Managing Vivipary in Pecan

Crop loss due to vivipary (i.e., premature germination of nuts) is a major profit-limiting problem for certain pecan (Carya illinoinensis) farming operations.  There is need for orchard management tools and strategies enabling better control over the incidence of vivipary.  Field research assessing the influence of irrigation and nitrogen (N) management, and certain bioregulators {i.e., fluridone [an inhibitor of abscisic acid (ABA) biosynthesis] and ABA} exposure on incidence of vivipary, found that the incidence of vivipary can be influenced by any one of these factors.  In ‘Cheyenne’, that relatively high soil moisture and high plant N concentration during mid- and late-summer increases the incidence of vivipary.  In ‘Sumner’, fruit exposure to fluridone during development triggers earlier germination than non-treated fruit; and in ‘Oconee’ treatment of developing fruit with either fluridone increases vivipary and ABA treatment decreases vivipary. This indicates that crop loss to vivipary can be reduced by altering water and N management strategies so that trees experience some degree of water stress and are not excessively N fertilized during the mid- to late-stages of fruit development. There is also the possibility of regulating vivipary via timely use of certain plant bioregulators.