Selection of varieties based on when exactly a crop is getting sown is one of the key components in protecting the yield during an abnormal increase in temperature as seen during the recent heat wave in March-April. 

Some select villages in 25 districts of Bihar, Madhya Pradesh, Uttar Pradesh, Maharashtra, Haryana and Punjab are part of risk-prone 151 clusters created by ICAR through its National Innovations in Climate Resilient Agriculture (NICRA) programme across the country, where technologies were demonstrated that helped minimise the negative impacts of heat waves.

Heat wave impact

The heat wave coincided with the grain filling and development stage of wheat resulting in yellowing and shrivelling of the grain and forced maturity— with an average yield losses between 15 and 25 per cent, according to a report titled “Heat Wave 2022: Causes, impacts and way forward for Indian Agriculture” authored by Santanu Kumar Bal, JVNS Prasad and Vinod Kumar Singh of Central Research Institute for Dryland Agriculture.

Ways to solve the problem

Timely sowing and adoption of heat-tolerant varieties PBW03, DBW187 and DBW222 along with a spraying of Potassium Nitrate at 0.5 per cent at boot leaf and anthesis stages minimised yield loss in the two clusters in Punjab to only 3-5 per cent of normal productivity in wheat. Technologies such as mulching in sugarcane, ridge and furrow conserved the soil moisture and minimised the stress, the report said. 

Heat tolerant wheat varieties DBW173, Raj4120 and Raj4079 contributed to containing yield loss by 5-6 per cent in the clusters of Baghpat, Jhansi, Hamirpur, Chitrakoot, Pratapgarh, Kaushambi, Bahraich, Gonda, Maharajganj, Gorakhpur, Kushinagar and Sonbhadra districts in Uttar Pradesh, where maximum temperatures were higher by 3-4 degrees over the normal temperature in the second fortnight of March 2022. “ If the monsoon is delayed, farmers should adopt short-duration paddy to make sure of timely sowing of wheat. Else, they need to select those late wheat varieties, in case there is a delay in its sowing due to late harvesting of paddy. Even crop should also be selected based on sowing time,” said Singh, one of the authors of the report.

Heat tolerant and late sown variety of chickpea RVG202 and timely sowing of mustard variety Pusa Bold also escaped the heat stress at maturity in the selected clusters of Madhya Pradesh, according to the report.