مجله پژوهش های پنبه ایران
سال دهم شماره 1 (پیاپی 19، بهار و تابستان 1401)

The salinization of soils and the optimal use of this vast area, the search for a suitable solution for the cultivation of a suitable crop is a priority of research. The cotton plant is semi-tolerant to salinity, but depending on the extent of species diversity, the yield alone cannot provide a reasonable indication of stress tolerance. Therefore, the study of biochemical and physiological characteristics of different species should provide comprehensive information on the cultivation and distribution of different species at different salinity levels.

The objective of this study was to evaluate the potential of different cotton species at different salinity levels. 8 species of Delinting cotton seeds, including G. herbaceum, G. arboretum, G. hirsutum, and G. barbadense, were grown in three replicates in large nylon pots using a randomized complete block design with three non-salinity levels (less than 4 dSm-1), medium salinity (8-9 dSm-1), and high salinity (12-13 dSm-1).

The results showed that at high salinity, non-phenolic compounds and phenolic content were highest and lowest, respectively, in the seed coat of Dr. Omumi and Golestan cultivars. At high salinity, the phenolic content of the seeds was highest in the Golestan cultivar. The lowest amount of tannin in the seed of Sepid cultivar was at salinity of 8 to 9 dSm-1, which decreased by 3.9%, 8.7% and 5.6%, respectively, compared to Dr. Omumi, Barbadens and Kerman indigenous cultivars at this salinity. Arbariums had the highest and lowest glycine-betaine concentrations at 8 to 9 dSm-1 and Mehriz at 12 to 13 dSm-1, respectively. At moderate salinity, protein concentration was highest in seeds of Mehriz variety. The protein concentration in the seeds of Golestan variety at both salinity levels and Dr. Omumi variety in non-saline environment increased significantly compared to the other varieties. At high salinity, the leaves of the Golestan cultivar had the lowest wax concentration among all cultivars, while at medium salinity the greatest wax accumulation was observed in the seed coat of the Golestan cultivar. The Golestan variety showed the highest proline concentration in the leaf at high salinity. The highest and the lowest proline content in the root were observed in Termez 14 at high salinity and in Dr. Omumi at medium salinity. At 8-9 dSm-1 salinity, Mehriz and Barbadens cultivars had the highest seed and fiber weight, respectively, while the lowest seed and fiber weight was recorded in Arbarium cultivar.

At 12-13 dSm-1, the cultivars Arbarium and Bomi-kerman had no bolls. It appears that the Golestan cultivar is the most tolerant to salt stress compared to other cultivars because it contains more proline, tannin, phenol, and wax. The varieties Bomi-kerman and Sepid, which stop flowering at high salinity, are also sensitive to 12-13dSm.-1

Background and Goal: 

The planting date is an important factor affecting vegetative and reproductive characteristics, the length of the growing season, and ultimately the quantity and quality of cottonseed. When the planting date is delayed, the flowering period coincides with high temperatures, increasing the number of bolls dropped and decreasing the number of bolls per plant. Since the new cotton varieties (Armaghan, Shayan, Khorshid, Khordad and Sajdi) are usually early maturing and use less water, they are accepted by farmers. However, in some cases they are planted too late. Since the proper planting date for these varieties has not been determined, this project was undertaken to determine the optimal planting date for new cotton varieties.

Five varieties named Armaghan, Shayan, Khorshid, Khordad, and Sajedi (as subplots) were planted on three planting dates: May 10, May 31, and June 20 (as main plots) with four rows on each plot. This experiment was conducted using a split-plot experiment based on a randomized complete block design with three replications at the Neyshabur Agriculture and Natural Resources Research Station in 2019 and 2020. Irrigation was done using a tape (negative pressure irrigation system) with a drip spacing of 20 centimeters and a flow rate of 4 liters per hour. Five plants were randomly selected. The parameters measured were: Number of vegetative and reproductive branches per plant, plant height, number of immature and mature bolls per plant, weight of bolls, cotton seed yield. Analysis of variance and comparison of the mean values of the traits were performed using MSTATC and Excel and least significant difference (LSD).

