The C4 rice may take a long while before a commercial release, but it is targeted to give a yield of 50 percent higher than check varieties (benchmark for high yield).

Achim Dobermann in "Future Intensification of Irrigated Rice Systems" said that by 2020 rice yield in irrigated areas must increase to a yield potential of 12 metric tons (MT) per hectare in the dry season and eight to nine MT per hectare in the west season.

And C4 rice is needed in order to keep a high yield in delta areas which will be the most adversely impacted by climate change, according to the International Rice Research Institute (IRRI).

As the major trait of C4 plants – mainly the efficient use of carbon (which represents the C in C4) for more efficient photosynthesis that will enhance rice productivity – is found outside the rice specie, perhaps the only way to develop this high-yielding rice may be through genetic engineering.

"The only tool we can see now that will allow us to see that kind of gene in rice is through genetic modification so you can increase the capture of solar energy (that will be turned into) biomass," said IRRI Deputy Director General William G. Padolina in Growth Revolution Magazine's "Climate Change and Rice Report."

C4 rice is being developed to carry the trait normally found in C4 plants such as sorghum, corn, and sugarcane which have higher yield despite lower irrigation requirement unlike the conventional C3 rice which is water-thirsty.

IRRI Director General Robert S. Zeigler said what is alarming is that climate change will have more negative impact in the highly rice-productive delta areas including the Mekong Delta (covering Vietnam which is world's second largest rice exporter).