*3.2. Ethylene Production (C2H4) and Respiration (CO2) Rates*

The differences were not found in either C2H4 production or respiration rates (CO2 production) at harvest date (Figure 1a,b). After 30 days of storage, C2H4 production was highest (*<sup>p</sup>* ≤ 0.05) in fruit treated with 500 mg·L−<sup>1</sup> chitosan while it was lowest (*<sup>p</sup>* ≤ 0.05) in fruit treated with 100 mg·L−<sup>1</sup> chitosan (Figure 1a). For the rest of the storage period, C2H4

production was lower (*<sup>p</sup>* ≤ 0.05) for both 100 and 500 mg·L−<sup>1</sup> chitosan-treated fruit than that for the control samples. As for the respiration, control fruit displayed the highest respiration rate during the cold storage than the preharvest chitosan-treated fruit (Figure 1b). While there was a lower CO2 production with the higher chitosan concentration, the mean values of CO2 production in 100 and 500 mg·L−<sup>1</sup> chitosan pre-treated fruit were not statistically significant. At the end of the storage, the highest CO2 production was found in control fruit (20.0 mg·kg−1·h−1), followed by 100 mg·L−<sup>1</sup> (16.4 mg·kg−1·h−1) and 500 mg·L−<sup>1</sup> (14.3 mg·kg−1·h<sup>−</sup>1) chitosan-treated kiwifruit. Moreover, a significant effect of the days of storage at 0 ◦C was observed for C2H4 production and respiration rates (Table S3).

**Figure 1.** Effects of preharvest chitosan application on (**a**) ethylene production and (**b**) respiration rates during cold storage in 'Garmrok' kiwifruit. Vertical bars indicate SE with n = 3. \* indicates significant differences between treatments at each sampling date, according to the least significant difference (LSD) test at *p* ≤ 0.05.
