New Delhi: The government is considering phasing out? PBW-343, India’s most successful wheat variety, which constitutes almost 80% of the grain output of Punjab, Haryana and western Uttar Pradesh—the top three wheat producers in India.
In spite of being a workhorse variety since 1995, when it was first approved for commercial cultivation, PBW-343, in recent years, has been affected by rising winter temperatures and is now prone to fungal diseases such as leaf- and stripe-rust, as reported by Mint on 12 March.
“PBW-343’s performance in recent years has been worrying, and we are considering phasing this variety out,” confirmed a senior scientist in the agriculture ministry, requesting anonymity. “Research has been consistently on to develop better varieties and, while poor heat tolerance is one of the reasons, I wouldn’t go so far to completely attribute it to climate change.”
“The case for phasing out is strong, but we also need better, compensatory wheat varieties,” the official said, adding that diseases were always evolving and, many a time, unexpected mutations of disease strains occur, which badly affect even the best of crops.
Of the approximately 220 varieties of wheat being sown in India, PBW-343 has been the most popular since the Green Revolution, and is used in about 25% of the 27 million ha under the crop’s cultivation, and roughly 55% of the total wheat output in the country, according to statistics from the agriculture ministry.
Beginning 2000, wheat production has been on a decline in India, with the average harvest between 2001 and 2006 dipping to 69.74 million tonnes (mt), according to figures from the Indian Agricultural Research Institute (IARI). Agricultural commissioner N.B. Singh in a recent presentation to the agriculture ministry, emphasized that “there have to be viable alternatives to PBW-343, if we have to step up wheat production...”
B. Mishra, who heads the Directorate of Wheat Research (DWR) at the Indian Council of Agricultural Research (ICAR), said: “Developing heat-tolerant varieties has always been a priority, but over the last few years, an increased number of our research projects have consistently focused on the heat-tolerance aspect.”
He said that many varieties from IARI, Punjab Agricultural University and DWR were being tested, but clearances were still a long way away.
“We have identified a few promising varieties, but they have to be cleared at the Central level, which will take at least three years,” he said. “But there are some varieties, such as DBW-17, which have been released last year. Let’s see if farmers take to them.”
Phasing out a wheat variety is mainly about promoting newer varieties and stocking them at grain procurement centres across the state—such as universities and commercial outlets.
“It’s a gradual process and involves convincing the farmers of the benefits of a better variety. Technically, the farmer can still get the old variety, but once farmers are convinced of a better seed, they shift to it,” said S.S. Singh, principal scientist at IARI.
A rise in winter temperatures is a salient feature of global warming, according to international consensus as well as researchers in India. Meanwhile, a 2007 report by India’s official weather watchers—the Indian Meteorological Department—on the effects of climate change on India, says: “...There has been a 0.67° Celsius rise in winter season. During the winter season, since 1991, rise in minimum temperature is appreciably higher than that of maximum temperature over northern plains. This may be due to pollution, leading to frequent occurrences of fog.”
A recent study by researchers S.S. Hundal and Prabhjyot Kaur of the Punjab Agricultural University found that a one-degree rise in temperature decreased wheat yields by nearly 10%. The research analysed 30 years of weather data from different parts of Punjab, and extrapolated yields till 2015.
Reduced heat tolerance means that a slight increase in temperature would shrivel the grain. Moreover, a particularly virulent version of the disease called yellow rust has also weakened PBW-343.
PBW-343, which Mishra calls “the benchmark for all future wheat in the country”, was the engine to an ascending graph of wheat production through 2000, when India recorded a bumper crop of 76.37mt. Meanwhile, farmers are also starting to fret about the effect of the heat on their favourite wheat variety.
“It’s given excellent results in the past,” said Ajaipal Gill, a Punjab farmer.
“There’s no perfect genotype of wheat and slight variations have to be incorporated in genotype design to maintain a good yield consistently. But climate change seems to be affecting PBW-343 since the past few years.”