Grain and Plant Nitrogen Relationships in Eight Spring Wheat Crosses, <i>Triticum aestivum</i> L.¹

Abstract

Samples of high and low grain protein content (%) were compared from each of eight spring wheat crosses. The high protein samples were obtained by compositing 14 F 3 progeny rows from the high end of the F 3 distribution curve; the low protein samples were obtained similarly from the low end of the F 3 distribution curve. These composites were seeded at three Montana locations and evaluated for agronomicharacteristics and for grain and plant nitrogen to help determine the nature of the expression of grain nitrogen content in spring wheat. Grain nitrogen content was negatively related to grain yield and to the graln‐straw ratio. High and low protein composites at Bozeman produced the same amount of above ground plant nitrogen, and each translocated the same percent of nitrogen to grain. However, grain nitrogen content of the high protein composite was significantly higher because of the distribution of a similar amount of nitrogen to a smaller amount of grain. Differences in plant growth characteristics among the eight crosses seem to account for the differences in grain nitrogen content.