Potato Review

14 POTATO REVIEW MARCH/APRIL 2022 HEAT STRESS P OTATO growers now recognise high temperatures as the greatest threat of the key abiotic stresses, and coping with heat stress is now identified as a more difficult challenge even than drought, according to Syngenta Biostimulants Technical Manager Andy Cunningham,. “Growers most frequently cited the effects of heat in limiting tuber bulking, leading to lower yields and more variable tuber size,” he said. “The resulting uneven growth and associated cracking, impacting on tuber quality, was also highlighted.” Results of a grower and agronomist viewpoints survey into the current and future Feeling the heat Potato response to stress from high temperatures revealed. role of biostimulants in potato crop agronomy showed that 37% of farmers questioned ranked heat stress of very high impact (9 or 10 out of 10), with a total of 70% scoring it as seven or higher. Just 13% perceived the effect on their crops to be a score of four or below. Overall for stress impact, heat was ranked at 74 out of 100, compared to drought at 71, nutrient deficiency at 64 and intensive light at 57. Growers and agronomists recognised temperatures of 24 - 25⁰C would result in heat stress during the growing season, but even at temperatures above 20⁰C believed that tuber bulking would be slowed, added Andy. “During periods of heat stress affected plants would be less effective in taking up irrigation water, along with risk of triggering further stress when applying cold water onto heat stressed potatoes was also pointed out. Drought and heat stress is inextricably linked for growers.” The research highlighted that while 40% of potato growers currently see biostimulants as highly important for stress management in their crops’ agronomy (ranked as 7 or more), 80% believe they will be in the next five years. Biostimulant action In-depth research at the University of Nottingham has given an insight in to how Syngenta’s biostimulant Quantis acts inside the potato plant, to make it better able to withstand the detrimental effects of heat. ➜ Quantis trials - FlurPen measure of leaf photosynthetic activity Quantis trials - Licor measure of leaf effciency Quantis field application timing