Qualidade de sementes de canola submetidas a maturação com herbicidas

Abstract

Canola cultivation has become important for use in production systems in the Southern Region of Brazil. However, the uniliformity of silage maturation and the lack of research related to the ideal time to harvest the plants has caused excessive losses in production. One of the alternatives to be adopted is the application of maturing herbicides, since besides allowing a harvest with the silicas in more uniform maturation, also contributes to the reduction of the exposure of the seeds to the unfavorable climatic conditions. The objective of this study was to evaluate the effect of the application of maturation herbicides on canola cultivation at two different times and the effects of these treatments on the physical, physiological and sanitary quality of the seeds of the crop. The experiment was conducted in a randomized complete block design, in the factorial arrangement 7x2 + 2 (herbicide x season + control) with four replications. The Hyola 50 hybrid canola plants were matured with the herbicides glufosinate ammonium (2,0 L ha-1), paraquat (2,0 L ha-1), glyphosate (3,0 L ha-1), diquat (2,0 L ha-1), saflufenacil (0,07 L ha-1), 2,4-D (1,0 L ha-1) and paraquat + diuron (2,0 L ha-1), at the time G3 (when the first ten main stem silica has a width greater than 4 cm) G4 (when the first ten shafts of the main stem begin to mature), plus two witnesses for each epoch, the first being harvested on the day of application of the products, and the second kept in the field until complete maturation. In order to verify the physical, physiological and sanitary quality of the canola seeds, the first counts of germination, germination, seedling length, dry mass, cold test, accelerated aging, thousand seed weight, electrical conductivity, speed index emergency and sanity test. The plants that did not receive treatments and remained in the field until the end of the crop cycle presented seeds of better physical, physiological and sanitary quality. Among the herbicides used, better results were observed when diquat was applied. On the other hand, the use of glyphosate and 2,4 - D caused the greatest damage to canola seeds. It is possible to carry out the application of maturing herbicides in the canola and the most appropriate moment for the use of this practice is in the G4 season, where the crop enters the phase of physiological maturity.