Plant Traits Related to Productivity of Maize. I. Genetic Variability, Environmental Variation, and Correlation with Grain Yield and Stalk Lodging¹

Abstract

Numerous physiological traits act and interact with each other and the environment to determine maize ( Zea mays L.) grain yield and stalk lodging. Plant breeders need to know the most important traits on which to concentrate breeding efforts. Our objectives were to: (i) evaluate genotypic variation and effect of environment on 21 plant traits measured on 76 maize hybrids representing four maturity groups; and (ii) determine the relationship of these traits to grain yield and stalk lodging. The four groups were evaluated separately at several locations for grain yield and stalk lodging in 1984 and at single locations in 1984 and 1985 for plant traits. This investigation reports on an extensive evaluation and comparison of individual traits related to grain yield and stalk lodging in maize. For all groups, significant variation among hybrids was observed for most traits when analyzed over 2 yr. From six to nine traits in each group exhibited significant hybrid ✕ year interaction. However, 13 of 21 traits exhibited significant hybrid ✕ year interaction in at least one of the four groups. Evaluation of phenotypic correlations indicated none of the plant traits was significantly and consistently correlated with grain yield or stalk lodging over the four groups. The correlation between a given trait and grain yield or stalk lodging was affected by relative maturity and hybrid genotype, as well as the environment. These results indicate the relationship between plant traits and productivity is complex and that the use of a single plant trait in a breeding program would likely be ineffective in improving grain yield and/or stalk lodging resistance of maize