21 April 2023
New trials reveal interesting results on countering heat stress.
THE increasing occurrence of extreme weather events poses a significant challenge to potato cultivation.
Heat and drought stress reduces productivity, causes physiological defects in tubers, and damages crops. However, recent studies have shown that natural technologies containing plant hormones and betaines can mitigate or control potato plants' response to heat stress.
The Met Office is predicting that 2023 will be hotter than 2022. In the UK, the top 10 warmest years since 1884 have occurred in the past two decades. The highest temperature ever recorded in the UK is 40.3C, set in Lincolnshire on July 19th last year. On the same day, 35C was exceeded for the first time in Scotland. Whilst multiple records were broken in 2022, this year those are expected to be exceeded.
Drought and heat stress are problematic in potato cultivation as modern varieties are adapted to grow at temperatures between 14C and 22C. Potato productivity is reduced at higher temperatures, typically whenever 25C is exceeded during the day.
Potato plants under abiotic stress conditions suffer a disturbance in normal hormonal regulation, plant metabolism and photosynthesis. Reactive oxygen species (ROS) are generated and these cause membrane damage and cell death. As a consequence, the rate of photosynthesis is reduced, the movement of assimilates from the leaves to the developing tubers is disrupted and biomass accumulation is compromised.
The result is inhibition of tuberisation, secondary tuberisation, reduction in tuber bulking and ultimately loss of yield. In addition, heat stress causes physiological defects such as early skin set which is often followed by skin cracking and a loss of tuber quality. The earlier a heat wave occurs, and the longer it lasts, the more negative its impact.
However, there are natural technologies that can minimise these losses to heat stress as recent trials with seaweed extracts prove. Full details of these trials are available in the May issue of Potato Review. Click here if you don't already receive a copy.