INTERRELATIONSHIPS BETWEEN GRAIN PROTEIN CONTENT AND INDICATORS OF NITROGEN STATUS OF WHEAT PLANT

Grain protein content is one of indicators of small grains quality. It is important trait, but negatively correlated with grain yield what represents obstacle in small grains breeding on quality and yield, simultaneously. The objective of investigation is to estimate interrelationships between grain protein content and some physiological indicators of nitrogen status in wheat. Tested indicators of nitrogen status in wheat plant are: nitrogen content in aboveground plant part at anthesis (Nanthesis), grain nitrogen content (Ngrain), nitrogen content at straw (Nstraw), nitrogen content at whole matured plant (Ntotal), nitrogen harvest index (NHI), nitrogen reutilization (NreU), nitrogen lost or gained (Npost anthesis) and physiological efficiency of nitrogen (PEN). According to obtained correlation coefficients, NHI and NreU expressed statistically high significant and positive influence on grain protein content. Influence of Npost anthesis was, in some investigation years, statistically high significant and positive, while influence of PEN on grain protein content was statistically high significant and strong, but negative. Influence of indicators of nitrogen accumulation efficiency, like: Nanthesis, Ngrain, Nstraw and Ntotal on grain protein content was insignificant during entire investigation. Such notice could mean higher importance of nitrogen utilization, as a part of process of nitrogen nutrition, in grain protein synthesis. Obtained results could achieve to better understanding of grain protein synthesis and overcoming some evident obstacles in wheat breeding programs.