IRANIAN JOURNAL OF COTTON RESEARCHES
Year:2019 | Volume:7 | Issue:1|Papers Count:7

Cotton has been traditionally grown in rows spaced from 75 to 100 cm. Narrow row spacing have been found to increase yield potential in cotton due to better sunlight penetration and more uniform spacing of the cotton plants in the field. A field experiment was conducted to study the effect of planting date on yield and yield components of cotton with three planting systems at Sabzevar Agriculture and Natural Resources research center in 2013. This experiment was carried out as split plot design based on randomized complete block design with three replications. Factors were: planting date (Conventional (22 May) and late planting (22 June) as main plots and planting system; ultra narrow row spacing (20 cm (25 plant. m-2), conventional spacing (50 cm (10 plant. m-2) and broadcast seeding (8 plant. m-2) as subplots. The results showed that planting date and planting system had significant effect on plant height, number of bolls, boll weight and seed cotton yield. Late planting was decreased plant height (13. 61%), number of boll (27. 41%), boll weight (14. 63%) and seed cotton yield (24. 83%) as compared with conventional planting date. Narrow row spacing was better than other planting system for all traits. There was no significant difference between conventional spacing and broadcast seeding. Overall, ultra narrow spacing rows and conventional planting date (May 22) was the best treatment for achieving high yield in cotton under Sabzevar conditions.

Genotypes 43259, 43347, N-200, Tabladila, Chukrova, B-557, Sepid-2 and Sahel in the form of randomized complete block design (RBCD) in Hashem-Abad Cotton Research Station located in eleven kilometers northwest of the city of Gorgan for a crop year were examined. The experiment in four replications with 20 × 80 cm planting pattern and length eleven meters were planted in four rows. mean Duncan test at level 1% were compared and correlation was found in the above genotypes. The results of variance analysis showed that the genotypes difference on total seed cotton, yield of first picking, the number of monopodia, thirty boll weight, plant height and yield of second picking were significant at 1% and number of sympodia, length of sympodia, length of monopodia and number of bolls is significant at the 5% level. The results of comparison of mean traits showed the N-200, 43259, 43347 and B-557 cultivar were superior to other cultivars. In the first picking of seed cotton, results showed that the N-200 and B-557 respectively (2863 and 2725) kg per hectar of seed cotton had the greatest product in first piking. 43259, 43347, Ç ukurova cultivars have lower height than other varieties. Correlation table showed between first picking of seed cotton and total seed cotton is positive correlation(0. 879) and correlation between them was significant at 1%. Between length and number of sympodia was positive correlation and significant at 5%(0. 399).

In order to evaluate the effect of irrigation, foliar application of methanol and plant density on morphophysiological traits, yield and yield components of cotton, a split-split-plot experiment based on randomized complete block design with three replications was conducted in Birjand, Iran in 2014. The main plots were irrigation interval (irrigation after 120 and 240 mm cumulative evaporation), the sub-plots were methanol spray (0, 10and 20 volume percent) and the sub-sub-plots were plant density (10 and 20 plants. m-2). The results showed that irrigation interval significantly affected plant height, branch number of main stem, stem diameter, stomatal conductivity, chlorophyle index, relative water content, boll number per m2, yields of seed, lint, seed cotton and biological. As decreased irrigation interval from 240 to 120 mm cumulative evaporation, these traits significantly increased by 16. 3, 48. 8, 25. 3, 105. 4, 11. 6, 23. 6, 60. 9, 60. 8, 76. 6, 68. 9 and 55. 6%, respectively. Also, foliar application of methanol significantly increased boll number per m2, yields of seed, lint, seed cotton and biological. Moreover, plant height, boll number per m2, yields of seed, lint, seed cotton and biological increased by 14. 4, 23. 5, 15. 4, 26. 7, 21. 2 and 17. 6 %, respectively with the increase in olant density from 10 to 20 plants. m-2. The results showed that irrigation after 120 mm cumulative evaporation, application of 10volume percentof methanol and density of 20 plants. m-2 are suitablefor thecultivation of cotton in Birjand, Iran.

