IRANIAN JOURNAL OF COTTON RESEARCHES
Year:2018 | Volume:6 | Issue:1|Papers Count:7

To investigate the effects of city sewage on yield and yield components and the contamination balance of heavy metals in Ray Zone, an experiment in form of randomized complete block design with four replications and 5 treatments: Includes Treated domestic wastewater (T1), untreated domestic wastewater raw sewage, (T2) irrigation with well water and treated wastewater as interlaced (T3), irrigation with well water and untreated wastewater as interlaced (T4) and Well water as a control (T5) was conducted. The study showed that the effect of treatments on yield and its components was significant and best yield performance was achieved from untreated city wastewater. A significant difference at 1% level of earliness was observed among the treatments that the highest percentage of earliness with 75/8% belonged to Control which well water was used and untreated city wastewater had the least percentage of earliness. Significant differences at 1% level of the amount of manganese, copper, iron, nickel, cadmium and lead in cotton seed was observed among treatments. This study showed that the effect of treatments on yield and yield components were effective and the best performance was obtained using untreated home wastewater. The reason is that in this type of wastewater have more nutrients that play an important role in the production of bolls numbers and the performance of final yield. In arid and semi-arid regions like Iran reuse of water can be a means to compensate for water shortages.

High seed cotton yield is ultimate objective of any crop-breeding program. In order to achieve this goal, hybrid development is an important step. Diallel cross method of producing hybrid seed cotton, is one of the most common approaches. In this study, in order to determinate the general and specific combining ability in cotton, seven cotton genotypes were crossed by unilateral Diallel. The study was conducted during two years. Crosses were done in the first year and in the second year, seven parents with the resulting diallel hybrids (totally 28 genotypes) were evaluated in order to investigate the success rate of hybridization and heterosis calculation based on randomized complete block (RCB) design with three replications. Studied genotypes were included Lambright، Tabladilla، B-557، Sindos-80، Zeta-2، Tashkand-2 andNO. 200. In this study, some of quantitative and morphological traits of cotton including percentage of fruiting plants, plant height, boll weight, average number of boll, total seed cotton yield and earliness percentage were evaluated. Statistical analysis showed that NO. 200*Tashkand-2 hybrid by total seed cotton yield b of 5139Kg per hectare was the first class and the best among all. However, B-557*Tabladilla, Tashkand-2*Tabladilla and No. 200*B-557 with 80%, 78% and 77% early maturity had higher earliness than others, respectively. In terms of heterosis percentage, Sindos-80*Lambright hybrid had higher yield at the rate of 33. 4% and in terms of early maturity, NO. 200*Lambright hybrid by 26. 5% higher than high parent were the best hybrids. Among the parents, Lambright and Tashkand-2 were the good general combinatory in view of yield and early maturity. However, among the hybrids, NO. 200*Tabladilla and Tashkand-2*Tabladilla were the best specific combinatory in terms of yield and early maturity.

In order to evaluate the effects of pigweed (Amaranthus retroflexusL. )on growth properties of cotton (gossypium hirsutum), this research was conducted in Agriculture and Natural Resources Research Center of Tehran province in 2014. Field trial was based on randomized complete block design with 9 treatments (consisting of three Amaranthus retroflexus emergency times coincide with cotton cultivation, two-leaves and four-leaves of cotton and three plant densities including (3, 6 and 12 Amaranthus retroflexus per square meter) in three replications. The results showed that all cotton quantity properties consisting of plant height, number of sympodia and monopodia, height and lenght of the first sympodia, leaf area index, leaf and stem biomass, number and weight of boll, and cotton yield in all treatments reduced compared to control treatment (cotton cultivation). The difference among treatments was significant in all traits except quality traits at the level of 1% so that emergence of pigweed coincide with cotton emergence by density of 12 plant pigweed, Morphological traits and cotton yield decreased. Due to the significant reduction in cotton yield in the presence of weed compared to conrol treatment, consideration of Amaranthus retroflexus time weeding is mandatory. Considering that the highest cotton yield reduction was related to plant density of 12 pigweed and coinciding germination of pigweed with cotton cultivation time, it is necessary weed control of pigweed from the beginning growth season and timely weeding at sowing time before formation of boll.

