Effect of Defoliation on yield and yield components In Maize (Zea mays L.)Hybrids in Iran

Defoliation or leaf damage by factors such as pests, diseases, mechanical damages and hail leads to decrease photo-assimilate translocation to the kernels and yield decrease in corn. In order to theexperiment was laid out in the north of Khuzestan in Iran during summer ٢٠١٣-٢٠١٤. The experimental design was split plot in randomized complete block (RCBD) design with four replications. Main factor was three types of maize hybrids included Single cross ٧٠٤, Single cross٧٠١(SLD٤٥/١/٢-١× MO١٧), Single cross mobin(SLD ٤٥/١/٢-١× SLH ٢/٢٩/١٤/٢-٤/١) and sub factorwas defoliation included removal of upper leaves of ear, removal of lower leaves of ear, Control orno leaf removal. The results showed that the highest and minimum yield of hybrids related to byranged ١٤.٢٩, ١٣.٦٦ ton/ha and ١٠.٠١ ton/ha treatments of Single cross ٧٠٤ + no leaf removal ,٧٠١+no leaf removal and Single cross Mobin+ removal of upper leaves respectively. And also there were difference between treatments in yield and component yield, the grain and biological yield, number of grain per row and number of row in ear in the level of probability ١% significant andharvest index was no significant.