Suppression of witch-weed (Striga hermonthica) in sorghum: Cowpea mixture as affected by cowpea varieties and planting patterns

Abstract

An experiment was conducted during the 2002 and 2003 cropping seasons on a striga infested field at Bauchi in the Northern Guinea Savannah ecological zone of Nigeria in order to evaluate the effect of some cowpea varieties and planting patterns on striga suppression. Sorghum variety (SAMSORG 14) was grown in mixture with three cowpea varieties (Kano 1696, Yaro da kokari and IT89KD-288) and three planting patterns (alternate ridge, 1:1 and 2:1 sorghum: cowpea combination ratio on same ridge). These treatments were factorially combined in a randomized completely block design and replicated three times. Sorghum intercropped with cowpea variety Kano 1696 in alternate ridge significantly reduced striga density and striga dry matter production. The same factorial combination also gave the highest percent nitrogen (N) in sorghum grain, total N uptake by sorghum, cowpea and the highest contribution of symbiosis to N uptake of sorghum. It could be suggested from this study that any striga control package to be developed for small scale farmers around the study area, should consider intercropping sorghum/cowpea as a central focus. However, screening of more cowpea varieties should be taken into cognizance in order to determine the most suitable variety for reducing striga seed bank. © 2007 Academic Journals.