Physics is often associated with technical words that are complicated and too complex for non-physicists to fully grasp. Dr. Boonrak Panchaisri and Dr. Jiranat Techarang of the Science and Technology Research Institute, Chiang Mai University, have simplified challenging physics terms into "plant breeder", which they use to define their mission in bringing new rice varieties from the laboratory to the rice field. With the know-how in physics, the researchers not only support the rice farmers but also foster the sustainability of the Thai rice industry.

In spite of the many varieties of Thai rice grown across the country, some famous Thai rice varieties such as Thai Jasmine Rice (Khao Dawk Mali 105), RD6, RD15, Sangyod Phatthalung, and etc., can only be harvested once a year and are susceptible to diseases and pests, making Thai rice far less competitive than Vietnamese or Indian rice. This is precisely the challenge that the two researchers aimed to address—how to solve this in a way that serves the Thailand rice industry and fosters sustainable growth and progress. The researchers’ efforts began in 2002 when they started to use low-energy ion beam to develop new rice varieties. It was not until 2005, when the researchers were the first in the world to successfully used low-energy ion beam to breed Thai Jasmine Rice.

The success in breeding new rice varieties using low-energy ion beam was achieved over the three-year research project, “Innovative Physics Using Low Energy Ion Beam for Quality Rice Breeding (2014-2017)” granted to Dr. Boonrak Panchaisri and Dr. Jiranat Techarang. In this project, both researchers invented and developed the technique, processes and tools, which are considered to be the first and the most comprehensive in Thailand. Their work has revolutionised Thai rice production in that the resulting new varieties are high in number, yield and quality and can supply the demand of consumption, food processing and agro-industry markets, directly improving farmers’ livelihoods and the overall industry. The application of low-energy ion beam for rice breeding has been refined to the point that almost all desired characteristics in a rice variety can be obtained and accepted by Thai rice farmers. To date, these new rice varieties, nicknamed “ion-beamed rice”, are being grown in 16 provinces, spanning the northern, central and western parts of the country.

For twenty years the Chiang Mai University’s researchers have attempted to develop new technology applicable to Thai rice breeding that does not involve genetic engineering or GMO technology but efficient mutation induction using ion-beam technology. At the initial phase of the research, they went through trials and errors to develop and improve the efficiency of both the technique and the tools.  Dr. Boonrak recalled that the development of the technique for the “ion-beamed rice” began during the so-called variety crisis—the introduction of the American Jasmine rice brought about awareness of the need to improve Thai rice varieties.  

“In 2002, Thai farmers were really struggling because the US researchers were able to grow their Jasmine rice and 5,000 Thai rice varieties were kept at the International Rice Research Institute (IRRI). Suddenly, they just announced their success in developing a new Jasmine rice variety from our Thai Jasmine rice variety, Khao Dawk Mali 105. The new rice variety supposedly had many desirable traits, and the researchers were planning to patent it. Our farmers came out in droves to protest because the Americans acquired the rice from IRRI without the Material Transfer Agreement (MTA) and the resulting new variety should not have been patented. It was when I was advised by the Director of the Thailand Centre of Excellence in Physics (ThEP) and the funding to begin our research,” explained Dr. Boonrak of the inception of his project.

Dr. Jiranat joined the team in 2013 as an assistant researcher. Her ground-level position then had expanded and greatly expedited the work.

“We, Chiang Mai University research team, began working with a research institute in China’s Wuhan Province,” she explained. “They suggested using low-energy ion beam to stimulate mutations in rice, but looking at it from a physics angle, we just couldn’t see how this could have worked. So, we went back to basics to figure out which ion to use. Then Dr. Boonrak tried and failed, and then he tried again many times. There was a long period of time that all of the seeds he treated and planted just died. After about one and a half years, he could figure out the reason behind it, and then he started to repeat the process again with a local rice variety. He bombarded the seeds with low-energy ion beam and planted them in a tray, on a small scale. He found that out of 5,000 seeds, eight of them had changed their leave colour from purple to green. This was the real start of our rice breeding project. Then we started working on breeding Thai Jasmine rice (Khao Dawk Mali 105) for rice cultivation in the North. The goal then was to create Jasmine rice varieties that are high yielding, have better grain quality, have high nutritional value and are resistant to diseases and pests. Now we’re focusing on creating rice varieties that can supply the demand of the rice industry in the 4.0 era.”