This study aimed to analysis of reasons for the decrease the area cotton cultivation in Agricultural lands of Central District of Gonbad-e Kavos County in Golestan province. The research is descriptive and survey. The target populations in the study consisted all of 15234 farmers residing in two rural districts (Fajr and Soltanali) in central district of Gonbad-e Kavos County. Using random sampling 375 of them were selected as research sample. Data gathered through a questionnaire and its face validity was confirmed by experts of extension and agronomy. The reliability analysis was conducted with Cronbach’ s alpha method and coefficient was 0. 83. Data were analyzed using SPSSwin19 software. The results showed according to respondents, the most important causes of the decline in cotton cultivation were little or no skilled worker for traditional cotton picking, labor shortage and high wages of skilled workers. Factor analysis showed constituent factors of unwilling farmers to plant cotton respectively placed in nine factors such as social-agricultural, labour, technical-agricultural, production and market infrastructure, the profitability of production, agricultural-supportive, mechanization, institute-technical and inputs quality explain 61. 47% of the total variance of unwilling to plant cotton. This study recommended paying attention to the mechanization of cotton planting, protecting and harvesting and develop its machine harvest aimed at reducing costs, especially labor costs with emphasis on applied research in the field of making proper and inexpensive machinery for planting, growing and harvesting.

Weed seed abscission and their accumulation in the soil annually, cause formation of a persistent weed seed bank that is the origin of future weed infection for many years. In order to survey the relationship between weed seeds in soil seed bank and the weed population during growing season of cotton field, this experiment was conducted in Golestan province in 2004-2005. Based on the results, 49 species of weeds belong to 19 families were recorded that Cyperus rotundus L., Amaranthus spp., Echinochloa spp., Hibiscus terionum L., Paspalum paspaloides (Michx. )Scribner had the highest density in cotton field respectively. The most frequent weeds were Amaranthus spp., C. rotundus, Solanum nigrum L., Abutilon theophrasti Medic., Convolvulus arvensis L. and Echinochloa spp. . Survey of soil samples showed, after Amaranthus spp. that were observed in 90 % of soil samples, the most frequent weeds in soil seed bank were Stellaria media L., Chenopodium album L., C. rotundus and Portulaca oleracea L. respectively. Poa annua L., S. media, C. album, Amaranthus spp. and C. rotundus had the highest density in soil seedbank. The results showed a strong linear relationship between weed seeds in soil seedbank and seedling numbers in the cotton fields for all of weeds.

Cotton is one of the most useful and economical plants that its cultivation is going to the decrease in Iran because of manual harvesting difficulties. Knowing the mechanical properties of the different parts of the cotton will help in selection and substitution of the mechanized method instead of a manual method. 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 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 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). Totally, the minimum force and energy of picking were shown at Golestan variety, and the maximum force and energy of picking were shown at Kashmar variety.

Some cotton genotypes take up potassium more potentially from the growth media and they are also different in response to K fertilizer application. Identification of these genotypes represents a very effective strategy for best cotton production in K deficient soils and optimum K fertilizer application. A hydroponically experiment was carried out to compare and rank 25 cotton genotypes through cluster analysis for K use and response efficiencies in deficient and sufficient K conditions. The results showed that potassium deficiency resulted in significant decrease in root and shoot dry weights of cotton genotypes. Also, by supplying sufficient potassium for the plant, its concentration and uptake increased in the root and shoots of cotton. Cluster analysis categorized cotton genotypes into four non-efficient, moderately efficient, efficient and highly efficient groups in terms of potassium use efficiency (deficiency conditions), in which the SKT133, Sepid and Mehr genotypes were stood in efficient cluster and Shayan, N2G80, Golestan and Sajjadi genotypes were found in the highly efficient cluster. Other genotypes were in non-efficient or moderately efficient groups. Also, in response to potassium application (sufficiency conditions), cotton genotypes were classified into four non-responsive, low responsive, moderately responsive, and responsive clusters. Accordingly, the genotypes of the Sahel, M13, Sajjadi, Tabladilla and Latif were identified as responsive genotypes. Sajid genotype, which is both highly efficient and responsive to potassium, is therefore recommended for use in any state of available soil potassium (deficiency or sufficiency).