Deadly beauty: Striga asiatica devastates crops by infecting roots

USDA

[LAGOS] Nigerian farmers who tested new maize crops resistant to the widespread Striga plant parasite are so enthusiastic about their increased crop yields that they are selling more seeds than the official distribution channels.

The crops were developed in the Nigerian laboratories of the International Institute for Agricultural Research (IITA). They dramatically cut maize losses from the root-infecting Striga, or witchweed, during two years of trial cultivation by farmers in Borno State in northern Nigeria.

Nigeria's Institute for Agricultural Research began distributing the new parasite-resistant maize seeds in December 2008.

Abebe Menkir, the lead scientist on the research project at IITA, told SciDev.Net that some farmers in Borno state were already producing large quantities of resistant seeds and selling them on to farmers in and outside the region. He was unable to say how many seeds are being — and will be — distributed through official channels.

"The farmers say they couldn't wait for the official release of seedlings because the variety is successful, cutting losses," says Menkir. 

Menkir said the next step was to distribute the parasite-resistant maize in other countries in West and Central Africa.

The varieties, known as Sammaz 15 and 16 contain genes that diminish the growth of parasitic flowering plants such as Striga, which attaches to the maize root. Both Sammaz varieties tolerate heavy Striga infestations without suffering crop losses.

"A normal maize variety without resistance to Striga can sustain from 60 per cent to 100 per cent grain yield loss in farmers' fields that are severely infested," Menkir told SciDev.Net. Sammaz 16 loses just ten per cent of yield in an extreme invasion.

Sammaz 16 is a late-maturing variety requiring 110 to 120 days of growth, whereas Sammaz 15 can often be harvested at 100 days and is more suitable for regions with short growing periods or unpredictable water supplies.

Agronomy researcher Michael Aken'Ova from the faculty of agriculture at the University of Ibadan, said that producing resistant and tolerant cultivars such as Sammaz is the most economically feasible, easily accessible, safe and sustainable approach to combat losses due to Striga, particularly compared to labour-intensive methods such as weeding.

He added that he is sure that the resistant crops will soon make it to the farmers who need them, with the aid of leaflets, radio magazine programmes and messages in local languages.