Location: Cereal Crops ResearchTitle: Pleiotropic effects of HvMKK3 alleles on preharvest sprouting, seed dormancy, and malting quality
|SWEENEY, DANIEL - Cornell University - New York|
|ROONEY, TRAVIS - Cornell University - New York|
|SORRELLS, MARK - Cornell University - New York|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/8/2021
Publication Date: N/A
Interpretive Summary: Preharvest sprouting (PHS) occurs when rains or humid conditions cause the barley seed to sprout on the mother plant prior to harvest. The sprouting can severely damage the barley and therefore fails to meet malting quality standards rendering the value of the harvested barley to a much lower price point. Thus the growers and producers of malting barley are presented with significant risk when deciding to grow the crop in regions of the US that may exhibit conditions such as high humidity or precipitation during harvest time. The accomplishments in this manuscript are that we 1) identified mutations in 3 three genes in different barley lines that drive the propensity to preharvest sprout, two of which in particular have large effects on the trait 2) tracked the 3 gene's inclusion in North American barley varieties 3) described the how the 3 genes interplay with each other to either push barley to preharvest sprout or remain dormant 4) measured the effect of these genetic mutations on the overall malting quality of the barley and 5) developed genetic markers that allow for scalable and rapid identification of the mutations. The contributions of our findings is that breeders and producers will now have tools to screen barley varieties that have either already been developed or are in the process of being developed for propensity to preharvest sprout. The markers will bolster prediction of quality and add confidence to those currently in the barley growing industry or those considering growing barley.
Technical Abstract: Preharvest sprouting (PHS) can severely damage barley (Hordeum vulgare L.) malting quality and is of particular concern in locations with a high frequency of precipitation around harvest. Malting quality and PHS resistance are often negatively correlated and the SD2 locus on chromosome 5H has been associated with both traits. Using three spring barley populations, PHS, seed dormancy, and germination rate were mapped over six time points to identify changes in genetic control of these traits during after-ripening. HvAlaAT1 at the SD1 locus was associated with long-term dormancy and reduced germination rate. Ninety lines were Sanger sequenced for HvGA20ox1, but variants were not associated with PHS or germination traits. The allelic state of HvMKK3 was strongly associated with genetic PHS susceptibility in North American spring two-row barley germplasm and interactions between HvAlaAT1 and HvMKK3 were associated with changes in seed dormancy and germination rate over time. Several malting quality traits were associated with HvMKK3 alleles. KASP markers were developed for the causal mutations in HvAlaAT and HvMKK3 and a diagnostic mutation in HvGA20ox1. Haplotypes with PHS resistance, short primary dormancy, and a high germination rate were identified that could be useful for breeding for PHS resistance and malting quality.