محمدرضا زنگی

Diverse plant genetic materials are potential treasures that are considered valuable support for plant breeding programs, because the plant breeding research is based on wide genetic diversity, and basically, without diversity, breeding and selection will have no meaning. This study was conducted to evaluate the diversity of different cotton landraces and identify the traits affecting their yield. 

In this study, 44 landraces of cotton were cultivated in the agricultural research station of Kashmir during the two years of 2018 and 2019. The traits of the number of open and closed bolls, crown diameter, crop yield, boll weight, number of monopodial and sympodial branches, plant height, and crop maturity were measured. Descriptive statistics, trait × genotype (GT) biplot analysis, factor analysis, and cluster analysis were used to investigate the objectives of this research. Statistical analyzes were performed based on the average of two-year data. In analyzing of descriptive statistics, JUMP software was used, SPSS 21 software was used for factor analysis and cluster analysis, and GEA-R software was used for GT biplot analysis. 

Based on the average of two-year data, the range of boll weight and the number of closed bolls were high, which indicates the diversity of the investigated genotypes for the mentioned traits. Comparison between genotypes based on multiple traits made it possible to distinguish different genotypic groups. Cluster analysis of studied traits classified the genotypes into four main groups. The first group obtained from cluster analysis was earlier, but had the lowest average plant height, the number of monopodial and sympodial branches, the number of open bolls, and crown diameter. On the other hand, the second and third groups had the lowest amount of earliness. The genotypes of the second group had the lowest boll weight, the number of shoot branches, and the crown diameter, and the third group had the highest plant height, the number of branches, and the number of open bolls. The genotypes of the forth group had the highest earliness and the number of closed bolls. In order to increase earliness and reduced the plant height, the selection of genotypes from the first group for breeding programs can be helpful in obtaining cultivars with greater tolerance to environmental stresses, including drought. It is also possible to use the genotypes of the third group with the highest number of open bolls to cross with the genotypes of the first group in order to create quality and early cultivars. 

 There was considerable genetic diversity among the studied landraces in terms of most of the evaluated traits, indicating high potential for improving these traits through targeted selection in the breeding programs. The boll weight was the most important factor affecting the yield of cotton, and the fiber component had a greater effect on the boll weight of some studied genotypes than the seed component.

Cotton is a vital industrial crop worldwide, recognized as a strategic commodity in many countries and particularly well-suited for cultivation in arid and semi-arid regions. Its significance stems from its potential to generate employment, its diverse applications—including fiber production, animal feed, and vegetable oil—and its compatibility with sustainable agricultural practices compared to other crops, such as corn. 

To evaluate key traits and identify the most suitable cotton cultivars for the Sistan region, a study was conducted involving 14 cotton cultivars. The experiment was designed as a randomized complete block design with three replications, carried out at the Zahak Agriculture and Natural Resources Research Station over two crop years (2021-2022 and 2022-2023). 

Analysis of the composite data revealed significant differences in several traits. Traits such as earliness, number of bolls per plant, boll weight, yield from the third row, and yield per hectare showed significant differences at the 1% probability level. Additionally, the number of sympodial branches, yield from the first row, and yield from the second row were significant at the 5% probability level. The cultivars exhibited distinct characteristics, with Latif (6,932 kg/ha), Khordad (6,880 kg/ha), Golestan (6,766 kg/ha), Khorshid (6,664 kg/ha), and Sepid (6,394 kg/ha) demonstrating the highest yields per hectare. In contrast, the Armaghan variety yielded the lowest at 3,408 kg/ha. Among the cultivars, Khorshid and Khordad had the shortest growth periods, while the white cultivars had the longest growth and ripening times. 

The Latif and Golestan cultivars showed more stable production compared to others, particularly under changing climate conditions in the second year of cultivation. Considering the impacts of climate change and environmental challenges such as increasing water and soil salinity, these cultivars offer better production sustainability. Additionally, Khorshid and Khordad cultivars, with their earlier maturation, are well-suited to the Sistan region's climatic conditions, including its 120-day winds. These cultivars not only have shorter growth periods but also rank among the highest in yield.

