Strigolactones Induced Vegetative and Reproductive Growth in HLB-infected Plants

Strigolactones (SL) are carotenoids derived novel plant hormone with multiple physiological and anatomical functions. Two year old greenhouse grown HLB-infected and healthy control Sweet orange ‘Valencia’ (Citrus sinensis L. Osbeck) trees were used for this study. Tress were sprayed at an interval of three months with 10 µM SL. Trees were grouped in four categories based on SL treatment; SL treated HLB-infected trees, HLB-infected tress, SL treated healthy tress, and healthy control tress. Similar experiment was also conducted in citrus grove at CREC, Lake Alfred, FL with 10 trees each for above mentioned four treatments. Healthy control trees were sprayed in a commercial grove at Marion County, Fl. SL spray applications in greenhouse conditions resulted in early induction of spring and summer flush and early flowering in HLB-infected trees in comparison to control and HLB-infected non-sprayed tress. The number of new vegetative branches were more in SL treated HLB trees in comparison to other treatments. Fruit peduncle diameter and fruit diameter was greater in SL treatments. Flower retention, fruit drop, and various anatomical parameters were also evaluated.