EFFECT OF ALLELOPATHIC COMPOUNDS OF SOME ROOT WEED PLANTS ON THE GERMINATION AND SEEDLING GROWTH OF SOME CROPS

Abstract

A laboratory experiment was conducted in field crop department-College of Agriculture-Tikrit Univ. During 2009 ,to determined the effect of allelopathic compounds which obtained from the extract of root systems of some weed plants like, Johnson grass Sorghum halepens,Eruca plant E.sativa,common sow thistle Sonchus oleraceus and cheese weed Malva parviflora,on the germination and seedling growth of wheat, barley and corn crops. The results which obtained were: 1-The extract of common sow thistle roots ingibited the seed germination and seedling growth significantly than other extracts for all crops . 2- The Johnson grass extract inhibited the plamule length of corn seedling about 29.9% than the control treatment, while the cheese weed root extract reduced the seedling growth of wheat about 23.3%. 3-The Johnson grass root extract reduced the radical length of wheat about 38.2% comparing with control-treatment . 4-Dry weights of plamule of all crops which studied were affected significantly. The highest reduction obtained from common sow thistle plant root extract the reduction percentages were 36.5% ,51.3%,and 28.1%for wheat, barley and corn respectively. 5-The radical dry weights of corn seedling reduced significantly when the seeds treated with common sow thistle plant root and Eruca plant root the percentages were 76.3%and 80.3%respectivly.