MSc

The importance of mango as a commercial fruit crop suffers very much due to the biennial bearing habit observed among most of the superior cultivars. Another important problem faced by mango cultivators is the enormous shedding of young fruits and flowers which will result in great loss.
An attempt is made here to induce flowering in mango by application of ethephon at different concentrations in the first experiment. The different concentrations of ethephon tried were 100, 200, 300 and 500 ppm along with water spray as control. These sprays were given at 15 day intervals, the first spray commencing on September 15 th 1981. The varieties tried were Banganapally, Imampasant, Mundappa and Neelum.
In all the varieties tried ethrel treatment induced early flowering, the optimum concentration being 200 ppm. By the application of ethephon more number of inflorescences were produced. The optimum concentration which induced maximum flowering in Banganapally and Neelum was 200 ppm, 300 ppm in Imampasant and 100 ppm in Mundappa. The percentage of hermaphrodiate flowers and male flowers produced in a panicle were not affected by treatments. The yield of fruits were found to increase by ethephon treatment. In Banganapally and Neelum maximum number of fruits were produced by 200 ppm, while 300 ppm and 100 ppm were found best for Imampasant and Mundappa respectively, In a overall analysis maximum content of carbohydrates was observed just before flowering and it reduced gradually after flowering. A similar trend as that of carbohydrates was observed for carbohydrate/nitrogen ratio.
In Experiment 11 an attempt was made to tackle the premature fruit-drop by application of NAA and GA. Their effect on initial fruit set and quality of fruits were also observed. The treatments were as follows.

NAA - 0,10,20,30 and 40 ppm
GA - 0,25,50,75 and 100 ppm

The chemicals were applied three times at weekely intervals, the first spray commencing when the panicles were in full bloom. The varieties tried were Banganapally, Imampasant, Mundappa and Neelum.
Generally GA treatments were found better in increasing fruit set and GA 100 ppm particularly proved most effective in increasing initial fruit set when compared to other treatments in all the varieties studied.
Fruit drop at different stages of fruit development viz., mustard, pea, marble and pre-harvest stages were found to be effectively controlled by NAA treatments in all the varieties. Among the NAA treatments NAA 40 ppm proved to be the best treatment.
Increased fruit weight was observed by application of NAA 40 ppm in all the varieties. Fruit-length was found to be increased by GA treatment while girth was found maximum for NAA 40 ppm.
In all the varieties fruit quality was found to be enhanced by NAA treatments, in general, but notable effects were seen for NAA 40 ppm, the application of which resulted in maximum TSS, sugar content and Vitamin C.