United Nations (AP)-Researchers have developed new rice varieties that they say can yield up to 50 percent larger crops without fertilizer.

The new rice "has a great potential to become the second miracle rice in Africa," said Ken Fujimura, a senior adviser at the U.N. Development Program’s office, which promotes technical cooperation with developing countries.

The West African Rice Development Association, supported by UNDP, created the New Rice for Africa by crossing African and Asian specials, the U.N. agency said.

In addition to the significant gains in production, UNDP said the new rice varieties, known by the acronym NERICA, also matures 30 to 50 days earlier than the currently grown varieties. They are also substantially richer in protein, more tolerant to disease, drought, and acid soils, and resistant to some of the mot damaging insect pests in West Africa, the agency said.