Pleiotropic effects of the wheat domestication gene Q on yield and grain morphology
Transformation from q to Q during wheat domestication functioned outside the boundary of threshability to increase yield, grains m−2, grain weight and roundness, but to reduce grains per spike/spikelet.
Mutation of the Q gene, well-known affecting wheat spike structure, represents a key domestication step in the formation of today’s free-threshing, economically important wheats. In a previous study, multiple yield components and spike characteristics were associated with the Q gene interval in the bread wheat ‘Forno’ × European spelt ‘Oberkulmer’ recombinant inbred line population. Here, we reported that this interval was also associated with grain yield, grains m−2, grain morphology, and spike dry weight at anthesis. To clarify the roles of Q in agronomic trait performance, a functional marker for the Q gene was developed. Analysis of allelic effects showed that the bread wheat Q allele conferred free-threshing habit, soft glumes, and short and compact spikes compared with q. In addition, the Q allele contributed to higher grain yield, more grains m−2, and higher thousand grain weight, whereas q contributed to more grains per spike/spikelet likely resulting from increased preanthesis spike growth. For grain morphology, the Q allele was associated with reduced ratio of grain length to height, indicating a rounder grain. These results are supported by analysis of four Q mutant lines in the Chinese Spring background. Therefore, the transition from q to Q during wheat domestication had profound effects on grain yield and grain shape evolution as well, being a consequence of pleiotropy.
KeywordsGrain shape Mutation Spelt Spike Threshability Yield components
Quantitative trait locus
Recombinant inbred line
Thousand grain weight
We thank Beat Keller (University of Zurich) and Justin Faris (USDA-ARS) for providing the Forno × Oberkulmer mapping population and CS Q mutants, respectively. We also thank John Alcock, Matthew Tovey and Fiona Wilkinson (University of Nottingham) for their help with field and laboratory work. This study was partially supported by Natural Science Foundation of China (No.: 31430064), Natural Science Foundation of Jiangsu Province, China (No.: BK20160714), Research Excellence Foundation for the Overseas Chinese Scholars, Ministry of Human Resources and Social Security, China (No.: 8020012), China Scholarship Council‒University of Nottingham Research Excellence Scholarship, Jiangsu Collaborative Innovation Initiative for Modern Crop Production, and ‘111’ Project (No.: B08025).
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Conflict of interest
The authors declare that they have no conflicts of interest.
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