Effect of seed coating with biocontrol agents on stand establishment of sorghum

Abstract:

Poor stand establishment is the single largest cause of replanting in tropical sorghum, costing Mexican growers an estimated 15-20% of seasonal input budgets. This research tested whether seed coating with biocontrol agents could protect seedlings against soil-borne pathogens and improve field emergence. Five seed treatments—Trichoderma harzianum, Pseudomonas fluorescens, Bacillus subtilis, a combined formulation of all three, and an untreated control—were evaluated on sorghum variety ‘Costeña-310’ over two seasons (2022-2023) at Villahermosa, Tabasco. The combined coating raised field emergence to 88.9%, compared with 64.3% in the control, and seedling vigour index climbed by 47%. Root colonisation by Fusarium spp. fell from 31.4% in untreated plots to 8.7% under the combined treatment. Grain yield followed suit, with the combined coating producing 4.12 t ha^-1 versus 2.87 t ha^-1 for the control. These results make a case for integrating multi-organism seed coatings into sorghum production packages in the humid tropics of Mexico.