Chemical treatment, different conditions and storage periods on the physiological quality of rice seeds

Seed is considered as the main input in agriculture, which must have physiological quality to reach its maximum productive potential. In addition, the germination test is one of the parameters to analyze the viability and represent the emergence in the field when sowing is carried out in ideal soil conditions. Therefore, this work aims to evaluate the germination percentage of rice seeds (Oryza sativa) cultivar IRGA 431 CL from the year 2021 with and without seed treatment, stored for different periods in prototypes of vertical silos and big bags. The experiment was carried out at the Post-Harvest Laboratory of the Federal University of Pampa – Alegrete Campus, where they remained for 6 (six) months. The germination tests were set up every 30 (thirty) days throughout the storage period, in the laboratory of the Cooperativa Agroindustrial de Alegrete LTDA. The design to be used was completely randomized (DIC), three-factorial (2 x 2 x 6) for the factors seed treatment levels, type of storage and storage period. There are twenty-four treatments, each with four replications, totaling ninety-six experimental units + initial analysis + final analysis (composed of 4 replications for the use or not of seed treatment). The factors were composed of two seed treatments (T1: with seed treatment; T2: no seed treatment), two storage levels (A1: prototype mini silo; A2: prototype big bag) and six different storage periods (P1: thirty days; P2: sixty days; P3: ninety days; P4: one hundred and twenty days; P5: one hundred and fifty days and P6: one hundred and eighty days). After setting up the germination tests, the counts were performed on the fifth and fourteenth day after insertion in the incubator. The results indicated that there was a reduction in the percentage of vigor and germination throughout the storage period, under the presence of seed treatment, regardless of the type of storage used. Storage in impermeable packaging is less harmful to the physiological quality of the seeds, and the percentage of germination was higher than 80% in all treatments, in accordance with Normative Instruction No. 45 of 2013 for commercialization. From the first 30 days, the portion of treated seeds started to have a decrease in the physiological quality of rice seeds.