Physiological quality of soybean seed cultivars by osmoconditioning

Abstract

Soybean cultivars present seeds of different physiological quality and they lose vigor and germinative

potential during their permanence in the field after maturity. Therefore, this study was settled to evaluate the response ability to osmotic conditioning of seeds of six soybean cultivars – Confiança, UFV-16, Splendor, Garantia, UFVS 2005 and UFV-18 – harvested at the R8 stage and 15 and 30 days later. The cultivars were multiplied in the field, in a randomized complete-block design, with four replications. The osmotic conditioning of the seeds were carried out with a polyethylene glycol solution (PEG 6000), at -0,8 MPa, with 0.2% of Captan fungicide, at 20 °C, during 96 hours. Non conditioned seeds were used as control. The following characteristics were evaluated: first and final counting on germination test; seedling emergence rate and emergence speed index in the field; and electric conductivity. Harvest delay decreases seed germination and vigor, with different intensity, depending on the cultivar. The osmoconditioning reduces the leaching of solutes by the seed and positively affects the seed germination and vigor of all cultivar studied, more pronouncedly when seeds are much more weathered.