Improving the Microbiological Quality of Substrates and Biological Control Strategies to Optimize First-Generation Greenhouse Potato Seed Production in West Cameroon

Abstract

Potato production is on the increase in tropical regions, but yields remain low, generally between 3 and 11 t/ha, due to poor seed quality and phytosanitary pressures. First-generation seeds are a promising solution for improving productivity, but they require pathogen-free organic growing substrates (soil, compost, and sand mixtures) to guarantee plant health. The aim of this study, carried out from January to June 2022 in Bayangam, Cameroon, was to assess the microbiological quality of greenhouse substrates and propose biological control strategies. Analyses carried out before and after sterilization revealed high initial contamination of the irrigation water, with 193 CFU/mL total coliforms, making it unfit for use. Bacterial loads, including Streptococcus spp. and Shigella spp., as well as fungal populations such as Fusarium spp., were significantly reduced after sterilization. Pathogenicity tests identified Fusarium sp. as the most virulent, causing lesions of 7.66 cm2 on potato leaves after 7 days. Furthermore, aqueous extracts of Tephrosia vogelii showed high antifungal activity, with inhibition rates reaching 93.71% against Fusarium subglutinans. These results demonstrate the importance of rigorous control of the microbiological quality of substrates and confirm that sterilization, combined with the use of botanical extracts, represents a sustainable alternative to chemical pesticides, thus contributing to healthy seed production and food security in Cameroon. Keywords: Potatoes, Microbiological quality, Sterilization, Pathogenicity, West Cameroon.