عنوان مقاله [English]
Introduction: Determining the best conditions for plant growth can be effective in increasing the yield of crops. One of the factors affecting crop yield is plant density. Plant density is one of the most important factors affecting the optimum exploitation resources and in competition of weeds with crops (Akram Ghaderi et al., 2002). Increasing of plant density in order to compensate for reduced yield, causes changes in the morphology traits of cotton and can affect cotton yield (Jost & Cothren, 2010). This research, was done to determine optimum density and proper planting pattern for four cotton varieties.
Materials and Methods: In order to investigate the effect of plant density and planting pattern on yield and yield components of four cotton varieties an experiment was conducted by factorial arrangement based on complete randomized block design with three replications and three factors during 2014 growing season in Darab. First factor was consisted of four levels of cotton varieties (Bakhtegan, Golestan, Aryan and Khandagh). Second factor was five levels of between row distance (30, 40, 50, 60 and 70 cm) and third factor was three levels of within row distance (10, 20 and 30 cm). Sowing was done on May 15th in 2014 and ten days after sowing, additional plants were thinned. At the end of the growing season, traits of number of boll in plant, weight of boll, seed cotton yield, ginning rate, lint yield and lint length were Measured.
Results and Discussion: The results indicated that the highest number of bolls in plant belonged to Bakhtegan and Golestan cultivars. The highest boll weight belonged to Bakhtegan (675 g m2) and Golestan (673 g m2) cultivars in between row distance of 30 cm and within row distance of 10 cm. Bakhtegan and Golestan cultivars in planting patterns with distances between and within the rows of 30 and 10 cm, 30 and 20 cm, 40 and 10 cm and 40 and 20 cm showed the highest seed cotton yield. Bakhtegan cultivar showed the highest lint yield at almost all levels of distances between and within the rows and it had a higher potential for producing ginning rate in comparison with other cultivars of this study. The maximum lint length was obtained between row distances of 30 cm, with 30.1 mm and Bakhtegan cultivar showed the highest lint length at the 10 cm within row distance.
Conclusion: Bakhtegan and Golestan cultivars had a higher potential for production of number of bolls in plant compared with Arian and Khandag cultivars and the highest boll weight was also obtained to these cultivars at between row distance with 30 cm and within row distance with 10 cm. Also in more compact plant density higher seed cotton yield, ginning rate and lint yield were obtained. Especially, two cultivars of Bakhtegan and Golestan showed greater flexibility for more compact densities. Therefore, sowing Bakhtegan and Golestan cultivars in more compact plant density is recommended in Darab city of Fars province.