Investigating the role of flavonoid biosynthesis in coat-imposed dormancy to facilitate the breeding of white-grained varieties of wheat

Lead Research Organisation: Rothamsted Research
Department Name: Unlisted

Abstract

The consumption of wholegrains is known to have significant health benefits: there is evidence that the fibre and phytochemicals that are present in wholewheat but less abundant in white flour protect against bowel cancer, diabetes and other diseases. However, most consumers reject wholegrain products, at least partly because of the bitter taste imparted by the proanthocyanidin (PA) pigments in the bran. White-grained wheat, which lacks PAs, can be used to make wholegrain products that are similar in taste and appearance to those made from white, refined flour but contain higher levels of fibre and other nutrients. White grain colour also confers a higher yield and protein content of refined flour. However, white wheat is a difficult target for breeders as grain colour is a maternal character controlled by three homoeologous loci. Also, white grained wheat is prone to pre-harvest sprouting (PHS) in which grain germinates in the ear, resulting in amylase accumulation and loss of bread-making quality. The aim of this project is to underpin the genetic improvement of white wheats through the development of molecular markers for grain colour and by investigating the interaction between grain colour, dormancy and sprouting resistance.
The R genes for grain colour encode transcription factors that control the PA biosynthetic pathway. We aim to survey the range of red and white alleles of the R genes present in UK germplasm and to develop allele-specific markers that can be directly utilised by breeders. We will assess the potential for improving the sprouting resistance of white wheats by introgressing white r alleles into PHS-resistant germplasm identified within the current HFN LINK programme. We will also identify genetic determinants that protect against sprouting in a mapping population of white wheats. In addition we will investigate alternative approaches to the development of PHS-resistant white wheat involving manipulation of the PA biosynthetic pathway.

Publications

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