It's a bit early to contemplate for many Scottish growers, but there's new hope for being able to combat heat stress in potato crops.

Syngenta has launched its first biostimulant in potatoes, Quantis, that it claimed can effectively help crops cope with the impacts of heat stress.

Following the UK’s most extensive research field trial of a biostimulant, analysis of a huge data resource revealed significantly increased yield for crops that had been under prolonged, or extreme heat stress.

The results indicate that Quantis could have an important role in potato agronomy programmes all the way from tuber initiation, through to crop bulking. Its value is even more apparent with the increasing incidence and severity of heat events in the UK, according to Syngenta's head of technical, Dave King.

The product delivers a readily available blend of organic carbon, amino acids, potassium and calcium to supplement the plant’s own molecular cell function, he pointed out.

Potatoes were under heat stress for quite long periods in 2020

Potatoes were under heat stress for quite long periods in 2020

“Acting directly as an antioxidant, it can help to counter reactive oxygen species (ROS or free radicals) that can cause significant damage, particularly within the foliage if leaves get too hot,” said Mr King. “It is believed to activate and enhance the potato plant’s natural capability to adapt to heat stress, to prevent damage.”

He explained Quantis strength lay in its relatively high proportion of short chain carbon molecules, which are particularly effective at helping the plant to prevent the creation of ROS during periods of stress. Furthermore, it helped with the 'scavenging' of accumulated ROS, to minimise their adverse effects.

“By filling the organic carbon gap when a plant comes under stress it can act to minimise its effects,” he advised. Quantis also contains amino acids that can help to protect plant structures from nitrogen and protein degradation when under stress as well as providing osmoprotectant regulators to help plants manage cell osmosis, which could help mitigate against crop stress.

Some biostimulants, typically with higher amino acid content, play an early role in plant development, but a greater understanding of how Quantis worked highlighted its position for stress prevention throughout the season, he added.

The highest returns in tuber yields were generated from three applications of it at 2 l/ha, applied from tuber initiation through the bulking phase. Application trials had shown it was fully compatible for tank mixing with all blight fungicides tested.

Quantis being applied to heat stressed potatoes last summer

Quantis being applied to heat stressed potatoes last summer

Reporting results of the extensive trials last season, Mr King said the 32 sites that had experienced conditions of greater than 25⁰C for more than four hours through the application window, yields were an average 2.2 t/ha greater. The 14 sites that experienced a heat event in excess of 30⁰C over that period recorded an average 1.9 t/ha yield increase.

In previous years of trials, the greatest effects on yield and tuber size were recorded in 2018, which coincided with an extremely hot and stressful growing season, he recalled. “It was notable from in season assessments that effects were apparent in the second phase of tuber bulking, when the crop came under extreme stress.”

Reviewing historic weather has shown the variability in heat events from season to season and location, but at some stage most crops will be subject to some effects, he pointed out.

Syngenta's field research this year will look at refining application timings and more controlled trials will also seek to tease out differences between varieties and other variables, such as irrigation and crop duration. Also, new Syngenta-funded research at Nottingham University will have an in-depth investigation into how Quantis works to alleviate heat stress and drought effects within potatoes.

The product will be available for use in this season, said Syngenta.