Abstract:
The present investigations were carried out in the College of Horticulture, Kerala Agricultural University during the years 1976-1979. The object of the study was to find out the effects of shading on the growth, flowering and fruiting behaviour of pineapple variety ‘kew’.
The treatments consisted of four levels of shade viz., 0, 25, 50 and 75 per cent. Shading was provided by coconut leaves on erected pandals over the plants and the intensity adjusted by using an ;Aplab’ lux meter periodically.
The number of leaves produced per plant was not influenced by shading. In fact the leaf area was found to increase especially at the later stages of growth under shade. Dry matter accumulation in the leaves also was not reduced considerably in shade indicating the capacity of pineapple to tolerate shade.
Early, uniform and increased flowering was noticed in plants grown under shade. Percentage of flowering was maximum at 50 per cent shade which probably indicated that the shade tolerance limit of pineapple is upto 50 per cent. Ethral was found to exhibit an inhibitory effect on flowering in the case of plants grown under shade above 25 per cent intensity.
Crown growth of fruits was greatly enhanced by shade treatments and therefore the contribution of crown weight to the total fruit weight was higher in the shaded plants. Fruit weight with crown was comparable in shade and in open. Developmental pattern of fruits was not found to be influenced by shade treatments.
Quality of the fruits in general, was decreased by shading. The acidity increased with shade intensity while the sugar and ascorbic acid contents decreased.
Nitrogen content of leaves increased by shading, during the later stages of growth. The shaded leaves also possessed higher magnesium and lower calcium contents at all stages of estimation. Chlorophyll ‘a’, ‘b’ and total contents of leaves increased as the intensity of shade increased. Destruction of chlorophyll in the leaves in the open as evidenced by the yellowish appearance of leaves was not noticed under shade.
Number of suckers produced per plant was not considerably affected by shading. Suckers produced by shaded plants were more vigorous than those produced by shaded plants were more vigorous than those produced by plants grown in the open.
