Physiological quality of five soybean cultivars submitted to water strees

Abstract

During the period of seeds germination, many factors are determinant to the establishment of seedlings in field, being the water stress a negative effect. To create or adapt new cultivars to these conditions, plants breeding programs are fundamental. With this, the aim with this work was to verify the physiological quality of soybean seeds submitted to water stress. Were used seeds of five soybean cultivars (Savana, Conquista, Valiosa, BRS Celeste and Baliza) and five osmotical potentials (0, -0.2, -0.4, -0.6 and -0.8 MPa) diluted into water. To evaluate the physiological potential of these seeds, were realized the germination test with four replications of 50 seeds, distributed between three germitest paper moistened with PEG6000 solutions, described above. The evaluation was performed on the eighth day, with the first count realized determining the percentage of normal seedlings on the fifth day after planting and vigor evaluation of shoot and root length. The biochemical evaluation was performed by the expression of isoenzymes esterase (EST) and catalase (CAT). Based on the results was possible to observe that with the increase of water stress occurs reduction in the physiological quality, as well as reduction in the development of seedlings, independently of cultivar. The cultivar Savana is the most tolerant to water stress when compared to the others. There is variation in the expression of catalase and esterase in function of water stress levels in which seeds of soybean cultivars are exposed during the germination process.