Germplasm Bred for Resistance to Striga hermonthica Exhibited High Resistance Levels to Striga asiatica Compared to Commercial Checks

Parasitic weeds belonging to the Orobanchaceae family are a menace in Sub-Saharan African (SSA). Specifically, the two witchweeds from the genus Striga, S. hermonthica and S. asiatica, are jointly responsible for land abandonments and cereal yield reductions in the SSA. Factorial experiments involving fourteen maize genotypes and two levels of Striga asiatica infestation (infested and noninfested) were conducted under pot and laboratory experiments at the Department of Plant Production Sciences and Technologies, University of Zimbabwe, during the 2014/2015 season. A 14 x 2 factorial pot experiment was arranged in a 7 x 4 alpha-lattice design replicated four times, whereas the laboratory agar gel was arranged in a complete randomized design with four replications. Results revealed significant differences (p < 0.05) for S. asiatica and genotype main effects for the recorded traits. S. asiatica-infested genotypes had lower biomasses than noninfested ones. However, the University of Zimbabwe bred hybrids such as Ax31, Ax28, Ax7, and Ax32 had similar plant heights and stem, leaf, and cob biomass across the two Striga levels unlike the local checks, particularly SC513, SC537, and SC637, under Striga infestation. Moreover, these genotypes also had the least Striga germination percentage and furthest germination distance indicating that they are resistant/tolerant to Striga asiatica. The University of Zimbabwe bred hybrids, using Striga hermonthica resistance from the International Institute of Tropical Agriculture, exhibited resistance/tolerance to Striga asiatica compared to local checks. Therefore, these varieties could offer a better and viable Striga spp. control option to farmers in both S. hermonthica and S. asiatica endemic areas.

Automated summary

Parasitic weeds from the Orobanchaceae family pose a threat in Sub-Saharan Africa, with Striga hermonthica and S. asiatica responsible for land abandonment and reduced cereal yields. Through factorial experiments, it was found that maize hybrids bred at the University of Zimbabwe showed resistance/tolerance to Striga asiatica, offering a potential control option for farmers in endemic areas.