The results showed that the maximum number of closed bolls and the lowest number of vegetative and reproductive branches, number of open bolls and cotton seed yield belonged to the last planting date. On average, delaying the planting date reduced the cotton seed yield by 50.3%. The yield of cottonseed decreased by as much as 85.4% on June 20. The lowest and the highest yield of cottonseed were obtained in Armaghan variety on the last planting date and in Sajedi variety on the first planting date. The highest yield (3971.7 kg/ha) was obtained in Sajedi on the first planting date. Also, the lowest yield in Sedd cotton, which decreased due to late sowing, was obtained from Sajedi variety.

the results of the present study show that in Neyshabur area the planting of the mentioned varieties should be done by June 10, and further delay in sowing leads to a sharp decrease in yield (in some years due to the damage caused by the early autumn cold). However, the studied cultivars responded differently in this regard, and cultivars such as Sajdi and Khorshid, which had the highest yields overall in two years, showed the least decline compared to Armaghan, Shayan and Khordad cultivars.

Saline conditions and especially saline water can interfere with the uptake of ions by plants and lead to a decrease in crop yields. On the other hand, the application of potassium sulfate under these conditions reduces the negative effects of salt stress and leads to an increase in crop yield. Therefore, this study was conducted to investigate the effects of saline water irrigation on ionic ratios and yield of cotton in a two-year trial at Rudasht Salinity Research Station, Isfahan.

This experiment was conducted as a factorial split-plot design with four replications in a randomized block design. In this experiment, main plots include irrigation treatments of 4 (control), 8 and 12 ds.m-1 and sub-plots include factorial combination of three genotypes (mutant genotype LM 1673, LM 1303 and Shayan) with foliar sprays of potassium sulfate at three rates of 2, 4 and 6 kg per 1000 liters of water per hectare with control treatment.

The results showed that the effect of salinity treatments and cultivar and the interaction effect of year*salinity*number of spray solutions were significant on the amount of calcium in stems and leaves, chlorine in stems and leaves, potassium in stems and leaves, sodium in stems and leaves, and yield. The effect of potassium sulfate foliar spraying on calcium in stem, chlorine in leaf, potassium in stem and leaf, sodium in stem and leaf, and yield was also significant. In the two experimental years, increasing the salinity of the irrigation water resulted in an increase in the content of elements such as calcium, sodium and chlorine in the stems and leaves, but a decrease in the content of potassium. The results showed that in the first year of the experiment, the highest calcium content in the stem occurred with 4.1 mg.g-1 when treated with an irrigation salinity of 12 ds.m-1 in the genotype LM 1303 and a foliar spray of 6 kg.ha-1 potassium sulfate. In the second year, the amount of calcium in stem and leaf tissue of cotton was obtained in irrigation treatment with water with salinity 12 ds.m-1 and variety LM 1303 in foliar treatment with 4 kg.ha-1 potassium sulfate (3.16 mg.g-1) and foliar application of 6 kg.ha-1 potassium sulfate (4.33 mg.kg-1), respectively. In the first year of the experiment, the highest chlorine content in the stem was 23.4 mg.g-1 under irrigation conditions with saline water of 12 ds.m-1 and in the cultivar LM 1303 with foliar spray of 4 kg.ha-1 potassium sulfate. In the second year, the chlorine content of the cotton stem and leaves was measured when irrigated with water with a salinity of 12 ds.m-1 and the variety LM 1303 when foliar treated with 4 kg/ha of potassium sulfate (3.23 mg.g-1) and the solution spraying of 6 kg.ha-1 of potassium sulfate (5.92 mg.kg-1), respectively. In both years, potassium content in stems and leaves decreased with the increase in salinity of irrigation water, while foliar application of potassium sulfate led to its decrease. In the first and second year, the highest cotton yield of 3918 and 3696 kg ha-1, respectively, was obtained with genotype LM 1303 at salinity of 4 ds.m-1. Foliar application of potassium sulfate also increased the yield of sorghum, so that the highest yield of 3016 kg.ha-1 was obtained with application of 6 kg.ha-1 potassium sulfate.

The results show that the yield of genotype LM 1303 increased under saline and non-saline conditions by foliar application of potassium sulfate. Therefore, it can be said that the variety LM 1303 and foliar application of potassium sulfate can be used to improve ionic ratios in cotton and obtain the highest cotton yield under saline conditions in the region.

