Enhancing Wheat Breeding Through Selection Of Robust Disease Resistant QTL That Function In A Variable Climate

Plant breeders are continually reminded of their role in “feeding the nine billion”, a role that only increases in importance in the face of climate change. Recent results from crop modeling research indicates that warming has already reduced yield gains in most wheat growing regions and the trend is likely to continue. Other empirical reports suggest that even over very short periods of time, on the order of 25-30 years, adaptive changes have been documented in natural populations of wheat progenitors. Similarly, there are reports of accelerated phenology in the form of earlier heading dates among wheat cultivars grown over roughly the same time period. In effect, the impact of climate change is being felt right now and breeding programs must take steps to develop selection criteria for traits that will confer adaptation to climate change. While we don’t understand the entire suite of traits impacted, it is likely that warming will impact pathogen populations, and thus, the effectiveness of disease resistance QTL must be assessed. Fusarium head blight (FHB), also known as head scab, is a devastating disease of wheat worldwide. The literature tells us that in regions from central China to the UK FHB is expected to intensify in response to climate change. The plan of work for this sabbatical proposal is synthesize our FHB research and climate change research. Specifically, we will derive near isogenic lines (NILs) from the cross ‘Pembroke 2014’ / ‘IL06-14262’ will be derived from F4 plants that are heterozygous at the Fhb1 locus. Pembroke 2014 is homozygous for Fhb1 resistance alleles, while the Illinois parent carries the susceptible alleles. This will give us pairs of F4:5 lines derived from the same plant that are nearly identical. This will provide the opportunity to assess the impact of warming on the Fhb1 locus, the most widely used FHB resistance gene. Though IL06-14262 does not carry Fhb1 type resistance, it does have resistance derived from uncharacterized, quantitative, unmapped loci that are simply referred to as “native resistance genes”. Thus we can compare the effect of warming on Fhb1 derived resistance with native resistance. These F4:5 lines will be grown under control and warmed conditions. Two warming methods will be used: 1) active rhizosphere warming using heating cables and 2) passive night warming of the canopy using thermal fabric shelters; our lab has experience with both methods. The NILs will be evaluated for FHB resistance under control and warmed conditions and the impact of warming assessed. The second component of the sabbatical proposal pertains to genomic selection. To efficiently utilize “native” resistance genes, genomic selection is an attractive approach. This will be an excellent population in which to use genomic selection for FHB resistance in wheat. We have recently obtained an instrument suitable for developing markers from SNP data. These markers can then be used in marker assisted selection. Time will be spent in the lab of a colleague, currently generating SNP data for wheat breeding projects using genotyping by sequencing, to learn this technology so it can be implemented in our lab. The overarching goal of this sabbatical is for the climate change breeding objectives to become a part of the mainstream breeding program instead of a separate interest. To facilitate that transition, research that synthesizes the climate change objectives and FHB resistance breeding objectives will be conducted.