In an attempt to solve the problem of rice farming in Thailand,
either the cost-cutting method through a reduction of chemical fertilizer and plant diseases
and pest protection substances or the value-added method through a variety of processed rice products,
an undeniable basic factor is the quality rice varieties. These varieties must possess high yields,
photoperiod insensitivity (several cycles of breeding/year), strong rice stalks but not too tall,
and resistance to diseases and insects which may cause the economic losses. It will be better
if they have an aroma as special properties (containing 2-Acetyl-1-pyrroline or 2-AP)
and antioxidants such as anthocyanin and gamma-oryzanol, including other substances beneficial to the brain and nervous system
such as GABA (Gamma Amino Butyric Acid) as it is truly important for a premium product.
At present, Khao Niao Kho Khor 6 (glutinous rice) which is outstanding in its aroma and quality
for cooking whereas Khao Sang Yod Pattalung (red rice) which is rich in essential nutrients for the body
such as anthocyanin and niacin (vitamin B3) as well as iron and zinc [1] are currently gaining the popularity in
the market at higher prices, approximately 35 Baht / kilogram and 83 Baht / kilogram (brown rice) respectively.
However, these two varieties show some restrictions whereas the volume of production is insufficient to the needs
of consumers both domestic and overseas. For instance, Khao Kho Khor 6 provides low yields (averagely
300-400 kilograms / rai), boasts tall stalks (approximately 154 cm.), and becomes weak. As the rice plant falls over due to seasonal winds prior
to its harvest, it is unable to be harvested by machinery but by labor force, which adds up the production costs.
It is also photoperiod-sensitive and available for only one-cycle plantation per year during July-December and,
in addition, it is nonresistant to rice diseases and insects contributed to the economic losses,
for example, rice blast disease and brown planthopper. Needless to say, overuse of pesticides is the problem
which increases the number of patients and deaths due to agricultural chemicals year by year [2]
and destroys the biodiversity of paddy field and environment. Likewise, Khao Sang Yod Pattalung provides low yields
of averagely 330 kilograms / rai with two-meter tall varieties subject to no response to a fertilizer
for increasing its yields. This particular rice shows its high degree of photoperiod sensitivity and
allows only one-cycle production each year. The harvesting period which lasts up to 6 months and becomes longer
than other rice varieties may draw the problem of birds and rats.
This research project is aimed to improve both rice varieties through
the use of ion beam generated from a compact low-energy ion accelerator/implanter for inducing rice mutants whereby
this home-developed technique is served as one of the world’s first achievements [3].
This method therefore helps cut down the time periods from an improvement of rice varieties at least twice
when compared to plant crossing. This induced mutation takes up the time of only five generations whereas
a traditional improvement of plant crossing is time-consuming for at least 10 generations. In addition,
it can lower the time for an improvement to only 2.5 years if the mutated rice is photoperiod-insensitive.
Hence, an improvement adopting this new method can greatly reduce the costs of rice improvement
and satisfy the urgent demands of farmers within the limited time. An improvement of these two rice varieties aims to
select the mutated rice variety with quality for cooking equivalent to the wild type but promises other good properties
such as photoperiod insensitivity, low to medium height, strong stalk, fertilizer response,
effective booting and more ears of rice, and resistance to diseases and insects which may cause the economic losses.
As a result, the mutated rice with its yields totaling 600-900 kilograms / rai is anticipated.
The researcher team has currently developed a total of
103 mutated rice lines of Khao Kho Khor 6 and Khao Sang Yod Pattalung with the aforementioned properties
whereby these rice mutants retain similar or identical genetics of wild Khao Kho Khor 6 and Khao Sang Yod based
upon their specific or unique DNA bands analyzed by Microsatellite marker.
Among these rice plants, only 19 varieties with special quality and potential for commercial purposes are selected.
These include the followings.
