Relationship of the Kernel Sink for N to Maize Productivity1

Abstract

This study was designed to evaluate the relationship of zein content with yield potential of maize (Zea mays L.). Maize cultlvars were grown under different rates of N (0 to 201 kg/ha) with and without nitrapyrin (0.55 kg/ha) added to correlate protein content, kernel weight, and grain yield. Carbon‐14 dioxide was applied to maize hybrid, Pioneer 3369A, to determine the effect of N on sucrose translocation into kernels. The results indicate that zein and glutelins combined may serve as a functional N sink in the kernel to affect starch accumulation, kernel weight, and yield; however, zein may be more effective because its synthesis can be manipulated readily by N fertilization and genetic means. A positive correlation between zein content, kernel weight, and grain yield was consistently observed. The quantities of zein produced vary according to the amounts of N fertilizer applied. The increase in zein with higher rates of N fertilization (up to 201 kg/ha) did not decrease the nutritional quality of seed protein because increases in germ size and a slight increase in non‐zein protein in the endosperm occurred concurrently. Based on this data, the selection of maize hybrids which are capable of producing maximum amounts of zein with additional available N should provide a means of increasing kernel weight and grain yield through the greater N sink potential of these hybrids.