The bolls which are used in cotton in this research was separated from pedicles randomly; and the effects of loading speed and moisture content of boll on force and energy, that is needed for harvesting at four variety of bolls (Golestan, Khorshid, Sajedi, and Kashmar) in the different harvesting of cotton were was analyzed by using the traction-pressure device. The results showed that the effects of variety and speed of loading, and also mutual effects of variety in the speed of loading and harvesting time in variety has meaning on the force of picking in 1% level; , but the effect of harvesting time and mutual effect of harvesting time in the speed of loading is meaningless. The most picking force was 22. 7N (variety of Kashmar, loading speed=10mm/min); and the less force of picking was 4. 922N (variety of Golestan, loading speed=5mm/min). Also, the most force of picking in first harvesting belonged to Kashmar variety (23. 567N), and the less force of picking in the third harvesting was also belonged to Golestan variety (5. 967N). The effects of harvesting time, variety, the the speed of loading and mutual effect of harvesting time on variety in 1% level, and also the mutual effect of harvesting time on the speed of loading in 5% level has meaning on picking force; but the effect of variety on the speed of loading is meaningless. The maximum and the minimum energy of picking was respectively 96. 45mJ/mm (Kashmar variety, first harvesting) and 26. 476 mJ/mm (Golestan variety, third harvesting).

This study was carried out in Golestan-Hashemabad as split plot in a randomized complete block design with three replications in 2011 and 2012. Main plots were Planting date in three levels and sub-plots were seed coating in six levels. Except seed cotton yield, planting date hadn’ t significant effect on others yielding factors. Early planting with mean 12. 8 boll per plant, on time planting with mean weight of 30bolls 162. 9gr, early planting with 1955. 5 kg. ha-1mean seed cotton yield, 66. 8 gr lint and 41. 1% lint was better than other treatments. Interaction effect between planting date and year on all of yield factors non-significant. On time planting in secondth year with mean 18. 4 boll per plant and 30 bolls weight, 164 gr had better condition. Early planting in secondth year produced highest seed cotton (2845. 2 kg. ha-1). On time planting in secondth year produced the most lint weight and percent73. 2 gr and 45. 7% respectively. Seed coating hadn’ t significant effect on yield components except seed cotton. The highest boll per plant (13. 4) belonged to sulphur fuzzy seed coated. It can be related to sulphur role in flower fertilizing. Mentioned treatment produced heavier bolls (30 boll weight mean 164. 2 gr ). This result can be related to sulphur role in assimilation and carbohydrate allocation. Sulphur delinted seed coating produced the highest yield( 1896. 1 kg. ha-1). The delinted seed that coated with solution had the most lint weight and percent, 66. 2 gr and 41. 7% respectively.

The aim of this study was evaluating the economic and financial profitability of different cotton cultivation systems and its effects on cropping pattern in Gorgan County during 2014-15. Required information has been collected by stratified random sampling method from 50 farmers who cultivate cotton in three systems of crop cultivation including mono cropping, double cropping (cotton-bean), and intercropping (cotton-sesame). Data between three cotton cultivation systems was analyzed by using SPSS software. After that, the optimal cropping pattern of Gorgan County was determined by using 295 farmers in Gorgan and using mathematical programming model with GAMS software. The results of profitability showed that, double cropping systems of cotton compared to mono cropping and inter cropping systems has more than 18 and 26 percent economic profitability and 20 and 22 percent financial profitability respectively. The results of determining the optimal cropping pattern of Gorgan county showed that, double cropping system due to more economic and financial profitability than other products, was included in the copping pattern of the county and other cotton cropping systems removed from the model. According to the results of this study, it is suggested that by encouraging farmers to use a double cropping system, the total cultivation area of cotton could be increased in Gorgan County.

The cotton whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the most important cotton pests. To control the whitefly, methods of biological control, chemical, and crop control especially resistant cultivar can be used. In this study, the resistance of different cotton genotypes to the cotton whitefly, B. tabaci was evaluated in field conditions in Garmsar region. For this purpose, the damage of B. tabaci on 10 cultivars was carried out in a split plot design with four replications. The experimental cultivars were including: BC244, SKT133 SAHEL, NSK847, SNK2772, GKTB113, K8802, SKSH249, K8801, and VARAMIN. The results showed that the time of beginning of infestation was different in various cultivars as BC244 and VARAMIN cultivars were infested with the pest sooner than others. At the peak of infestation, the highest population of pest was found on BC244 and VARAMIN and the lowest infestation was in GKTB113 and K8802 cultivars. During sampling at different times, the highest infestation was on BC244 and VARAMIN cultivars, and the least infestation was on K8802, SNK2772 and NSK847 cultivars. By calculating the yield components at harvest time, it was determined that the pest reduced the number and weights of the boll. This decrease was significant in VARAMIN and SAHEL cultivars and the lowest yield reduction was observed in SNK2772. Therefore, based on infestation rate and damage, the most resistant cultivar to the pest is SNK2772 and the most susceptible cultivar is BC244, among the tested cultivars.