Varieties are the most important plant breeding achievement. Cotton new cultivars introduce for yield increase, earliness, biotic and abiotic stresses resistance. Before new cultivars introduction to farmers, value of cultivation and use of their must be evaluated and comprised with common cultivars for superior cultivars introduction by Value of Cultivation and Use(VCU) trials conduction. Seed cotton yield and its components and earliness and fiber quality are the most important aspects of cotton cultivars value af cultivation and use. Verticillium wilting is the most important cotton disease in Golestan province. Therefore, cotton high yielding and early and tolerant to Verticillium wilting new cultivars like Golestan and Latif bred and introduced by Cotton research Institute in recent years. This research conducted in order to value of cultivation and use (VCU) determination of cotton new cultivars in Golestan province conditions for cotton new cultivars commercialization purpose.

In order to evaluation of Value of Cultivation and Use (VCU) of SB35 and T3 new cotton genotypes in comparisons of Hekmat, Sajedi, Armaghan, Golestan and Sahel cultivars in Golestan procince, seed cotton yield and its components and some related morphological and fiber quality traits and Verticillium wilt tolerance, an experiment was conducted during 2016 and 2017 years in Cotton Research Institute Karkande cotton research station. Plant height, sympodial branches, monopodial branches number the highest sympodial branch and fifth monopodial branch length, boll number and 30 boll weight, seed cotton yield, earliness, fiber length, uniformity, fitness, strength and elasticity and Verticillium wilt plants percent were measured.

Results showed morphological traits and 30 boll weight and seed cotton yield in second tear more than first year and earliness in second year was more than first year. Also, studied new genotypes and cultivars determined 30 boll weight and seed cotton yield and fiber quality traits and Verticillium wilt tolerance were different. Golestan new commercial cultivar had the highest seed cotton yield and Sahel old cultivar had the highest boll weight and fiber length, strength and elasticity. Also, Hekmat new commercial cultivar had the finest fiber and Sajedi new commercial cultivar had the highest Verticillium wilt tolerance.

Based on results of this experiment and because of Verticillium wilt in Golestan province Sajedi cultivar suggested for introduction and commercialization as new commercial cultivar for cultivation. In order to evaluation of Value of Cultivation and Use (VCU) of SB35 and T3 new cotto genotypes in comparisons of Hekmat, Sajedi, Armaghan, Golestan and Sahel cultivars in Golestan procince, seed cotton yield and its components and some related morphological and fiber quality traits and Verticillium wilt tolerance, an experiment was conducted during 2016 and 2017 years in Cotton Research Institute Karkande cotton research station. Plant height, sympodial branches, monopodial branches number the highest sympodial branch and fifth monopodial branch length, boll number and 30 boll weight, seed cotton yield, earliness, fiber length, uniformity, fitness, strength and elasticity and Verticillium wilt plants percent were measured. Results showed morphological traits and 30 boll weight and seed cotton yield in second tear more than first year and earliness in second year was more than first year. Also, studied new genotypes and cultivars determined 30 boll weight and seed cotton yield and fiber quality traits and Verticillium wilt tolerance were different. Golestan new commercial cultivar had the highest seed cotton yield and Sahel old cultivar had the highest boll weight and fiber length, strength and elasticity.

Cotton is one of the world’s most important industrial products, grown for fiber and oilseeds. The evaluation of agronomic traits, especially early maturity and yield in cotton, is valuable and can be used to select better varieties. The purpose of this research is to obtain early and high-yielding varieties in Ardebil province.

In this study, 35 cotton cultivars and genotypes were evaluated for early maturity and yield in two consecutive years (2018-2019) in a three replicate randomized complete block design at the Moghan Agricultural Research Station.

