Predsetveni tretmani semena soje (Glycine max L.) u cilju poboljšanja kliavosti i uticaj zemljišne suše na kvalitet formiranog semena | Pre sowing treatments of soybean seed (Glycine max L.) with the aim of emergence improvement and the influence of soil drought on the seed quality | Предсетвени третмани семена соје (Glycine max L.) у циљу побољшања клијавости и утицај земљишне суше на квалитет формираног семена

The influence of pre-sowing treatment of priming soybean seed in potassium nitrate (KNO3), ascorbic acid (AsA) and potassium chloride (KCl) solutions on i) quality of seeds in stress conditions (salinity, low temperature and drought), ii) quality of aged seeds and iii) on the possibility of preserving seed was examined. Salinity was induced by different concentrations of NaCl (0 (control), 50, 100, 200 mM NaCl). The drought was caused by different concentrations of polyethylene glycol, which reduced the water potential of the solution (0 (control), -0.30, - 0.51, -0.80 MPa). The low-temperature effect was tested by seed priming at a temperature of 10 °С. The effect of seed priming into the mentioned solutions on the quality of the aged seed was examined by comparing the results obtained by primed aged and fresh seeds. Storing possibility of primed seed was determined by storing primed seeds at a temperature of 25 °C for 90 days and examining the quality every 15 days during that period. Then, 4 x 50 seeds of two soybean varieties (NS Zita and Victoria) was primed for each examined treatment. Seed quality was tested by using the standard germination test. In addition, lipid peroxidation intensity, free proline concentration and vitamin C concentration were examined eight days after sowing in 10 average seedlings (fresh) from each replication. The results showed that seed priming improved the germination energy, seed germination and germination rate in conditions of salt stress, low temperature and drought. Priming reduced the content of the lipid peroxidation while the content of the free proline was increased under stress. Seed priming of seeds preserved for a long period of time before germination may improve but as well it may reduce seed quality. Primed seeds can be stored at a temperature of 25 °C to 60 days after priming, before a significant reduction in its quality is observed. The impact of soil drought during vegetation of seed crops on the quality of the formed soybean seed was carried out in semi-controlled conditions in a three-year experiment. Two treatments were applied in which the plants were exposed to drought i) from beginning of flowering to the period of seed maturation, and ii) from the beginning of the filling of the seed to the period of seed maturation. As control served the plants that were produced under conditions of sufficient water supply during the entire vegetation. During the vegetation, the intensity of transpiration, leaf surface, dry matter content, number of nodules and their mass were analysed, the number of pods per plant and the number of seeds per pod at the stage of physiological maturity. After the harvest, seed quality was tested, using a standard germination test and cold test. Also, the content of protein and oil in the grain has been analysed. In soybean seedling the lipid peroxidation, free proline concentration and vitamin C were assessed The results showed that soil drought during the soybean reproductive stage has a negative effect on the yield components (number of pods per plant, number of seeds per pod and 1000 seeds weight). The leaf surface is decreased, as well as the intensity of transpiration, the dry matter content per plant, the number of nodules and their mass. Seed quality is deteriorating and significant deterioration is present in seeds that are sown after harvest under stressful conditions or in the germination phase are exposed to a lower temperature. The protein content increased while the oil content decreased. The lipid peroxidation and free proline content have increased while the proportion of vitamin C declined. With the increase in the length of the dry period, the effect was much stronger.