Project Number: 5348-21000-023-04
Project Type: Reimbursable

Start Date: Aug 01, 2005
End Date: Nov 30, 2009

Objective:
This proposed research will: (1) characterize the grain dormancy and germination of wheat mutants with increased and decreased ABA response isolated using germination based screens; (2) investigate whether wheat mutants with increased ABA sensitivity will have improved resistance to preharvest sprouting and to drought; and (3) determine the chromosome location of wheat ABA response genes with a view to cloning promising genes. This research will help us control the risk of preharvest sprouting and drought stress in U.S. bread wheat production, thereby contributing to Agricultural and Food Security.

Approach:
Plating experiments will be used to determine the ABA dose-response of ABA hypersensitive wheat during germination, and to determine the length of time required to afterripen or end dormancy. Wheat that appears to be more dormant will be tested for resistance to preharvest sprouting under greenhouse conditions that simulate cool moist field conditions known to stimulate sprouting. ABA hypersensitive will be examined for altered stomatal response to ABA using stomatal closure assays and transpiration rate assays. Drought tolerance will be accessed using stomatal conductance measurements, canopy temperature measurements using an infrared camera and field tests to determine the effect of drought conditions on harvest index. Finally, the ABA response genes identified using these ABA-response mutants will be mapped. BL-1 5/23/05; exp. 3 yrs. Documents NRI Grant. Log 27853. Formerly 5348-21220-003-07R (5/2008).