IRANIAN JOURNAL OF COTTON RESEARCHES
Year:2016 | Volume:4 | Issue:2 |Papers Count:8

Cotton is an important and strategic plant. This plant is susceptible to K deficiency. Some plants i.e. cotton has genetic differences in K uptake and use. The objective of this study was to investigate the K uptake and use efficiency of some cotton genotypes in two different soils and, to introduce the superior genotypes. For this purpose, a pot experiment carried out on 20 different cotton genotypes as a factorial in a completely randomized design with three replications. The first factor consisted of 20 cotton genotypes, the second factor was 3 plants growth media which included of washed sand mixed with soils that predominant in smectite (Kordkouy) and illite (Rahmatabad) and control (washed sand without soil). The plants were grown to 40 days and then harvested. The Amounts of dry matter weight and potassium in the leaves, stems and roots were measured. The results showed that the different cotton genotypes have different responses in different cultivation media. Sepid and N2680 genotypes in the Rahmat abad soil, Tabladila in the Kordkoy soil and Golestan in control had the most K uptake but, Khorshid, Armaghan and M16 genotypes showed the least K uptake in the Rahmat abad and Kordkoy soils and in the blank, respectively. The K uptake in the Kordkoy soil to other two treatments (control and Rahmat abad soil) decreased due to the dominant smectite and, followed by high potassium exhaustion. The results indicated that Khorshid, Armaghan and M16 genotypes with the least dry matter weight and the least potassium uptake categorized as an inefficient genotypes group and, NN2A19, N2680, SKT133 and BC244 genotypes with the most dry matter weight and medium potassium uptake considered as an efficient genotypes group. The genotype Sepid with the most dry matter yield and potassium uptake was efficient in potassium uptake but was inefficient in potassium use. The remaining genotypes with average dry matter weight and potassium uptake classified in a medium efficient group.

To evaluate the effect of salinity on accumulation of amino acids and the activity of antioxidant enzymes in some genotypes of cotton (Gossypium hirsutum L.) an experiment in a randomized complete block design with three replications was conducted in Anbar Olum’s research farm which is located in Golestan province. Treatments consisted of seven genotypes of cotton namely,Çukurova, opal, Shyrpan 539, 43200, Ciland, and a Sepid in a saline soil with the EC equivalent to 14.8 dS/m.The Voshmgir’s dam water was used for irrigation having the salinity of 2.5-3 dS/m. The 5th and 6thleaves and thirty days’ stems samples were taken. The results showed that the soil salinity had a significant effect on yield and physiological traits genotypes with more severe stress and activity of catalase, peroxidase, polyphenol oxidase and amino acids proline and glycine betaine increased. Among the genotypes, the activity of peroxidase, proline and glycinebetaine was a significant difference with 99% of confidence and the activity of catalase and glycinebetaine in Sepid genotype was higher but the Opal genotype showed a higher amount of peroxidase activity and proline content. According to the results collected from the field, the Opal genotype with 2256 kg/ha of seed cotton yield had the highest and the Cukurova with 1399 kg/ha of seed cotton yield had the lowest performance.

This experiment was laid out in order to study on effect of irrigation saline water on biochemical characteristics of mutant cotton lines in Isfahan Agricultural and Natural Resources Center, Iran at 2014-2015, by using of split plot arrangement based on complete block design with three replications. Experimental treatments were three irrigation water [4 (as control), 8 and 12 dS m-1] at main plots and three cotton genotypes (LM1673, LM1303 and Shayan) in sub plots. Results showed that the effect of irrigation using saline water on all traits was significant except reducing and non-reducing sugars. Effect of cultivar was significant on starch content and interaction between irrigation using saline water and cultivars was significant on soluble and non-reducing sugars, starch content and carotenoids. Irrigation by 12 dS m-1 saline water, soluble protein and soluble sugars increased as 50% and prolin content increased as 45% rather than control treatment. Proxidase (POX) enzyme activity in irrigation by 8 dS m-1 saline water treatment increased as 50% rather than irrigation by 12 dS m-1 saline water treatment. By increasing of irrigation water salinity, decreased chlorophyll content (40% rather than 8 dS m-1 saline water) and increased relief pigments such as carotenoids (50%) and anthocyanin (23%). In many traits, because of non-significant different amomg genotypes and with regards to high tolerance characteristics of Shayan genotype to salinity can be concluded that LM-1303 and LM-1673 had high tolerance to salinity same to Shayan genotype. With regard to higher soluble sugar, non-reducing sugar and carotenoids in LM-1303 genotype, can be concluded that this genotype had better physiological status under salinity compare to Shayan genotype.

To evaluate the distinctive morphological characteristics of cotton cultivars, and the correlation among different traits of cotton species, current research was conducted on Sahel, Golestan, Sepid, M-13, SKT-133, Latif, Termez 14, Barbadense and Doctor Omumi cotton cultivars from 2 different species of Gossypium hirsutum and G. barbadense in randomized complete block design (RCBD) during 2015 year in Hashemabad Cotton Research Station, Gorgan, Iran. Studied traits were included of plant height, number and length of sympodia and monopodia branches, the nodes numbers, bolls number and weight, seed weight, yield and lint percentage. According to the results, for all of the studied traits, significant statistical difference (p<0.01) were observed. This matter represents clear and distinct differences among evaluated cultivars. Characteristics of monopodia and sympodia branches did not follow a particular trend between the cultivars of two species and these traits were not considered depending on the plant species. Furthermore, the characteristics of plant height, number of bolls, boll weight, seed weight and lint percentage can be attributed to species type, so that Doctor Omumi cultivar from G. barbadense species and SKT-133 from G. hirsutum species produced the highest and lowest number of bolls, respectively. Boll weight was varied from 3.25 gr in Barbadense cultivar to 5.29 gr in Sahel cultivar. The highest lint percentage (42.2 %) was related to Golestan cultivar and the Barbadense cultivar from G. barbadense species had the lowest amount of lint percentage. Seed cotton yield had a significant positive correlation with boll weight and first harvesting. In contrast, there was a negative correlation between the number of bolls and lint percentage. According to the group comparisons, the G.hirsutum considering the traits: total yarn 10.9 %, length of the highest monopodia branch 27.48 %, first cut yield 753.15 Kg/ha, total yield 719.55 Kg/ha and the and boll weight 1.39 gr in comparison with G.barbadense was superior in a way that being high these traits compared to other agricultural traits had the most effect on total yield of the crop. Accordingly, knowing about the relations among the traits and their effect on the total yield can be helpful in increasing the production of this important plant.

