Higher glycinebetaine and antioxidant enzymes activity are associated with high temperature tolerance in potato

Potato is well adapted to temperate climate and predicted increase in temperature under current climate change scenario and this may have a profound effect on potato growth and productivity. A field study was conducted to analyse physiological and biochemical adaptations in potato cultivars for high temperature tolerance. Two potato cultivars viz. Chipsona-3 (sensitive) and Kufri Surya (tolerant) were grown under three temperature environments viz. control (E1), early planting (E2) and inside polyhouse tunnel (E3). The level of temperature under E2 and E3 treatment environments was nearly 5 and 10°C higher than the control during both tuber initiation (S1) and bulking (S2) stages. The results revealed that total sugar concentration in leaves and tubers increased but tuber starch content decreased under high temperature. Membrane stability index (MSI) and proline content decreased with increasing temperature levels, while glycinebetaine (GB) increased in both the cultivars and K. Surya maintained higher GB than Chipsona-3. Activities of antioxidant enzymes viz. superoxidase dismutase (SOD) and ascorbate peroxidase (APX) increased under high temperature in both the cultivars and K. Surya showed higher increase than Chipsona-3. Catalase activity increased in K. Surya but decreased in Chipsona-3 under high temperature. The study suggests that high temperature tolerance in K. Surya cultivar may be associated with increased antioxidant enzymes activities and higher GB concentration compared with Chipsona-3.