Interactions of Bambara groundnut (Vigna subterranean (L) Verdc) genotypes and phosphorus fertilizer rates in controlling Alectra vogelii

Abstract

Bambara groundnuts (Vigna subterranea (L.) Verdc) provide essential proteins for African farmers, but the yield is largely affected by Alectra vogelii infestation, particularly on nutrient-depleted soils. Laboratory and field investigations were conducted to assess the influence of phosphorus rates and Bambara groundnut genotypes on Alectra vogelii infestation. In the laboratory, a 4 × 26 factorial experiment, varying phosphorus rates (0, 20, 30 and 40 kg ha−1) across 26 genotypes, revealed a significant (p < 0.001) interaction affecting Alectra germination and furthest germination distance. Notably, at 40 kg P ha−1, Alectra seed germination and furthest distance were significantly reduced. In field studies, increasing phosphorus rates decreased Alectra shoot biomass and haustorial root attachments, except for a few resistant genotypes. Alectra counts at 109 days and grain yield demonstrated a significant (p < 0.001) interaction between Bambara genotypes and Alectra. Genotypes G15, G18, G20, and G25 exhibited no haustorial root attachments, with G18 achieving the highest grain yield per plant (23.41 g) under 0 kg P ha−1 on Alectra-infested soil. The synergy of Alectra-resistant genotypes with 40 kg P ha−1 proved to enhance the establishment and grain yield of Bambara groundnut.

Keywords

• Alectra vogelii
• Bambara groundnut
• defence mechanism
• phosphorous
• strigolactones
• Soil Sciences