Influence of Trichoderma harzianum on the growth of watermelon seedlings (Citrullus lanatus Thunb.)

Abstract

Objective: To evaluate the growth of watermelon seedlings of the Charleston cultivar inoculated with four doses of Trichoderma harzianum. Design/methodology/approach: A randomized complete block design with ten replicates was established. Watermelon seeds of the Charleston cultivar were sown in germination trays, and four doses of Trichoderma harzianum (T1: 1 g L⁻¹, T2: 1.5 g L⁻¹, T3: 2 g L⁻¹, and T4: 2.5 g L⁻¹), along with a control (0 g L⁻¹), were evaluated as treatments. The variables assessed were stem diameter, leaf fresh weight, stem fresh weight, root ball weight, number of leaves, stem length, robustness index, stem dry weight, leaf dry weight, and root dry weight. Results: The most outstanding treatment was T1, which produced the greatest seedling growth, followed by T2, which also contributed favorably to plant quality. Limitations on study/implications: The results are limited to only four doses of Trichoderma harzianum for promoting the growth of watermelon seedlings; however, they provide valuable information for optimizing microorganism-based biostimulant doses for seedling production under greenhouse conditions. Findings/conclusions: The application of Trichoderma harzianum exhibited a growth-promoting effect on watermelon seedlings. High doses of Trichoderma harzianum (T3 and T4) showed a limited effect on growth and, in some cases, may be less effective than lower doses.