INTEGRATED DIALELLIC WITH LINES OF DIFFERENT PROGRAMS CORN FOR THE WARM REGION

Abstract

The purpose of this study was to evaluate corn (Zea mays L.) lines from three breeding programas, with respect to general combining ability and to identify hybrids with a high level of heterosis. It was expected that the best hybrids would be those formad between lines breeding programas. In the 1982 rainfall season, a diallel desing with nineteen s₂ and from different s₄ lines was tested in two enviroments, one with Aw0 and the other one with Aw1 climates (Koppen classification). Griffing's genetic design number four was used. Lines were provided by Rio Bravo, Tamaulipas (arid, warm climate), Iguala, Guerrero (semi-arid, warm climate) and Cotaxtla, Veracruz (humid, warm climate) programs. The lines representad germplasm from Tuxpeno Crema 1, La Posta, ETO PB x Tuxpeno PB, San Juan, Brachytica, VS-521, B-670 and T₁₁ , a line froM H-507 which is a tropical double cross hybrid. Highly significant differences for locations and general and specific combining ability effects were detected. Lines with the largest additive effects were D7501-471-2 and LE-27. Lines from Rio Bravo formed the hybrids with the largest specific effects. Some hybrids yielded more than H-511, the best commercial hybrid. The best experimental hybrids were those formed with lines from different breeding programs, such as: LRB-14-413-7 x LE-36, D7501-471-2 X LE-27, D7501-471-2 x LE-36, D7501- 471-2 x LRB-16-411-2, LRB-213- 41 x LE-27, VS-521-34-2 x LRB-14-413-7.