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Scientists at the Philippine Nuclear Research Institute (PNRI) have developed the Carrageenan Plant Growth Regulator or CPGR that increases rice yields, an excellent natural fertilizer and prevents major diseases in rice and other crops.

PNRI studies showed that when carrageenan-deprived polysaccharide, a carbohydrate, is degraded through a very small dose of gamma radiation, it enhances rice growth.

When adopted by farmers, the new technology may boost rice production of 18.97 million metric tons, a record high, according to the Department of Agriculture. The boost in production is attributed to the three percent improvement in the average yield per hectare, which increased from 3.89 million tons per hectare in 2013 to 4 million tons per hectare in 2014.

The carrageenan research – conducted by the PNRI, Philippine Rice Research Institute, and UPLB – was funded by the Department of Science and Technology-Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development. Three bags of chemical fertilizer per hectare combined with 200 parts per million (ppm) or 20 milliliters per liter of CPGR yielded higher grain weight of 450 grams per 10 hills, says Dr. Gil L. Magsino of UPLB’s National Crop Protection Center.

In contrast, conventional farmers’ practice of applying nine bags of chemical fertilizer per hectare yield a grain weight f only 275 grams per 10 hills. Six bags of chemical fertilizer per hectare combined with the same amount of CPGR yielded 455 grams per 10 hills, says Magsino who headed the Bulacan trials.

Productive tillers or rice stems and the length of the panicles (that bear the grains) were significantly higher in the test crops compared with those cultivated through conventional farmers’ practice. Longer rice panicle is associated with producing more rice grains. NCPC studies also show that at a very small dose, CPGR is an effective organic fertilizer. It also induces resistance against rice tungro virus and bacterial leaf blight, both major rice pests.

CPGR strengthens the rice stem and thus prevents lodging, when grain weight pulls down the plant and bends it towards the ground. At the same time, CPGR is environment-friendly because it has no harmful effects on beneficial insects.

Carrageenan is a polysaccharide (carbohydrate) extracted from red edible seaweeds (popularly known as gulamang dagat or guso). It is widely used for its gelling thickening and stabilizing properties in the food industry and as a binder in products such as toothpaste and shampoo and in many biotechnology and pharmaceutical products. It’s the gelling agent that makes gulaman or the thickener in ice cream.

Plant growth promoters are substances which improve the overall health, growth, and development of plants. Carrageenan, specifically kappa-carrageenan, is abundant and has been tested to have similar growth promoting properties.

The agricultural benefits of carrageenan are achieved from its building blocks: the long-chain carrageenan polymer (“poly” for many) which can be broken down into shorter chain fragments known as oligomers (“oligo” for few).

These oligomers are readily absorbed by the plant where it can help their growth and development and also improve their resistance to diseases.

Using gamma radiation at the PNRI, researchers were able to cut up the polymer into oligomers without using chemicals or complicated and expensive processes.

Gamma-rays are extremely high frequency electromagnetic radiation, transmitted in waves or particles. They are similar to infrared and ultraviolet radiation, X-rays, microwaves, and radio waves.

CPGR can be made with nothing more than the organic carrageenan and water processed by gamma radiation. The product that is formed is not and can never be radioactive. The product that is formed is not and can never be radioactive. It is a clean and additive-free method that is safe, non-toxic, environment-friendly and, most of all, effective.

At PNRI, researchers first tested the CPGR in pot experiments inside greenhouses. Various concentrations were sprayed on the leaves of rice, pechay, mungbean, and peanut.

There was a very significant increase in product yield of almost 200 percent to 300 percent in mungbean and peanut when CPGR were used at a concentration of 60 ppm every other week. Yield increase for pechay was also 200% using the same concentration and rate of application.

Rice plants sprayed with 100 ppm three times (15, 45, and 75 days after transplanting) had 30% increase in yield compared with untreated plants. For rice, the effect was attributed to improved root growth and notable resistance to important diseases like tungro and leaf blight.

Apparently, spraying the CPGR enhanced the presence of friendly insects such as ladybird beetles and spiders that help control harmful insects like the brown plant hoppers and green leaf hoppers that are carriers of the diseases and spread them to healthy plants.

Formulations of the plant growth promoter were registered at the Fertilizer and Pesticide Authority in 2016.


Written by: 
Dr. Lucille V. Abad
Department of Science and Technology-Philippine Nuclear Research Institute (DOST-PNRI)

Published by:
Department of Science and Technology-Science and Technology Information Institute (DOST-STII)