RESPONSE OF Opuntia ficus-indica MILL. TO THE INJECTION OF CHEMICALS, FROST INJURY AND ROOT PRUNING

Abstract

With the aim of inducing floral budbreak, seven treatments were applied in a non producing prickly: pear orchard: 1) ethrel 0.1%, 2) malic acid 0.1%,• 3) KNO₃ 0.1%, and 4) CO₂ 0.1%. In all cases, aqueous solutions were injected in cladodes of more tban six months old, 5) root pruning 6) injected water and 7) control. The results observed were: the levels chlorophyll a and b were increased by KNO₃ (5% and 4%, respectively); ethrel also reduced chlorophylls a and b by 13 and 12.9% respectively; malic acid increased the number of floral buds per cladode, but significantly decreased the number of young succulent stems. Ethrel reduced days to floral budbreak almost 9 weeks compared with the control; KNO₃ promoted vegetative, but not flower budbreak; root pruning promoted vegetative and flower budbreak; while CO₂ and water did not have significative effects.