ISHS Acta Horticulturae 516: XXV International Horticultural Congress, Part 6: Culture Techniques with Special Emphasis on Environmental Implications Physiological Processes in Plants
ETHYLENE REGULATED RIPENING UNDER TROPICAL CONDITIONS AND THE DEVELOPMENT OF CROWN ROT IN BANANA |
| Authors: | R.A.K. Ranawaka, R.S.W Wijeratnam, S.K. Hewage |
| Keywords: | banana, crown rot, ethylene |
| Abstract:
Crown rot is known to cause severe postharvest losses in many countries, and can be particularly destructive during commercial ripening operations. Colletotrichum musae (Berk & Curt.) Arx, is considered the major pathogen associated with the disease. Ripening of banana is regulated in developed countries via temperature management and the external application of ethylene. In the tropics where temperature management might not be possible, fruits intended for domestic markets are also harvested at the mature green stage to withstand postharvest handling. Under such circumstances ripening needs to be regulated effectively in order to minimise losses. This might be achieved by the application of lower levels of ethylene. However, ethylene is known to enhance appressoria formation and the germination of spores of the crown rot pathogen. Studies were conducted using four popular Sri Lankan varieties of banana, to observe crown rot development during ethylene regulated ripening at ambient temperature. The response of the pathogen and its host to ethylene application at 0, 1, 10 and 100 ppm at 28°C were observed over a period of seven days. Observations indicated that while all four varieties were susceptible to the pathogen, lowest levels of disease symptoms were recorded in the Cavendish type Ambon, and the thin skinned Seeni Kehel varieties respectively, ethylene levels of 1 ppm showed least disease development and was most suitable for regulated ripening of the selected varieties at 28°C. Appressoria formation and spore germination increased with increasing levels of ethylene. Higher levels of ethylene also induced multiple appressoria formation on host tissue. | |
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