Morphology Of Striga Forbesii And Preliminary Screening For Resistance In Sorghum

Abstract

Striga forbesii Benth can be a serious pest problem on sorghum in Southern Africa. Its morphology, as found in the region, was described with the mention of a very small population on the species having an unusual floral form with strongly exerted style and stigma. It thus could be possible that there is some outcrossing in this predominantly autogamous species. The species produces up to 24,654 seeds per plant, and its seed production was compared with that of S. asiatica. Observation nursery screening showed that between 2.0 and 20.0 (%) germplasm accessions, from Zimbabwe, Botswana Swaziland, Lesotho and Angola, have resistance to S. forbesii. In addition, only 6.0 (%) from the Alad nursery and 3.2 (%) from the Karper nursery, which were introduced into the region, showed resistance. Preliminary results from advanced screening trials significant differential reactions to S. forbesii attack among sorghum varieties. Using the modified checkerboard design, five varieties, namely SAR 29, SAR 33, SAR 19, SAR 35 and SAR 37, showed good levels of tolerance of resistance to S. forbesii. The different reactions of susceptibility and resistance or tolerance were discussed relative to the test varieties