P. graminea is the casual agent of barley leaf stripe. An early selection method of resistant types of barley leaf stripe was realized and validated in this research. This new method, based on Microrganism Genetically Modified (MOGM) GUS2 construction, obtains results comparable with those of classical method, reduces the work time, the use of chemicals (pesticides) and productive plants as greenhouses. Moreover, the use of MOGM GUS2 is restricted in laboratory ambient, therefore the risk of environmental spread is reduced. The early selection method has allowed to estimate the reaction to P. graminea agent in 12 several barley types usually farmed in Italy. The results were compared both, with the classical method data based on artificial clone Dg2 inoculum, and with natural inoculum data obtained in field. At all times we observed a ranking likeness.