Allelopathy is a procedure in which secondary metabolites produced by plants, micro-organisms, viruses and fungi, control growth and development of other biological systems. Some plants may beneficially or antagonistically affect other plants through allelochemical compounds which may be released directly or indirectly from live or dead parts and cause allelopathic and phytotoxic effects. In Kerman (located in the South East of Iran) cultivating corn after winter wheat usually causes less growth and yield. This study was conducted to estimate the effects of different concentrations of two native Iranian wheat (Alvand and Falat) straw extracts on germination, radicle growth, coleoptile length, plant height, leaf area (LA), wet weight (WW) and dry weight (DW) of two hybrid corn varieties (single cross 704 and single cross 647). Results show that the straw extracts, have negative and significant effects on both corn varieties' growth and the significant allelopathic effects remained up to 90 days after wheat harvest; but decreased gradually up to 180 days after harvest. Base on the study results, we advise that before corn cultivation, wheat straw and residues should be eliminated from the field to avoid negative allelopathic effects of wheat straw on corn growth. Hence, it is recommended to let no-till fields as fallow for 6 months; to acquire convenient growth and high yield for corn.
