Avaliação da qualidade fisiológica e sanitária de sementes de arroz produzidas em diferentes épocas de semeadura na fronteira oeste

Abstract

The sanity of irrigated rice seeds is a subject that has become a guideline in the production of seeds. The vigor of rice seeds in many cases is not seen as a parameter to define the use of a given lot, only germination is a criterion of exclusion of the lot of commercialization, however, it is known that seeds of greater vigor generate plants of higher productivity. The objective of this work was to evaluate the effect of different sowing times and the application of fungicide at the reproductive stages R2 and R4 on the sanitary and physiological quality of seeds. For this, a bioclimatic experiment in randomized blocks with five sowing dates was sown in the 2018/2019 harvest, 09/06, 09/09, 10/09, 10/30 and 12/03/2018, three cultivars of rice, GURI INTA CL, IRGA 431CL and IRGA 424RI and treatments with and without fungicide at the reproductive stages R2 and R4. Afterwards the seeds produced were evaluated by the "Blotter test" method to know their infestation status and / or fungal infection. The vigor and germination of the seeds produced were also evaluated. For the variable incidence, the application of fungicide to cultivar IRGA 431CL was efficient to reduce the incidence. In the germination variable there was no statistical difference between treatments. The first germination count, the highest performance, was due to the third season, and the treatments with fungicide were efficient only for the first and second seasons of the cultivar IRGA 424RI. In the variable dry mass of seedlings the third epoch had the highest performance. The infestation of fungi in the seeds increases the extent to which the sowing delays. The delay in the sowing of the field of production causes reduction in the vigor of the seeds.