The response of Zimbabwean sorghum and maize landraces to Striga Asiatica infestation

Abstract

Sorghum and Maize are important cereals for food security in Zimbabwe. However maize and sorghum production in the smallholder farming sector is being threatened by witch weed, (Striga asiatica ), which has the potential to reduce maize and sorghum yields by 100%. Studies on sorghum and maize resistance to Striga asiatica have mainly focused on new improved crop varieties but very few studies have been done on local non improved varieties commonly called ‘landraces’. A controlled pot experiment was conducted at Henderson Research Station in Mazowe to test the hypothesis that early maturing sorghum landraces are more sensitive to Striga than late maturing landraces. We also tested the effect of Striga on two maize landraces. The results failed to support the hypothesis that early maturing sorghum landraces are more sensitive to Striga than late maturing landraces. Striga significantly reduced the vegetative growth rate as well as the above ground plant biomass of the late maturing landrace Khaki (p<0.05). The results also indicated that Striga increased the rate of growth in the other three sorghum landraces Nhongoro, Tsveta white and Musoswe but Striga had no significant effect on the above ground plant biomass (p>0.05). Striga asiatica caused a decline in the growth rate of the two maize landraces 2040 and 1714, but there was no significant effect on the above ground plant biomass (p>0.05),