Grain yield in cereal crops is a complex trait controlled by multiple genes and influenced by developmental processes and environment. Here we report the effects of alleles Rht8 and Ppd-D1a on plant height, time to heading, and grain yield and its component traits. Association analysis and quantitative trait locus mapping using phenotypic data from 15 environments led to the following conclusions. First, both Rht8 and Ppd-D1a reduce plant height. However, Ppd-D1a but not Rht8 causes earlier heading. Second, both Rht8 and Ppd-D1a promote grain yield and affect component traits. Their combined effects are substantially larger than those conferred by either allele alone. Third, promotion of grain yield by Rht8 and Ppd-D1a is through increasing fertile spikelet number. We speculate that Rht8 and Ppd-D1a act independently and additively in control of plant height, grain yield and yield component. Combination of the two alleles is desirable for adjusting plant height and enhancing grain yield and abiotic stress tolerance.

Triticum urartu (AA, 2n = 2x = 14), a wild grass endemic to the Fertile Crescent (FC), is the progenitor of the A subgenome in common wheat. It belongs to the primary gene pool for wheat improvement. Here, we evaluated the yellow rust (caused by Puccinia striiformis f. sp. tritici, Pst) reactions of 147 T. urartu accessions collected from different parts of the FC. The reactions varied from susceptibility to strong resistance. In general, there were more accessions with stronger resistance to race CYR33 than to CYR 32. In most cases the main form of defense was a moderate resistance characterized by the presence of necrotic/chlorotic lesions with fewer Pst uredinia on the leaves. Forty two accessions displayed resistance to both races. Histological analysis showed that Pst growth was abundant in the compatible interaction but significantly suppressed by the resistant response. Gene silencing mediated by Barley stripe mosaic virus was effective in two T. urartu accessions with different resistance responses, indicating that this method can expedite future functional analysis of resistance genes. Our data suggest that T. urartu is a valuable source of resistance to yellow rust, and represents a model for studying the genetic, genomic and molecular basis underlying interaction between wheat and Pst.

Wheat is the most widely cultivated staple food crop, and multiple types of food derivatives are processed and consumed globally. Wheat grain quality (WGQ) is central to food processing and nutritional value, and is a decisive factor for consumer acceptance and commercial value of wheat cultivars. Hence, improvement in WGQ traits is top priority for both conventional and molecular wheat breeding. In this review we will focus on two important WGQ traits, grain milling and end-use, and will summarize recent progress in China. Chinese scientists have invested substantial effort in molecular genetic and genomic analysis of these traits and their effects on end-use properties. The insights and resources generated have contributed to the understanding and improvement of these traits. As high-quality genomics information and powerful genome engineering tools are becoming available for wheat, more fundamental breakthroughs in dissecting the molecular and genomic basis of WGQ are expected. China will strive to make further significant contributions to the study and improvement of WGQ in the genomics era.