A new varieties of rice that can cause the second 'green revolution' will be developed

In order to develop rice and wheat which can give more harvest than traditional varieties, it is necessary to identify genes that enhance nitrogen absorption capacity and to develop new varieties of rice that can expect more harvest with less fertilizer Research has been reported that it has developed. This research has inherited the large agricultural revolution which was once called the " green revolution ", and it is expected that we can reduce the environmental impact by decreasing the amount of fertilizer used.

'Green revolution' crops bred to slash fertilizer use
https://www.nature.com/articles/d41586-018-05980-7

From the 1940's to the 1960's, grain productivity dramatically increased by introducing "varieties that could hope for more crops", "laying in more efficient irrigation (irrigation)" and "mass injection of chemical fertilizers and pesticides" We call the series of efforts that have improved to "green revolution". The agricultural revolution continued thereafter, and the world grain harvest, which was approximately 744 million tons in 1961, increased to 1.62 billion tons in 1985, more than doubled.

Mr. Kathryn Barton, a plant scientist at the Carnegie Institute , said, "If you thought that" the green revolution has already ended ", that is a mistake," even if you get more than double the yield, We point out that there is still room for improvement in grain cultivation technology.

Nutrients such as nitrogen are needed for plants to grow, including cereals. Crops can absorb nutrients adequately if they are fertile soils with a lot of nutrients and microorganisms, but if it is not so, chemical fertilizer is needed. Even in 2015 alone, it is said that about 104 million tons of fertilizer has been used throughout the world.

by US Department of Agriculture

Shandong Hu, a researcher at the Chinese Academy of Agricultural Chemistry, said that the use of large quantities of chemical fertilizers is harmful to both farmers and the environment. "When excessive nutrients contained in agricultural land flow into the river, lake, and sea, it causes a large occurrence of algae, consumes oxygen in the water, and it causes asphyxiation of fish and other aquatic organisms Therefore, we need to produce varieties that can produce high yields with less fertilizer, "Mr. Hu claimed.

The research team led by Mr. Fu focused on a substance called "DELLA protein" which has been identified as a cause of poor nitrogen absorption in plants and short stature. In conventional crops, the decomposition of DELLA protein is promoted by the plant hormone gibberellin . However, varieties developed under the "Green Revolution" are being improved so that the height of the plants will be low, in order to prevent lodging before harvesting by typhoons and monsoons. The research team thought that the DELLA protein degradation system was not functioning for some reason among the varieties developed in the "green revolution".

Therefore, the researchers compared 36 kinds of rice cultivar showing rice dwarf ( dwarf ) lower than usual, and investigated the nitrogen absorption capacity of each variety. And we identified genes that code for DELLA proteins and genes of proteins called growth regulators (GRF4). Mr. Fu discovered that GRF 4 promotes absorption of nitrogen and carbon in plants, promotes metabolism and growth, and that this GRF 4 counteracts the influence of DELLA protein.

Therefore, the research team developed and cultivated rice that express GRF 4 more. As a result, enough fertilizer than the varieties developed in the "Green Revolution" got a sufficient yield. The research team seems to be registering this rice as a new variety and applying for a patent.

Jennifer Fork, an environmental quality expert at the University of Delaware, said this strategy is promising as it reduces environmental harm caused by excess nitrogen and nutrients. But on the other hand, Anna Mikalak, an environmental engineer at the Carnegie Institute, said, "Whenever you think you've won, there is always something you can not imagine, and as you can expect to see what happens, We are not smart. "It shows a prudent attitude towards the birth of new varieties.