SUMMARYChromosomes 5A and 5D of wheat are important in determining the different responses of winter and spring varieties to vernalisation. Using single chromosome substitution lines in which chromosomes 5A and 5D of the variety Hope replace their homologues in the variety Chinese Spring, single genes having a large effect on the time to ear emergence were located distally on the long-arms of both chromosome 5A and 5D. The similar location of these genes on homoeologous chromosomes suggests that they are duplicate loci resulting from the polyploid nature of wheat. It is likely that the genes on chromosomes 5A and 5D are equivalent to Vrn1 and Vrn3 respectively, the genes for vernalisation requirement identified in other studies.Additional variation in the time to ear emergence was found in other substitution lines of chromosomes 5A and 5D. It is possible that this variation reflects multiple allelism at the Vrn1 and Vrn, loci. Also, by comparing the ear-emergence times of these substitution lines with alien substitutions in which chromosome 5CU of Aegilops umbellulata replaces either chromosome 5A or 5D of Chinese Spring, it was possible to relate the effects of chromosome 5A to those of chromosome 5D.

F4 progenies of a cross between durum wheat cultivar 'Greso' and an accession of Triticum turgidum ssp. dicoccoides with high protein content were analysed by two different electrophoretic procedures (A-PAGE and SDS-PAGE). Variation of storage proteins at the Glu-Al, Glu-Bl, Glu-B3 and Gli-Bl loci was studied. Electrophoretic analyses have shown that parents contain different alleles at each of the four loci considered and that protein components of T. dicoccoides are uncommon among cultivated wheats. Recombination between the Glu-B3 and Gli-Bl loci was observed. To determine the effects of the allelic variants on gluten properties, F5 grains from every F4 line were analysed for protein content and SDS-sedimentation value. Gluten quality was strongly associated with the allelic type of proteins coded by the Glu-B3 locus and, to a lesser extent, to those coded by Glu-Al. Mean sedimentation value of progenies possessing the 'Greso' Glu-B3 allele was significantly greater than that showing the T. dicoccoides allele. High molecular weight glutenin subunits coded by the T. dicoccoides Glu-Al locus were also associated with larger sedimentation values than null form of 'Greso'. Results of SDS-test, obtained for recombinants between Glu-B3 and Gli-Bl, confirmd that specific omega-and gamma-gliadins are only genetic markers of quality, whereas variation for LMW glutenin subunits coded at Glu-B3 is responsible for differences in gluten properties.

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