Effect of Seed Vigor on Intraspecific Competition and Grain Yield in Maize

Abstract

High‐vigor seeds result in faster emergence of seedlings and crop establishment than low‐vigor seeds. These characteristics could enhance plant competitive ability and could have direct effects on maize (Zea mays L.) grain yield. This study examined the hypothesis that seed vigor heterogeneity in maize seed lots could increase intraspecific competition and negatively affect crop grain yield. A 2‐yr experiment was executed combining two hybrid maize seed lots, possessing high‐vigor and low‐vigor seeds, in seven different distributions in the sowing row. The distributions of the plants originating from high‐ and low‐vigor seeds were evaluated at harvest for dry mass accumulation, prolificacy, number of grains per row, number of rows per ear, 1000‐grain mass, and grain yield. A replacement series design for data analysis of two homogeneous populations and five seed mixture populations was applied. We concluded that, in plant populations originating from heterogeneous seed lots, intraspecific competition was intensified, resulting in losses of dry mass accumulation and grain yield. Plants originating from low‐vigor seeds had less competitive ability and reduced plant dry mass accumulation and grain yield than those originating from high‐vigor seeds and were responsible for crop yield losses. Plants originating from high‐vigor seeds had a dominant effect on those originating from low‐vigor seeds and had no compensatory effects. The major production component affected by intraspecific competition was the number of grains per row.