Selection among and within full-sib corn families in Chiapas, Mexico

Three cycles of full-sib recurrent selection were conducted on three commercial corn (Zea mays L.) varieties: 'V-424' (early maturity), 'V-534' (intermediate maturity), and 'V-526' (late maturity) during 2002 to 2005. The objective was to increase grain yield but maintaining both the phenotype and the maturity of the original populations. Fourteen experimental varieties derived from cycles one, two, and three from the three populations, plus their respective original populations, were evaluated during the 2005 rainy season (Summer) and the 2006 irrigated season (Winter) in Ocozocoautla and Villaflores, Chiapas, Mexico. Significant differences among locations and varieties for the three populations were found for grain yield, while the interaction location x variety was significant only for population 'V-534'; experimental varieties 'V-424 Coita C3', 'V-534 Coita C3' and 'V-526 Villaflores; C3' had superior grain yields than to the original populations, without changes in their phenotype and maturity, with grain yield responses of 3.0 %, 5.2 %, and 4.2 % per cycle of selection, respectively.