Influence of Jasmonic Acid and Chlorpropham Treatments on Sprouting, Quality and Storability of Potato Tubers during Cold Storage

Abstract

The present investigation was carried out on Diamant potato tubers (Solanum tuberosum L.), harvested at their commercial maturity stage (May, 2017) in a private farm at Kom Hamada Behira Governorate, Egypt. The selection of tubers was based on size, absence of physical injuries, mechanical damage and disease infection. Tubers were packed in net plastic boxes (15 kg/ box), and were surface-disinfected by dipping in 2% sodium hypochlorite for 2-4 mins, then rinsed with tap water and air-dried. Potato tubers were immersed in solutions containing chlorpropham (CIPC) at 0, 50, 75 and 100 ppm and jasmonic acid (JA) at 0, 0.001, 0.01 and 0.1 mM/L, either alone or in combinations for 20 minutes and then were cured in the dark for one week at 20°C and 75% RH. After curing, the tubers were placed in the dark cold storage room for long-term storage (140 days) at 10±1°C and 85±5% relative humidity (RH). Treatments were distributed in design with three replicates for each treatment (one replicate = one box of 15 kg tubers). Tuber's firmness, dry matter, starch, acidity and ascorbic acid increased, while SSC and total sugars decreased with increasing concentration of CIPC. Chlorpropham at the concentration of 75 ppm of decreased the weight loss, decay and sprouting percent during cold storage or after removal from cold storage and kept at ambient temperature as compared with 50 or 100 ppm and control. Furthermore, the storability and shelf life of potato tubers have been extended significantly with 75 ppm in both the storage temperature conditions. Likewise, applied of jasmonic acid at rate of 0.01 mM JA/L caused noticeable increase in tubers firmness, dry matter, starch, acidity and ascorbic acid contents. Meanwhile, soluble solids content, total sugars, weight loss, decay and sprouting percent decreased during storage as compared with the other concentrations of jasmonic acid (0.001 or 0.1 mM JA/L) and the untreated tubers. Additionally, the storage and shelf life of tubers have been extended significantly with 0.01 mM JA/L dips during cold storage or ambient temperature at 25±2°C and 75-80 % RH.