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Effect of potassium nitrate, potassium phosphate and ethephon in floral induction of pineapple guava (Acca sellowiana [O. Berg] Burret)

The experiment was carried out in El Cortijo farm (La Vega, Cundinamarca, Colombia [ 04° 55' N and 74° 18' W ], 2350 m above sea level, 17° C average temperature, 1423 mm of annual precipitation, 85% of relative humidity, and 1.377 of sunshine hours/year). In the study, evaluation of foliar fertilizers KNO3 (potassium nitrate 13-0-46® 1%, 1.5%, and 2%), KH2PO4 (potassium phosphate; Cosmofoliar 0-32-43®; 0.5%, 0.75%, and 1.0%), and ethephon phytohormone (Ethrel® 48 SL; 100, 150, and 200 mg L-1) was done on six year old pineapple guava trees of Clone 41 ('Quimba'). The number of induced floral buds and formed flowers were evaluated, as well as the percentage of formed flowers, and the efficacy levels of inducting products. Application of KH2PO4 at 0.5% produced favorable results in each of the proposed variables; compared to 0,75% and 1% of the same product and, however there were a high number of induced and formed flowers, no significant differences with the control were found. With ethephon at 150 mg L-1 in floral induction and at 100 mg L-1 in flower formation good responses was obtained, but no differences with the control. The plant response to KNO3 was a low induction of floral buds and a negative efficacy in the proportion of flowers formed, and also phytotoxicity when KNO3 concentration was 2%.

Pineapple guava; flower formation; potassium nitrate; potassium phosphate; ethephon; product efficacy; phytotoxicity


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