Heterosis, i.e. hybrid vigor, is a commonly observed biological phenomenon used in crop production. The use of heterosis has greatly improved the productivity of cotton worldwide. Knowing the degree of heterosis, either relative to the parent (mean parent or better) or to the commercial control parent, is important in assessing whether hybrids outperform existing varieties. This information can influence the decision to invest in hybrid development. This research was conducted to estimate the effects of genes, heritability, and heterosis to determine the appropriate breeding methods to improve fiber quality and performance parameters and to determine the most efficient method of heterotic grouping for line classification.  In this study, seven maternal genotypes and three paternal genotypes of cotton from different heterotypic groups were crossed in the 2020 crop year in a North Carolina design (II). Three sets of hybrids produced along with their parents were grown in a baseline design of randomized complete blocks with four replicates at the National Cotton Research Institute's Hashemabad Research Station experimental field.  Analysis of the variance of the qualitative and quantitative parameters of the fibers showed that the effect of females, the effect of males, and the interaction between males and females were significant for all parameters except uniformity. The study of genetic parameters showed that the qualitative traits were affected by the additive and non-additive effects of genes. The proportion of non-additive effects in the genetic control of uniformity was higher than the additive effects, while for micronaire strength and 25% fiber length, the proportion of additive effects was higher. The high values of the narrow heritability estimates indicate that the occurrence of qualitative parameters is more influenced by genetic effects. Given the presence of additive effects and low estimates of narrow heritability for the trait kail proportion, it is promising to use breeding programs based on crosses to improve this trait. For other qualitative parameters, estimates of narrow heritability were high. Therefore, the use of breeding programs based on selection to improve these traits is promising. Examination of relative heterosis based on average parents showed that the range of heterosis was from -2.73 to 7.87%1, from 4.52 to 22.23%, from -0.05 to 4.32%, and from 1.25 to 55. For each of the micronaire, strength, elongation, and fiber quality index attributes, the heterosis was 6%.  These results show that since both additive and non-additive effects are involved in controlling fiber quality, it is possible to increase the possibility of collecting suitable additive genes and exploiting variance by choosing an appropriate breeding method such as periodic selection. It provided dominance. These results provide a basis for accelerating the development of hybrids with high fiber quality in cotton.

Cotton seedlings are attacked by several sucking pests such as cotton thrips (Thrips tabaci Lindeman), cotton aphid (Aphis gossypii Glover), green leafhopper (Empoasca sp.), and cotton whitefly (Bemisia tabaci Gennadius), which cause significant damage if not adequately controlled. Climatic factors such as temperature and relative humidity are among the most important external factors regulating insect populations. Since pests can cause severe damage to cotton fields in the early stages of cotton cultivation, the present study investigated pest population fluctuations and their relationship with weather factors. The results may be useful for integrated management of cotton pests.

This project was conducted in 2020 and 2021 at Darab Agricultural Research Station. The experimental field was divided into five replicates. From each replicate, 5 seedlings were randomly taken. The sampling unit was the number of pests on a cotton seedling. Sampling was done weekly. The meteorological data recorded on a daily basis was obtained from the Darab Meteorological Station, which is located 200 meters away from the project site. Using the correlation analysis, linear and non-linear regression, the relationship between the population of each pest and meteorological variables was investigated.

In the first year, with the germination of cotton seedlings, thrips infection also started (0.41 thrips per seedling) and then the thrips population density increased more than six times until the middle of June (2.74 thrips per seedling). When the weekly average maximum daily temperature exceeded 42 degrees Celsius, thrips population decreased. The results of the correlation analysis between the weekly average maximum daily temperature and the weekly average density of thrips showed that this correlation is negative and significant (P = 0.008; R = -0.68). By combining the data of both years of the experiment, the results of linear regression analysis showed that there is a significant relationship between the weekly average of whitefly density and the weekly average of daily relative humidity. The results of the present research showed that the most important weather factor influencing the cotton aphid population is the air temperature, so that when the air temperature is higher than 30 degrees Celsius, the activity of the aphid decreases drastically.

The results of this research showed that cotton seedling is faced with a wide range of pests, and weather factors, especially temperature and relative humidity, are effective on the onset of pest infestation at the initial growing stage of cotton, as well as on the density and fluctuations of the cotton pest population. Therefore, the results of this study can play an important role in the planning and application of integrated pest management programs for the cotton pests at the initial growing stage.

