Growth and flowering of Amaryllis and Hippeastrum are influenced by several factors. Among the various external, factors, light and temperature play important role in the development processes of the plants.

A. Environment

The environmental factors playa crucial role on the growth and flowering of Amaryllis and Hippeastrum.

1. Light

Treatment with long day was found to improve the growth and flowering. Increased day length promotes the number, weight and diameter of bulb-lets, while plants under short day fails to produce bulb-lets. Plants under short-day condition do not develop flowers. Intensity of light also affects growth and flowering. It is commonly observed that when plants are grown in shady places, the number and size of flowers are considerably reduced. White flowering is improved in higher light intensity. Reduction of light intensity adversely affects flowering and bulblet formation.

2. Temperature

For the best results, Amaryllis should be grown under conditions where the night temperature does not fall below 60 of (15.6°C). The minimum day temperature should range somewhat higher. In India, amaryllis grows best in outdoor conditions at the temperature of about 25°C and relative humidity ranging from 50 to 90 per cent. However, it can be grown up to 35° centigrades.



B. Growth substances

Soakmg of Hippeastrum bulbs m 3 concentrations each of of IAA, GA3, CCC and ethrel showed various responses to growth and flowering. IA increased the weight and number of bulb-lets while GA3 enhanced the flowers diameter and bulb weight. CCC (1000 ppm) increased the number of flowers per plant. Application of IAA at 100 ppm and GA3 at 10,100 or 1000 ppm twice as foliar spray at an interval of 15 days promotes the number of bulb-lets on the treated plants while concentration of CCC and etheral (1000 ppm) increased the weight of bulbs. All concentration of IAA, GA3 and 1000 ppm CCC increases the number and size of flowers.




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