127 Effect of environment on grain development, gene expression, kernel characteristics, and flour properties of wheat.

S. B. ALTENBACH, F. M. DuPont, D. Lieu, K. Cronin, and R. Chan. USDA, ARS, Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710.

Many complex environmental variables impact developing wheat grains in a field situation, resulting in reductions in yield and alterations in the performance of flour. While field experiments provide valuable information about the effects of environment on the grain, the number of uncontrolled variables in these studies inevitably complicates interpretations of results. We are taking a complimentary approach that involves growing plants under defined conditions in growth chambers and/or greenhouses. In experiments with three US wheat cultivars, we found that the duration of grain-fill was shortened when plants were subjected to high temperatures, high temperatures plus drought or reduced fertilizer levels. Despite similar effects on the duration of grain-fill, the impact of the treatments on grain weights and kernel characteristics differed. High temperature treatments led to kernels with average weights ~15% less than controls. Kernels from plants subjected to high temperatures and drought were shrunken and reduced in average weights by 20–35%. Average grain weights did not change in plants grown under reduced fertilizer levels, however this treatment resulted in a high percentage of yellow berries. Effects of these environmental parameters on gene expression, protein composition, and flour quality of wheat grains will be presented.