Validation of black point QTL in wheat

Abstract

Black Point (BP) is a dark discolouration of the embryo end of wheat and barley grains. It can result in reduced grain quality and value and is a significant problem in most Australian wheat growing areas. Estimated losses through downgrading have been as high as $50 million annually. Quantitative trait loci (QTL) for BP resistance have previously been identified in Sunco and Cascades. The aim of this study was to use a full diallele to validate these QTL and also to determine if two other varieties with increased resistance mirror existing sources of resistance or are potentially novel sources of resistance for BP. The BP resistant lines Lang, Cascades, SW95-50213, and Genaro, and one BP susceptible line, Cunningham were used as parental lines in the full diallele. As both Lang and Sunco are Cook derivatives, Lang was used to validate the Sunco QTL. Marker regression analysis confirmed the QTL on chromosome 2BS in Lang crosses. Genaro and SW95-50213, which are more resistant to BP than Sunco or Cascades, indicated an association between BP resistance and chromosomes 2B and 2A, respectively. The identification of markers for BP resistance in a number of different resistant sources will facilitate the pyramiding of genes for BP resistance in wheat.