Analysis of morpho-anatomical stem properties determining its mechanical strength in selected rye cultivars

The objective of the research was to compare important properties of the morphological and anatomical structure of stems of four open-pollinated rye cultivars in relation to their mechanical strength expressed by the failure moment, taking into account the possibility of using the stems for the manufacture of natural drinking straws. From the 2nd and the 3rd stem internodes, cross sections were obtained within which the number of large vascular bundles, the diameters of the stem and the central canal, as well as the thicknesses of the stem wall, scle-renchyma and parenchyma were determined. The differentiation in cultivar properties was mainly affected by the location of the internode within the stem. The stem diameter ranged from 5.2 mm (Dafikowskie Rubin) to 5.4 mm (Antoninskie). As compared with the 3rd internode, in the 2nd internode the values of the analysed traits ranged from 5 to 25% higher. In both internodes a significant correlation (r>0.680, p<0.01) between the stem diameter and the central canal diameter was found. In all the cultivars the failure moment depended significantly on the stem diameter for both the internodes (r >0.638, p < 0.01). The analyses carried out show that the 2nd internode is characterized by the most favourable properties affecting the mechanical strength of rye stems.