Performance of gerbera (Gerbera jamesonii) cultivars under fan and pad cooled greenhouse environments.

Performance of nine exotic cultivars of gerbera (Gerbera jamesonii) viz., Diablo, Lyonella, Ornella, Sunset, Tara, Thalassa, Tiramisu. Twiggy and Whitsun was studied under fan and pad cooled greenhouse environment, at Indian Institute of Horticulture Research, Bangalore, during July 1998 to June 1999. The maximum plant height (48.83 cm), number of suckers (5.16) and leaves (46.27) per plant were obtained with cultivars Tiramisu, Lyonella and Ornella, respectively, while the minimum growth of above parameters was obtained in cultivars Whitsun (47.88 cm), Sunset (3.82) and Tiramisu (26.74), respectively. Earliest flowering (47.88 and 57.47 days) was obtained in Whitsun and latest (83.10 and 88.30) in Tiramisu. The maximum diameter of flower (10.70 cm.) and length of flower stalk (58.27cm) were recorded in cultivars Tiramisu and Lyonella respectively. The thickest (0.70 cm dia) and heaviest (22.20 g) flower stalks were produced in Twiggy and the thinnest (0.60 cm dia.) and lightest (13.94) in Whitsun. The highest total number of flowers produced per plot in a year and mean number of flowers per plant and per month in a year were obtained in Ornella (1058.00, 47.26 and 5.02, respectively) followed by Thalassa (988.00, 44.52 and 4.61) and the minimum in Tara (591.33, 29.48 and 2.82) followed by Sunset (600.00, 31.15 and 3.11). Higher percentage of 1 st grade flowers were obtained in Lyonella (73.85). Sunset (70.41 and Tiramisu) (70.54) and lower in Tara (47.16) and Thalassa (47.87). Higher percentage of discard flowers was recorded in Thalassa (37.30) followed by Whitsun (20.47). Considering the overall performance, cultivars Lyonella, Ornella. Tiramisu and Twiggy are recommended for commercial cultivation. The temperature inside the greenhouse could be controlled from 24.7 to 30.5 o C when the ambient temperature varied from 27.4 to 35.5 0 C. The maximum drop of 8.0 o C and 6.7 o C was recorded during April and March, respectively. The RH in the green house varied from 44 to 77% while the outside RH was 20 to 67% when the rate of ventilation was 1018 cubic meter per minute.