RESPONSE OF MAIZE HYBRIDS TO POTASSIUM APPLICATION AT DIFFERENT POPULATION DENSITIES

Abstract

Maize producers in México confront a permanent challenge of getting a greater production at a lower cost. To increase the benefit/cost ratio, requires an optimal combination of factors involved in maize production. Some of these factors are variety, population density, disease resistance and mineral nutrition. The importance of potassium in crop production is well known; however, studies have out in México have showed no relevant effect of potassium application on grain yield. In this research it was studied the effect of potassium on grain yield and stalk lodging, and the genotypic responses to potassium rates combined with high population densities. The study was carried out at two locations representing the conditions of AhualulcoEtzatlán and Ameca-Cocula valleys, located in the central region of Jalisco, México. Three factors were studied: varieties (P-3288, B-840 and HV-313), population densities (50, 75, and 100 thousand plants
per hectare), and potassium rates (0, 120, and 240 kg ha^-1). The experimental design was a randomized complete block design with four
replications, under a factorial treatment arrangement (3 x 3 x 3). The traits measured were: grain yield (kg ha^-1), number of ears per plant,
percentage of healthy ears and percentage of plants with stalk and root lodging. Potassium applications did not have a significant effect
on any of the studied variables, although it increased grain yield at the highest plant density; however, the highest grain yield was obtained at 50 thousand plants per hectare without potassium application. The interaction varieties x densities x potassium was not significant, but potassium applications tended to reduce stalk lodging, mainly at the density of 50 000 plants. B 840 and P 3288 varieties reduced their yield as plant density increased, while HV 313 tended to increase it. Ears per plant, percentage of healthy ears, and stalk lodging were the more important traits which influenced on grain yield.