Gluten proteins and rheology of Mexican bread wheats as affected by environmental and genotypic factors

Resumo

The objective of this study was to determine the effect of environmental and genotypic factors on industrial quality and on the monomeric and polymeric protein contents and ratio of 24 rainfed bread wheat recombinant lines. The cultivation was done in five environmental conditions generated by agronomic management in the autumn-winter 2006/2007 cycle, at Roque, Guanajuato, Mexico. The mixing time (TMA), strength (ALVW) and extensibility (ALVPL) of the dough, gliadin (50PS) and glutenin (50PI) rich fractions, and their ratio (50PS/50PI), were evaluated. The best combinations of high and low molecular weight glutenins for TMA and ALVW were 1, 17+18, 5+10/Glu-A3c, Glu-B3g, Glu-D3b; 1, 17+18, 5+10/Glu-A3c, Glu-B3h, Glu-D3b; and 2*, 17+18, 5+10/Glu-A3c, Glu-B3g, Glu-D3b; for ALVPL it was 2*, 17+18, 2+12/Glu-A3e, Glu-B3h, Glu-D3b; and for 50PS they were 2*, 17+18, 2+12/Glu-A3e, Glu-B3h, Glu-D3b; and 1, 17+18, 5+10/Glu-A3e, Glu-B3h, Glu-D3b. The 50PS/50PI ratio was higher in genotypes with 2*, 17+18, 2+12/Glu-A3e, Glu-B3g, Glu-D3b. TMA is higher when temperature increases, and the best ALVPL is found under normal environmental conditions. Gliadin fraction and the 50PS/50PI ratio are higher when sulphur fertilization is done, and 50PI increases with drought and higher temperatures during grain-filling stage.