The effect of crop rotation on Verticillium wilt and agronomical & non agronomical characters of cotton

In order to evaluate the effect of crops rotation on agronomical and non agronomical characters of cotton in Karkandeh Station in Golestan Proviences .The first and second years planted cotton and stems were cut to pieces and ploughed in soil . In the third and fourth years 15 treatments includes: soybean ,barley, onion , ploughing ,ploughing흍 nitrogen ,tomato , wheat ,lettuce, broad bean ,green bean ,green pea ,sesame ,sorghum,colsa based on randomized complete block design with four replications were planted. The yield, boll weight, percentage of earliness, sympodial length, monopodial number, monopodial length, disease indexes of wilt and Verticillium wilt percent were measured. Population of Verticillium dahliae,in dried soil were assessed before and after treatments by using semi selective Alcohol agar medium. The results were compared using Duncan's multiple range test. The results showed that the highest yield of cotton in cotton urea cotton, and plowing plowing and cotton , sorghom cotton, and lowest yield in succession, canola forage barly cotton and Cotton Cotton garden cress, widest monopodial length forage barly cotton cotton and the highest of sympodial length,cotton 늊 犋涢 , that the highest of monopodial number , barely spinach cotton and , the highest percentage of earliness barely spinach cotton were measured. Percent increase in the population of ofVerticillium dahliae in cotton Cotton Cotton Cotton Cotton sequence from first to fifth respectively 52/5, 25, 5/13, 5/6 and 0, respectively.The results showed that, population ofVerticillium dahliae, were incresed after cotton in first year(35%- 70%),in second year(14%- 36%),third year(12%- 15%),fourth year(4% - 9%) and fifth year without increase. Population ofVerticillium dahliae, were increased after wheat(66.7%),barley(68%),colsa(33.3%0,forage barly(48.5%- 54.5%),lettuce(25%- 39%),onion(52%),soybean(36%), ploughing(36%), ploughing흍 nitrogen(50%), green bean (12.5%) and sorghum(62.5%). population ofVerticillium dahliae, were decresed after tomato(6.6%), and sesame(26.6%).