The application of Trichoderma fungus can be used to obtain seedlings of higher quality for plantations. The objective of this study was to evaluate the effects of Trichoderma isolates on the germination and initial growth of açaí seedlings. Two trials were set up. In the laboratory, the seeds were inoculated in suspensions prepared with each of the isolates for 24 h, and they were arranged in trays containing filter paper in a completely randomized design with five replicates containing 50 seeds each. For the control, the seeds were submerged only in water. Part of the seedlings resulting from seeds treated and not treated with Trichoderma were transferred to bags containing forest soil and were submitted to seven modes of application of Trichoderma and kept in a nursery. The speed of germination and hypocotyl were not influenced by the biological treatment. The application of the different Trichoderma isolates positively influenced the height, collar diameter, number of leaves, root size, leaf area and root, and aerial part dry mass of the açaí seedlings. The application of the Trichoderma isolate TAM01 on the preplanting substrate and biweekly applications on the postplanting substrate was the combination that most positively influenced the development of açai seedlings.

Trichoderma is a beneficial fungus that can be used in both the control of phytopathogens and in promoting germination and plant growth. Thus, this study aimed to evaluate the effect of five Trichoderma isolates (T09, T12, T52, Tc and Tce) in seven different application modes on seeds and seedlings of the Khaya ivorensis A. Chev. (African mahogany). Fungi applications were tested by microbiolization of the seeds, in the pre-planting substrate, by monthly applications in the seedlings and in four combinations of these three treatments. Under laboratory conditions, the germination, germination speed index (GSI), and radicle and hypocotyl lengths were evaluated in seeds, treated and untreated, with Trichoderma. In the nursery, it was evaluated the height, root collar diameter, number of leaflets, root length, and the dry weight of root system and aerial part in seedlings with different forms of Trichoderma application. Trichoderma isolates did not influence germination percentage, GSI and radicle length. The fungus application methods in the K. ivorensis seedlings increased the height and leaflets number of the plants by at least one of the Trichoderma isolates tested in this study.Trichoderma spp. e seus efeitos na qualidade fisiológica das sementes e no desenvolvimento de mudas de mogno africano RESUMO: Trichoderma é um fungo benéfico que pode ser utilizado tanto no controle de fitopatógenos como na promoção da germinação e do crescimento de plantas. Assim, objetivou-se avaliar o efeito de cinco isolados de Trichoderma (T09, T12, T52, Tc e Tce), em sete modos de aplicação, sobre sementes e mudas de Khaya ivorensis A. Chev. (mogno africano). Foram testadas aplicações dos fungos via microbiolização das sementes, no substrato pré-plantio, em aplicações mensais nas mudas e, em quatro combinações desses três tratamentos. Em condições de laboratório foram avaliados a germinação, índice de velocidade de germinação (IVG) e, o comprimento da radícula e hipocótilo, em sementes tratadas e não tratadas com Trichoderma. Em viveiro, avaliou-se altura, diâmetro do coleto, número de folíolos, comprimento da raiz e, a massa seca da parte aérea e sistema radicular em mudas com as diferentes formas de aplicação de Trichoderma. Os isolados de Trichoderma não influenciaram a porcentagem de germinação, o IVG e o comprimento da radícula. Os modos de aplicação dos fungos avaliados nas mudas de K. ivorensis aumentaram a altura e o número de folíolos das plantas, por pelo menos um dos isolados de Trichoderma testado neste trabalho.Palavras-chave: tratamento biológico; sementes florestais; fungos; promoção de crescimento; Khaya ivorensis Trichoderma spp. and its effects on seeds physiological quality and seedlings development of African mahogany Rev. Bras. Cienc. Agrar., Recife, v.15, n.1, e5843, 2020 2/7