A SINGLE GENETIC-LOCUS ASSOCIATED WITH STARCH GRANULE PROPERTIES AND NOODLE QUALITY IN WHEAT

An extensive survey of wheat cultivars showed a complete association b etween the presence of a granule bound starch synthase (GBSS-4A) null mutation and the classification of the respective cultivar into the wh ite salted noodle category. Since flour swelling volume (FSV) is a sta ndard assay of hour used to identify cultivars that have potential for the production of white salted noodles, the results of the survey wer e investigated further by studying the genetic association of GBSS-4A null genotypes and FSV. A study of 34, F2 derived families, from a cro ss between wheat cultivars Reeves (good noodle texture, high FSV) and Kulin (poor noodle texture, low FSV), provided clear evidence for the generic association of a granule bound starch synthase (GBSS-4A) null mutation and FSV. The molecular basis for the affect of the GBSS-4A nu ll mutation was not simply due to a decrease in amylose content in the starch granules. Instead, the null mutation most likely causes a subt le change in starch structure as indicated by the association of high starch viscosity with high FSV and the GBSS-4A null genotype. The stud y suggests that assaying for the GBSS-4A null mutation at the DNA leve l may provide a valuable screen for noodle quality at early stages in a breeding program aimed at good white salted noodle quality. (C) 1998 Academic Press Limited.