STRIGA ON RICE IN WEST-AFRICA - CROP HOST-RANGE AND THE POTENTIAL OF HOST-RESISTANCE

Striga aspera and Striga hermonthica can cause serious losses in uplan d rice in the guinea savanna areas of West Africa. In pot experiments, seed from Striga spp., collected from maize and rice crops in norther n Ivory Coast, were sown with maize, rice, miller and sorghum. S. aspe ra collected from rice and maize, grew on maize, sorghum and rice, but not on miller. S. hermonthica from either maze, sorghum or rice showe d no specificity and parasitized all four test crops. S. asiatica coll ected from maize and Andropogon sp. grew on maize and rice, but not on millet. In field experiments, five cultivars of Oryza glaberrima and two cultivars of Oryza sativa, TR47255-B-B-5-4 and IR49255-B-B-5-2, of fered partial resistance to S. aspera. These rice cultivars also showe d lower levels of parasitization by S. hermonthica. Parasitization of rice by 17 Striga stems m(-2), reduced rice grain yield by about 50%. Growth of O. glaberrima appeared to be less affected by Striga parasit ization than a susceptible O. sativa cultivar. (C) 1997 Elsevier Scien ce Ltd.