EFFECTS OF GENOTYPE, PLANTING PATTERN, AND PLANT DENSITY ON PLANT-TO-PLANT VARIABILITY AND GRAIN YIELD OF CORN

Three experiments were conducted near Guelph in 1971 and 1972 with the objectives of studying (1) the effect of planting pattern, plant density, and genotype on plant-to-plant variability in corn (Zea mays L.), and (2) the effect of this variability on grain yield. All three studies entailed detailed measurements of the height of individual plants at various times during vegetative development, and of per plant grain yields. Frequency distributions of individual plant height and grain yield were normal; a coefficient of variability was used to characterize the variation within each treatment. In the first experiment, plant density was found to have a significant effect on plant-to-plant variability in grain yield; row spacing did not affect variation among individuals in either plant height or yield. The second experiment involved study of five double-cross hybrids, five single-cross hybrids, and the 10 possible 50:50 mixtures of the single-cross hybrids. Single-cross hybrids were more uniform and higher ...