Cotton is one of the most important agricultural products in the world, which has caused diseases and pests due to continuous cultivation and geographical and climatic conditions. Control of cotton pests with ground spraying equipment results in physical plant damage, lower crop yields and quality, water loss, and pesticide use. The use of drone spraying is one of the new methods of precision agriculture that plays a role in sustainable agricultural production and reduces the use of pesticides that damage soil and plants. The aim of this study is to investigate the efficiency of UAV sprayers in cotton cultivation and compare these sprayers with other general cotton sprayers.
 

In this study, a drone sprayer was compared with two sprayers commonly used in cotton production (tractor mounted sprayer and lance mounted sprayer). This project was based on a split-plot design in a completely randomized design with three replications. The main treatments of the experiment included the type of sprayer at three levels (tractor mounted sprayer, sprayer with lance and UAV sprayer) and the sub-treatments included the plant position at three levels (top, middle and bottom of the plant). The image processing method was used to evaluate the quality of spraying, including the numerical median diameter (NMD), volumetric median diameter (VMD), spray quality, and percentage of surface coverage using a water sensitive card (WSC). The WSCs were placed at three plant locations at the bottom, middle, and top of the cotton plant on the boll branches. Immediately after spraying, WSC were collected from the field and scanned separately with a scanner for use in ImageJ® image processing software.
 

The highest number of droplets under the influence of sprayer type was observed in the lance sprayer with about 1361 droplets in all levels of the cotton plant, which was not significantly different from the boom sprayer (1000 droplets). Depending on the type of sprayer, the lance sprayer and the high pressure sprayer were expected to have the highest number of drops. The UAV sprayer had the lowest number of drops with 317 drops. There is no significant difference between the three different top, middle and bottom positions of the crop in terms of NMD in the drone sprayer and the boom mounted tractor sprayer. In the tractor mounted sprayer, the top plant position has the largest NMD, which is significantly different from the middle and bottom plant positions. Also, the evaluation of the three sprayers in each of the three plant positions showed that there is a significant difference between the tractor-mounted boom sprayer and the lance sprayer in the upper plant position, while there is no significant difference between them and the UAV sprayer. There is also no significant difference between the three sprayers in the middle and lower position of the plant in NMD. According to the results, in the different treatments, 50% of the droplet sizes have a diameter less than 200 μm. According to the index for spray quality, the sprayer with lance with a value of 3.62 is the one with the lowest spray quality. According to this index, the best spray quality is the tractor mounted sprayer with a value of 2.43. In terms of spray quality index, the drone sprayer and the lance sprayer as well as the tractor mounted sprayer and the lance sprayer are not in the same group. In addition, the tractor mounted sprayer had the best uniformity of VMD. In this study, the best NMD was obtained with the drone sprayer. The highest percentage of spray coverage was recorded with the lance sprayer at a rate of 5.5% at the top of the plant position. The lowest percentage of spray coverage at the top of the plant was measured with the drone sprayer at a rate of about 2.94%. The effective field capacity and field efficiencies of the three sprayer types showed that the highest field efficiency occurred with the drone sprayer at 78.95%, which was 1.38 and 2.31 times that of the tractor-mounted boom sprayer and lance sprayer, respectively.

The drone sprayer had the best spraying performance, and when the farm is large, the drone sprayer was the fastest spraying machine. The tractor mounted sprayer is the best option when there is no pest outbreak or force majeure.
At the pest outbreak or the impossibility of tractor movement in the field due to rain or irrigation, the best and fastest method is drone sprayer. At the same situation, and on unavailability of drone sprayer, The only option on the table is lance sprayer, although it has the lowest spraying efficiency. In terms of spraying speed, water saving and pest control; using a drone sprayer was the best option.

Despite the new varieties of cotton that have been improved, introduced and marketed in recent years thanks to the efforts of cotton breeders, increasing the genetic diversity of the country's gene bank and introducing new varieties with higher yield, earlier maturity and better fiber quality. This study was conducted to evaluate the agronomic and quality traits of cotton varieties bred using different breeding methods that have shown their superiority over commercial varieties in one or more traits in Hashem-abad region of Gorgan. This research was conducted to determine the effectiveness of the measured traits of cotton genotypes.

