Growth, flowering, fruit set and fruit development in kodampuli

Abstract

The present investigations were carried out in the Department of Pomology and Floriculture, College of Horticulture, during the year 1993 – 94. The study was undertaken with the objectives of understanding the growth and flowering pattern of the tree, floral biology, fruit set, fruit development and fruit drop in ‘Kodampuli’. The studies were conducted on four male trees and three hermaphrodite trees of about seven years age, receiving similar cultural practices. The studies indicated that shoot growth in ‘Kodampuli’ was seasonal with one main flushing period commencing from January and extending upto May. The shoot activity noticed during the remaining period of the year was very low. However, scattered flushes occurred throughout the year. The mean growth varied significantly from month to month with a peak growth during the summer months. Individual trees also showed significant variation among them in mean growth. However, there was no significant difference among the two types of trees, viz., male and hermaphrodite trees. The colour of emerging leaves showed marked difference among the male and hermaphrodite trees. In male trees, the emerging leaves were light green in colour while they showed a pinkish red colour in hermaphrodite trees. Flowering pattern of male and hermaphrodite trees were almost similar. However, male trees of ‘Kodampuli’ showed a protracted period of flowering extending over four to five months starting from the month of November onwards. In hermaphrodite trees, flowering started a little later in December and confined only to two to three months. Peak flowering in both type of trees was during January to April. The flower bud development took 32 days from visual emergence to anthesis in male flowers but only 28 days in bisexual flowers. ‘Kodampuli’ was observed to be androdioecious with male and bisexual flowers borne on separate trees. In male trees, the flowers occurred as cymose inflorescence having three to seven flowers per inflorescence. Bisexual flowers of hermaphrodite trees were borne singly and rarely in groups. In male flowers peak anthesis was between 16 30 and 17 00 hours and in bisexual flowers it was between 17 00 and 17 30 hours. Anther dehiscence occurred 10 hours prior to anthesis. Stigma became receptive 30 hours before anthesis and retained receptivity upto 12 hours after anthesis. Anther number and pollen per flower varied significantly among the two types of flowers. Number of pollen produced per anther was significantly higher in male flowers. The pollen fertility was also higher for male flowers. Sucrose at concentrations of 2, 4, 6, 8 and 10 and boric acid at concentrations of 25, 50, 75 and 100 ppm were found to promote pollen germination. However, calcium nitrate at all concentrations tried (25 to 100 ppm) drastically reduced the pollen germination. A combination of four per cent sucrose and 75 ppm boric acid gave maximum germination (67.00 per cent). Pollen was found to be viable for six days in the dehisced bud condition and the viability was greatly reduced thereafter. Low temperature storage conditions gave better results when stored as staminal column or as pollen grain alone. The pollination in ‘Kodampuli’ was found to be effected by insects. ‘Kodampuli’ was found to be an often cross pollinated crop. Hand pollination with pollen from male flowers increased the percentage fruit set as compared to self pollination or open pollination indicating the importance of male trees in a population for improved fruit set. There was no apomictic fruit development in ‘Kodampuli’. The fruit drop after set was found to be 35.50 per cent and the major part of the drop occurred during the first thirty days. The fruit attained maturity in 130 to 140 days after fruit set. The developing fruits followed a sigmoid growth pattern. The chemical composition of the rind showed an increase in T. S .S. content till maturity. Total acidity increased upto 80 days after fruit set and showed a gradual decline towards ripening. Ascorbic acid content was also high in the initial stages and decreased towards maturity at ripening the rind of the fruits had on an average 6.68 per cent acidity, 7.2 mg/100 g ascorbic acid, 80 Brix T. S. S. and 1.04 per cent reducing sugar. The mucilage developed around the seed towards ripening had 2.04 per cent reducing sugar and 3.3 per cent acidity. There was a loss of 75 per cent fresh weight on drying. The trees varied for the number of fruits harvested.