Allelopathic Effects of Field Binweed (Convolvulus arvensis L.) Extract and Residuals on Wheat (Triticum aestivum L.)

With regards to importance and frequency of bindweed in wheat fields، an experiment was conducted to evaluate allelopathy effect of different parts of bindweed in different extract concentration on wheat germination and yield as factorial experiment in randomized complete block design with three replicates in 2007 and 2008. Four levels of organ extracts including leaf، shoot، root and intact plant extract of bindweed in four concentrations composing 1:5، 1:10، 1:15، and 1:20 v/v were used. Distilled water was used as control. All extracts decreased germination and its components in wheat. Greatest decreasing effect was belonged to root extract. Root and intact plant extracts as 1:5 concentration inhibited wheat germination. Anova of glasshouse results showed that there were significant differences among direct and interaction effects on wheat attributes. Low leaf extract concentration and high root extract concentration indicated more inhibition effect. Increasing extract concentration from 1:20 to 1:5 decreased all attributes، significantly. Decreasing in seed number per plant، 100 kernel weight and yield in 1:5 were 76. 17، 94. 66 and 99. 1% compared to control، respectively. Field trial confirmed glasshouse results. Generally، root and intact plant extract or powder had more growth restriction than shoot and leaf powder or extract on wheat attributes. In field condition، applying bindweed extract and residual decreased wheat yield 74. 84% and 88%، respectively. It may be related to gradual leaching of allelochemicals from residuals of bindweed in growth season that affect growth and yield of wheat.