DEPENDENCE OF EXTENSOGRAPH PARAMETERS ON WHEAT-PROTEIN COMPOSITION MEASURED BY SE-HPLC

Size-exclusion HPLC measurements were made on the total protein from f lours of 158 wheat lines grown at five locations (31 at all sites and an extra one at three locations). Closely spaced cuts in the chromatog rams were made at elution times differing by 0.4 min. The percentage o f the protein that eluted up to each time was correlated With Extensog raph dough maximum resistance (R-max) and dough extensibility (Ext). F or R-max, maximal correlation (r = 0.489(**) for all locations) was o btained for the percentage of protein eluting before 13.2 min, corresp onding to estimated molecular weights equal to and greater than 250 00 0. In the case of Ext, the highest correlation (0.859** for all locat ions) was obtained for the percentage of protein in the flour which el uted before 16.8 min, which included essentially all the flour polymer ic protein with estimated molecular weights above 52 000. The differen t dependencies of R-max and Ext provide a basis for manipulating these parameters in predictable ways in breeding programs. (C) 1997 Academi c Press Limited.