From the fields of Kansas to the farms of Punjab, Bihar and Madhya Pradesh, drones are helping researchers to develop and monitor improved varieties of wheat and fight a pest that is becoming more dangerous due to climate change

Testing a drone over wheat fields in Pusa, Bihar. (Photo by Manish Kumar)

Many heads turned when drones, or unmanned aerial vehicles, started hovering over the expansive farmlands of Kansas. It was not a military exercise. Researchers at Kansas State University are using drones for a very different purpose — to develop a climate-resilient wheat variety that can combat rising heat and drought.

The same drones with enhanced equipment are now flying over the wheat fields of Punjab, Bihar and Madhya Pradesh. Kansas is known as the wheat basket of the United States, a distinction associated with Punjab in India. They share many similar agricultural problems — stripe rust is one of them. The rust attacked the standing wheat crop in Punjab and Kansas early January this year, shocking many wheat experts.

Globally, stripe rust, leaf rust, root rust and spot blotch have been destroying wheat fields for centuries. But in recent years, stripe rust has become more frequent, forcing wheat breeders to race against time and develop new rust-resistant varieties. Experts say this pest is mutating faster, attacking newer wheat varieties and spreading to more areas due to climate change.

India is facing an extreme stripe rust crisis right now. A stripe resistant wheat variety PBW 343 released in 1996 became so popular with farmers in Punjab, Haryana and Uttar Pradesh that it occupied nearly 25% of 27 million hectare of wheat fields. After 10 years, it was phased out as it became severely susceptible to stripe rust in 2006.

A new variety, HD 2967, was released in 2011 to counter the rust menace. This variety too became susceptible to stripe rust in barely five years. In January, HD2967 became prone to rust in a few districts of Punjab. The variety is sown in nearly 10 million hectares. Now, a new variety HD 3086, and PBW 725 and WH 1105 are replacing HD2967.

Race against time

The battle against rust becomes grim as a new variety of wheat with a new resistance to rusts takes nearly 10 years to develop. Uttam Kumar, a wheat breeder with the Global Wheat Programme of CIMMYT and Borlaug Institute of South Asia (BISA), told indiaclimatedialogue.net that stripe rust pathogens are becoming stronger with every attack. “We have to ensure that the new variety is more resilient to the rust,” he said.

A rust attack can become an epidemic depending on the wind pattern. A stronger wind can destroy or severely impact wheat yield.

The struggle does not end with the development of new rust-resistant wheat. One of the most daunting tasks is to convince farmers to use the new variety. H.S. Gupta, Director General of BISA, points out that farmers develop trust and habit of using the same variety season after season. “A lot of effort goes into convincing them to use the new rust-resistant wheat,” he said.

Changing weather

Rising temperatures and changing rainfall patterns have further stoked rust attacks. The situation is so alarming that in 2011 at the International Wheat Stripe Rust Symposium in Aleppo, Syria, scientists and policymakers from 31 countries said in a statement, “Climate change brings rising temperatures, and has increased the variability and intensity of rainfall, contributing to the spread and severity of rust diseases. Emerging variations (or races) of rust are showing that they can adapt to extreme temperatures – a phenomenon not seen before.”

Gupta agrees that combat against rust resistant wheat is going on for many decades, but the situation has aggravated with rising temperature. “We need resources, efficient data to develop climate resilient wheat variety. Slowly, the data collection is becoming efficient,” he said, adding that BISA and CIMMYT are adding new technology to boost faster collection of data.

“Drones are a part of fast data collection initiative,” he says.

Drones at work

Initially, drones were used in 2014, under a research funded by the Kansas Wheat Alliance and carried out by Kansas State University for efficient and fast data collection using near-infrared light to select high yielding, heat and drought resistant wheat lines.

Drones patrol wheat fields in Kansas. (Photo by Conrad Kabus)

Daljit Singh, a researcher of plant pathology at Kansas State University, points out that drones have a vast potential to assist in wheat variety development. Under the guidance of Jesse Poland, Singh mounted a point and shoot camera on a drone to study the wheat lines. “Drones at KSU captured two sets of data —normalized difference vegetative index (NDVI) and near-infrared light,” he told indiaclimatedialogue.net.

“NDVI calculates greenness of the plant and near-infrared light measures its heat resistance,” he said. If a plant reflects low infrared light, it means the plant is heat-stressed.

Earlier, data was collected through a manual field visit that would take two persons nearly two working days. Drones collect the same data with additional data sets in barely 20 minutes.

Farmers benefit

Experts of BISA, CIMMYT and KSU are collecting similar data from the wheat fields of Punjab, Bihar and Madhya Pradesh. They are also using data to directly benefit the farmers.

Uttam Kumar said that apart from developing climate-resilient wheat, BISA has been developing a series of calculators for providing precise information to farmers. Using the data collected through drones, BISA’s urea calculator application determines the precise amount of nitrogen needed in the field.

Thus farmers are told the exact amount of urea needed in a wheat field. “It’s a massive supportive information for poor farmers of Bihar,” Kumar said. Most farmers in the state are poor and farming is hardly mechanised. Under such circumstances, saving on urea and water saves farmers a lot of money.

In a situation where climate change is making water supplies more erratic, wheat is a better bet than India’s other major cereal crop, rice. Wheat needs less water than rice – 766 litres to grow one kg, where rice needs 2,200 litres. So it is important to safeguard India’s wheat crop.

Bihar has one of the lowest wheat yields in the country, 2,210 kg  per hectare, while in states like Punjab, the per acre wheat yield is more than double at 4,895 kg per hectare.

“One of the biggest challenges in India is diverse weather and farming practices. Punjab suffers from stripe rust but Bihar suffers largely from spot blotch disease,” Uttam Kumar said.

The drone research in Punjab, Madhya Pradesh and Bihar is a joint initiative by BISA, CIMMYT and KSU. The three partners are planning similar drone use in Pakistan, Bangladesh and Afghanistan.