Effect of N-Dimethylaminosuccinamic Acid on Ripening and Respiration of Apple Fruits

The amount of chlorophyll in peel and flesh of apples was lower throughout the season when a spray of 4,000 ppm of N-dimethylaminosuccinamic acid (Alar) was applied in mid-May, two weeks after bloom. The pattern of chlorophyll disappearance during maturation and ripening was not altered, however, indicating that Alar did not noticeably advance or delay maturity. A mid-July application of 2,000 ppm significantly reduced respiration of stored fruit at 0 °C, whereas a mid-May 2,000-ppm spray did not. With most cultivars, the mid-May spray of 4,000 ppm reduced the respiration rate at 20 °C during the ripening phase.