Potato Review

www.potatoreview.com POTATO REVIEW MARCH/APRIL 2021 27 POTATO SCIENCE LIVE A nalysis of data fromgrowers’ eld trials, independent crop consultants and researchers across the UK revealed signi cantly increased yield for crops that were under prolonged heat stress, following use of a newbiostimulant, the annual Potato Science Live conference heard. Syngenta Technical ManagerMichael Tait said of the 32 sites experiencing conditions of greater than 25 C for more than four hours, yields were an average 2.5 t/ha greater. e 14 sites that experienced a heat event in excess of 30 C recorded an average 2 t/ha yield increase. Michael highlighted plant physiological studies that indicate where potatoes are under the e ects of oxidative stresses, they are unable to assimilate proteins to transport down into tubers. In fact, theymay even be drawing on plant reserves to counter the stress factors. In the initial years of Quantis trials, the greatest e ects on yield and tuber sizewere recorded in 2018, which coincidedwith an extremely hot and stressful growing season, he said. “It was notable from in season assessments that e ectswere apparent in the secondphase of tuber bulking, when the crop came under extreme stress.” Reviewing historic weather has shown the variability in heat events fromseason to season and location, but that at some stagemost crops will be subject to some e ects, he warned. Furthermore, as climatic conditions have changed over recent years, extreme and prolonged heat periods are becomingmore frequent “Quantis is a derivative of sugar cane processing, which delivers a readily available blend of organic carbon, amino acids, potassium and calcium that supplement the plant’s own Biostimulant boost to heat-stressed potatoes Trial results on Quantis, the rst biostimulant from Syngenta, were amongst the insights shared at the recent Potato Science Live event. molecular cell function,” saidMichael. “Acting directly as an anti-oxidant it can help to counter reactive oxygen species (free radicals) that can cause signi cant damage, particularly within the foliage if leaves get too hot. It is believed to activate and enhance the potato plant’s natural capability to adapt to heat stress, to prevent damage.” He said Quantis also provides osmoprotectant regulators to help plants manage cell osmosis, which could help contribute to the heat stress mitigation. Biostimulant responses do appear to be crop and stress speci c, saidMichael. “It’s only through this detailed research that you canbegin to tease out just where andwhen eachproduct will be e ective.” It is considered likely that some crops would respondmore positively than others, according to soil and growing conditions, along with any varieties’ natural resilience to heat stress. However, the trial contained somany varieties andmultiple variables that it was impossible to pick out individual traits this season, he added. Whilst trials have so far shown e ects fromthree applications of 2.0 l/ha fromtuber onset through to bulking phase, for 2021 continued Syngenta eld researchwill look at re ning application timings. More controlled trialswill also seek to tease out di erences between varieties and other variables, such as irrigation and cropduration. Syngenta’s NewFarming Technologies team is using predictive heat forecastingmodels, with the aimof identifying potential for precision targeting of applications prior to stress periods in the potato growing season, along with some other crops. New Syngenta research funded at Nottingham University will also lead an in-depth investigation into howQuantis is working to alleviate heat stress and drought e ects within potato plants. Quantis is planned to be available in limited commercial volumes for the 2021 season. Blight programmes meet challenge of changing clones WHILE the dynamic adaptation of new genotypes of potato blight continues to put pressure on management strategies, Michael said he believes the work of AHDB and James Hutton Institute in tracking genotype populations has been instrumental in telegraphing potential problems early. Monitoring in 2020 con rmed the continued spread of themore aggressive EU_36 across the country, along with greater incidence of EU_37 associatedwith reduced sensitivity to uazinam, he said. It has also picked up further reductions in the proportion of the 13A2 genotype that had been seen to be less susceptible to phenylamides. “Importantly the work at JHI, to test for any potential reduction in e cacy of the key fungicide groups, has shown continued high levels of control of mandipropamid (Revus) against all ➜ Blight leaf lesion Quantis trial field sign