The fundamental cause of alternate bearing in pecan [Carya illinoinensis (Wangenh.) K. Koch] is unknown, but is closely linked to the size of the dormant season carbohydrate pool. Nut yields (over a period of up to 78 years) were evaluated, for 66 cultivars, in regards to alternate bearing intensity (I). Best-fit regression analysis indicates no association between I and fruit ripening date (FRD) or nut volume; although, there was moderate association with post-ripening foliation periods (PRFP) in that I tends to decrease as the length of the PRFP decreases. Multiple regression models indicated that FRD and nut volume were poor predictors of I, however PRFP possessed significant inverse predictive power. Late-season canopy health, as measured by percentage of leaflet retention, decreased as FRD approached early-season ripening. Late-season photoassimilation rate was higher on foliage of trees with late FRDs than those with mid-or early-season ripening dates. Sprays of either Alar or ProGibb to the canopy of either "On" or "Off" trees altered return bloom the following year. These data provide new insight into the complex nature of alternate bearing in pecan and are interpreted to indicate that alternate bearing in pecan is regulated by; a) gibberellins during the time of fruit development, and b) the size of the carbohydrate pool at about the time of bud break.
Fall defoliation was followed by a depletion of carbohydrate (CHO) reserves and reduction or prevention of yield if defoliation occurred prior to November 1. Refoliation of August-defoliated trees restored the depleted reserves in current season’s wood tissues by December 1 but either completely prevented or greatly reduced yield the next year. September defoliation caused the greatest depletion of reserves and prevented pistillate or staminate flower production the next year. Defoliation on November 1 had no significant effect on CHO reserves.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.