Estudo da promoção da germinação de sementes e desenvolvimento inicial em Paspalum regnellii Mez.

Abstract

Known commonly by grass waterlogged, Paspalum regnellii Mez it is a native grass of the southern Brazilian fields of perennial cycle, characterized as a great potential forage feed. However, even presenting itself as a quality forage resource, this species also presents limiting considered common for native forage species, especially for the germination and early growth processes. In order to evaluate the influence of the weight storage and the quality of the seed weight was carried out by separation of two batches of P. regnellii seed collected from two (2013 and 2014), resulting in four density grades for each batch (extra light, light, medium and heavy). After this process, the seeds from each class were placed in gerbox and germinated in B.O.D. chamber being used completely randomized design in a 2x4 factorial design. At 27 days after the test installation, the following variables were evaluated: First count, speed index, relative frequency and percentage of germination as well as the incidence of fungal genera. It is also made to assess the integrity of the seeds through the electrical conductivity test. In order to promote the increase in the percentage germination of P. regnellii, there was a second experiment in which we evaluated different methods aimed at overcoming seed dormancy. Three different methods were tested: scarification of the seed coat seeds with sandpaper number 180 and soaking in sulfuric acid (H2SO4); 2) Soaking the seeds in water at 60°C; 3) Treatment with potassium nitrate (KNO3) and the biostimulant Stimulate®. After treatment, the seeds were placed in gerbox and placed in B.O.D. camera, using a completely randomized design. They were evaluated at 27 days after the experiment installation the following variables: First count, speed index and percentage of germination. In order to evaluate the effect of Trichoderma on emergence and early growth of P. regnellii they were tested increasing doses of two biological products composed by the species Trichoderma harzianum in the 2x109 and 5x109 CFU concentrations mL-1. The experiment was conducted in a greenhouse and divided into two stages, the first consisting of reviews of emergence and early development of plants 40 days after sowing, and the second consisting of plant development assessments at 70 days after sowing . From the results obtained it was observed that the seeds with the highest density in both batch (2013 to 2014) showed increased vigor when compared to the seed light. Potassium nitrate and biostimulant promoted increase in the values of the variables first count, speed index and percentage of germination. From the seed treatment with Trichoderma can be seen that the two evaluated biological products promoted the development of shoot and root system of P. regnellii in two stages of evaluation.