The Effect of Group-5 Chromosomes on the Free Polar Lipids and Breadmaking Quality of Wheat

Free (hexane-extractable) polar lipids (PoL) were determined in flours milled from wheats differing only in their group 5 chromosomes. Ditelosomic lines lacking the short arm of chromosome 5D (DT5DL) were much harder and had less free PoL than normal wheats or the corresponding 5A ditelosomics (DT5AL). Substitution of chromosome 5D of Chinese Spring (CS) by homologous chromosomes from other varieties or by 5U from Aegilops umbellulata, and of chromosome 5A of CS by 5U, gave a series in which increasing hardness was strongly correlated with decreasing free PoL. Analysis of CS x CS(Hope 5D) crosses that were non-recombinant or recombinant for the genes Vrn3/vrn3 (spring/winter habit) and Ha/ha (soft/hard endosperm texture) showed that there was transgressive segregation of two (or, possibly more) genes controlling levels of free PoL. One of these genes could be allelic to Ha, or is closely linked to it. The second gene is probably located on the long-arm proximal to Vrn3. The new genes have been given provisionally the symbols Fpl-1 and Fpl-2. Loaves made by the Chorleywood Bread Process with flour from ditelosomic and substitution lines showed marked decreases in loaf volume with decreasing free PoL. Limited evidence from recombinant lines supported the link between Fpl-1 and Fpl-2 and loaf volume.