Determination of appropriate isolation distance in seed standard production of cotton cv. Mehr in Ardabil province

The current study was carried out to determine the most appropriate isolation distance in seed production cottom farms in two cropping years at Moghan agricultural Research Station. Cotton cv. Mehr as conventional cultivar in this region was cosidered as female parent cultivar or pollen receptive and Red leaf and Okra leaf cultivars were considered as male parent or pollinator. The marker genotypes were planted with distances of 80, 160, 240, 320, 400, 800, 1600 and 3040 cm from both side with mathernal parent. Seeds obtained from female parent cultivar were grown in the second year in factorial experiment with randomized complete block design in four replications and after growing in six-leaved stage the total number of plants and out-crossing plants were counted and percentage of outcrossing were calculated for different isolation distances. The out crossing percentage average in isolation different distances and their interactions in both markers showed significant difference. Out-crossing rate in 80cm isolation distance between female parent with Red leaf and red Okra leaf male parents were 11 and 4.5%, respectively. Totally  in both Red and red Okra leaf male parents in 80 cm of isolation distance maximum out-crossing happened but in 80 to 400cm distances it was reduced extremely and teneded to be zero. Results are showing low rate of out-crossing in cotton and giving good idea for researchers in hybrid seed producers to consider maximum 4 cm of isolation distance getting net and standard cotton seed.