Exploiting variation in grain protein to determine environmental effects on processing quality (PhD)

The challenge

The amount and properties of gluten proteins in wheat grains are the major determinants of processing quality of white flour. UK millers require a protein content of at least 13%. Protein quality is equally important, with the requirement for ‘strong’ (highly elastic) protein for breadmaking wheats. The lack of protein content and quality stability in commercial varieties is of serious concern to wheat breeders, farmers, millers and bakers. Both are under genetic control and strongly influenced by the environment. Agronomy (e.g. nitrogen fertilisation) and weather (e.g. temperature and precipitation during grain development and maturation) both influence protein quantity and quality. However, genetic and environmental influences are not fully understood.

The project

This studentship will determine how environmental factors influence the stability of functional protein content and quality of wheat. The work will exploit genetic variation in grain content and composition, and develop genetic markers for increased stability. Building on previous AHDB-supported research, the project will adopt two main approaches:

1. The work will conduct a genetic analysis of these two traits. This will involve a population of 90 doubled haploid lines, from the cross Malacca (average grain protein content, low stability) and Hereward (high grain protein content, high stability), in replicated field trials in three environments. High-density molecular maps of these lines are available and traits will be mapped as QTLs and KASP markers.

2. Near isogenic lines (NILs) are available from the same cross. The NILs have ‘good’ or ‘poor’ alleles at quality QTLs in, otherwise, the same genetic background. The NILs will help determine the impacts of the environment on individual aspects of protein quality. In particular, they will help find differences in stability of quality between alleles and QTLs, determine mechanisms and identify markers for stable high-quality alleles. Quality tests will include grain protein compositional analysis, together with flour rheology and test baking.  

The benefits

The student will gain a variety of new skills, including genetic mapping, agronomy (field and glasshouse agronomy) and quality testing techniques (research laboratory and baking industry). Information on genetic markers will help provide powerful tools for plant breeders. The project will also help farmers to better target and reduce nitrogen fertiliser use.