Uso de thichoderma spp. na emergência de plântulas de gravioleira e produção de mudas em diferentes substratos e ambientes.

Abstract

The soursop is a fruit of great importance for the Brazilian Northeastern region. Currently, the crop is expanding, and studies are needed to increase plant availability for new orchards. Thus, this work aimed to evaluate the effect of Trichoderma spp. in the initial growth of soursop seedlings, as well as to study the influence of environments and different substrates in the development of seedlings. The experiments were conducted at the Federal University of Campina Grande (FUCG), at the Center for Agro-Food Science and Technology (CAST), Pombal-PB campus. For the first experiment, soursop Morada variety seeds were obtained from fruits of the commercial orchard located in the Gado Brabo Farm, in the municipality of Aparecida - PB. The soursop seeds were submerged for a period of 24 hours in the respective treatments: T1 = Test, seeds submerged in distilled water; T2 = Trichoderma harzianum at 2x108 CFU concentration; T3 = Trichoderma longibrachiatum at 2x108 CFU concentration; and T4 = T2 + T3. The evaluated characteristics were seedling height, stem diameter, number of leaves, dry shoot mass, root dry mass, total dry mass and Dickson quality index. Also for the second experiment, the seeds of the Morada variety were also sown on the substrates composed of different combinations of cattle manure, goat manure, coconut fiber and basaplant, which varied from 25 to 50%, combined with soil in proportions of 25, 50 and 100%, according to their respective treatments. The experiment was conducted in two environments: A1- Covered vivarium with sombrite® 50% mesh and A2 - the open sky. The variables analyzed were: emergence speed index, emergency percentage, CO2 assimilation rate, transpiration, stomatal conductance, CO2 internal concentration, water use efficiency and instantaneous carboxylation efficiency at 60 days after sowing. During planting 60, 80, 100 and 120 days after sowing, evaluations were done for plant height, stem diameter and leaf number. At the end of the experiment, at 120 days, the root length, dry shoot and root mass, total dry mass and the Dickson quality index were determined. Based on the data from the experiments, it was concluded that Trichoderma harzianum and Trichoderma longibrachiatum Didn't affect the growth promotion of soursop seedlings under the conditions in which the work was developed. For the second experiment, the vivarium environment with sombrite® 50% was the best for seedling formation, and the treatments containing bovine 1Orientador(a): Drª. Marinês Pereira Bomfim, UFCG/CCTA manure are more favorable for the formation of soursop seedlings, with emphasis on T2 and T5 treatments, for to present higher concentrations of soil in their compositions, providing a reduction in the concentrations of basaplant or coconut fiber, which are more expensive materials, without loss of seed quality.