GENETIC-IMPROVEMENT IN MILLING AND BAKING QUALITY OF HARD RED SPRING WHEAT CULTIVARS

Genetic selection for improved milling and baking quality of hard red spring wheat (Triticum aestivum L.) has been well documented. Few stud ies have examined whether improved cultivars have resulted from select ion for quality. Forty-five hard red spring wheats developed from 1911 to 1990 and commercially produced in the U.S. Pacific Northwest regio n were evaluated for milling and baking quality using grain harvested from three Idaho locations in 1989 and two locations in 1990. Regressi on analysis, using year of release as the independent variable, indica ted significant improvement in mixing tolerance (0.046 degrees yr-1), mixing time (0.019 min yr-1), and corrected loaf volume (0.079 ml yr-1 ). Flour protein content declined significantly (-0.018 g kg-1 yr-1). There was no significant change in flour yield. The relative improveme nt of cultivar baking quality over time was greater for flour from irr igated environments than that from dryland environments. Rank summary of eight important quality traits indicated that nine of the 10 best q uality wheat cultivars have been released since 1970. When grown under contemporary cultural practices, recently released cultivars are gene rally superior to older cultivars in overall baking quality and are co mparable to older cultivars in milling performance.