Analysis of Salt Tolerance of ‘Golden Gold’ Peach Varieties

In this study, the salt tolerance of yellow peach varieties (‘Golden gold’) was identified and analyzed in order to determine varieties with excellent resistance. Photosynthetic parameters, the content of Na+, K+, and malondialdehyde (MDA), the activity of antioxidant enzymes and other physiological indexes of ‘Golden gold’ peaches were measured after the introduction of salt stress using NaCl. The results showed that under salt stress, the stomatal conductance (Gs), net photosynthetic rate (Pn), transpiration ratio (Tr), water utilization ratio (We), activities of photocooperative enzymes (RuBPCase and FBPase), and K+ content in the roots and leaves of all varieties decreased, and among these physiological indexes, there was no significant difference between J2+S and the blank control (J). The contents of MDA and proline in J2+S leaves increased the least, so the effect of salt stress was minimal. The superoxide dismutase (SOD) activity, peroxidase (POD) activity, catalase (CAT) activity, and Na+ content in the roots and leaves of all ‘Golden gold’ peach varieties increased, and the difference between J2+S and J was significant, with the largest increase. The results of principal component analysis, membership function analysis, and comprehensive evaluation showed that the salt tolerance of nine ‘Golden gold’ peach varieties was ranked as follows: ‘Golden gold’ No. 2 > ‘Golden gold’ No. 5 > ‘Golden gold’ No. 8 > ‘Golden gold’ No. 6 > ‘Golden gold’ No. 1 > ‘Golden gold’ No. 3 > ‘Golden gold’ Parents > ‘Golden gold’ No. 4 > ‘Golden gold’ No. 7. Correlation analysis showed that Pn and We were positively correlated with the D value (p < 0.01), and Tr, SOD, and CAT were also positively correlated with the D value (p < 0.05). Pn, We, Tr, SOD, and CAT can be used as the main reference indexes for screening the salt-tolerant varieties of the ‘Golden gold’ series.