Influence of Environment on Stability of Corn During Vegetative Growth1

Abstract

Purpose of this study was to determine stability during vegetative growth for a diallel series of 10 corn hybrids (Zea mays L.) and their 5 inbred parents under greenhouse and field environments and to compare parenthybrid relationships in the two environments. Measurements were taken on fresh weight, adventitious root number, and leaf number at successive ages.Analyses of variance within ages, across environments, and within environments across ages were completed for each character. Genetic variation in terms of other variability was expressed by ratios between genotype and environmental variance. Correlations between parents and hybrid progeny in each environment and between characters within and between environments were determined.Growth was more rapid in the field. Leaf number was least variable and fresh weight most variable. For each character and type of germplasm there was greater variation between locations than between years. Environmental variance and ratios between field and greenhouse means for individual genotypes usually were higher for hybrids, while relative genetic variation in terms of other variability was higher for inbreds.Respective variances were usually higher in the field. Age ✕ replicate and age ✕ genotype ✕ replicate interaction variances for both inbreds and hybrids were higher in the field where measurements were taken on different plants than in the greenhouse where successive measurements were taken on the same plants.The association of inbred performance with general combining ability rating by diallel analysis was higher in the constant greenhouse environment. Also, hybrid performance was always more closely related to respective midparent values in the greenhouse. Associations between environments for fresh weight leaf number were usually significant by the third age of sampling at 650 thermal units. In all environments, associations between fresh weight and leaf number were most marked.