Effects of Striga hermonthica infestation on improved maize cultivars in Ghana

Abstract

Four improved composite varieties of maize (Zea mays L.) grown by farmers in the savanna zones of Ghana and one striga-tolerant single-cross hybrid were screened under two levels of striga infestation in replicated field trials at Nyankpala in 1993 and 1994 to determine the effects and severity of striga infection on the varieties. Effects due to striga infestation and varieties were significant (P< 0.05) for grain yield and some plant and ear traits. The striga infestation level W variety interaction was not significant for any of the traits. Striga infestation reduced plant height by 18.8 per cent, increased lodging by 136.9 per cent, but had no significant effect on the number of leaves per plant in the varieties. Ears per plant, ear weight, grain weight, ear acceptability, and grain yield declined by 22.9, 50.0, 16.5, 24.0, and 66.0 per cent, respectively, in the varieties in response to striga infestation. The results showed that (i) striga infestation had profound detrimental effects on growth and productivity of all the maize varieties, (ii) these effects were less severe in the striga-tolerant hybrid than in the composites, and (iii) breeding to improve cultivar tolerance to striga needs emphasis. Ghana Jnl.agric. Sci Vol.31(2), 1998: 187-196