EFFECT OF KERNEL WATER CONCENTRATION AT HARVEST AND DRYING METHOD ON GRADES OF RED SPRING AND DURUM WHEATS

Abstract

Effects of kernel water concentration at harvest, and windrow compared to artificial drying, were determined in two red spring (Triticum aestivum L.) and three durum (T. turgidum L. var. durum) cultivars. Grain harvested at kernel water concentrations of 1000 to < 170 g water per kilogram kernel dry weight was dried in the field in simulated windrows or artificially in a forced-air oven (40–45 °C). Test weight and commercial grades were determined. Artificial drying of immature wheat reduced grades, primarily due to numbers of green kernels. Green kernel levels reduced grades of windrowed durum wheat in 1 of 3 years. In the absence of grade-limiting levels of green kernels, test weight limited grades of durum in 1 year, particularly in the windrowed treatment. In a separate experiment, percentages of green kernels were determined in field-scale windrowed and standing hard red spring and durum wheat crops. Levels of green kernels declined at similar rates in standing and windrowed crops. The kernel water concentration at which level of green kernels dropped to 0.75%, the maximum level tolerated in the top grades of hard red spring and durum wheat, was lower in dry years when maturity was forced than in moist years.Key words: Wheat (red spring), wheat (durum), windrowing, artificial drying, test weight