Polymorphism ofWaxy Proteins in Wheats and Production of Partial and Total Bread and Durum Wheat

Waxy proteins are a group of proteins coded by genes located on the chromosomes 7A, 7D and 4A (Wx-A1, Wx-DI, Wx-BI loci) of cultivated wheat which are responsible for the amylose synthesis of the starch endosperm. The identification of null genotypes at each of three waxy loci is important because the absence of waxy genes is associated to a reduction of amylose content and, as a consequence, to different flour properties· Electrophoretic separations performed on different varieties, lines and accessions of cultivated bread and durum wheat, have permitted the detection of null alleles at each of the Wx-1 loci. The amplification of waxy gene fragments by the polymerase chain reaction (PCR) technique has been performed on the same materials in the attempt to detect further polymorphism and to ascertain the cause of the lack of expression of the null genotypes. The single null forms detected at each locus have been used to produce bread and durum wheat lines carrying different level of deficiency for these proteins in order to understand the influence of different amylose content on the technological and qualitative properties of flours.