Effect of planting time and plant density on the number of grains and yield of a maize hybrid in the central region of Córdoba (Argentina)

Abstract

The change in the sowing date of maize modifies the response in grain yield to the plant density. The objective of this work was to study in the central region of Córdoba, Argentina, the effect of sowing date and plant density on the determination of the yield and its components. The experiments were conducted in the field in 1995/96 and 1996/97 and included different sowing dates (October to December) and plant densities (3.7 to 15.2 pl m⁻²) with the Morgan-370 hybrid. Late sowings and high densities reduced the number of ears per plant and grains per ear, but did not affect the spikelet morphogenesis in the upper ear. The quantity of photosynthetic active radiation intercepted during the 31 days around silking explained the variation of the number of grains per plant. December sowing decreased the yield. At early sowing dates, a higher number of plants per m² is necessary to get high yields, but not at late sowing dates.