Rice is one of the few agricultural commodities (aka soft commodities) that has not gone up significantly in price in the last few months as you can see in the 5 year chart below (Source: Indexmundi).
During December, the price of rice averaged 536.78 USD per metric tons and it has started to go up allegedly because more farmers are switching to more profitable crops such as wheat and corn which would reduce rice production this year.
Unfortunately, for investors, the only ETF I found to bet on the rise of the price of rice is RJA (ETF tracking roger agriculture commodities index: RICI-A) but it contains only a few percent of rice, a large part of it is wheat and corn.
If you have access to the French stock market, you could also buy the rice certificate RICEF PI OPENN (FR0010606509 - 1377N). However, with such products you have to be careful of the cost of holding it for a long period. See chart below (Source: Boursorama)
I have seen some other blogs recommend Thai and Vietnamese ETF to get exposure to the price of rice, but this is really a stretch.