MSc

Investigations were conducted on the floral biology, pollination and fruit development in pineapple varieties Kew, Queen, Mauritius and Charlotte Rothschild in the College of Horticulture, Kerala Agricultural University, during the period from December 1980 to October 1981.
The four varieties under study did not show significant difference in the number of days required for the completion of various developmental changes of the inflorescence. The time requirement of the varieties for the developmental changes are as follows:
1. Colour change in the apical region to
Visible appearance of inflorescence - 5.87-6.08 days
2. Visible appearance of inflorescence to - 16.39-16.66 days
Opening of the first flower
3. Opening of the first to last flower - 13.89-14.68 days
4. Opening of last flower to harvest maturity - 94.18-98.80 days
5. Total inflorescence development period - 128.42-133.00 days
The rate of flower opening varied from 4.99 to 5.97 flowers per day. Total number of flowers produced in an inflorescence was 72.87 to 86.44 in between the varieties. Kew was superior to the other three varieties in the above two characters. In all the varieties flower opening started from the base of the inflorescence and progressed up towards the crown region in a spiral pattern.
There was no difference in the morphology of flowers in the four varieties of pineapple.
Flower opening and anther dehiscence started early in the morning hours and reached a peak at 4-6 am. Flowers showed satisfactory receptivity from 4 to 10 am on the day of flower opening; the most optimum time for hand pollination being 5 to 8 am. Pollen grains of all the varieties were yellowish and were 30-60 microns (µ) in diameter. The average pollen diameter of kew was 50.45 , µ, Mauritius 47.30 µ, Charlotte Rothschild 46.30 µand Queen 43.40 µ. Pollengrains of Mauritius and Charlotte Rothschild were spherical and those of Queen and kew were slightly ovoid. Pollengrains gave satisfactory germination when incubated for 3 hours in a medium containing 8 per cent sucrose and 1.5% agar. Of the varieties tested kew had highest number of fertile pollengrains followed by Queen, Mauritius and Charlotte Rothschild. Pollen production per flower varied from 1250 to 12, 500 and the average for the varieties were: Mauritius 5030.15, Charlotte Rothschild 4839.09, Queen 4331.80 and kew 4112.46. Pollengrains could not be stored more than three days in the methods employed in the present study. Of the methods tried, storage of flowers at 240C over calcium chloride in a desiccator was the best followed by low temperature storage of flowers at 40C. Kew had the longest shelf life followed by Queen, Mauritius and Charlotte Rothschild. It appeared that natural agencies like vind and insects did not effect cross-pollination in pineapple varieties under Kerala conditions. Out of the cross-combinations tried, K x Q, Q x M, Q x C and C x M were superior and C x K was the least compatible combination.
Length and girth of fruit and crown increased gradually during the fruit development in kew pineapple and showed a tendency to stabilize between 135th to 142nd day after visible appearance of inflorescence, when the fruit neared harvest maturity.
A gradual increase in the weight of fruit, peel, crown and pulp was noted throughout the development of pineapple fruit except for the tendency to stabilize when harvest maturity neared.
Dry matter content, T.S.S., soluble carbohydrates, Vitamin C and carotenoid pigments increased with advancement of fruit development and remained without appreciable changes at harvest maturity.
Acidity of the fruits showed an increasing trend throughout the development period of pineapple.
pH decreased from the early stages of development till harvest maturity was attained. Towards the last stages of development also, the same trend continued eventhough the decrease was not significant statistically.
Crude fat content and Tannin content showed decrease with the advancement of maturity. A sharp decline in tannin content was observed after 86th day of visible appearance of the inflorescence.
The fruits of pineapple variety kew were found to reach harvest maturity between 133 to 138 days after flowering under Kerala conditions.