Selenium effect on wheat grain yield and quality applied in different growth stages

Small field plot experiments were carried out at the testing station of the Central Control and Testing Institute in Agriculture in Verk? Meder (Slovakia) in the experimental years 2014/2015, 2015/2016 and 2016/2017. Selenium salts in the form of sodium selenite and sodium selenate were applied in growth phases: end of tillering (BBCH 29) and flag leaf ligule and collar visible (BBCH 39). The effect of experimental years 2014/2015, 2015/2016 and 2016/2017 on the yield of wheat grain was not statistically significant within the observed variants. The achieved mean yields were in the range from 10.06 ? 0.81 to 11.07 ? 0.29 t/ha in 2014/2015, from 9.82 ? 0.54 to 10.32 ? 0.10 t/ha in 2015/2016 and from 11.23 ? 0.76 to 11.64 ? 0.51 t/ha in 2016/2017. Selenate in comparison with selenite influenced the selenium accumulation in wheat grains more positively. However, a significant difference was recorded in variants with selenite application in the flag leaf growth phase in comparison with the end of tillering phase. The influence on the content of macroelements P, K, Ca and microelements Cu and Fe was observed in sodium selenite only; its application decreased the element content in comparison with the control variant. Statistically significantly higher values of fiber and fat were achieved after application of selenium in the flag leaf growth stage in comparison with the end of tillering.