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United States Department of Agriculture

Agricultural Research Service

Research Project: HORMONAL REGULATION OF WHEAT STRESS RESPONSES
2009 Annual Report


1a.Objectives (from AD-416)
Agronomically important genes for wheat will be identified and deployed using a genetic approach in wheat and Arabidopsis. The genetic mechanisms by which the plant hormones abscisic acid (ABA) and gibberellin (GA) control pre-harvest sprouting, stand establishment, and drought and cold tolerance in wheat and Arabidopsis. Spring and winter wheat cultivars with durable resistance to stripe rust, soilborne disease, cold and drought, and improved end-use quality will be developed.


1b.Approach (from AD-416)
Multiple approaches will be employed. The genetic diversity of wheat plants will be increased using wide crosses to wheat relatives and thorough mutagenesis and selection of new traits. We will determine whether ABA sensitivity controls grain dormancy and tolerance to preharvest sprouting using wheat mutants with increased and decreased sensitivity to ABA. The degree to which preharvest sprouting, drought tolerance and cold tolerance depends upon ABA sensitivity will be determined using association mapping, and wheat mutants with increased and decreased ABA sensitivity. The mechanisms by which GA signaling controls seed dormancy and plant height using Arabidopsis as a model system to determine exactly how GA response genes control gene expression during seed germination. New sources of genes giving superior end-use quality, disease resistance, and resistance to cold and drought conditions will be identified through characterization of material from the USDA-ARS National Small Grains Germplasm Collection. New approaches for deployment of these genes through the identification of new molecular markers, use of molecular markers to score segregation in breeding lines, employment of Bayesian statistics, and classical statistical plant breeding. Documents SCA with WSU. Formerly 5348-21220-003-09S (07/08).


3.Progress Report

This project examines the genetic mechanisms by which the plant hormones abscisic acid (ABA) and gibberellin (GA) control pre-harvest sprouting, stand establishment, and drought and cold tolerance in wheat and Arabidopsis. A Doubled Haploid mapping population was developed in order to markers linked to the Rhizoctonia resistance gene in Scarlet-Rz1, collaborative work was conducted to examine the drought tolerance of ABA hypersensitive wheat plants in the field and collaborative work was conducted to develop breeder-friendly markers for stripe rust resistance. In Arabidopsis, progress was made in examining the phosphorylation of the DELLA protein RGL2,, a wheat mutant with increased water use efficiency was identified and evaluated at Central Ferry and Lind WA under drought conditions and two QTLs were identified that are associated with resistance to stripe rust in Stephens wheat. The molecular markers that flank the QTLs for stripe rust resistance are being used in breeding programs in WA and ID to select for durable stripe rust resistance. This research is relevant to NP301 Component 2 “Crop Informatics, Genomics, and Genetic Analyses” and to National Program Problem Statements NP301 2C: Genetic Analyses and Mapping of Important Traits, and NP302 2B: Understanding Plant Interactions with Their Environment. This project is monitored by the ADODR through weekly meetings.


Last Modified: 11/28/2014
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