Effect of different irrigation regimes on growth, grain yield and its components of grain sorghum (Sorghum bicolor L.) cultivars under Isfahan conditions

Effect of four irrigation regimes (irrigation after 100,130,160 and 190 mm evaporation from class A pan) on yield and its components of four grain sorghum cultivars namely Local Ardestan, Payam, Sepedeh and Kimya was studied, using split plot design with four replications, in Research Field Station of Faculty Agriculture, Isfahan Technology University. Analysis of variance and mean comparison between treatments showed that yield and its components had negative response to water stress condition, and with increasing irrigation intervals from I1 to I4 these values decreased significantly. Therefore, grain yield reduced 9% in I2, 27% in I3 and 51% in I4 in comparison to I1. There was considerable variation among the cultivars in grain yield and its components. Results also showed maximum plant height and biological and grain yield in local Ardestan, maximum grain per panicle in Sepideh and latest maturity to Kimya cultivars. Irrigation×cultivar had significant effect on grain yield and its components of sorghum cultivars. Local Ardestan cultivar had the least yield reduction under this conditions.