London, Oct 10 (IANS): Scientists have found a way to improve yields of some crops by understanding their evolutionary process that made them significantly more productive than others over the years, a study said.

The research carried out at Cambridge and Oxford universities, which was published last week in the journal eLIFE, divided plants in two broad categories - C3 and C4 - keeping in view the way they use photosynthesis to convert sunlight and water into carbohydrates.

In C3 plants carbon dioxide is first fixed into a compound containing three carbon atoms while in C4 plants carbon dioxide is initially fixed into a compound containing four carbons atoms.

According to the research, C4 plants are around 50 percent more efficient than C3 plants. Just three percent C4 plants contribute 30 percent to terrestrial productivity.

The study said that using C4 plants can improve yields and solve the problem of food scarcity.

Most C4 plants include maize, sorghum, millet and sugarcane and are native to tropical and sub-tropical regions.

Rice, a crop vital to the nutrition of huge numbers of people across the world, is a C3 plant.

The study also said that all C4 plants evolved independently from C3 plants. Scientists, however, think this process took place over many millions of years.