Investigating and Developing Resistance to FHB in barley

The barley breeding and genetics program at the U of M is engaged in a comprehensive research effort to understand the genetics of resistance to FHB, develop technology to enhance breeding efforts, and release new varieties with improved levels of FHB resistance.  This research effort is supported through federal, state and industry funded grants.

Research funded through the MN Small Grains Initiative is specifically designed to complement the federal and industry grants.  The objectives outlined in the state proposal are two-fold; 1) developing strategies for DNA marker-assisted selection (MAS) for FHB resistance in the breeding program, and 2) investigating the genetics of new sources of FHB resistance.

This past year we had several breeding lines in preliminary yield trials that were advanced through the program based on MAS.  Four of these lines carried a resistance gene located on chromosome two, and five others carried a gene on chromosome six.  These genes have been shown to reduce FHB severity. Performance of these lines in yield trials was mixed.  Five of the nine lines had yield levels similar or better than Robust. Grain samples from these lines are currently being evaluated for malting quality to determine whether any can proceed to advanced yield trials next year.

Our second objective is to conduct a genetic study of a new source of resistance.  This FHB-resistant accession, called Hor211, is similar to other sources of resistance Chevron and Frederickson in that it is poorly adapted to Minnesota and has little value as a malting variety.  However, studies we have conducted indicate that Hor211 likely contains different resistance genes than those we have already identified.

We have evaluated a genetic mapping population, created using Hor211, in three environments and constructed genetic maps of chromosomes one and two. Chromosome one is important because hulless barleys, like Hor211, have been associated with resistance to FHB in previous studies and the gene controlling this trait, called nud, is on chromosome one. However, if this gene is responsible for resistance to FHB in Hor211, it will not be useful in a malting barley variety.

Chromosome two is important because all of the other genetic studies of resistance to FHB in barley have identified a resistance gene on chromosome two that is associated with late heading. Our hypothesis was that genes, other than those on chromosome two, are responsible for the resistance in Hor211.  Our results to date now support that hypothesis.  We cannot detect a quantitative trait locus (QTL) or gene for resistance on either chromosome one or two.  While this is a negative result in terms of detecting a new QTL, it gives us confidence that we will discover new QTL for resistance to FHB as we continue to map the genome and ultimately use this resistance by marker-assisted selection.   

As we identify, test, and implement DNA markers that identify genes from various sources, we should be able to more effectively manipulate these genes and combine them into new breeding lines.  These breeding lines are eventually evaluated for yield, malting quality, and other important agronomic traits, and the most elite lines will become candidates for new barley varieties for the region.

– Dr Kevin P. Smith, University of Minnesota barley breeder