Patogenicidade de fusarium graminearum em sementes de cultivares de soja

Abstract

Soybeans suffer from the incidence of several fungal diseases, which can occur from the seedling stage, when the presence of Fusarium graminearum affects pre-emergence seedlings, leading to low productivity. The lack of crop rotation and the direct planting system in straw favor the survival of the pathogen. The objective was to evaluate the pathogenicity of an isolate of Fusarium graminearum obtained from wheat, inoculated into seeds of 16 soybean cultivars, observing whether there are different effects on the degree of pathogenicity in each cultivar. The experiment was conducted at UFFS - Campus Erechim, in a completely randomized experimental design (tests conducted in the laboratory) and randomized blocks (test in a greenhouse), comprising: T1) WITHOUT Fusarium graminearum inoculation; and T2) WITH pathogen inoculation. The following were evaluated: i) germination (%); ii) seedling length (cm); iii) incidence of Fusarium graminearum; and iv) seedling emergence in the field. The data obtained were subjected to analysis of variance, and when significant, test of means. It was observed that Fusarium graminearum causes damage to germination, length and emergence of seedlings, after inoculation into seeds, in all soybean cultivars evaluated. The DM 57i52IPRO and BMX Garra IPRO cultivar, even with seeds inoculated with the pathogen, has a longer seedling length (11.3 cm), demonstrating that the cultivar is less susceptible to the pathogen. The sowing time indicates that the temperature interferes with the infection of the seedlings by the pathogen and, depending on this, there is a difference in the emergence of soybean seedlings when the seeds are inoculated with Fusarium graminearum.