Continued studies on respiration rate determination of russet type potatoes stored under different storage conditions (P-22)

Respiration rate is an important aspect in maintaining potato quality during storage. The objective of this study was to determine respiration rates among tubers treated with and without chlorpropham (CIPC; 20 ppm) stored at three storage temperatures. Russet Burbank, Clearwater Russet, and Ranger Russet tubers were cured at 12.8°C and 95% relative humidity (RH) for 14 days, after which the temperature was ramped down (0.3°C/day) to 5.6, 7.2, or 8.9°C (95% RH). Respiration rates (mg CO₂ kg^-1 h^-1, mg O₂ kg^-1 h^-1) were determined monthly for 8 months using the static method. This was the second year of a 2-year study. Variety, storage temperature, and storage period all showed significance. A significant interaction was observed between cultivars and storage period, between temperature and storage period, and finally between storage temperature, CIPC, and storage period. Ranger Russet consistently showed higher respiration rate regardless of temperature or sprout control throughout the storage period (1.87 mg CO₂ kg^-1 h^-1, compared to 1.71 mg CO₂ kg^-1 h^-1 for Clearwater, and 1.61 mg CO₂ kg^-1 h^-1 for Russet Burbank). The respiration rates remained consistent with and without sprout control application until sprout development occurred after 4 months, especially in Ranger Russet. The respiration rate was higher at 8.9ºC than the other storage temperatures (1.92 mg CO₂ kg^-1 h^-1, compared to 1.66 mg CO₂ kg^-1 h^-1 for 7.2ºC and 1.61 mg CO₂ kg^-1 h^-1 for 5.6ºC). Russet Burbank had a higher respiration quotient (RQ; 0.83 compared to 0.78 for both Clearwater and Ranger Russet), and 5.6°C had a lower RQ (0.75 compared to 0.82 for both 7.2 and 8.9°C). These findings can be used to predict storage requirements, weight loss potential, and overall storability of specific russet cultivars.