STABILITY OF YIELD AND FORAGE QUALITY OF CORN HYBRIDS

Abstract

In México the need for better corn (Zea mays L.) forage hybrids has increased quickly. The objective of this study was to identify stable corn hybrids with higher forage and quality production for different regions. In 2004 four hybrids from the National Research Institute for Agriculture, Forest and Livestock (INIFAP) and three commercial ones were evaluated at six locations greatly differing in altitude and climate: Pabellón, Ags., Iguala, Gro., Chapingo, Méx., Valle del Yaqui, Son. and Torreón, Coah. (Spring and Summer). A randomized complete blocks design with three replications was used at each location. Fertilization varied from 180 to 220 kg ha^-1 N and from 70 to 90 kg ha^-1 P across locations. Plant density was 80 000 plants/ha. Total dry matter production (TDM), neutral detergent fiber (NDF), acid detergent fiber (ADF), in vitro digestibility (IVD) and crude protein (CP) were measured, and production of milk per hectare (MPHA) was estimated. Interaction hybrid x location was detected only for TDM and MPHA (P ≤ 0.05). The subtropical hybrid ‘H-376’ was the best for TDM across locations, yielding from 17.6 to 23.0 t ha^-1. The highland hybrid ‘H-157’ had also good response, but only in more favorable locations as Pabellón, Iguala, Chapingo, and Torreón Spring with yields varying from 20.0 to 23.9 t ha^-1 of TDM. The control ‘ABT-7887’ was the best in forage quality with less NDF content and higher IVD, outyielding hybrid ‘H-376’ in 37 and 33 g kg^-1, respectively. Hybrids H-376 and H-157 were stable in MPHA production and had good responses across environments, especially at Iguala, Pabellón, Sonora and Torreón Spring, where they yielded between 11.5 and 13.8 t ha^-1. The control ‘Z-23’ had better response in more favorable locations, as Sonora and Pabellón, where it yielded more than 15.0 t ha^-1.