Grain Composition and Productivity of Maize Hybrids Derived from the Illinois Protein Strains in Response to Variable Nitrogen Supply

Abstract

The Illinois Long‐Term Protein Selection strains of maize (Zea mays L.) have been employed in a variety of studies investigating the genetic and physiological control of maize grain composition. These prior studies, however, have not assessed the grain composition and yield potential of these strains in hybrid combinations with an elite tester, or in response to supplemental N. Our objective was to study the interactive effect of genotype and N supply on productivity and grain quality for hybrids with a wide divergence in grain protein. Hybrids derived from the Illinois Protein Strains were evaluated in a 2‐yr field experiment where N rates were varied from 0 to 235 kg ha−1 (in eight 34‐kg increments), along with a current commercial hybrid sharing the same female parent (FR1064). The Illinois Protein Strain hybrids produced grain protein concentrations that reflected the strain parents, with all hybrids except Illinois Low Protein showing increased grain protein in response to increasing N supply. Many other strain attributes were also manifested at the hybrid level, including the relative differences in kernel weights and the inverse relationship between grain protein to both starch concentration and grain yield. Nitrogen supply positively enhanced grain yield in all hybrids, primarily by increasing kernel number. Nitrogen supply also impacted the yield–protein relationship by stimulating protein synthesis rather than by inhibiting starch production. These results demonstrate the strong genetic control of grain composition in maize hybrids, which can be modulated by the positive effects of N on reproductive sink capacity and seed protein synthesis.

Maize (Zea mays L.) Genotypes Differ in Phenology, Seed Weight and Quality (Protein and Oil Contents) when Applied with Variable Rates and Source of Nitrogen

“…In Uribelarrea et al found that abundant nitrogen supply stimulated protein synthesis in high protein genotypes and that protein and oil had a positive correlation. However, reported that higher inputs of nitrogen did not result in higher protein in maize in the conventional cropping system [3]. In both years, the hybrid has more SPC when applied with urea and AS than CAN resulting in N-source × genotype interaction (Table 6).…”

“…Grain quality is a major issue especially in low input farming systems. Assimilate supply can be altered by N availability and by genotype, and that both can effect yield and grain composition [3]. Grain composition is a result of the genetic make-up of the endosperm sink, the maternal plant, and the environment [3].…”

“…Assimilate supply can be altered by N availability and by genotype, and that both can effect yield and grain composition [3]. Grain composition is a result of the genetic make-up of the endosperm sink, the maternal plant, and the environment [3]. Efficient use of N is considered one of the most important inputs needed for increasing maize grains weight and protein concentration [4] and profitability [5].…”

“…Genotype also plays a large role in determining the kernel's ability to utilize the available assimilates for storage product deposition, as providing high levels of N cannot overcome a genetic tendency towards low kernel protein [3]. Maize varieties clearly differ in how efficiently they utilize N for storage product formation, and as a result yield [3], and much of this variation appears to be due to genetically determined processes within the maternal plant [7].…”

“…Maize varieties clearly differ in how efficiently they utilize N for storage product formation, and as a result yield [3], and much of this variation appears to be due to genetically determined processes within the maternal plant [7]. According to Fageria et al in the 21 st century, nutrient efficient plants will play a major role in increasing crop yields compared to the 20 th century, mainly due to limited land and water resources available for crop production, higher cost of inorganic fertilizers, declining trends in crop yields globally, and increasing environmental concerns [8].…”