At https://phys.org/print450598731.html … rice is grown in rice paddies – a wetland environment. Why? Plants do not like excessive waterlogging – and some plants actively dislike it. On the other hand there are plant variants that adapt to watery conditions. For example water forget me not is a variation on the forget me not. Rice, I suppose, is a grass – a variation in related grasses. In S and SE Asia periodic flooding comes with the annual monsoon season – and can last several months at a time. Rice plants developed a strategy to cope with this, it is thought, and a gene in rice has been isolated. It allows rice to survive flood plain conditions – hence the paddy fields.