FEED VALUE OF FORAGE MAIZE HYBRIDS VARYING IN TOLERANCE TO PLANT-DENSITY

The yield response of forage maize (Zea mays L.) genotypes to plant de nsity is not as clear as for grain hybrids, where density tolerant and sensitive types have been identified. A study including field trials, laboratory analyses, and in situ digestibility tests with one density -tolerant and one sensitive hybrid was conducted with plant densities of 4 to 16 plants m-2. The investigations concentrated on stover. Ther e are differences in sensitivity to planting density in forage maize y ield. Differences between sensitive and tolerant genotypes in plant de nsity range for maximum yield were 0.43 and 1.18 plants m-2 for grain and forage, respectively. The decreased sensitivity for grain compared with forage was 50.7 and 100.0% for the sensitive and the tolerant hy brid, respectively. It was not possible to separate the tolerant and s ensitive hybrids in terms of total digestible nutrients (TDN), a measu re of overall feed value. For plant densities lower than those require d for maximum dry matter yield, there was a significant difference bet ween the tolerant and the sensitive hybrid in TDN.