Jujiro Maruo and the Rice Cultivar ‘Shinriki’ -From three ears to millions of acres-

Author: Dr. Toshihiko Nishio
Translated and edited by: Shinji Kawai and Abigail Huster, Department of Horticulture, Oregon State University 

Publication: Summer 2021

Improvements in agricultural technology and breeding helped struggling Japanese farming communities in the early 20th century. Since the 1990s, Dr. Toshihiko Nishio, a Japanese rice farming system researcher, published over 150 stories about these innovations. By showing how these discoveries derived from careful observation, patience, and in some cases, serendipity, we hope that farmers will realize how ordinary people can contribute to the advancement of their local agricultural communities and beyond. 

One Unique Rice Plant

If you trace the pedigree of any thoroughbred race horse, it is said that you will eventually end up at one of the same three mares. Japanese rice cultivars seem to be the same. Many recently released cultivars can be traced back to one or more of the same five or six cultivars from the Meiji era about 100-150 years ago. The strong desire of farmers and breeders to create and share improved rice cultivars has powered this phenomenon.

Among these cultivars is ‘Shinriki’ (God’s Power). This cultivar in particular contributed to the dramatic improvement in yields seen in the late 1800s. ‘Shinriki’ was discovered in 1877 by a farmer, Jujiro Maruo, from Nakajima village. This was as the last major Civil War in Japan was ending, and people were shifting their efforts back into rice farming.

Maruo found the single rice plant that would become ‘Shinriki’ in a rice paddy planted with another cultivar. This one plant was distinctively different. It had medium-sized spikeless grains and exceptionally numerous tillers (tillers are the side shoots of grasses, which result in a single plant with many stems). Maruo was always on the lookout for opportunities to improve rice cultivars. He often collected and grew out heirloom cultivars to search for useful traits, so it is no surprise that he noticed this chance variant.

When he saw this unique rice plant, Maruo immediately collected seeds from three ears.
He planted them out in the following season. Amazingly, the yield was 25% higher than any of the other cultivars. He first named it ‘Kiryoyoshi’ (Good Looking), but then reconsidered and named it ‘Shinriki’ (God’s Power) as Maruo attributed his discovery to divine intervention.

‘Shinriki’ is a late season rice cultivar. It is a short plant with numerous tillers. The leaves are erect, which was a new trait in that period. The eating quality of the rice is not the best, but the plants are wonderfully high-yielding due to more ears being born on more stems. ‘Shinriki’ ushered in a new era of multi-eared high yielding rice cultivars in Japan.

Forming a Seed Co-op

As many inventors know, without some good publicity a new technology will just sit on a shelf, regardless of its merits.  In agriculture extension and outreach are vital when introducing farmers to new cultivars or other innovations. In the case
of ‘Shinriki’ rice, farmer- breeder Maruo was helped by a community leader from Yobe village, Zenroku Iwamura.

Iwamura heard about ‘Shinriki’ and introduced the nation to the cultivar in 1886, nine years after its original release. He published a report in the Ministry of Agriculture and Commerce’s journal stating that ‘Shinriki’ yielded 25% more than other contemporary rice cultivars. The article triggered an exponential increase in planted acreage of the new cultivar.

He then asked local farmers to form a seed co-op in order to increase the quality of seed available. At that point, quality control of seeds was less established than it is now. The co-op allowed for a plentiful supply of highly pure seeds, which boosted adoption of the cultivar. The farmers in the co-op also benefited financially from this arrangement.

‘Shinriki’ dominated the Central and Western regions of Japan from the end of the 19th century into the early 20th century. Fish
and soy meal were becoming available to use as fertilizers over the same time period, which also increased yield. Farmers were also adopting dry rice cultivation systems and the use of draft animals, which enabled an off-season crop and later planting dates. ‘Shinriki’ was well adapted to these changes, and yielded more with higher fertility. It reached a peak acreage of 580,000 ha (1.4 million acres) in 1919, comprising one-fifth of all rice acreage in Japan. Unfortunately, Maruo did not get to witness his cultivar’s glory days as he passed away in 1889 at the age of 75. He was gentle, honest and faithful, and it was said that he never tired of visiting rice fields.

Shinriki’s Legacy

Takashi Ike wrote an excellent book that describes the background of 30 rice cultivars developed by farmers. It also discusses their influence on future rice breeding. He claimed that 72 pure line cultivars were selected out of ‘Shinriki.’ The agricultural station in each prefecture of Japan conducted their own research to select a line out of ‘Shinriki’ that would be uniquely adapted to their own environment. Ike also reports that as many as 64 modern cultivars were developed from crosses with ‘Shinriki’. It is possible that all current major rice cultivars can be traced back to ‘Shinriki’.

Soon Shinriki’s genetics began to spread beyond Japan. The high-yielding cultivar ‘Taichung No. 65’ was bred in Taiwan
by Eikichi Iso in 1927 using ‘Shinriki as a parent. This variety was also widely grown in Okinawa. In Malaysia, the cultivar ‘Mashuri’ was bred by Japanese breeders with ‘Taichung No. 65’ as a parent in 1965. ‘Mashuri’ can be grown with minimal fertilizer inputs and was welcomed by many poor farmers in Southeast Asian countries like Bangladesh, India and Myanmar.

All of these cultivars were born out of the three ears of rice that Maruo found in his rice paddy in Nakajima Village in 1877.

‘Shinriki’ Today

Today, there is a rice wine brewery in the town where Maruo found those original ears that would become ‘Shinriki’. Each year, in a field ringed by mountains in three directions, the brewery continues to plant ‘Shinriki’ rice in collaboration with the local agricultural co-op. In May they hold a planting ceremony where over a hundred fans of the cultivar gather from far and wide to join in the rice planting. After harvest, pure rice wine is brewed from the crop. The town honors Maruo with several signs and monuments.

Japan’s Ministry of Agriculture has records of rice yield per acre dating back to 1883. Yields increased rapidly in the late 19th and early 20th centuries. While the use of draft animals and increased fertilizers contributed to this, there is no doubt that ‘Shinriki’ was a vital contributor to the surge in Japanese rice production.