According to The Asahi Shimbun, with temperatures rising in Japan at faster than the global average, farmers and scientists are locked in a high-stakes battle to develop varieties of rice and fruit that are less vulnerable to heat.
Success in this field was evident in early September as rice paddies in the Kamiogi district of Satte, Saitama Prefecture, were growing well even though the average temperature in the prefecture for August was about two degrees higher than average.
The rice paddies are managed by Yoshitaka Funakawa, 68, president of an agricultural corporation that has been using the Sainokizuna rice variety in recent years.
"We will likely be able to secure first-grade rice quality because the plants are growing as nicely as in normal years," Funakawa said.
Saitama rice farmers began working on new varieties after the mercury in Kumagaya hit a then domestic record of 40.9 degrees in summer 2007.
The Saitama prefectural agricultural technical research center found that most of the 300 or so new rice varieties being developed at the time had rice kernels with insufficient starch due to high temperatures.
However, one new strain, Sainokizuna, showed no evidence of being affected by the heat.
One of its characteristics is an ability to lower the temperature of its rice leaves and stalks by absorbing enough water, even on the hottest days. As heat problems did not arise with this variety, its kernels produced the required amount of starch.
Sainokizuna was formally registered as a new rice variety in 2014 and Saitama farmers quickly began planting it. In 2018, the variety had spread to about 4,000 hectares, or about 12 percent of the entire acreage for rice paddies in the prefecture.
"Its popularity spread because it continued to produce stable, high-quality rice even as hot summers continued," noted an official at the prefectural research center.
According to the Japan Meteorological Agency, average temperatures in Japan had increased by 1.19 degrees in comparison to the end of the 19th century. That is higher than the global average of about 1 degree.
Higher temperatures play havoc with rice quality.
For example, in 2010 when much of Japan baked during the summer, the ratio of first-grade rice throughout Japan was only 62 percent, or a decrease of more than 20 percentage points over the previous year.
A team at the National Agricultural and Food Research Organization (NARO) issued forecasts based on assumptions made by an intergovernmental panel of the U.N. framework convention on climate change. If global average temperatures at the end of the current century rose the maximum 4.8 degrees in comparison to before the Industrial Revolution, rice harvest in Japan would increase by 12 percent over the end of the 20th century, but 80 percent of that rice would likely be of a low quality.
In its road map to deal with climate change, the government has led the charge to promote ways to reduce the poorer quality of farm products.
That has led to research in other prefectures, such as Hiroshima and Toyama, to develop new rice varieties that are also resilient to higher temperatures.
In 2014, the Koinoyokan variety fostered by NARO was designated by the Hiroshima prefectural government as a variety that rice farmers should grow more of. Now, about 1,200 hectares of rice paddies are dedicated to that variety.
Toyama has also designated a new variety that is considered to be even tastier than the famed Koshihikari variety.
Fruit farmers are not sitting back, either.
A report by the farm ministry showed that about a dozen or so prefectures in recent years had reported "unshu mikan" fruit as being affected by higher temperatures. The heat apparently stops the growth of the fruit pulp even as the skin covering that pulp continues to grow.
Exposure to stronger sunlight is also apparently the cause of bad coloring on apples and grapes that are exposed to excessive sunlight.
To deal with the mikan fruit pulp problem, farmers spray a liquid that slows the growth of the pulp skin.
A new apple variety that continues to have a dark red color even with higher temperatures has been introduced in some areas.
In central and southern Aomori Prefecture in northern Japan, apple farmers have been encouraged to turn to a peach variety that grows well even in hotter areas. Peach harvests have increased seven-fold over the past decade.
"The spread of global warming could greatly change the best areas for rice farming, making the Tohoku region no longer viable for growing high-quality rice," said Yasushi Ishigooka, a senior researcher at NARO.
While implementing comprehensive measures to slow down the rise in temperatures is a must, Ishigooka said other measures were also needed, such as changing cultivation and harvest periods or improving the variety of produce grown.
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