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ABSTRACT A research trial was conducted at the Agricultural Research Institute, Dera Ismail Khan to investigate the allelopathic effect of congress grass applied alone or in combination with half and full recommended doses of commercial herbicides (Puma Super and Buctril Super) during the year 2010-11. The results revealed that weed control strategies including hand weeding (30 and 60 days after sowing), application of herbicides and use of congress grass water extract significantly controlled weeds over the weedy check. Among the treatments, herbicide Puma Super full recommended dose (625 mL ha-1) significantly increased leaf area index, leaf area duration, crop growth rate, number of tillers, number of grains spike-1, 1000-grain weight and grain yield.
While, weed density and dry weed biomass were minimum in hand weeding. The findings revealed that, in order to obtain maximum yield of wheat, the plots should be kept weed free by hand weeding throughout the growing season or weeds should be suppressed by application of herbicide like Puma super with recommended dose. It is therefore concluded that herbicides can be used to control weeds in wheat field where labor is expensive.
Key words: Allelopathy, congress grass, Parthenium hysterophorus,weeds, wheat, yield.
INTRODUCTION Wheat (Triticum aestivum L.) is the most important staple food crop for more than one third of the world population. It is also an important grain and staple food crop of Pakistan and accounts for nearly 36% of the total cropped area, 30% of the value added by the major crops and 76% of the total production of food grains.
Although wheat production has increased in our country but average yield does not go beyond 30-35% of its optimum potential and this rate is very low as compare to other advanced wheat producing countries of the world (Hussain et al., 2007). To meet the rising demand, wheat production should be 18.86 million tons against present 16.8 million, a shortfall of 2.36 million tons (Hassan, 2007). The area under wheat has been increased by 2% in Punjab, 9.4% in Khyber Pakhtunkhwa (KPK), and decreased by as much as 30% in Sindh and 60% in Balochistan.
Among the yield limiting factors, weeds intervention is one of the most important but less recognized constraints in Pakistan (Qureshi and Bhatti, 2001). Weeds compete with...