Varietal Responses in Spring Barley to Natural and Artificial Lodging and to a Growth Regulator

Abstract
SUMMARY: Eight varieties of spring barley differing in their morphology and resistance to lodging were grown in a trial as main plots which were split for seven treatments: a natural control (C), a control with plots which were mechanically supported (S) and four artificially induced lodging treatments: permanent early lodging (PEL); temporary early lodging (TEL); permanent late lodging (PLL) and temporary late lodging (TLL). The seventh treatment (GR) was an application of the growth regulator BAS 09800W. In comparison with S, treatments PEL, TEL, PLL and TLL reduced grain yield by 38–1, 24–8, 22–0 and 13–9 % respectively. Natural lodging in C plots reduced the yield of the two weakest strawed varieties, Guilden and Jupiter, by 8 and 10% respectively in comparison with treatment S. Yields (C) of these two varieties were increased by GR which had no effect on the yield of other varieties, but reduced grain size in some cases. Treatment GR significantly reduced but did not eliminate natural lodging in weaker strawed varieties and reduced the length of the top four internodes. Lodging reduced grain size in terms of 1000–grain weight and sieving fractions and increased the content of husk and protein. Lodging susceptibility was positively correlated with plant height but showed no clear relationship with the number of vascular bundles, stem diameter, wall thickness, or with the content of lignin, cellulose and hemicellulose in the basal internodes. Lodging resistance appeared to be closely associated with short basal internodes.