Study on cold resistance of several important litchi and longan germplasms and their intraspecific/ intergeneric hybrids

摘要

In order to study the cold resistance of litchi and longan, 32 accessions including cultivars of litchi and longan, intraspecific hybrids of litchi and longan, and intergeneric hybrids between longan and litchi were selected as materials. In this study, the relative electric conductivity and the damage rate were calculated by measuring the electric conductivity of all accessions' leaves under different low temperature treatment. Then the lethal dose-50 temperature (LT50J was used as the main index toevaluate the cold resistance of all accessions and selected germplasm resources with strong cold resistance, this was calculated using the Logistic regression equation for the damage rate. The results showed that 'Fengduziyuan' longan has an excellent cold resistance with the lowest LT50 of -6.01°C, followed by 'Fengliduo' longan with an LT50 of about -4.97°C. The longan intraspecific hybrid 'FD 82' and intergeneric hybrid 'Shizi No.26' were the most susceptible to cold with a LT50 of about 0.27 and-0.90°C respectively. In addition, there was a wide separation in cold resistance among the ten intergeneric hybrids and their parents. 'Zaozi No.l' and 'Shizi No.19' had a stronger resistance to cold with a LT50 of about -4.41°C, compared to 'Shizi No.26' which had a weaker cold resistance. The results the superiority in creating a new germplasm resource with an excellent cold resistance can be reached through distant hybridization.