Screening and identification of lettuce germplasm for tolerance to high and low temperature

摘要

The optimal temperature range for growth of lettuce [Lactuca sativa L.) is 15-20°C, but the ambient temperature in summer in Beijing often reaches 35°C, even up to 40°C. Growth inhibition emerges under high temperatures in summer. On the other hand, in Beijing's winter, the climate is chilly. The edible part of the lettuce is the leaves, and it requires warm weather for the growth of leaves. In order to screen for heat and cold tolerance of lettuce, we used 55 different lettuce cultivars as experimental material. We compared their agronomic characteristics under normal and high temperature to select heat-tolerant lettuce and we used two methods to test the cold tolerance, which were the capacity to survive through the winter and growth recovery to select cold-tolerant lettuce. The results provide relevant material in the study of heat and cold tolerance in lettuce. Also, the results will have direct impact on the production of lettuce during summer and winter and will provide a better possibility to deal with heat and cold injury during lettuce production in China.