Striga-resistant Sorghum: A Managed Screening Reveals Promising Genotypes

Abstract

Sorghum (Sorghum bicolor L. Moench) is a major staple crop in sub-Saharan Africa. In Niger (West Africa), despite being the second most cultivated cereal, sorghum yields remain low and are exacerbated by Striga hermonthica infestation in smallholder farming systems. The development of new sorghum varieties resistant to Striga is one of the objectives of the crop improvement program in Niger. This study aimed to evaluate the resistance and tolerance of sorghum genotypes developed within the Niger breeding program under managed Striga infestation. Eighteen genotypes, derived from crosses between elite but susceptible varieties and the resistant donor SRN39, were phenotyped in a pot assay under low-fertility sandy soil. Striga seeds collected from hotspots fields were inoculated in the pot at two periods (during sowing and after pre-condition treatment). The number of Striga plants was recorded at 45, 60, and 90 days after sowing, along with sorghum and Striga biomass traits. Two-way ANOVA revealed highly significant genotypic effects for Striga counts and biomass loss in sorghum. Significant variation was observed among genotypes, allowing classification into resistant, moderately resistant, tolerant, and susceptible groups. The combined use of molecular markers, Striga counts, and biomass loss proved effective for identifying superior genotypes. These results provide promising candidate lines for deployment in Striga-infested areas of the Sahel and support future multi-location evaluations to ensure resistance stability.