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In order to evaluate the landraces of barley in northern region of Iran (Azarbaayjan, Khorasan, Mazandran and Zanjan Proviences), 411 landraces barley collected from 42 cities of the aformentioned provinces were studied in a simple and observational experiment with 5 blocks in Karaj and Gorgan research exprimental field in 1996. The resistance evaluation were performed based on agronomical characters including germination time (days), 50% flowering (days) plant height(cm), maturation time (days) and grain yield (gr/plot), stembase color, auricle color, number of rows per head, glume color, awm color and head length were measured and determined in apropriate times. Statistical analysis were done on the measured and determined data:
including estimation of population parameters, correlation coefficient between the character pairs and a stepwise multiple regression between grain yield and other characters. The results showed that there was a considerable range(2-9) in the infection type. The infection type “7” was the most frequent one and different resistant types were found in all regions. Most of the resistant types were from the first three mentioned above regions. Among the examined
germplasms there was a negative correlation between the susceptibility to
powdery mildew and yield (r=-O.494). There was also a negative correlation
between plant height and this susceptibility (r=-O.33). The character of
susceptibility could independently reduce 24% of yield.