To evaluate the effects of leaf mulches from three leguminous trees and genotypes, fifteen sorghum accessions were studied in plots inoculated with seeds of root parasite Striga hermonthica during wet 2006 at Moutourwa (northern Cameroon). The same genetic material was screened in pots trials during the 2007 cropping season in Ngaoundéré to assess their varietal response to Striga infestation. In pots and in field, results showed that soghum cultivars differed significantly with respect to number of emerged Striga plants. Under high and uniform infestation, three promising varieties namely S35, CS54 and Défé Gala constantly recorded low number of parasite plants and low host damage score. Mature plant resistance was also expressed by delay of parasite emergence and inhibition of its development, low reduction in sorghum growth and production (dry matter and grain yield) in comparison with susceptible varieties. Globally, in pot trials, Striga infestation reduced sorghum height, panicle weight and grain yield by 36.6%, 33.7% and 56.5% respectively in comparison with uninfected control. Application of leaf mulches from leguminous trees decreased Striga emergence (31.5% at maturity), and host damage (20.47%), and in contrast, increased sorghum height (22.36%), dry matter accumulation (25.15%) and grain yield (23.25%). Fertilization of resistant sorghum genotypes further reduced Striga emergence and partially mitigated its effects on sorghum yield. Adoption of an integrated approach encompassing high yielding Striga resistant and/or tolerant varieties combined with use of organic fertilization may provide a cheap and easy to apply method for Striga control under low-input farming systems.
