the two lines (r= 0.21 and r= 0.20 for intermediate and late lines, respectively), and not significant. This confirms that selecting lines using only the grain yield of their test crosses is not a completely reliable procedure, and justifies the strategy of performing both evaluations.