Study on cold tolerance of introduced walnut seedlings under natural cold stress.

Abstract

Taking seedlings of 7 introduced walnut cultivars and 1 local cultivar as samples, preliminary assessment on their cold tolerance was conducted through analyzing 3 physiological and biochemical indexes under natural cold stress. The results showed that with the decrease of natural temperature, 3 indexes namely relative electrical conductivity, MDA and proline content tended to increase. However, the increase extents were different among the cultivars. Based on comprehensive analysis of all 3 indexes, 8 cultivars were divided into 3 groups according to their cold tolerance. The group I with 2 introduced cultivars Buccaneer and Axel showed high cold tolerance, next came group II with 4 cultivars Coenen, Parisienne, Hanson and Juglans sigillata, and group III with 2 introduce cultivars Lara and Fernette showed the lowest tolerance.