yield and quality traits

One of the main components of wheat flour is starch, its relative content and chemical composition affect the quality of the products obtained from wheat.

Starch is a glucose polymer composed of two different types of structures: amylose and amylopectin. Amylose is a linear polymer with D-glucosyl units linked by α 1-4 bonds. Amylopectin has a branched structure: it also has α 1-4 bonds but every 20-25 glucosyl there are ramifications due to α 1-6 bonds.

Achieving higher grain yields is a difficult task due to the number of genes involved, their interactions and the importance of environmental effects. This complexity determines that taken as a single trait, yield shows low heritability. Instead of improving overall yields, a more effective strategy is to focus on yield components, such as grain weight, spikes per unit area, grain number per spikelet and spikelet number per spike (SNS). Among these, SNS is an attractive trait for wheat breeders because it shows a higher heritability compared to the other yield components.

Grain protein content (GPC) is one of the most important quality factors for pasta and bread wheats. Breeding for an increase in GPC is difficult because the genetic variation for this character is small compared to variations caused by the environment, besides there is a negative correlation between GPC and grain yield.

The rice Grain Width and Weight 2 (OsGW2) gene was previously described as a negative regulator of grain weight and width. It encodes a RING-type E3 ubiquitin ligase (1). The wheat homolog in wheat is the TaGW2 gene, with homoeologues in the three genomes, although the most closely studied to date is the A genome homoeologue, TaGW2-A1.