Evaluation of the reversible germination control effect of 1,4- dimethylnaphthalene on potatoes

To investigate the sprout-inhibiting effect of 1,4-dimethylnaphthalene on potatoes and evaluate its feasibility as a potato storage sprout inhibitor, trials were conducted in Dingxi City and Linxia Hui Autonomous Prefecture, Gansu Province. Using the thermal fogging method, 1,4-dimethylnaphthalene thermal fog was dispersed throughout potato storage pits, and its effects on potato sprouting rate, sprout length, safety, respiration intensity, nutritional quality, and field yield traits were measured. The results showed that, at intervals of 30–35 days, continuous applications of 1,4-dimethylnaphthalene thermal fog at 20 mL/t five times (Dingxi) and four times (Linxia) prevented sprouting throughout the storage period of 242 days in Dingxi and 195 days in Linxia, resulting in a 0% sprouting rate at the end of storage. In contrast, the control started sprouting after 60 days of storage and reached a 100% sprouting rate by 120 days. Furthermore, sprout length was positively correlated with storage time, reaching 3.4-6.8 cm in the storage pits of both locations by the end of the storage period. No phytotoxicity was observed in any of the 11 potato varieties tested throughout the storage period following treatment. Upon the termination of dormancy, the respiration rate of the control potatoes increased rapidly. However, treated tubers maintained significantly lower respiration rates at the end of storage 7.26-9.02 mg/(kg·h) compared to the control group 12.32-15.46 mg/(kg·h) (P < 0.05). Regarding nutritional quality, the treatment effectively preserved the dry matter, starch, and protein contents across the various potato varieties with no significantly adverse effects on reducing sugars and vitamin C (P > 0.05). Field germination experiments showed that treatment significantly improved field emergence rate (P < 0.05) and increased the proportion of large tubers by 2.87%-14.61% compared to the control. An average yield increase of 8.65% was achieved, though the differences were not significant (P > 0.05). In summary, 1,4-dimethylnaphthalene exhibited good effects in inhibiting potato sprouting, delaying respiratory metabolism, maintaining storage quality, and increasing field yield, indicating its potential as a safe and efficient potato sprout inhibitor.