The physiological quality of cotton cultivar seeds (Gossypium hirsutum var. latifolium L.) was evaluated in laboratory by the simulation of water potentials with polyethyleneglycol-6000 (0.0; -0.2; -0.4; -0.6; -0.8 and -1.0 MPa), at 25ºC using germitest paper as substrate. A completely randomized design in a 4 × 6 factorial scheme with four replications of 50 seeds each was used. The studied variables were: germination percentage, first count of germination, germination velocity index, accelerated aging in water, electrical conductivity, humidity, vigor classification, radicle length and radicle/shoot length ratio. The effect of water stress on seed viability and on plantlet vigor was severe at potentials below -0.4 MPa. The 'CNPA 187 8H' cultivar was the least sensitive to the tested osmotic potentials, both in terms of germination and of vigor. The 'BRS-201' cultivar was mostly affected by the viability and vigor tests under water deficit conditions. Differential viability and vigor between cultivars were observed under the water stress levels.
Gossypium hirsutum var. latifolium L.; PEG-6000; vigor; water potential
