Pod Abscission and Changes of Endogenous Hormones in Vanilla Pod Under Different Fruit Load

Po d abscission in Vanilla is very serious during pod development. In order to solve this problem,the changes of endogenous plant hormones and pod abscissions under different fruit load were examined in this study. Three levels of fruit load after pollination were set by fruit thinning i.e. 1, 8-10 and all vanilla pods were retained as control. The contents of IAA, GA, ZR and ABA in pods from day 0 to day 60 after pollination were measured using enzyme-linked immunoassay. The results showed that the pod abscission rates of three fruit load treatments were positively correlated with the numbers of pods that retained. The contents of IAA and ZR were higher in earlier stage. while ABA content was higher in the middle and late stage, and GA content maintained a relatively low level.The higher ratio of IAA/ABA and(IAA +GA +ZR)/ABA were related to less pod abscission.Proper adjustment of fruit load may generated a hormone balance for pod retention. This study will provide theoretical basis for solving the problem of vanilla pod abscission during its production.