مجله پژوهش های پنبه ایران
سال هشتم شماره 2 (پیاپی 16، پاییز و زمستان 1399)

Abstract Deterioration of seeds is one of the important factors in reducing seeds vigor and limit germination. In order to investigate the effect of gibberellic acid hormone on recovery of seeds, and seedling growth in Varamin cotton seed. The experiment was done randomly three times. The experimental sets consisted of two decline levels (48 and 96 hours) with witness and 2 dense levels of gibberellic acid hormone (500 and 1000 PPM) with witness, and the treatment of gibberellic acid hormone was completed in 3 styles (before deterioration, after deterioration and before and after the deterioration. The results showed that the combination of treatments at 500 PPM without deterioration indicated that plumule length, root length, dry root weight, the amount of seed reserves, efficient use of reservoir seed, seed fraction of the resources consumedhad the best treatment. In the prime applying experiment before deterioration, in 500 PPM density with rate and uniformity of germination, D10, D90, plumlule length, root length, dry root weight, dry plumule weight, usage amount of reserves, effective use of resources, consumption and seed fraction, had the bestresult; and at 1000 PPM level the percentage of germination, demonstrated the highest improvement. Finally, in general we can say that gibberellic acid can recover deteriorated seeds.

 Seed rot, seedling diseases and trips are the most important causes of cotton losses. Seeds of cotton cultivar of Varamin were dressing with fungicides sulfur, Carboxin-Thiram and micronized sulfur and insecticides imidacloprid and thidiocarpwith range of 5 gram of insecticide and fungicide for 1000 gram of seeds alone or both application .Seeds were planted in sterilized sand and irrigated with sterile water.The diseased seedling and decayed seed were removed from soil, washed with sterile water and surface sterilized with 0.5% sodium hypochlorite, and cultured on PDA media amended with antibiotics. Fungal isolates were identified based on morphological features.The results showed that the best fungicides and insecticides for seed disinfection are micronized sulfur, micronized sulfur with imidacloprid, sulfur, sulfur with thidiocarp, Carboxin-Thiram with thidiocarp, Carboxin-Thiram with imidacloprid, sulfur with thidiocarp,and sulfur with imidacloprid respectively. Fungal isolates belonging to Alternaria sp., Aspergillus sp., Basipetospora sp., Bipolaris sp., Cephalosporium sp., Cheatomium sp., Cladosporium sp., Fusarium spp., Geotrichum sp., Melanospora sp., Monascus sp., Myrothecium sp., Mucor sp., Penicillium spp., Rhizoctonia sp., Rhizopus sp.,Sclerotium sp., Ulocladium sp. were isolated with varying frequencies of embryo and seed coat ,decayed seeds and diseased seedlings

Cotton is the most important fiber crop in Iran and as well as the world. The acreage of cotton is about 80,000 ha in Iran. The present study aims to determine the parameters of the SSM-iCrop2 model and evaluate the ability of the model to simulate cotton growth and yield in different regions and environmental conditions of Iran. Different aspects of crop growth are organized as sub-programs including phenological development, leaf area changes and dry matter production and distribution. Soil water balance sub-program is entered in the model to simulate changes in soil water and determination of stress severity. Simulation by the model is done on a daily basis and requires data related to atmosphere, soil and crop management. The model was tested for Iran conditions. To estimate the coefficients and evaluation of the model, data obtained from experiments conducted in various areas of the country were used. The model was evaluated using independent data following estimation of genetic parameters. The results indicated acceptable efficiency of the model in prediction of daily simulation including days to maturity (RMSE=8.4 day, CV=6.5 %) and seed cotton yield (RMSE=56.6 g/m2 and CV=13.9 %) for parameterization and seed cotton yield (RMSE=50.4 g/m2, CV=12.8 %) for evaluation. Also, the results showed that RMSE and CV values for simulation of yield, Evapotranspiration, and used water were respectively (77.6, 12.9%), (150.3 and 16%) and (178.5 and 19.6%) in major cotton production areas of Iran. These results indicate that estimates for variables are acceptable.

