Cold Injury Susceptibility of Pecan as Influenced by Cultivar, Carbohydrates, and Crop Load

Abstract

Abstract Exposure of 13-year-old trees of several pecan [Carya illinoensis (Wangenh.) C. Koch] cultivars to severe cold in the winters of 1983-84 and 1984-85 resulted in the death of several healthy bearing trees of alternate-bearing cultivars (‘Chickasaw’, ‘Cheyenne’, ‘Cherokee’, and ‘Shoshoni’), while less tree death occurred in moderately bearing and relatively minor alternate-bearing cultivars (‘Cape Fear’ and ‘Desirable’). ‘Chickasaw’ trees entering winter after bearing a heavy nut crop the previous season experienced greater tree death and reduced midwinter trunk tissue levels of starch, sugars, and K than did trees with a light nut crop the previous season. The increased susceptibility of heavily bearing trees, especially of alternate-bearing cultivars, to extreme winter cold may be due to the effect of heavy fruiting on tree reserves and subsequent cold acclimation.