Cold hardiness of Dongzao×Linyilizao seedlings and the selection of cold-hardiness candidates

The production of Chinese jujube was greatly damaged by cold injury in recent years.This research was carried out in order to find out the heredity and variation rules of cold-hardiness of jujube and find out the excellent cold hardiness candidates in jujube.In this thesis,cold hardiness of Dongzao crossed with Linyilizao cultivars and their hybrid seedlings at different growing period was measured by conductance.The results are as follows: cold hardiness of the branches is stronger in deep winter(end of December) than the one before germination time (middle of March) and that of the seedlings is stronger than their parents at the same time.Cold hardiness of the seedlings present a drastic variation among the population and form a normal distribution at different time and different treatment-temperature,which show that cold hardiness of the seedlings is a multi-gene controlled quantitative characteristics.10 useful cold hardiness candidates were selected for future research.