Testes rápidos na avaliação do vigor e qualidade sanitária de sementes de trigo mourisco

Abstract

Buckwheat (Fagopyrum esculentum Moench) has gained space in the Brazilian agricultural scenario. It presents good adaptation in the crop rotation system, is a forage option with capacity for animal nutrition, in addition to serving for human consumption due to the nutritional and nutraceutical properties of the flour produced from its grains. However, the verification of the physical, physiological and health potential of seed lots is essential when looking for a satisfactory initial establishment of seedlings in the field. Thus, this study aims to determine the physical, physiological and health quality of buckwheat seeds, evaluate the pathogenicity of Fusarium spp. in buckwheat plants, as well as to determine a method of rapid evaluation of seed viability through mass electrical conductivity and exudate pH tests. Three different experiments were carried out, the first aimed to determine the physical, physiological and sanitary quality of seed lots and to evaluate the pathogenicity of Fusarium spp. on buckwheat plants. The weight of a thousand seeds, moisture content, germination count on the 5th and 7th day, seedling length and dry mass, filter paper health test and pathogenicity in a controlled environment were evaluated. The lots showed high physiological quality in the germination evaluation (5th and 7th day). There was a high incidence of Fusarium spp. in all batches, which can be reduced with seed asepsis. Isolates of Fusarium spp. were pathogenic to buckwheat plants. In the second experiment, the objective was to determine the viability of buckwheat seed lots through the mass electrical conductivity test, as well as to adjust the test methodology to obtain a quick and accurate evaluation of the seed lots viability. The electrical conductivity evaluated different quantities of seeds (25 and 50), water volumes (25, 50 and 75 mL) and soaking periods (1, 2, 4, 6, 8 and 24 hours), at temperatures of 25 and 30 °C. It was concluded that mass electrical conductivity was efficient in discriminating vigor classes in buckwheat seed lots. In the third experiment, the objective was to determine the viability of buckwheat seed lots using the exudate pH test methodology. The exudate pH test was evaluated at temperatures of 25 and 30 °C for soaking periods of 20, 40 and 60 minutes. It was concluded that the exudate pH test with the presence of seed coat was not efficient in discriminating buckwheat seed lots. With this study, it is possible to verify the importance of seed health evaluation and its implication in the initial establishment of seedlings in the field. It was also observed the importance of studying vigor tests, as well as the response of the plant species as a function of different methodological arrangements.