This experiment was carried out for 2 years in Cotton Research Station of Karkendeh and Hashabad region in factorial–split plot using randomized complete block design with 3 factors in 4 replications. The purpose of evaluation was effects of tillage date, various levels of nitrogen fertilizer and plant date of cotton with cover crop on yield, yield components and weed density of Golestan cotton verity. Two tillage date were as first factors, two various levels of nitrogen fertilizer were as second factors and four plant date cotton with cover crop were as sub-factors. Composite variance analysis of traits showed that both region and tillage date had no effect on yield, yield components and weed density. The stage plant seedlings did not properly covered in cotton rows. Most weeds of cotton were observed in cultivation vetch after emergence of cotton treatment. In the second stage, vetch was covered among cotton rows and the highest number of weeds was observed in cotton treatment. The lowest number of weeds was related to cultivation vetch before emergence of cotton treatment and this treatment, in addition to having the lowest yield had the lowest weeds.

In order to study of flora, functional and structural diversity of weed species, cotton fields of Gloestan province (6 cities) were surveyed during 2012 year. Randomized sampling method as W shape was conducted by using 0.5×0.5-meter quadrate, systematically. In this study, 38 weed species belong to 16 families were recorded which most of them were from Poaceae by 10 species and Amaranthaceae by 4 species. Among different weed families,Poaceae, Cyperaceae and Fabaceae had the most relative abundance in cotton fields, respectively. Based on the results, 76% of recorded weeds were annual and the rest were perennial, also 71% of identified weeds were broad-leaved and the rest were narrow-leaved. Cyperus rotundus and Alhagi camelorum were the most important weeds from narrow-leaved and broad-leaved weeds, respectively. The highest number of species were observed in Ali Abad and Aq Qala (16 species) and the lowest observed in Kord koy (8 species). Among different cities, Ali Abad and Aq Qala (63%), Ali Abad and Galikesh (62%) and Ali Abad and and Bandar Gaz (62%) had the highest similarity index but Kord koy and Aq Qala had the lowest similarity index (8%). The highest Shanon diversity index (2.13) was observed in Galikesh city and the lowest value (1.57) observed in Kord koy city. The highest Simpson diversity index (0.29) was observed in Bandar Gaz and Bandar Torkaman cities and the lowest value (0.15) observed in Galikesh city.

Assessing specific relationships among lint-yield, cottonseed-yield and some important agro- morphological traits, in commercial varieties of Varamin, was the main objective of the present study to use in the future breeding programs. To achieve the above objective, the seeds were planted in 10 lines with 2 meters long in each block, based on RCBD with three replications during 2009-2010 years. Plant height, number of bolls per plant, mean boll weight, leaf length, leaf width, number of branches per plant, length of fiber, chlorophyll content, fiber yield, lint percentage, lint-yield and cottonseed-yield were measured. Correlation analysis indicated that the traits of boll weight, (r= 0.97), cottonseed-yield (r=0.93), fiber weight (r=0.90), leaf width (r=0.77), fiber length (r=0.70), leaf length (r=0.66) were significantly correlate with lint-yield. Stepwise regression results for lint-yield, as dependent variable, showed that the traits of boll weight, fiber weight, lint percentage and number of bolls per plant were respectively entered in the regression model, as the most effective independent variables. Path analysis results indicated that the trait of boll weight had the maximum direct effect (0.366) and the traits of boll weight and lint percentage had the maximum indirect effects (by increasing fiber weight character) on lint yield. Total results showed that the trait of boll weight had the maximum direct and indirect effect on increasing lint- yield therefore, we can use it in the future breeding program for improvement of lint-yield. Lint-yield and lint percentage were the most important characters on increasing fiber weight. In other words, these two above-mentioned traits had the maximum direct and indirect effect on fiber weight, respectively. Finally, the traits of boll weight and lint-yield were recognized the most important characters for improving cottonseed-yield of Varamin cultivar.

The development of mechanized harvesting as a way to reduce 30% the cost of production could raise the competitiveness of cotton production and maintain in the country. Using defoliator before machine harvesting is necessary to cleaning harvesting and high quality. To evaluate the effect of spraying time of defoliator and speed of cotton harvesting machine on machine performance and quality of cotton fiber, an experiment was carried out in Cotton Research Station of Hashemabad, Gorgan in 2014. The studied factors in this research were included two levels of spraying time of defoliator, two levels of cotton varieties suitable for mechanical harvesting and three levels of forward speed. The experimental design was split split plot in randomized complete block design with three replications and three factors. Results showed that harvesting time and speed did not affect the quality of the fiber. The effect of variety was significant on fiber quality, the importance of choosing the most suitable for mechanized harvesting of leads. Sepid variety in terms of quality index fibers had priority compared to the Golestan, and was suitable for machine harvesting.