Document Type : Agricultural Zoology
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Abstract
Birds are considered as important key pests of sunflower. This survey was conducted in Karaj & Khoy regions during the summer of 2003 and 2004. In this experiment, 1309 heads of sunflower were randomly selected and damage rate were estimated in sunflower fields of agricultural research stations of Karaj and Khoy. Mean damage rate in Karaj was 45.3%, while in Khoy it was 21%. In Karaj, Zarghan (82.75%) and CMS19 (2.1%) were sensitive and resistant varieties, respectively, while in Khoy, followed by Sor (65.1%) and Eroflore (0.2%). In Karaj, early harvesting varieties suffered more damage (20.25% - 75.66%) than late harvesting varieties (2.1% - 82.75%). Morphometric measurements were made on head height from the ground surface, head diameter, sterile area to head diameter ratio, head angle, head shape and form of stem, and their correlation with bird damage were investigated. Pearson correlation was used for the first four factors and ANOVA and t-test for the two other factors. There was significant correlation (using Pearson correlation) between bird damage rate and the following factors: head height from ground surface, head diameter, sterile to head diameter ratio, and head angle (p <0.05). ANOVA and t-test showed significant differences between different head shapes and stem forms in sunflower varieties
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