In order to investigate the effect of different methods, levels and salinity of irrigation water ‎on cotton, a two-year experiment was carried out‏ ‏at the Hashemabad Cotton Research Station ‎in Gorgan city.‎‏ ‏The experiment was performed in a randomized complete block design with ‎three replications. So, four salinity levels of irrigation water (1, 4, 8, 12 dS/m) as main factors, ‎four different levels of irrigation water‏ ‏‎(33, 66, 100 and 133% of water requirements) was ‎considered as the first factor and two irrigation methods (complete irrigation and Partial Root ‎Dry irrigation/PRD) were considered as the second factor. The results showed that compared ‎to control, cotton yield decreased by 41%, 22% and 19%, in 12, 8 and 4 dS/m salinity, ‎respectively. The water use efficiency was reduced at rate of 30, 18 and 16 percent. As the ‎salinity of irrigation water increased, the average weight of the boll, fiber index, earliness and ‎the fibers decreased significantly. As the moisture level increased, the yield of cotton, average ‎boll weight, the number of seed in a boll and the number of bolls increased significantly. In ‎additional the water use efficiency of the 133, 100 and 66% treatments compared to 33 ‎percent decreased by 32, 16 and 10 percent,‎‏ ‏respectively. The cotton yield under133, 100 and ‎‎66% treatments decreased by 32%, 16% and 10%, respectively, compared to the 33% of the ‎water requirement. Although PRD reduced crop yields by 15 percent compared to full ‎irrigation treatment, but the water use efficiency increased by 36%.‎‎‎‎‎‎

One of the reducing methods of salt stress damage effects is useing substances that increase seed germination and plantlet establishment in salt stress conditions. In this research potassium and glycine effects were evaluated by randomized complete block design with four replications at Agriculture and Natural Resource Research Stations of Kashmar and Feizabad in none salt and salt conditions during 2015 and 2016. Treatments were such as: 1-Control (spray with water) 2- Folar application (FA) of potassium 1% at 50 percent of flowering and boll set stages (50% of F&B) 3-(FA) of glycine (100Mm) at (50% of F&B) 4- Seed priming with glycine 1% (SPG) 5- (FA) of potassium 1% and glycine 100Mm 6-(SPG) and (FA) of potassium 1% 7- (SPG) and (FA) of glycine and 8- (SPG)+ (FA) of potassium and glycine. Results showed Seed priming and foliar application of potassium and glycine significantly increased number of plant per area unit at salt stress conditions. Results also showed experimental treatments increased leaf relative water content and significantly reduced shedding of flower and boll per plant in comparison with control. Consequently, boll number per plant and seed cotton yield were significantly increased following foliar application of potassium and glycine. Therefore, seed priming with glycine and foliar application of glycine and potassium at 100 mM and 1% respectively increase plant growth and seed cotton yield under salt stress conditions.

In order to determination Value of Cultivation and Use (VCU) of Cotton new foreign cultivars in Fars province (Darab), seed cotton yield and its components, earliness and fiber quality were evaluated. Cotton six new foreign cultivars included Carisma, Lydia, PG2018, BA440, Flash and Edesa and studied traits were seed cotton yield, boll number of each plant, boll weight, earliness, lint percent, fiber length, fitness, elasticity, strength, uniformity, yellowness and brightness. Results showed studied traits affected by environment conditions during trial conduction years. New foreign cultivars Carisma in first year and Lydia in second years had the highest seed cotton yield and lint percent respectively. PG2018 were the earliest cultivar. Golestan control cultivar had the most fiber length and fittest fiber and Lydia new foreign cultivar had the highest fiber strength, uniformity and brightness. Based on trial results new foreign cultivars, Carisma, Lydia and PG2018 are recommendable for cultivation in Fars province. Cotton six new foreign cultivars included Carisma, Lydia, PG2018, BA440, Flash and Edesa and studied traits were seed cotton yield, boll number of each plant, boll weight, earliness, lint percent, fiber length, fitness, elasticity, strength, uniformity, yellowness and brightness. Results showed studied traits affected by environment conditions during trial conduction years. New foreign cultivars Carisma in first year and Lydia in second years had the highest seed cotton yield and lint percent respectively.