Abstract
The effect of different irrigation treatments, various levels of N and K, and exogenous applications of gibberellins (GA), abscisic acid (ABA), XE-1019 (anti-GA), and fluridone (anti-ABA), on vivipary of pecans was studied. Vivipary (preharvest germination) of pecans was significantly reduced by maintaining optimum soil moisture throughout the growing season. Low soil moisture during late summer was more detrimental than low soil moisture during early summer. A close correlation between preharvest germination and delayed involucre dehiscence was established, indicating an interaction between these disorders. Preharvest germination was enhanced in overcropping seasons. The possibility that preharvest germination is induced by various stress conditions is further discussed. Decreased vegetative growth and poor embryo development were also associated with preharvest germination. Soil applications of N and K remained without a clear effect upon preharvest germination. Exogenous applications of GA (1 mM) drastically increased levels of preharvest germination in both water stressed and non-water stressed trees. Chemical induction of preharvest germination by GA was detected from the time the embryo started its rapid growth phase (dough stage), until harvest (normal involucre dehiscence). Application of GA to the leaves was more effective in inducing preharvest germination than when it was applied to nut clusters. Neither ABA or XE-1019 significantly reduced preharvest germination. Fluridone was ineffective in inducing preharvest germination.
Zertuche, Manuel I. (1986). Effect of gibberellins, abscisic acid, various irrigation treatments, and different levels of nitrogen and potassium upon vivipary of pecans (Carya illinoensis (Wang) K. Koch). Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -437527.