Abstract:

Eighty-four sweetpotato varieties were identified for cold tolerance, and the survival rate, relative conductivity, antioxidant enzyme activity and osmoregulatory substance content under low-temperature stress at 4 ℃ were determined and analyzed, and comprehensive evaluation was carried out using statistical methods such as principal component analysis and cluster analysis. The results showed that there were significant differences in cold tolerance among sweetpotato varieties selected from different regions during low-temperature stress at 4 ℃, the survival rate of sweetpotato seedlings of the cold-tolerant varieties was significantly higher than that of the weakly cold-tolerant varieties after 4 ℃ low-temperature stress, the survival rate of sweetpotato seedlings of Liaohanshu 21 was the highest(81.1%), followed by Xushu 33(72.5%). The antioxidant enzyme activities and osmolyte contents of Liaohanshu 21 and Xushu 33 were higher than Sushu 28 and Wanshu No.7 before and after stress (0 h and 48 h). Correlation analysis and principal component analysis showed that SOD activity, POD activity, CAT activity and proline content were significantly positively correlated with the survival rate of potato seedlings, and the comprehensive analysis showed that Liaohanshu 21 and Xushu 33 were the most cold-tolerant, while Sushu 28 and Wanshu No.7 were the least cold-tolerant.

Key words: sweetpotato, cold tolerance, physiological characteristics, principal component analysis, cluster analysis