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 germplasms, 22 accessions including cultivars of litchi and longan and intraspecific hybrids of litchi and longan along with the intergeneric hybrids between longan and litchi, were used as the materials for the experiment. The relative electric conductivity and the damage rate were calculated by measuring the electric conductivity of leaves of all the accessions under different low temperature treatment. Then the lethal temperature (LT50J was determined as the main index to evaluate the cold resistance of all accessions and selected germplasm resources with strong cold resistance. It was calculated through the logistic regression equation for the damage rate. The result indicates that 'Fengliduo' longan had excellent cold resistance with the lowest LT5o that reached to -4.97°C with at par result in 'Huanongzao' longan (LT50 about -4.96°C). The longan intraspecific hybrid 'FD 82' and litchi intraspecific hybrid 'MS 78' were most susceptible to cold with LT50 of about 0.27 and -0.96°C, respectively. In addition, there was a wide difference in cold resistance among five intergeneric hybrids and their parents. 'Zaozi No. 1' had stronger cold resistance with LT50 of about -4.41°C, however,'Zhongzi No. 8' had weaker cold resistance with LT50 that only reached -1.89°C. From the experiment, it can be said that distant hybridization technique is a promising tool for creating new germplasm resources with excellent cold resistance in litchi and longan.