EFFECT OF THE ARCHITECTURE OF THE PLAN AND THE POPULATION DENSITY ON PERFORMANCE AND CORN STURVER QUALITY

Abstract

The influence of plant architecture and population density on the yield and nutritive quality of maize (Zea mays L.) stover, was studied on five genotypes. These were four lines of different leaf angle and prolificacy: a) horizontal leaves, or "Normal" architecture, and one ear per plant; b) erect leaves above ear and horizontal leaves below ear, or "Mock" type architecture, and one ear per plant; e) all leaves erect ("Piña" type) and one ear per plant; and d) "Prolific" of two ears per plant and normal architecture; it was also included a commercial hybrid (H-30; normal architecture). The experiment was done at Chapingo, State of México, under irrigated conditions using two plant densities (50 000 and 150 000 plants/ha). Compared to the low population density, the high one caused a reduction in stover yield per plant in all genotypes, because biomass accumulation decreased in each stover component (leaf, stem, husk and cob); besides, the high population diminished the stover quality since it decreased the stem digestibility in all the lines (not in the hyhrid) and increased in 3% their neutral detergent fiber content. The erect-leaf lines ("Piña" and "Mock") and the "Prolitic " one had more biomass in husk, leaf and cob, and had more digestible cobs and husks, as well as less neutral detergent fiber content, than the "Normal" line of horizontal leaves. The maize hybrid yielded more stover than the four lines, due to its higher stem and cob dry weight, although its stover quality was less than in the lines because of its higher fiber content.