Abstract:

Malus sieversii is an important germplasm resource, and valuable for genetic improvement and conservation of genetic diversity of apples. In this paper, one-year-old seedlings from 7 populations of Malus sieversii in Gongliu and Xinyuan of Xinjiang were used. Cold hardiness of the seedlings was determined by means of the EIS method in comparison with EL method. The results with different cold hardiness determination methods indicated that there was no obvious difference in the semilethal temperature within populations of Gongliu and Xinyuan. In contrast, there was significant difference in the semilethal temperature between the two populations. The semilethal temperature of Gongliu populations was significantly lower than that of Xinyuan populations. Thus, the cold resistance of Gongliu populations was higher than that of Xinyuan populations. Among the six parameters (τ,ψ,r,r₁,r_e and r_i) in the Single DEC model of electrical impedance spectroscopy, was obtained by three parameters (r₁,r_e and τ) was able to be used t determine semilethal temperature of the tested samples. The semilethal temperature obtained by r₁ and r_e was extremely significantly correlated with the conductivity method, suggesting that r₁ and r_e could be used to determine the M. sieversii cold resistance. The cold hardiness estimated by the EIS method was basically similar to that, assessed by means of the traditional EL method. The EIS method is superior over the EL owing to its time saving and no incubation.

Key words: Malus sieversii, Electrical impedance spectroscopy (EIS), Cold hardiness, Specific resistance in the single DCE(r₁), Extracellular resistance(r_e)