EFFECT OF COBALT IONS ON FLORAL MALFORMATION, YIELD AND FRUIT-QUALITYOF DUSHERI MANGO (MANGIFERA-INDICA L)

A four year study of malformation in mango (Mangifera indica L.) revea led that a single foliar spray application of 1000 ppm cobalt sulphate prior to flower bud differentiation in the first week of October succ essfully reduced floral malformation by 93, 94, 87 and 84% in each yea r respectively, as compared with the earlier recommended treatment of naphthalene acetic acid (100 ppm) and with unsprayed control trees. Th e single foliar spray of cobalt sulphate was more effective in reducin g floral malformation than a double spray. This treatment also increas ed fruit yield in all four years. The foliar application of cobalt imp roved fruit weight, size, TSS/acid ratio and the total sugars in the f ruit. Experimental findings based upon three years' data clearly demon strated that the deficiency or toxicity of cobalt is not related to th e cause of mango malformation because the concentrations of cobalt did not vary between healthy and malformed organs.