Russia is requesting payment in rubles for grain. In addition to this, the grain will only go to "friendly countries" and to countries in real need for food.
The Western countries are accusing Russia of a geopolitically motivated attack on global food security, while Russia accuses the West of applying irresponsible "sanctions".
The ruble has gained significant value in the past 3 months. This new requirement will probably result in an increment in the demand for rubles with a subsequent improved conversion rate.
For further information, please read the following [article] (https://www.zerohedge.com/commodities/russia-will-now-demand-rubles-grain-worlds-largest-wheat-exporter)