Damage potential and reproduction of Heterodera avenae on wheat under Syrian field conditions
AbstractThree trials were conducted to asses the effects of three levels of initial population densities (Pi) of Heterodera avenae (15.3, 27.6, 40.4 eggs and juveniles/g soil) on growth and yield of two wheat cultivars (’Sham 3’ of durum wheat and ’Sham 6’ of bread wheat) and nematode reproduction, under field conditions in North East Syria, during the growing season 2006-2007. Reduction of yield components of both wheat cultivars increased with the increase of Pi of H. avenae and reached maxima of 56.6% and 49.6% in grain yield and 49.5% and 44.6% in straw yield in durum and bread wheat, respectively, at the greatest initial population density of 40.4 eggs and juveniles/g soil. A similar trend was observed for the reduction of plant height in both cultivars. Durum wheat was more sensitive than bread wheat to the nematode. Significant negative linear regressions were observed between Pi of H. avenae and yield components of both wheat cultivars. Final population densities (Pf) of H. avenae were positively correlated with Pi, whereas reproduction factors (Rf) were negatively correlated with Pi on both wheat cultivars.