Época de colheita e qualidade de sementes de Brassica napus L

Abstract

The canola (Brassica napus L. var oleífera) is an oleaginous plant species belonging to the family of crucifers, developed on the basis of the genetic improvement of rape. The present study aimed to identify the ideal moment for harvesting canola seeds, aiming their physiological quality. The experiment was carried out on the property of Mr. Armando Santi, located in the municipality of Chopinzinho - PR. The canola (Brassica napus L. var oleífera) is a species held experiment between the periods that follow the harvest of corn crop safri-nha, in crop rotation, and predate the soybean planting season 2017/2018. The experimental design was randomized blocks, with 4 treatments and 3 replications. The collection comprised 4 distinct dates after anthesis. The first collection was held on 09/16/2017, respectively, being repeated every 7 days (7, 14, 21 and 28), until the moment of the total harvest of the field. The total collections were performed 4 with an amount of 3 samples per collection, totaling 12 samples. 1000 pods were selected from a total of 10 plants perplot. Once collected, the samples were processed and stayed for 7 days in the refrigerator to 5 Cº to overcoming dormancy physiological, until the completion of the laboratory. After the completion of pre-cooling, we carried out the laboratory tests of moisture (U), germination speed index (GSI), Speed of germination (VG) and dry mass x fresh mass. For the culture of canola, any harvesting season in the interval between the 7th day after anthesis (DAA) until the 28º DAA, proved to be uniform, i.e., not presented variability in seed physiological quality. Due to the low variability, determines that the culture of canola, any date compreendente the equivalent period of 7 to 28 DAA, the harvest may be held. However, crops performed early, or before the point of maturation fisiologica culture, tend to aprensentar quality losses fisica/fisiologica due to mechanical damage in the tegument, mainly, breaks or crushing of seeds. In hybrids of canola, the point of maturation in addition to being represented by the change in their coloring, also is related to the moisture content of the grain. So, is the point of maturation when 40-60% of the grains have changed their color from green to brown presenting moisture content of around 35 %. The results obtained in the analysis of moisture demonstrate that the 28th day after anthesis (DAA), the moisture content of the grains corresponded to the point of physiological maturity. All tra-tamentos showed germination Over 80%, which did not differ statistically from the other variables analyzed under the review of the ANOVA (5%). For the culture of canola, the harvest point aiming at the production of seed will occur after the stand of plants present the point of physiological maturity, extending up to the point of dehiscence of silÍquas. It is up to the producer to determine which is the best period for the completion of the harvest.