تاثير تراكم بوته بر ويژگيهاي رويشي و زايشي سه رقم پنبه

The effects of plant density on vegetative and reprodutive characteristics of three cotton cultivars

The effects of inter-and intra-row distances, and their interactions on vegetative and reproductive characteristics of three cotton cultivars under dryland farming conditons were studied at Karkandeh research Station of cotton, Kordkoy, Gorgan. The experiment was conducted in a randomized completely block design as split-split plots with four replications with cultivar as main plot, inter-row distance as sub plot and inter-row distance as sub-subplot. There were three cotton cultivars (Sahel, Siokra and Zeta-2) seeded at two row width (80 and 100 cm) and three intra- row distances (10, 20 and 30 cm). Results showed that Zeta-2 had more branches than other two cultivars. Also, the effect of intra-row space on measured characteristics was more than inter-row spaces so that monopidal and sympodial branch length, and the number of sympodial branches per monopodial and main stem decreased as intra-row distance decreased from 30 to 20 cm whereas, decreasing row width from 100 to 80 cm had no effect on measured parameters exceptionally the number of sympodial branches per monopodial. Inter- by intra row distance interactions showed that for Sahel cultivar as plant density increased, main stern height, monopodial branch length, sympodial branch number, the height of the highest boll and the diameter of the base of main stem decreased but for Siokra and Zeta-2 only monopodial branch length and sympodial branch number decreased in higher plant densities. Based on the above cited results appears in higher plant density inter-plant competition for water and nutrient uptake decreases plant canopy extension, and sequentially plant size.