A) Two varieties of glutinous rice with an aroma from Khao Kho Khor 6: MRD6-11 and MRD6-12 (Figure 2.2)
B) Three rice varieties with an aroma from Khao Kho Khor 6: MRD6-17, MRD6-19, and MRD6-27 (Figure 2.2) and three rice varieties from Khao Sang Yod Pattalung: MSY-1-1, MSY-1-3, and MSY-2-1 (Figure 2.3)
C) 12 varieties of colored rice
C.1) Six varieties of Khao Jao Kam (purple rice);
two varieties developed from Khao Kho Khor 6: OSRD6-4 and OSRD6-14; other four varieties developed from
Khao Sang Yod Pattalung: OSSY-3, OSSY-8, OSSY-17, and OSSY-25 (Figure 2.4)
C.2) Mutated Khao Sang Yod Pattalung shares similar
or identical properties and colors with its wild variety (red color). However, it is photoperiod insensitive with a
shorter height, shorter harvesting period, and higher yield. These five mutants are OSSY-14, PISY-1, PISY-2, PISY-3,
and PISY-4. (Figures 2.5 and 2.6)
The mutated rice lines reveal that the low-energy ion beam technology leads to a broad spectrum of mutation phenotypes such as short stalk, photoperiod insensitivity, effective booting and more ears of rice, resistance to diseases and insects, color alteration of brown rice (white rice, purple rice, or red rice), and alteration of the proportion and volume of Amylose and Amylopectin (glutinous rice or rice). Therefore, this technology is viewed as the technology with a much higher efficiency than the gamma ray technique from the radioactive isotope, previously used for rice improvement.
The researcher team is now improving the rice with pro-vitamin A and rice with longer storage periods from Thai rice. It is also found that three varieties of wild rice are more extremely outstanding for beta-carotene than any other wild rice varieties. Meanwhile, mutated white jasmine rice 105 (HyKOS21) with the expression of only LOX-3 gene exhibits the highest storage periods (the highest percentage of germination but the lowest lipid peroxidation) under both an ordinary condition and an urgent condition compared to other five rice varieties (white jasmine rice 105, Khao Pratum Thani 1, Khao Chai Nat 1, Khao Kho Khor 6 and upland rice) with the expression of LOX-1, LOX-2, and LOX-3 gene or other two rice varieties (Khao San Pa Tong 1 and Khao Kho Khor 10) with the expression of LOX-1 and LOX-3 gene. Accordingly, such rice is subject to breeding in the planting season of year 2016 to obtain the rice grains for an improvement of rice with pro-vitamin A and mutated rice with special quality which lasts longer for its storage through the low-energy ion beam-induced mutation during the off-season rice of year 2016.
[1] ผาณิต รุจิรพิสิฐ, วิชชุดา สังข์แก้ว และ เสาวนีย์ เอี้ยวสกุลรัตน์, “คุณค่าทางโภชนาการของข้าว 9 สายพันธุ์” Agricultural Sci. J. 43(2) (Suppl.), 2012, 173-176, (From http://www.crdc.kmutt.ac.th/Data%202012/CRDC6/data/173-176.pdf )
[2] สำนักงานคณะกรรมการวิจัยแห่งชาติ (วช.), “ยุทธศาสตร์การวิจัย (พ.ศ. 2555-2559) : ภาคเหนือ ”, พ.ศ. 2554.
[3] S. Singkarat, A. Wijaikhum, D. Suwannakachorn, U. Tippawan, S. Intarasiri, D. Bootkul, B. Phanchaisri, J. Techarung, M.W. Rhodes, R. Suwankosum, S. Rattanarin, L.D. Yu, “A Simple Ion Implanter for Material Modifications in Agriculture and Gemology”, Nuclear Instruments and Methods in Physics Research - Section B: Beam Interactions with Materials and Atoms 365-Part A (2015) 414-418.
Principal Investigator: Associate Professor Dr. Liangdeng Yu1)
Collaborators: Dr. Boonrak Phanchaisri2), Dr. Jiranat Techarung1,*), Asst. Prof. Dr. Udomrat Tippawan3), Asst. Prof. Dr. Chaveewon Phanchaisri4),
Affiliated Institute: 1) Thailand Center of Excellence in Physics, 2) Science and Technology Research Institute, Chiang Mai University, 3) Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, 4) Faculty of Engineering and Agro-Industry, Maejo University, 5) Department of Biology, Faculty of Science, Chiang Mai Rajabhat University, *) Post-doctoral Fellow