Top wheat variety feels climate-change heat

Top wheat variety feels climate-change heat
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First Published: Mon, Mar 12 2007. 12 12 AM IST
Updated: Mon, Mar 12 2007. 12 12 AM IST
New Delhi: Climate change, especially rising winter temperatures, may have begun to take the sheen off India’s most popular wheat variety PBW-343.
While it remains a wheat variety that is still a hit among farmers and experts alike since its introduction in 1995, scientists are now saying PBW-343 has poor tolerance to heat.
“Even though it had great yield (tonnes per hectare) it had relatively lesser tolerance to heat,” said S.S. Singh, a wheat scientist with the Indian Agricultural Research Institute (IARI) here.
Reduced heat tolerance means that a slight increase in temperature would shrivel the grain. Added to this, a disease called yellow rust has also weakened PBW-343.
One of the approximately 220 varieties of wheat being sown in India, PBW-343 has been the country’s most popular since the green revolution, and is used in about 25% of the 27 million hectares under wheat production. PBW-343 was the engine to an ascending graph of wheat production through 2000, when India recorded a bumper crop of 76.37 million tonnes.
While there’s no official move yet to try and nudge out this variety from farmers’ fields, there’s a letter circulating in the Directorate of Wheat Research (DWR), Karnal, which expresses extreme concern over the effect of high temperatures on wheat production.
“Developing heat-tolerant varieties has always been a priority,” said B. Mishra, project director, DWR. “But over the last few years, an increased number of our research projects have consistently focused on the heat-tolerance aspect.”
Various varieties are in different stages of testing across the country, and leading the pack is a variety called DBW-14, sown this November. It’s a hybrid formed from a wheat called Raj 3765—a variety common to the extremely hot wheat plains of Rajasthan. The final results of the tests will be out only after the harvesting season in April.
Meanwhile, farmers are also starting to fret about heat and their favourite wheat variety.
“It’s given excellent results in the past,” said Ajaipal Gill, a farmer in Punjab. “There’s no perfect genotype of a 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 a few years.”
Since 2000, wheat production has been on a decline in India. Between 2001 and 2006, the average harvest has dipped to 69.74 million tonnes, according to figures from the Indian Agricultural Research Institute.
A study by researchers S.S. Hundal and Prabhjyot Kaur of the Punjab Agricultural University found that a one-degree increase in temperature decreased wheat yield by nearly 10%.
The study, which is based on a popular simulation model called CERES, analysed 30 years of weather data from different parts of Punjab.
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First Published: Mon, Mar 12 2007. 12 12 AM IST
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