Yield losses in maize due to Striga hermonthica in West and Central Africa

Abstract

Striga hermonthica (Del.) Benth. is the most important species of parasitic weed affecting cereal crop production in Africa. Yield losses due to the parasite and yield advantages offered by tolerant maize varieties were estimated from experiments conducted in West and Central Africa between 1983 and 1989. The experiments were carried out under natural infestation in experiment stations and farmers' fields, and under uniform artificial infestation in the screenhouse. TZB and PR7843, the two most widely grown open-pollinated (OP) varieties in West and Central Africa, were susceptible to Striga with yield losses of 68 and 79%, respectively. Yield losses of 100 randomly drawn (hybrid and OP) varieties averaged 68%. Yield loss was determined by the level of tolerance of the host variety and by the severity of infestation. Tolerant varieties suffered lower yield reductions and, often, produced 2.0 - 2.5 times the yield of susceptible varieties, especially under high infestation. Grain yield was significantly correlated to the host plant Striga damage score - the composite, non-destructive indicator of host tolerance. Tolerant varieties identified here were resistant to maize streak virus and other diseases endemic in West and Central Africa.