RELATIONSHIP BETWEEN SPRING VIGOR AND GRAIN YIELD IN CORN

Abstract

In an experiment designed to study the relationship between seedling vigor and grain yield in corn (Zea mays L.), 25 single-cross hybrids, of a range in spring vigor (6 involved crosses between inbred parents of high seedling vigor, 6 were crosses between parents of low seedling vigor, and 13 were crosses between inbreds of high and low vigor) were grown in test for 2 yr near Woodstock, Ontario. In the 1st yr, hybrids were evaluated for differences in: rate of emergence; visual vigor rating; plant height, dry weight, and leaf number at several dates during early vegetative development; leaf area index (measured after pollination); and final grain yield. In the 2nd yr, hybrids were evaluated for differences in seed size (weight/kernel), visual vigor rating, and grain yield. No differences were detected among hybrids in rate of emergence. In the 1st yr, the visual vigor score was positively related to early plant height, but not to any of the other measures of seedling vigor. A positive relationship between seed weight and visual vigor rating was observed in the 2nd yr. The mean grain yield of the three groups of hybrids corresponded directly with their initial vigor rating in the 1st yr (i.e., crosses among high vigor inbreds outyielded high × low crosses; high × low crosses outyielded low × low), but not in the 2nd yr. Among individual genotypes, no relationship was evident between any measure of spring vigor and grain yield, in either year.