RESPONSE OF Coffea arabica L. TO THE EXOGENOUS APPLICATION OF A HOMOBRASSINOLIDE

The research was carried out in a coffee plantation in order to know the exogenous response to the homobrassinolide application. The experiment initiated with sanitary pruning of trees and fertilization of 200 g de 17N-17P-17K per plant. The treatments evaluated were: 1) HBr 0.5% +1.0% KNO3; 2) HBr 0.5%+ 2.0% KNO3; 3) HBr 1.0% +1.0% KNO3; 4) HBr 1.0% +2 % KNO3; 5) HBr 0.5%; 6) HBr 1.0%; 7) KNO3 1.0%; 8) KNO3 2.0%; 9) and water alone was used as a control Treatment were distributed in a randomized block design with five repetitions, and morphological and physiological variables were recorded. The variables evaluated were number of flowers, number of fruits, polar and equatorial diameters of fruits. The number of flowers and fresh weight of 100 fruits increased in all treatments including the control were recorded. The higher increase occurred with the potassium nitrate application while the highest number of coffee fruit occurred with the application of 1% HBr alone. The largest size of fruits was observed with the application of 2% KNO3 in combination with 1.0% HBr. Single and/ or combined application of potassium nitrate and brassinosteroid induced a differential response in flowering and fruiting of C. arabica. The individual or in interaction application of potassium nitrate and brassinosteroid induced a differential response in flowering and fruiting of C. arabica cv catimor, but the effect on the different morphological and physiological variables exceeds the control.