The results showed that percentage of earliness and seed cotton traits were significantly affected by plots and varieties over two years. Among the varieties, the highest seed cotton of the first crop seed cotton and total seed cotton was 3454 kg/ha and 5431 kg/ha observed in the variety Shayan, while the highest second crop seed cotton and the earliness percentage were 2323 kg/ha and 74%. in the avant-garde variety. Based on the cluster analysis according to the Ward method, cotton varieties were divided into three different clusters. In cluster 1 were the varieties K8801, Sahel, Bakhtegan, Khorshid, Mehr, K8802, BC244, SKSH249, Avangard, Opal, N2G80, SKT133, Khordad, Sajedi, GKTB113, Latif, NSKB23, NSK847 and Varamin, in cluster 2 were Sk- G (A-4), Shirpan 603, O10, Tabladila, Belizovar, Shirpan 533, Tashkent, Olatn and 4-s4 varieties, and in Cluster 3 were Nazili, No. 228, No. 200, B557, Armaghan, Golestan and Shayan varieties. Cluster 2 cultivars were the best in terms of earliness and cluster 1 cultivars were the best in terms of first-pick seed-cotton, second-pick seed-cotton and total seed-cotton. Third cluster cultivars excelled in seedcotton.

Evaluation of the results showed a wide range of variability in terms of early maturity and seedcotton in the studied cultivars. Among the cultivars studied, Avangarde genotype was better in terms of early maturity, Shayan cultivar in terms of first harvesting and total seedcotton. Therefore, Avangarde genotype and Shayan cultivar can be recommended for Moghan region.

Due to the scarcity of fresh water resources, one of the main solutions to supply agricultural water resources is the use of unconventional water, including agricultural water drainage, saline water resources and effluents. In Khuzestan province, a total of about four billion cubic meters of drainage water is produced annually. The volume of water in the Karun Basin alone is about two billion cubic meters per year. One of the areas where sugarcane drainage has accumulated and is now a serious concern is the 35,000-hectare sugarcane wetland, located south of Ahwaz on the border with Iraq. Drainage production due to various activities, especially agriculture in Khuzestan province, is one of the serious problems. Sugarcane production and fish farming are the main producers of drainage in southwestern Khuzestan. In order to optimal use of sugarcane drainage, the effect of these waters on the quantitative and qualitative properties of cotton in the Cultivation and Sugarcane Industry of Mirza Kuchak Khan during 2018 and 2019 was investigated.

Experimental cultivation was performed in 8 lines of 30 meters with intervals of 60 x 20 cm. The field soil had a silty to loamy clay texture.. The experimental design was split-split plots with 3 replications. Three planting dates: February 28, March 29 and April 29 as the main plot, three irrigation treatments including sugarcane drainage, Karun river water, and intermittent irrigation with Karun water and drainage (combined) as a sub plot and three cotton cultivars included Golestan, Khorshid and Shayan were considered as sub-plots. The first planting date was 28th February, after plowing, disc and fertilizing. Thus, fuzzy seeds were disinfected using carboxin tiram fungicide and Gachu insecticide and then planted at appropriate depth according to field soil conditions. Irrigation planning was done based on measuring the percentage of soil moisture before irrigation and the depth of root development. Thus, in each irrigation regim, one day before the irrigation operation by measuring soil moisture to a depth of 100 cm, soil moisture deficiency is determined according to the depth of plant development by considering the maximum amount of management allowed deficit (MAD) equal to 60% of soil water holding capacity. In order to measure the yield components, five plants in each treatment were identified and measured on these plants. Cotton was harvested three times. Data were analyzed using MSTATC software and Duncan test. Finally, the best treatments were identified and introduced in terms of planting date, type of irrigation and cultivars that have better yields.