In this study, 5 genotypes 90-10481, 92-34, 92-48, Va-1, and Va-2 were compared along with controls Golestan and Varamin in the form of a randomized complete block design with three replicates in 2018-2019 by using the combined analysis method and principal components analysis with GTBiplot graphical analysis and selecting the best genotypes.

Based on the results of combined analysis of height traits, number of sympodial branches, number of bolls, percentage of earliness, yield (30 bolls, first picking, second picking) and total yield, fiber yield (30 bolls), of seed weight (30 bolls and first picking), fiber length, uniformity, fiber fineness, firmness, fiber elasticity, total percent lint, and percent lint of 30 bolls were significant at the 1% statistical level when genotypes were examined. According to the obtained results, four components had a higher root than two (5.88, 5.27, 3.12 and 2.05). The first four components explained 90.65% of the total changes between the data. In the first component with a value of 32.65, early maturity and weight of 30 bolls traits, in the second component number of bolls and total yield, in the third component fiber length and strength traits, and in the fourth component fiber elongation and fineness traits and percent lint explained the changes. The greatest variation shown by the biplot diagram in genotypes Va-1 and VA -2 in traits related to yield included total yield, number of bolls, yield at first picking, yield at first picking, and earliness. VA -genotypes Va-1 and VA -2 are positively correlated with each other and negatively correlated with genotypes 92-48, 90-10481 and 92-34 and Golestan cultivars. VA -1 genotype has a zero correlation with the varamine variety, since they have an angle of about 90 degrees. Therefore, VA -1 genotype and Varamin variety have different genetic background that causes their differences.

The results show that the Va-1 and Va-2 genotypes are capable of introducing new varieties and can also be used in breeding programs to create greater genetic diversity. In addition to their high yield, they were earlier than the other genotypes studied. Genotype Va-1 proved to be an early maturing genotype with high uniformity of fiber and high yield at the first harvest. Genotype Va-1 had the highest yield among the studied genotypes with a high number of bolls and sympodial branches. These traits can be taken into account in breeding programs to improve commercial varieties and to produce new varieties.

Crops with high WUE and appropriate irrigation methods are critical for irrigation water management. Because of the indeterminate growth habit of the crop, this issue is particularly important in cotton production. Under high irrigation conditions, the balance between vegetative and reproductive growth may be upset. There are many reports showing the superiority of belt irrigation methods over conventional methods such as furrow irrigation. Considering the limited water resources in Iran, this experiment was conducted to study the response of cotton cultivars to irrigation rates and methods.

In this experiment, foreign and domestic commercial cotton varieties were compared in terms of yield and water use efficiency (WUE), in the form of split blocks on CRBD with 3 replications in 2022-2023 cropping seasons. Irrigation after 30% and 100% water evaporation from the pan in the main blocks. 13 cotton varieties were established in sub-blocks (plots) as sub-factors. Cultivars included of Golestan, Latif, Sepid, B557, Khordad, Partow, Taban Mai, Maxa, Lider, Loduz and American Genetics.

the effects of treatments on all traits studied were significant. The interaction between irrigation and cultivar on the traits was significant, except for the number of sympodial branches and fiber content. In the first year, the yield of Golestan and Partov cultivars was higher than the others when irrigated after evaporation of 30% of the husk water. Golestan, B557 and Khordad had higher yield when irrigated after 100% evaporation, which was due to their ability to form and retain more bolls per plant. Sepid and Lodouz varieties had the lowest yield in the first year. In the second year, Golestn and Khordad were superior to the other cultivars when irrigated after 30% pod evaporation. When irrigated at 100% evaporation from the pan, Golestan, Mai, and Taban had higher yield. The lowest yield this year was obtained by Leeder and Loduz varieties when irrigated after 30% evaporation from the pan. The most likely reason for these yield losses was the loss of balance between vegetativeand reproductive growth, which resulted in completely excessive growth, especially in the Loduz variety. This higher vegetative growth resulted in a reduction of the WUE value.

the local cultivars Golestan, Khordad and Partow and the Turkish cultivar Mai showed higher yields under belt irrigation. Due to the high vegetative growth potential in Leeder and Golestan, irrigation management of these varieties is more important than that of the others.