Increasing the Grain Yield and Grain Protein Content of Common Wheat ( Triticum aestivum ) by Introducing Missense Mutations in the Q Gene.

Grain yield (GY) and grain protein content (GPC) are important traits for wheat breeding and production; however, they are usually negatively correlated. The Q gene is the most important domestication gene in cultivated wheat because it influences many traits, including GY and GPC. Allelic variations in the Q gene may positively affect both GY and GPC. Accordingly, we characterized two new Q alleles ( Q s1 and Q c1 -N8 ) obtained through ethyl methanesulfonate-induced mutagenesis. Compared with the wild-type Q allele, Q s1 contains a missense mutation in the sequence encoding the first AP 2 domain, whereas Q c1 -N8 has two missense mutations: one in the sequence encoding the second AP 2 domain and the other in the microRNA172-binding site. The Q s1 allele did not significantly affect GPC or other processing quality parameters, but it adversely affected GY by decreasing the thousand kernel weight and grain number per spike. In contrast, Q c1 -N8 positively affected GPC and GY by increasing the thousand kernel weight and grain number per spike. Thus, we generated novel germplasm relevant for wheat breeding. A specific molecular marker was developed to facilitate the use of the Q c1 -N8 allele in breeding. Furthermore, our findings provide useful new information for enhancing cereal crops via non-transgenic approaches.