Crop Biotech Update

IITA Releases Maize Resistant to the Parasitic Witchweed

January 16, 2009

Good news for farmers in West and Central Africa (WCA). Researchers from the International Institute of Tropical Agriculture (IITA) and Nigeria’s Institute for Agricultural Research (IRA) announced that they have successfully developed maize varieties resistant to the deadly weed Striga. Also known as witchweed, the parasitic plant infests some 50 million hectares of cereal crops and is responsible for billions of dollars worth of crop damage every year in Africa. Controlling the parasitic weed is a challenge. It can produce tens of thousands of tiny seeds which can remain dormant in the soil for many years. Underground, Striga parts connect to crop roots and feed on them, reducing yield dramatically and sometimes even destroying entire fields.

Trials of the witchweed-resistant maize varieties — TZLComp1Syn W-1 (Sammaz 16) and IWDC2SynF2 (Sammaz 15) — have shown great potential for increased maize production not only in Nigeria but also in other countries in the WCA Region. Sammaz 16, a late-maturing maize variety, produces 3.2 tons per hectare under heavy Striga conditions. Even under extreme infestation, harvest loss from this variety is less than 10 percent. Sammaz 15, on the other hand, could yield 4.42 tons per hectare. This is 23 percent higher than the average production of local varieties under weed infestation. IITA released the maize varieties late last year.

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