EFFECT OF TWO GROWTH RETARDANTS UNDER DIFFERENT CONDITIONS OF WATER SUPPLY ON GROWTH, SEED & OIL YIELDS OF RICINUS COMMUNIS

Castor oil is of increasing importance for its various pharmaceutical and industrial uses. For possible plantation in extensive arid areas in Egypt, improving the water economy of the castor bean plants would be of great importance. Results of studies during 1981 – 1983 with the local variety Hindy 21 showed that while the readily available soil water produced the heaviest vegetative growth, the intermediate irrigation intervals were most suitable for larger fruits and seed yields than the more or less frequent ones. In comparison with the control, CCC at 2000 ppm significantly increased the yield of seeds, the oil % and yield and the oil content of ricinoleic fatty acid. At 1000 ppm of B-9, the heaviest yields of seeds and oil and % of oil were obtained. With the interaction treatments between 4 concentrations of each of the two growth retardants and 3 irrigation intervals, the highest yields of seeds were with B-9 at 1000 ppm and CCC at 2000 ppm when the plants were irrigated at the intermediate interval.