The results showed that the highest yield with 1712 kg/ ha was related to the planting date of 28 Feb. Yield of the first planting date was 42% and 574% higher than the planting dates of 29 March (1204 kg/ha) and 29 April (254 kg/ha), respectively. The total yield of cotton on the date of 29 March was 374% higher than the date of 29 April. The highest percentage of early maturity was related to the first planting date, which was not significantly different from the second and third planting date. There was no significant difference in different dates in terms of early maturity. In terms of mean boll weight, the first planting date had a higher boll weight of 11.5 and 87.6% than the second and third planting dates, but the difference between the date of the first and second crops was not significant in terms of boll weight, but The difference between these two planting dates and the third planting date was statistically significant on boll weight. The number of bolls per plant on the date of the first crop was 35 and 147% higher than the date of the second and third planting date, respectively, while the date of the second planting date had 83% more bolls than the date of the third planting date. There was no significant difference between treatments in terms of lint percentage but the second planting date had a higher lint percentage. Among irrigation water quality treatments, the yield of irrigation treatment with Karun water and intermittent irrigation with Karun water and drainage (combined) were not significantly different. Karun water irrigation had 12% higher yield than drainage irrigation, while the yield of irrigation with Karun water was only 6% higher than combined irrigation, this difference was not statistically significant. Among cotton cultivars, the highest yield with 1159 kg /ha was related to Golestan cultivar, which was 16.8% higher than Shayan cultivar. Shayan cultivar is one of the cultivars in which high temperature caused the flowers to dry out. The reason for the decrease in yield of Khorshid and Shayan cultivars was more withering and falling flowers at higher temperatures than Golestan cultivar. Golestan cultivar was more tolerant to salinity and heat stress than the other two cultivars. For this reason, it had more yield than Khorshid and Shayan cultivars and it seems to be a suitable cultivar for Khozestan. The effect of irrigation water quality treatments on fiber quality properties was not significant so that the highest strength with 26.84 was related to the date of the first planting (Feb.28), which did not differ significantly from the date of the second planting (March 29).. The effect of planting date on fiber strength at the level of 1% was significant. There was a significant difference between cotton cultivars in terms of strength and micronair at the 5% level. Shayan cultivar had the highest strength compared to the other two cultivars. The fiber strength of Golestan and Khorshid cultivars was statistically the same. Among cotton cultivars, Shayan and Golestan cultivars were significantly different from Khorshid cultivar at 5% level and had the lowest micronair. According to the results of this study, the first planting date on Feb 28 and intermittent irrigation with Karun water and drainage (combined) and Golestan cultivar is recommended for Khuzestan region.

Although most cotton production costs are spent on manual harvesting of the product, moving toward the mechanization harvesting of production and development of cotton cultivation .In order to evaluate the effects of planting pattern and row spacing on quantity and quality of cotton harvesting, this experiment was carried out split- plot using RCBD with Four replications in Karkandeh Cotton Research Station Kordkooy, during 2014-2015. Main-plots were cluster varieties of cotton (T3, Kashmar and Sajedi) and sub-plots included four planting patterns (single row 20×0.96, twin row 10×0.96, 20×0.96, 30×0.96 cm). The composite analysis results showed that planting pattern of twin row was significant on yield, earliness percentage, performance of cotton harvesting machine and post harvest. Also Mean comparisons revealed that the 10 and 20 cm row spacing in the 96 cm row at center had the highest yield and earliness percentage and harvest efficiency in compared with other planting patterns. Also, the result of correlation coefficient of traits showed a significant relationship between machine yield and height of first sympodial from ground branch germination, number of bolls, post harvest losses and seed cotton yield. Finally, the plant density and row spacing should be changed in such a way that the cotton yield is not significantly affects.

Mepiquat chloride (PIX) is an important management tool to reduce stress damage in cotton plants during germination. In this study, the effects of different drought levels and the amount of mepiquat chloride (PIX) were investigated on growth indices and antioxidant enzymes as well as the malondialdehyde and hydrogen peroxide contents of seedlings in two cotton cultivars under laboratory conditions. The study was laid in a completely randomized design using 0, 5, and 10 g/l Pix and also under different drought levels using 0, -4, and -8 bar polyethylene glycol 6000 in petri dishes on two cultivars of cotton plant, namely Sahel (drought sensitive) and Shayan (drought resistant). Germination indices as well as physiological parameters of seedlings were measured under drought and Pix treatment after 4 days. Results showed that the use of Pix increased the germination percentage, root length, dry and fresh weights of seedlings, and the activity of peroxidase and catalase enzymes of cotton cultivars under drought stress while drought stress alone reduced these parameters. Drought also increased oxidative indices such as malondialdehyde and hydrogen peroxide in seedlings of Sahel and Shayan cultivars while Pix application reduced these indices. In general, the results of this study showed that the use of Pix improved growth responses and antioxidant system of the two cotton cultivars and the response of cultivar Shayan was better than Sahel.