Dr. Boonrak explained that initially, there were two methods of breeding rice. The first was the conventional breeding method which tended to take around one decade to obtain a genetically stable rice variety. The second method relied on gamma ray technology, which could shorten the duration of the breeding programme. Gamma ray, however, is very dangerous and must be properly handled and disposed. Moreover, the resulting varieties were not satisfying because there were still undesirable characteristics such as low yield and sensitivity to pests and diseases.

“The laws in Thailand prohibit the use of GMO technology, so there are only two possibilities of conventional cross breeding and mutation induction. Conventional cross breeding is the crossing between two parental varieties. Plants must be grown and selected until you get the desirable traits. For a single rice variety, it may take eight years if you are lucky. More likely, it will take 10, 13 or even 20 years in some cases. Mutation induction with gamma ray, electron beam and fast neutron is not so efficient, which is why we chose low-energy ion beam.” explained Dr. Boonrak.

“Our first ion implanter we developed was very large and difficult to use. The efficiency of the first equipment was low. So, we and ThEP researchers developed a compact ion implanter, a smaller version, about two metres tall, which is easier to use. We then developed bio-sample holders made of copper, with all the details adjusted to the size and shapes of the grains from each rice varieties. For example, the grains of the Thai Jasmine rice are thin and long, so we asked our technicians to make holes in the holder to fit them. Japonica rice grains, which are big and round, and Sangyod Phatthalung rice grains, which are small, will require its own sample holder. After we have obtained suitable sample holders, we would pack each grain into it and use the low-energy ion beam to bombard the grains. Afterwards, we would select the new rice mutants until we achieve the characteristics that we wanted. Some rice varieties which may have been tall could turn short. The rice grains that used to be purple could turn to white color. Basically, the plants have been mutated.” said Dr. Jiranat.

Following the 2005 success of being the first in the world to use low-energy ion beam to improve the Thai Jasmine rice, the researchers have spent the ensuing years continuing to develop and improve Thai rice varieties. They went on to improve the two popular Thai glutinous rice variety, RD6, and the red bran rice variety, Sangyod Phatthalung.

“Our aim is two-fold,” said Dr. Boonrak. “First, we wish to help our farmers to become more competitive and have higher income. Second, we wanted to add value to the rice industry, which extends much further than the simple grain; noodles, flour, healthy rice, rice oil and other rice-based products. We don’t know what the industry will need in the future, so we now have the technology to prepare for such demand. To date, we have developed more than 100 new ion-beamed rice varieties.”

As a result, the model is expanding to other sixteen provinces across the country: Ratchaburi, Uttaradit, Phrae, Sukhothai, Kamphaeng Phet, Phitsanulok, Phichit, Phra Nakhon Si Ayutthaya, Saraburi, Lop Buri, Prachin Buri, Sing Buri, Ang Thong, Chai Nat, Pathum Thani and Kanchanaburi.

“We started out small, on a small plot of land, to test and see whether it would succeed and naturally turn into a model for other areas.” added Dr. Jiranat. “But it was so successful that farmers began to tell their friends from other provinces to join in. They were very impressed, so we expand to Uttaradit. Recently, in the off-season of 2020, the rice for animal feed has adapted very well, yielding about 1.2 tonnes per rai, which is considered an above average high yield. That year the weather condition was quite dry and high in temperature, so the growing condition was not optimal for rice farming, but our rice variety could survive and prospered.”

The team is not just working on Thai rice varieties, it is also working on some Japonica rice varieties, using the same ion-beam technology for rice breeding. For example, brown Japonica rice for health-conscious consumers and Japonica rice for mass market consumption. This is based on the researchers’ visions that future customers of the Thai rice industry will have various needs, which will require many rice varieties. Moreover, the researchers are of the opinion that rice should be capable of supplying the demand of other markets and industries such as healthy food market, pharmaceutical and cosmetic industries. They also believe that for Thai rice must be distinguished from competitors’ to sustain growth and competition. In short, rice grains must be more than just food.

“It is more than about a grain, it is about using rice for more than just for food,” said Dr. Boonrak. “We used to think of rice as just food, but for this sector, we already have a lot of competitors. Vietnam and India, for example, can produce cheaper rice. We must not look over other industries that are high in values, which rice can supply to their demand such as food processing, pharmaceutical industries and others. We can develop rice varieties to target all of them. First and foremost, we must have varieties that are high in yield, resistant to diseases and pests, tolerant to drought and flooding and good for milling. Then, we can think outside the box and make rice more than just rice for consumption. For instance, we can have varieties for healthy food, pharmaceutical and cosmetic industries. Different pigmented rice, low glycemic rice for people with diabetes—the possibilities are endless. As plant breeders, we must use our imaginations and bring these ideas to light.”