THE INTERACTION OF DORMANCY AND WATER-SENSITIVITY OF BARLEY WITH TEMPERATURE

Newly-harvested Scotch barley was dried and put into storage at 90, 100, 110 and 120° F. One sample at each temperature was cooled at a slow rate (2° F./week) and one at a fast rate (2° F/day). The loss of dormancy and water-sensitivity was followed throughout the drying and storage periods. Dormancy and water-sensitivity were lost most rapidly at high drying and storage temperatures. The optimum drying and storage conditions produced a non-water-sensitive, non-dormant barley within 14 days of harvest. Calculation of regression coefficients for percentage loss of dormancy and water-sensitivity per day at average storage temperatures enabled activation energies to be calculated for the two processes. These were 17·5 and 18·3 kcal/mole respectively. Two very similar processes are therefore involved in dormancy and water-sensitivity and their removal.