Abstract

Several hormones are known to be involved in the regulation of the fruit ripening process, including abscisic acid (ABA). However, the effect this hormone has on the fruit may depend upon factors such as genotype, environment and interplay with other hormones. Towards a better characterization of the effects of ABA on sweet cherry fruit ripening and the role the genetic background may play in this effect, ABA was applied exogenously to four different sweet cherry varieties: Bing, Glenred, Lapins and Royal Rainer. These varieties were characterized physiologically, including fruit growth and changes in chlorophyll absorbance in planta throughout fruit development (season 2017- 2018). Fruits presented typical double-sigmoidal curve with Glenred fruits having the shortest growth window. Chlorophyll IAD decreased to values near zero from light green to pink stage in all the varieties, with Glenred and Royal Rainier decreasing earlier. In order to characterize the effect of ABA on ripening and fruit quality in these varieties, plants were treated at the pink stage, with ABA (ProTone®). At harvest, the ABA treatment increased fruit color and anthocyanin IAD in Bing and Lapins, while these parameters were not affected in Royal Rainier and Glenred. ABA biosynthesis inhibitors decreased fruit color and anthocyanin IAD in Glenred. Levels of soluble solids increased only in Bing upon ABA treatment. Based upon these results, we conclude that ABA alters ripening-related physiological parameters in a variety specific manner.