Abstract
Mature green Williams and Lady's Finger bananas grown on the east coast of Australia were obtained at about 6-weekly intervals over a 12-month period. Individual fingers were held at 20°C in air containing ethylene at 0.001, 0.01, 0.1, and 1 ?L L-1 and green life was assessed as the time taken to reach the respiratory climacteric as determined by carbon dioxide evolution. The green life of both cultivars was extended as ethylene was reduced over the whole range of concentrations examined with the rate of increase in the logarithm of green life quadratically related to a logarithmic decrease in ethylene concentration. For Williams bananas, the green life was about 27-33 days at 0.001 ?L L-1 and 11-12 days at 0.1 ?L L-1 and for Lady's Finger it was about 44 and 11 days, respectively. A survey was conducted over 12 months of the concentration of ethylene in cartons of Williams bananas in commercial shipments on arrival at the Sydney wholesale markets. Of the 363 cartons analysed, the mean ethylene concentration was 0.06 ?L L-1 and ranged from 0.28 to <0.002 ?L L-1 with 15% of cartons containing ethylene at ?0.1 ?L L-1. It was concluded that the accumulation of ethylene that currently occur in commercial road shipments of bananas was significantly reducing green life and that any intervention that reduced ethylene levels should extend the marketing period.
