Assessment of Sorghum bicolor (L.) Moench. varietal resistance and the effect of aqueous extracts on Striga hermonthica (Del.) Benth. seed germination

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Résumé

Striga hermonthica is widespread in several regions of Burkina Faso. It attacks crops of agronomic interest, causing losses ranging from 20 to 100% of grain yield in sorghum varieties. This study carried out at the weed science laboratory from October 2022 to February 2023 aims to identify sorghum varieties resistant to Striga hermonthica and local plants that inhibit or stimulate its germination. Fifteen varieties of sorghum has been evaluated for their germination stimulant capacity production using the agar gel method. The roots of two seedlings of each variety were buried in the opposite position in the agar medium containing Striga seeds. The effect of nine local plants on Striga hermonthica seeds germination has been evaluated by preparing 10% aqueous extract for each plant by macerating a mass of 10 g of powder in 100 ml of sterile distilled water. The inhibitory effect was estimated by conditioning the Striga hermonthica seeds during 14 days in each of the plant aqueous extracts and the stimulatory effect by the application of aqueous extracts on the Striga hermonthica seeds. The results revealed Rsoe 38 (MGD=0.74cm), Icsv 1049 (MGD = 0.74cm), Ouédzouré (MGD = 0.81cm), Grinkan (MGD = 0.85cm), Rsoe 15(MGD = 0.85cm) and B 35 (MGD = 0.97cm) as resistant to Striga hermonthica germination. Parkia biglobosa and Tephrosia purpurea have proved effective in inhibition while Andira inermis and Albizia zygia stimulate it. The promotion of resistant sorghum varieties and plants with inhibitory or stimulatory effects could be an important asset for the biological control of Striga hermonthica in the most infested areas.

Mots-clés

Weed, Biological Control, Inhibition, Stimulation, Cereal.