Title: Differences in Dry Matter Production and Nitrogen Uptake and Partitioning

Grain protein concentration of wheat is influenced by numerous factors. When determining a wheat variety's ability to produce protein, the plant's ability to uptake and translocate nitrogen is critical. A greenhouse study was conducted to assess differences in nitrogen use among different wheat varieties. The objective was to determine if there are growth characteristics and/or nitrogen uptake and translocation patterns that result in grain with higher nitrogen levels. Varieties from six wheat market classes currently being grown in the Pacific Northwest were used in the study but complete data were collected on only three spring classes- Winsome and ID0377S hard white; WPB936 hard red; and Penawawa, soft white. Varieties were planted in pots and grown under typical greenhouse conditions for cereal grains except that surplus nutrients were provided. Flag leaf chlorophyll readings were taken through early grain fill and destructive sampling was done at anthesis and plant maturity. Plant parts were separated and analyzed for dry matter production and nitrogen concentration. The spring grains showed several trends that appear to influence the plants protein production. Winsome had the highest harvest index and grain yield with poor grain nitrogen, the result of a dilution effect. ID0377S had a high harvest index and grain yield with high grain nitrogen. WPB936 produced little dry matter, had a low harvest index and grain yield. WPB936 had a low total nitrogen uptake, but the low grain yield allowed the concentration of a high amount of nitrogen into the grain. Penawawa produced a large number of tillers and the largest volume of dry matter. Penawawa had a low grain nitrogen concentration, a low harvest index and left a significant amount of nitrogen in tiller tissue