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United States Department of Agriculture

Agricultural Research Service

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Research Project: Genetic Improvement of Barley

Location: Cereal Crops Research

Project Number: 5442-21000-036-00
Project Type: Appropriated

Start Date: May 13, 2013
End Date: May 12, 2018

Objective:
Objective 1: Identify the genetic structure and relationship of Russian wheat aphid resistance to domestication, and the chromosome locations of genes for aphid resistance in barley. Sub-objective 1a. Determine the relationship between RWA resistance and domestication. Sub-objective 1b. Test barley lines against international RWA biotypes. Sub-objective 1c. Map greenbug reaction in five new sources of resistance. Objective 2: Determine expression of ethylene signal transduction genes during barley tissue culture and regeneration. Objective 3: Transform barley with constructs containing genes for resistance to Fusarium head blight or reduced deoxynivalenol content. Sub-objective 3a. Transform and test barley with candidate genes for reduced FHB and DON identified through model systems. Sub-objective 3b. Transform and test barley with RNAi constructs against fungal genes for reduced FHB and DON.

Approach:
The goal of this project is the genetic improvement of barley (Hordeum vulgare L.) by application of molecular genetics and biotechnology to increase disease and pest resistance. Research will target molecular mapping approaches for resistance to greenbug [Schizaphis graminum (Rondari)] and Russian wheat aphid [RWA Diuraphis noxia (Kurdjumov)], insect pests that are of increasing importance as barley production moves west and additional aphid biotypes are discovered. Initial association mapping of RWA resistance suggests involvement of genes for domestication. This association will be further investigated using an expanded population and single nucleotide repeat (SNP) markers to identify candidate genes in key genomic positions. Additional biotypes of RWA will be tested on the expanded population to identify biotype-specific resistance. The two named greenbug resistance genes Rsg1 and Rsg2 do not provide protection against some of the new isolates emerging in farmers’ fields. Eight new sources will be mapped using F6 derived lines from crosses to a winter barley cultivar. Fusarium head blight (FHB) and resultant contamination of grain with the mycotoxin deoxynivalenol (DON) are ongoing problems in major barley production regions. Genetic transformation research will continue with candidate genes for resistance and low DON. In conjunction, ongoing research to improve tissue culture regeneration and transformation systems will continue to examine the role of ethylene in regeneration and to test improved transformation constructs carrying genes for reducing FHB and DON. Transformation constructs will be designed to separate genes of interest from selectable marker genes, and to insert the genes of interest into euchromatic areas that provide stable expression.

Last Modified: 4/20/2014
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