Qualidade fisiológica de sementes de algodão submetidas ao condicionamento osmótico e secagem

Abstract

The osmotic conditioning or priming is considered a promising technique to speed up germination and to improve seed performance. This work was carried out to evaluate the drying effects of three cotton cultivars primed seeds on the germination of this species. Seeds of the CNPA 8H, BRS 200 Marrom and BRS-Verde cultivars were imbibed, or not, in PEG-6000 solution, in the concentration of 178.34 g L-1 at 25°C, corresponding to the water potential of -0.4 MPa, during 24 hours. After the conditioning, the seeds were oven dried at 35°C for 0, 2, 4, 8, 16 and 32 hours, and, in each period, the water content of the seeds was determined. The drying and priming effects were evaluated by the germination test, speed of germination and mean time of germination. For CNPA 8H cotton cultivar, the post-priming drying of the seeds must be carried out during two hours. The BRS 200 Marrom cotton cultivar seeds have their germination improved when they are imbibed in PEG-6000 solution or when they are later dried for 4, 8 or 32 hours. The BRS-Verde cultivar cotton seeds show a better germination performance by osmotic conditioning after 2, 4 or 32 hours of drying.