Dry Matter Accumulation and Partitioning as Affected by Thinning in a Non-Prolific Maize Hybrid

Abstract

The objective of the present field experiment was to examine how plant density and enhanced source, i.e. thinning treatments, may affect grain yield and its components for a non-prolific maize hybrid, SC704. The environment of the hybrid maize crop was changed at intervals over its life cycle by removing every other plant in rows equispaced at 75 cm apart with a population of 13.34 plants m-2. The plants were grown with no water or nutrient restrictions. Results showed that earlier thinning was associated with greater stem, leaf, shoot and ear dry weight accumulation, ear kernel weight (EKW) and kernel number per ear row (KNER). In this ways the greatest of these characteristics were obtained in thinning at sowing i.e. 6.67 plants m-2 throughout. Delay in thinning until the 12-leaf stage reduced stem dry weight and EKW significantly. Thinning at tasseling also resulted in significantly lower stem dry weight accumulation compared to thinning at sowing. At final harvest, the stem dry weight of plants thinned at tasseling was 20.47% (P<0.05) lower than those thinned at sowing. Similar effects were found upon delay in thinning until tasseling on leaf, shoot, and ear dry weight accumulation. Delay in thinning until the 12-leaf stage or later, also reduced EKW significantly compared to plants thinned at sowing. This reduction was attributable to decreased KNER and 1000-kernel weight. According to these results, KNER and 1000-KW were found to be yield components sensitive to light environment.