Philippine: Carrageenan Plant Growth Promoter helps rice resist tungro disease and leaf blight

Date:12-29-2020

PHILIPPINE Council for Agriculture, Aquatic, and Natural Resources Research and Development (PCAARRD) Director Marlita Carlos said the recently commercialized plant growth promoter of the Department of Science and Technology (DOST) is effective in helping rice crops resist tungro disease and leaf blight.

Carrageenan Plant Growth Promoter (PGP), which the DOST had been promoting for farming applications after it was proven to be compatible with different cropping systems, helps develop rice resistance against rice tungro virus and bacterial leaf blight.

Rice tungro disease is caused by the combination of two viruses, which are transmitted by leafhoppers. It causes leaf discoloration, stunted growth, reduced tiller numbers and sterile or partly filled grains.

Tungro infects cultivated rice, some wild rice relatives and other grassy weeds commonly found in rice paddies. Meanwhile, bacterial blight is caused by Xanthomonas oryzae pv. oryzae. It causes wilting of seedlings and yellowing and drying of leaves.

Carlos said that the plant growth promoter had been shown to improve rice resistance to tungro virus and bacterial leaf blight based on several field tests of cultivated rice in different regions.

Carrageenan also helps in strengthening the rice crops' extensive root systems, which can better withstand the effects of lodging during typhoons.

The PGP also had the effect of driving away harmful pests without harming insects and arthropods, which are naturally beneficial to crops. Not only does the PGP increase the number of cavans, but it also made each cavan heavier and fully laden with rice. With the PGP, farmers could earn up to an additional P16,000, an increase in income by over 19 percent.

Red seaweed extract carrageenan, which is widely used in the food industry as an additive, has now been successfully processed for agricultural use as a foliar fertilizer that is expected to boost rice production and pest resistance.

The DOST had made the technology available to the private sector in Central Luzon recently.

Aside from the recent launching in Central Luzon, the product is currently being launched nationwide by various technology adopters, distributing it through various dealers, cooperatives and other possible arrangements.

The Fertilizer and Pesticide Authority (FPA) had even certified the carrageenan PGP for commercialization in rice, with plans to widen its coverage to include other crops in the near future. For an optimal amount of nine liters per hectare, farmers could use the PGP along with conventional fertilizers.

Carrageenan is extracted from seaweeds and is mostly used as a food additive for its gelling, thickening and stabilizing properties.

The technology developed by the Philippine Nuclear Research Institute of the Department of Science and Technology (DOST-PNRI), led by Dr. Lucille V. Abad, has been able to unlock the other beneficial applications of carrageenan through irradiation technology.

Scientists from DOST-PNRI developed the PGP from carrageenan, a natural polymer extracted from red seaweed. Using the fabricated liquid handling system at PNRI's Electron Beam Irradiation Facility, the carrageenan solution is processed using electron beams into a foliar fertilizer sprayed at certain stages in the plant's life.

The PGP was funded by the DOST-Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development and tested in cooperation with the University of the Philippines-Los Baños National Crop Protection Center.

Through radiation processing, carrageenan was modified into an effective plant promoter. The growth promoter had been proven to contain essential micro and macro nutrients that help in the growth of crops like palay, pechay peanut and mungbeans.

Abad said the technology had been a product of almost 10 years of testing in seven regions that included several verification trials. Pilot tests for the positive effects of the carrageenan were initially carried out in Pulilan town in Bulacan. This later expanded to 5,000 hectares in seven regions for verification trials.

The formula was set for field trials by the Department of Agriculture from 2015 to 2019 to cover several provinces in Luzon, Panay Island, Zamboanga and Davao, for a total of around 35,000 hectares of farmland.

Farmers can maximize the potential yield of their crops when using PGP in conjunction with more efficient farming methods and proper timing.

Other food crops such as mungbean, peanut, leafy vegetables, corn, sugarcane, and banana are also being subjected to PGP field tests, where results showed an increase in yield by around 35 percent for mungbean and around 40 percent for peanut.

According to Abad, the formula has been proven to increase rice yields by as much as 30 percent versus the yield from average farmer practices.

She said the growth promoter fits well in the smarter rice production model, which promotes the use of mechanical rice transplanting, hybrid seeds and the use of plant growth promoter.