Assessment of natural variability in leaf morphological and physiological traits in maize inbreds and their related hybrids during early vegetative growth

Abstract

ABSTRACTThe superior growth of maize hybrids and some inbreds may be linked to key leaf growth features and critical components in carbon and nitrogen metabolism. Here, we performed simultaneous growth, physiological and heterosis analyses of morpho-physiological traits in four maize inbreds (B73, Mo17, Sids7, Sids63) and two hybrids (B73 × Mo17&Sids7 × Sids63). B73 and Sids7 exhibited alternate superiority over Mo17 and Sids63 in most growth traits. Both hybrids gained an early advantage over their parental inbreds in growth. They showed relatively similar behavior in many growth traits but differed significantly in biomass accumulation. Physiologically, B73 and Sids7 predominated in total pigments. Further, B73 contained the highest levels of sucrose, glucose, amino-N, and total N among inbreds. Both hybrids did not significantly differ in sucrose and total soluble sugars. However, Sids7 × Sids63 had consistently higher N fractions than B73 × Mo17. Both hybrids showed common and specific heterotic patterns. The superior growth of B73, Sids7, and hybrids is positively correlated with a set of leaf morphological (leaf area, leaf breadth, and LAI) and physiological (total chlorophyll, total pigments, and total N) traits. Advantages in these traits and efficient resource utilization support the superior growth of maize genotypes.