Abstract
The survey carried out in the canal irrigated districts of Punjab revealed that some 28 weed species in addition to the unidentified grasses have been found infesting the wheat fields. The distribution pattern as determined in terms of frequency and density of weeds was not uniform in the various districts surveyed. However-, Ifelitotio indica, Pholaris inor,, .4naga1lis arvensis. Cheno,podum album a.nd Rtomex dentatus appear to be the predominant weeds of these districts. The frequency of Avena falua, art-other abnoxious weed, was quite high in Faisalabad, Gujranwala, Qnsoor, Sargodha and Sheikhupura districts although its density was relatively low in these districts,
INTRODUCTION
The Punjab Province of Pakistan is divided into two major ecological regions namely submountainous region and plains. The submountainous region lies between 300 and 600 in above the sea level and includes Attock, Jhelum and Rawalpindi districts. The cultivated area of these districts is mainly rainfed. Of the total cultivated area of 11.49 million hectares of Punjab about 7,2 hectares is canal irrigated. while. the remaining falls within the precincts of the add zone, wheat is cultivated on 4158.7 thousand hectares in the canal irrigated districts** Though the evolution of new high yielding, fertilizer responsive and disease rcsistant varieties of wheat has brought about a real break - through in. wheat production and the country was able to produce the exportable surplus in 1983, but this status could not be maintained in the subsequent years due to hostile weather, However, still the yield per unit area is much less than the other advanced countries of the world. Many factors are attributed to this yield gap but weeds are known to bring about substantial reduction in the yield of wheat grain.
