Crop Specific Safety Concerns Rice

Every crop has a different relationship to the environment, which means environmental impact assessments must be conducted on a case-by-case basis. Different crops pose different threats when it comes to out-crossing or escaping cultivation. The following plant specific characteristics are taken into account for risk assessment.

General information

Rice belongs to the plant genius Oryza. Species of this genus can be found in all tropical regions of the world. Cultivated rice - Oryza sativa and sometimes Oryza glabberima - is grown predominantly in Asia (550 of the 608 million tonnes grown worldwide in 2004), but also to a lesser extent in Africa, the Americas, and southern Europe (Italy, Spain, Portugal, Greece, and France). There are two well-established types of cultivars – “japonica” with round kernels (e.g. for risotto) and “indica” with long kernels (e.g. Basmati). Rice is mostly used for food, but some rice, in particular rice by-products, are used in animal feed (rice bran) or in industrial products.

Is out-crossing of rice transgenes possible?

Rice is predominantly self-pollinating, which means that rice plants usually fertilise themselves with their own pollen. But cross-pollination also occurs at a rate of approximately one to four percent. Rice is mostly cultivated on irrigated or flooded wetland.

Wild grasses closely related to rice (~20) can be found in all rice producing countries. Gene flow from cultivated rice to wild rice species is considered infrequent, but nonetheless possible. One weedy rice species known as Red Rice (O. sativa f. spontanea) is common in the Mediterranean region and causes problems for rice growers by forming hybrids with cultivated rice.

Can rice plants survive in the environment?

Rice is a tropical, subtropical, and warm temperate crop, growing best with summer temperatures of 24–25°C. Itis reported to have little or no frost tolerance. Temperatures of 0.5 to 5°C are lethal after 24 hours. Rice plants can survive only in habitats where the winters are very mild.