Pinpointing regions of the barley genome contributing to hybrid disease susceptibility

Primary Author: Shaun Clare

Faculty Sponsor: Robert Brueggeman

 

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

 

Abstract:

 

Principal topic

Barley is an essential ingredient in beer and whiskey. Barley breeding allows for the improvement of barley by crossing two different parents to contribute favorably to offspring for traits such as yield and disease resistance. The increased use of hybrid varieties that possess genes from each parent (heterozygous) rather than favorable genes from either parent (homozygous) has allowed increased yield termed hybrid vigor. However, two lines that are resistant to a disease called net blotch have been shown to be susceptible to the disease when in a heterozygous state. Identifying the mechanism that allows two resistant parents to produce susceptible offspring is important to avoid releasing varieties that do not perform for growers.

Method

To identify the gene responsible for the hybrid susceptibility, ~2000 offspring were propagated with mosaic genomes of each parent. Single nucleotide changes in the genome that are known to be different between each parent were used on the susceptible offspring as a roadmap through the mosaic to pinpoint the region of the genome responsible for susceptibility.

Results/implications

The susceptibility region of the genome has been pinpointed to a five million nucleotide region within the barley genome that contains over five billion nucleotides. Next steps include adding additional markers by sequencing genes and validating which genes in the region are responsible for susceptibility. Removal of this gene will allow for the development of barley varieties that are healthy under disease pressure to ensure secure production of quality barley to feed the beer and whiskey industry.