Influence of plant height and of leaf number on maize production at high plant densities

Abstract

This experiment was conducted in Ames, Iowa, US, with the purpose of verifying if reduction in plant height, through the use of dwarfing genes, or leaf number, by growing short season genotypes, can be a useful strategy to reduce barrenness and improve maize tolerance to drought and high plant population stresses. Five genotypes were tested: a full season hybrid, a short season hybrid, and three dwarf lines, containing the homozygous recessive genes d3, br2 and d1. Each genotype was planted at four plant populations: 25,000, 50,000, 75,000 and 100,000 plants.ha^-1. There was no significant drought stress during the entire growing season of 1994. High plant population decreased number of grains per ear of dwarf lines and did not affect this variable for hybrids. Consequently, differences in yield between hybrids and dwarves were greater at the higher plant populations. Inbreeding depression, unimproved genetic background and poor plant architecture limited the response of dwarf grain yield to the increase in plant population.