Abstract:

【Objective】 In order to establish a method for salt tolerance screening of Chrysanthemum as well as to discover salt tolerant germplasms for chrysanthemum breeding, salt tolerance of 30 species from Chrysanthemum and its relative genera was identified in comparison with two chrysanthemum cultivars. 【Method】 Four species from Chrysanthemum and its relative genera were hydroponically cultured in Hoagland solution supplemented with NaCl at different concentrations of 0, 40, 80,120, 160 and 200 mmol?L-1, respectively. The proper screening concentration of NaCl was determined using the ratio of injured leaf area per plant. The regression equation models regarding the correlation between the stressed duration and the ratio of injured leaf area per plant were established, from which the time when the ratio of injured leaf area per plant reached 50% of the whole plant was figured out. The salt tolerance of 32 taxa was sequenced based on the time. This sequence was compared with those judged from other leaf morphological indexes. A comprehensive evaluation of salt tolerance of 32 taxa was made by using hierarchical clustering analysis.【Result】The proper NaCl concentration for screening salt-tolerance was 120 mmol?L-1. Variation coefficients of different indexes under the NaCl concentration were great, and correlation coefficient between sequences of salt tolerance based on different indexes was high. Three types of equations including 32 regression equations were established, and the regression equations all demonstrated good regression effects. 【Conclusion】 Salt tolerance screening of plants from Chrysanthemum and its relative genera can be achieved effectively and rapidly by leaf morphological indexes. Clustering analysis showed that 32 taxa could be divided into extremely salt tolerant, salt tolerant, moderately salt tolerant and salt sensitive grade, respectively. Artemisia japonica, Aster spathulifolius, Crossostephium chinense are extremely salt tolerant, Tanacetum vulgare and Chrysanthemum crassum are salt-tolerant, seven taxa represented by Artemisia vulgaris, Leucanthemum vulgare are moderately salt tolerant, 14 taxa represented by Chrysanthemum zawadskii, Ch. chanetii, Ch.vestitum, Ch. lavandulifolium are salt sensitive ones.

Key words: chrysanthemum, germplasms, salt tolerance, leaf morphological indexes