They are early-maturing (75-100 days) and are relatively tolerant to major stresses of Africa’s harsh growth environment. However, not all these characteristics are found in one single Nerica variety. Early maturity for example is much appreciated by farmers, especially women farmers, as it allows them to have food during the ‘hunger period’ while waiting for the harvest of other crops. Additionally, studies show that some Nerica varieties have on average a 25 per cent higher protein content than imported Asian varieties. Currently, there are 18 Nerica varieties (Nerica-1 to Nerica-18) suited for upland growth conditions. Nerica-4, which is tolerant to drought and phosphorus deficiency, is the most widely adopted upland variety, grown in more than ten SSA countries.

In 1998/1999, AfricaRice started to extend its Nerica programme to the rainfed lowland ecosystem. The lowlands – where rice is grown in bunded fields that are flooded for at least part of the growing season – are generally more fertile than the uplands.