INVESTIGATING TRENDS IN VEGETABLE CROP RESPONSE TO INCREASING TEMPERATURE ASSOCIATED WITH CLIMATE-CHANGE

A thermogradient tunnel, 8.6 m wide and 31.9 m long, generating temper atures ranging from ambient at one end to ambient plus approximately 4 degrees C at the other, was used to assess the potential impact of in creased temperatures associated with global warming on the growth of I ceberg lettuce (Lactuca sativa L.), leek (Allium ampeloprasum L.) and Roscoff cauliflower (Brassica oleracea var. botrytis L.) crops, Optimu m mean temperatures for head weight in Iceberg lettuce and trimmed wei ght in leeks were identified as 12 degrees C and 15.7 degrees C, respe ctively, corresponding to temperature rises of 2 degrees C and 2.4 deg rees C above the average ambient temperature during the experiments. I ncreased temperatures gave consistently earlier maturity of lettuce, d elayed cauliflower curd initiation by up to 49 days and increased the final number of leaves in cauliflower by 36. The implications of these effects are discussed in relation to global warming.