The interaction of stem strength with plant density and nitrogen application in wheat progeny from parents with varying stem strength

Abstract

Lodging is largely influenced by the strength of the stem, which is determined by the length of the internodes, the thickness of the stem and stem cortex and the solidity of the stem. The aim of this study was to study the effect of different N treatments and plant densities on stem strength of selected cultivars and their hybrids. Four combinations of plant density and N fertilizer were evaluated. Plant height, length and diameter of each internode, stem cortex and pith thickness, breaking weight and stem strength were measured. When plant density and N fertilizer increased, stem strength decreased, but the combined effect of these two factors was higher than when applied separately. The cultivar which performed the best in all treatments was a double haploid which expressed the solid stem trait for all internodes. Cultivars and hybrids with normal stems performed the poorest. Breaking weight was positively correlated with stem strength for all four treatments. Shorter internodes caused stronger stems. Stem cortex thickness was also positively correlated with stem strength for all the treatments. This shows that the thicker the stem cortex and the thicker the pith, the stronger the stem of the plant.