Desempenho de Trichoderma asperellum como agente promotor de crescimento de mudas de alface e sob cultivo hidropônico

Abstract

Lettuce (Lactuca sativa L.) is the most widely consumed leafy vegetable in Brazil, and hydroponic cultivation stands out for its productive efficiency and quality. Plant growth-promoting microorganisms, such as Trichoderma asperellum, have been used as a sustainable alternative to stimulate root development, nutrient absorption, and stress tolerance. This study aimed to evaluate the effect of inoculating different T. asperellum strains (URM 5911, CBMAI 1622, and BV10) on the growth of lettuce seedlings (cv. Gabriela) and their subsequent performance under hydroponic cultivation, comparing two application methods: seedling inoculation and direct inoculation in the nutrient solution. The experiments were conducted in a nursery and in a hydroponic NFT system. In the nursery phase, inoculation was carried out at 7 and 25 days after emergence, with assessments of root length, shoot growth, and biomass. In hydroponics, plants derived from previously inoculated seedlings and plants inoculated directly in the nutrient solution were evaluated at different cultivation periods. The results demonstrated that the fungus effects were dependent on the strain, the application method, and the cultivation time. In the nursery phase, strain URM 5911 stood out by increasing total weight and root biomass, conferring greater seedling vigor. In hydroponics, during the early growth period, inoculated seedlings showed advantages in root length and total biomass, whereas at the end of the cycle, inoculation via nutrient solution favored shoot biomass production and total weight. Nevertheless, seedling inoculation maintained superior performance for root dry mass. It can be concluded that both application methods present specific advantages: seedling inoculation favors initial development and root vigor, while inoculation in the nutrient solution enhances aerial biomass and overall productivity. Strain selection proved decisive, with URM 5911 and BV10 showing the most consistent results, while CBMAI 1622 exhibited less expressive effects under the evaluated conditions. These findings highlight the potential of T. asperellum as a bioinput for promoting growth in hydroponic lettuce systems.