Abstract

Black oat crop occupies the largest area during winter. It is important for animal production, crop rotation and dry matter production of approximately 3.8 million hectares in Rio Grande do Sul State. To ensure sowing, seeds are produced which must have high quality standards and must be evaluated by seed testing laboratories. Given this, the present study evaluated the physical and physiological quality of oat seeds analyzed by the Seed Analysis Laboratory of UNIJUI from 2006 to 2014. 2,910 samples were evaluated; 2,229 were evaluated with seed production process; 357 were evaluated with seed analysis of own use and 324 were evaluated with tetrazolium analysis. The samples obtained through seed production process were analyzed in terms of their physical and physiological aspects, while the own seed and tetrazolium test used were evaluated only in terms of their physiological attributes, following the methodology described in the Seed Analysis Rules. The data were analyzed through descriptive statistics for each variable studied per year, and the averages, maximum and minimum standard deviation and coefficient of variation were identified. The data were also evaluated based on their dispersion, and compared to weather occurrences and  national standards, in order to estimate the percentages of samples approved. Seeds produced according to the National Seed system had high levels of physical and physiological quality from 2006 to 2010. However, between 2011 and 2014, 14.0 and 14.5% of the samples were above the standard levels for seeds of other cultivated species and harmful prohibited species respectively. The own used seeds showed greater variability and dispersion, with 18.1 and 31.7% samples below the standards for germination in the years 2006 to 2010 and 2011 to 2014, respectively, while the samples analyzed through the tetrazolium test showed approved levels of 19.4 and 12.5%, respectively. The major physiological qualities were obtained in 2008, 2010 and 2011 and the lowest in 2009, 2012 and 2014. It is noteworthy that the seed quality is related to years with levels of rainfall and appropriate temperatures for vegetative development, physiological maturity and harvest.

Key words: Avena strigosa (Schreb.), purity, germination, tetrazolium.