Maize ( yield potential).

Abstract

Average grain yields of maize vary substantially among the temperate, subtropical, and tropical regions. Although the level of agronomic and economic inputs could explain much of the lower yield in the tropics, there appear to be regional differences in maximum grain yields for crops grown under nonlimiting conditions. These yield differences seem associated with partitioning of total dry matter to grain: efficiency of total biomass production appears similar for the regions. At higher latitudes, grain yield tends to be limited by processes that influence the supply of assimilates for grain filling; in the lower latitudes (tropical) yield tends to be limited by processes that control grain sink development. Factors that influence crop growth rate, partitioning of dry matter to the developing ear, spikelet fertility, and kernel abortion may influence grain number in tropical maize. Weight of individual grains is considered in terms of factors that might influence the size of the individual kernel sink and the supply of assimilates for grain filling. Describes the maize plant and notes a few special charactersitics of the crop as a cereal. Focuses on limitations to grain yields in tropical maize (from lower elevations), with description of some physiological factors involved and suggestions for genetic avenues to improve grain yield. Emphasis is on improvement of yield efficiency through dry-matter partitioning.-from Authors