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. TheQgene is the most important domestication gene in cultivated wheat because it influences many traits, including GY and GPC. Allelic variations in theQgene may positively affect both GY and GPC. Accordingly, we characterized two newQalleles (Q^s1andQ^c1-N8) obtained through ethyl methanesulfonate-induced mutagenesis. Compared with the wild-typeQallele,Q^s1contains a missense mutation in the sequence encoding the first AP₂domain, whereasQ^c1-N8has two missense mutations: one in the sequence encoding the second AP₂domain and the other in the microRNA172-binding site. TheQ^s1allele 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-N8positively 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 theQ^c1-N8allele in breeding. Furthermore, our findings provide useful new information for enhancing cereal crops via non-transgenic approaches.

Keywords:wheat quality;agronomic trait;mutation;breeding