Initial Low Oxygen Stress Offers No Scald Control Benefits to `Starkrimson Delicious' Apples in 0.7 kPa O2 Storage

Abstract

In a 2-year study, the benefits and risks of an initial low O2 stress treatment (ILOS; 0.04 kPa O2 for 10 days) as a supplement to 1.5 or 0.7 kPa O2 storage for controlling scald in `Starkrimson Delicious' apples (Malus ×domestica Borkh.) were evaluated. The fruit were picked from 15 orchards and harvested over five successive weeks to generate a wide range in maturity. Storage in 0.7 kPa O2 did not adequately control scald in fruit picked at starch index between 1.0 and 2.1 (10% to 35% scald), but reduced watercore-induced breakdown in fruit picked at starch index ≥2.4 (0–9 scale). The ILOS treatment gave a statistically significant but commercially nonsignificant scald control benefit to fruit held in 1.5 kPa O2 in 1 year, but not to fruit held in 0.7 kPa O2. ILOS did not increase alcoholic taste, but increased skin purpling in 0.7 kPa O2-stored fruit from the final harvest in 1 year. ILOS decreased flesh firmness in fruit picked at starch index ≥1.7 and increased watercore-induced breakdown in fruit picked at starch index ≥2.1 in both years.