American-Eurasian J. Agric. & Environ. Sci., 15 (11): 2214-2229, 2015 ISSN 1818-6769 © IDOSI Publications, 2015 DOI: 10.5829/idosi.aejaes.2015.15.11.12608 Corresponding Author: Abdul Mateen, Department of Plant Pathology, University of Agriculture Faisalabad, Pakistan. 2214 Identification of Leaf Rust Virulence Pattern on Wheat Germplasm in Relation to Environmental Conditions in Faisalabad Abdul Mateen, Muhammad Aslam Khan, Abdul Rashid, 1 1 1 Muhammad Hussain, Shams Ur Rehman, Maqsood Ahmed 2 3 4 Department of Plant Pathology, University of Agriculture Faisalabad, Pakistan 1 Wheat Research Institute, Ayub Agricultural Research Institute, Faisalabad, Pakistan 2 Department of Plant Pathology, KPK Agricultural University of Peshawar, Pakistan 3 Pest Warning and Quality Control of Pesticides Sialkot, Pakistan 4 Abstract: One hundred and fifty varieties/lines were screened against wheat leaf rust. The natural environmental conditions of Ayub Agricultural Research Institute, Faisalabad were favorable for the development of leaf rust disease of wheat. Out of 150lines/cultivars which were screened against brown/leaf rust, 29 lines/cultivars were immune, the resistance was showed by 57 varieties and remaining all was susceptible. Values of area under disease progress curve (AUDPC) of all varieties were calculated. Also from the virulence and avirulence formula studied show that 57 varieties of leaf rust were avirulent and 49 varieties were virulent by leaf rust fungi, respectively. Environmental factors had great effect on the progress of leaf rusts diseases of wheat. Correlation between disease severity and environmental factors was also determined. Maximum varieties/lines showed comprehensible response to environmental factors. Four environmental factors (Temperature, Relative Humidity, Wind Speed and Rainfall) showed significant influence to disease severity. Five varieties/lines V-15, V-45, V-77, V-102 and V-118 showed considerable response to all environmental factors against brown rust. Utilization of this data for wheat improvement coupled with national varietal and gene deployment is discussed. The compiled field results exhibit that although the virulence frequency for some of the leaf rust resistance genes remained low, yet the presence of virulence against them is alarming under the circumstances when genetic base of resistance is stumpy in the presently cultivated varieties. On the basis of data these environmental factors were tested for correlation with leaf rust severities. It was concluded that screening and identifying the virulence pattern of leaf rust on wheat germplasm and utilizing these virulence genes on advanced lines may be helpful to produced for rust resistance in wheat to get maximum production. Key words: Leafrust Virulence Pattern Resistance source Epidemiology Correlation INTRODUCTION an area of 8.80 million hectare and gives 25.09 million tons Wheat (Triticum aestivum L.) is the most essential wheat is attacked by number of diseases caused by fungi cereal crop of the world. It is the most widely grown crop (rusts, smuts, bunts etc), bacteria (bacterial leaf blight, and is staple food its increasing demand due to increase bacterial mosaic, black chaff etc) and virus (wheat dwarf, in population of Pakistan, its requirements have become wheat spot mosaic, wheat streak mosaic etc). Wheat rusts increasing day by day. Of the total area (approximately problem has emerged due to attack of fungus not only in 215 million hectares) sown to hexaploid and tetraploid Asia but all over the wheat growing areas of the world. wheat (Triticum aestivum and T. turgidumvar. durum) However, leaf rust caused by fungi (Puccinia recondita) worldwide, 44% (95 million hectares) is in Asia. Of this, 62 also called as brown rust, stripe rust caused by fungi million hectares are located in just three countries: China, (Puccinia striiformis) also called yellow rust and stem India and Pakistan [1]. In Pakistan, wheat is grown under rust caused by (Puccinia graminis) called as black rust is of production [2]. Despite of its economic importance,