The objective of the research was to determine and compare values of forces necessary to separate a rachis of four selected varieties of spelt at the use of two levels of potassium fertilization. The tests were carried out with a testing machine MTS Insight 2. Measurements were carried out separately for upper, central and bottom zone of a rachis. Based on the obtained results, it was stated that the researched varieties of spelt show a considerable variability on account of rachis strength in particular rachis zones. In the upper zone, the level of the applied potassium fertilization did not influence the rachis strength. It was related to all the researched varieties and the force values, at which separation of the rachis segment occurred, were within 1.09 to 1.67 N in relation to the variety. In the lower zone of rachis, its strength in all varieties was the biggest regardless the applied potassium dose.