Straw Bending and Lodging in Landrace Barley: Finite Element Modelling

Abstract

Barley genotypes selected by farmers or breeders for dry climates need to cope with wide variation in rainfall from year to year. Vigorous vegetative growth is needed for yield when drought terminates growth early, but this character can lead to lodging in years with above average rainfall. Barley cultivars and landraces bred adapted to these conditions have thinner straw than higher-yielding cultivars adapted to more favourable growing conditions and may lodge in a different way. Using straw dimensions and material properties derived from Kurdish landraces of barley, a finite element model of lodging straw under wind and gravity loading was constructed. Bending moments due to gravity and wind were explicitly calculated. For the thin-strawed landrace phenotypes, as lodging progressed, gravity became the dominant influence. The model was used to prioritise different straw parameters that influence lodging. Increasing straw diameter was the most promising way to improve resistance to lodging, since diameter showed more variation than straw length and gave greater gains in stiffness than increasing the longitudinal modulus of the straw material