Evaluating the Antagonistic Potential of Pythium oligandrum against Alternaria solani and Its Growth Promotion Potential across Different Potato Cultivars and Soil Types

Sammanfattning

Pythium oligandrum is an oomycete known for its dual role as a biocontrol agent and plant growth promoter. This study explored its antagonistic activity against Alternaria solani and its effects on potato growth under different soil types and cultivars. Three main sets of experiments were conducted: (i) in vitro confrontation assays, (ii) growth response of the cultivar ‘Desiree’ and ´Kuras´ across four different soil types, and (iii) growth responses of twelve potato cultivars to P. oligandrum inoculation. In vitro confrontation assays revealed clear suppression of A. solani, confirming the strong antagonistic potential of P. oligandrum. Biotron experiments showed that the effect of P. oligandrum on potato growth varied depending on soil type and cultivar. In the soil type experiment, significant increase in plant height was observed in compost soil and increased tuber yield in 50% sand + 50% compost soil in cultivar ‘Desiree’. Across twelve potato cultivars, responses varied: while ‘Altus’ showed enhanced height and reduced dry weight, ‘Agria’ exhibited reduced height, and other cultivars showed no significant changes. These findings indicate that the effectiveness of P. oligandrum is dependent on soil type and genetic background. Overall, this study supports the potential use of P. oligandrum in sustainable agriculture as an alternative to chemical fungicides while depending on cultivar and soil type.