Electrophoretic identification and technological characterization of Pakistani wheats

Wheat cultivars grown in Pakistan at three locations (Faisalabad, Khanewal, and Bahawalpur) during 1987-88 and 1988-89 crop years were characterized for various physicochemical, rheological, milling, and baking characteristics. Identification of these cultivars was done by the use of acid polyacrylamide gel electrophoresis (acid-PAGE). High molecular weight (HMW) glutenin subunits were determined in the presence of sodium dodecyl sulfate (SDS-PAGE). No U.S. hard white wheats also were compared with the Pakistani wheats.Differences in electrophoretic patterns for each cultivar were observed with acid-PAGE, but the presence of gliadin and HMW glutenin subunits were not affected by growth location and crop year. Some differences in the intensity of the various bands were observed across cultivars. A Pakistani wheat (Faisalabad 83) and an American wheat (KS84) each possessed a distinct double band, which is readily distinguishable. These cultivars may be used as a reference in assigning mobilities for further identification of wheats. The presence of the HMW glutenin subunit 20 in only the two old excellent chapati quality Pakistani wheats, C591 and C273, indicates that this band may have a relationship with chapati quality, but needs further confirmation. HMW subunits showed relationships with some grain, flour and bread quality traits.Pakistani wheats possessed higher 1000 kernel and test weights of more than 30 g and 60 lbs/bu, respectively. Grain hardness by barley pearler, NIR, and the KSU hardness tester indicated that the Pakistani wheats had hardness comparable to American hard white wheats. Test weight and flour yield were not significantly affected by cultivars and years. Barani 83 had a protein content (NIR) significantly higher than the rest of the Pakistani wheats. Farinograms revealed a significantly very long mixing time and stability for the Pakistani wheat, Barani 83. Blue Silver and Faisalabad 83 had weak gluten, while the others had medium strong gluten quality. The whole meal mixograph peak time was also the highest for Barani 83. Falling number and Rapid Visco Analyzer (RVA) analyses indicated low amylase activity in Pakistani wheats, though the falling number was reduced by the wet harvest that occurred in Bahawalpur during the 1988-89 crop year. The RVA indicated almost identical times to reach peak viscosity for each cultivar, but the peak height was much lower in the case of these wet harvested samples.