Our research aims to increase the diversity of grain quality traits available in wheat with a particular focus on starch content and composition traits. Currently, our main project is called Production of wheat lacking B-type starch granules. This is funded by the BBSRC via the Crop Improvement Research Club (CIRC). The project is a collaboration between NIAB and the John Innes Centre, Norwich.
Starch is a major component of cereal grains and its functional properties have a significant impact on grain utilisation. Of considerable importance is the size and shape of the starch granules. In wheat, barley, rye and most of their wild grass relatives, there are two types of starch granules, called A- and B-type. These differ in size, leading to a bimodal granule-size distribution that is unusual amongst plant starches and not found in other grasses, including Brachypodium, oats, rice and maize. The smaller, B-type starch granules have negative impacts on many end-uses of wheat and barley. So far, attempts to reduce or remove B-granules from these crops by breeding have failed. The reason for this is the lack of genetic variation in B-granule content between cultivars. The lack of genetic variation in granule-size distribution that is observed between cultivars of domesticated wheat and barley contrasts with that available in related wild species, such as Aegilops (Goat Grasses, members of the Triticeae tribe and closely related to wheat). Exploiting this observation, we generated a population of Aegilops segregating for B-granule content and we are using this to study the genetic basis of B-granule initiation. Our ultimate goal is to identify the gene responsible for the control of B-granule content in Aegilops and manipulate the corresponding gene wheat and barley to produce B-granules-less lines with improved processing properties.