Sugar Composition and Freezing Tolerance in Barley Crowns at Varying Carbohydrate Levels

During hardening, carbohydrate content in winter cereals is affected by light intensity, which in turn affects freezing survival. To determine whether total carbohydrate content affects composition of individual sugars and whether particular composition is related to freezing tolerance, three barley ( Hordeum vulgare L.) cultivars, differing in carbohydrate composition and in response to a controlled freezing test, were hardened under six light levels. At each level, total crown sugars were measured by water/ethanol extraction and high‐pressure liquid chromatogrphy and at four light levels plants were freeze tested. Carbohydrate composition changed depending on total carbohydrate content, and maximum freezing resistance was not found at the maximum simple sugar level. In addition, the relationship between kill temperature and total carbohydrate was different for the three cultivars. A simple relationship between carbohydrate composition and freezing tolerance was not found, but results suggest that the three cultivars may allocate total carbohydrate differently for cryoprotection.