Seed Cotton Yield Research Articles

SCREENING OF COTTON (GOSSYPIUM HIRSUTUM L.) GERMPLASM AGAINST COTTON LEAF CURL VIRUS (CLCUV)

Cotton Leaf Curl Virus (CLCuV) is a devastating disease affecting cotton production worldwide, particularly in South Asia and Africa transmitted by the whitefly (Bemisia tabaci). CLCuV infection leads to severe symptoms, including leaf curling, vein thickening, stunted growth, and significant yield losses. Developing resistant cotton varieties is the most suitable strategy for managing CLCuV, given the limitations and environmental concerns associated with chemical controls. This study aimed to evaluate the resistance and susceptibility of different cotton varieties to CLCuV under natural field conditions and artificially infected condition using a disease severity scale ranging from 0 (highly resistant) to 5 (susceptible). A total of five cotton varieties, were assessed at three critical growth stages: vegetative, flowering, and boll formation. Disease severity, and yield components were recorded to determine extent of resistance of each variety. The results indicated that genotypes and treatments had significant variation in control compared to T1. According to DSI, NIAB-852 was scored as resistant with 10% infected leaves. FH-142 and CIM-496 were scored as tolerant according to DSI with 10-25% infection in leaves. NIAB Karishma and CIM-448 were scored as moderately susceptible with 50-75% infection. All genotypes had significant reduction in number of bolls, boll weight and seed cotton yield in T1 than control. These findings provide valuable insights into the effectiveness of existing cotton germplasm against CLCuV and highlight the need for continuous evaluation and development of resistant varieties. The study highlights the importance of generating resistant cultivars, thereby ensuring sustainable cotton production.

Effects of planting date and density on cotton cultivars in sub‐Saharan Africa rainfed conditions: A case study in Mali

AbstractMali is among Africa's three biggest cotton (Gossypium hirsutum L.)‐producing countries, and cotton growing is the principal driving force behind Mali's agricultural sector. Cotton production is rainfed on small‐scale family farms as a commercial crop alongside staple crops grown for subsistence. Cultivar choice, planting date, and planting density are critical elements for seed cotton yield that should be optimized. This study aimed to understand the interactions between planting dates and planting densities for the optimal production of four cotton cultivars in Mali. Two trials were set up in two seasons at the Finkolo and N'Tarla research stations. A split‐plot design with four replications was used, with planting dates (early and delayed by 3 weeks) as the main plots and planting density (41,666; 83,333; and 166,666 plants/ha) and cultivar (Malian NTA MS334, Togolese STAM 129A, Australian SIOKRA L23, and Brazilian BRS 293) as the subplots. In 2021, seed cotton yield was 1263 kg/ha for early planting versus 361 kg/ha for late planting. Medium and high planting densities produced the same yield level, higher than the low planting density. Regardless of the planting density, early plantings' average capsular weight and seed index were higher than those of late plantings. The African cultivars (STAM 129A and Malian cultivar NTA MS334) were the most productive. Due to significant interactions on fiber percentage and to optimize cotton yields in Mali, planting should be early, with planting densities higher than 41,666 plants/ha, and either of the African cultivars tested should be used.

Phosphorus High-rate application through band placement improved cotton productivity under arid climate

The plant-available soil phosphorus rate and methods for applying phosphatic fertilizer and soil P-fixation capacity are critical factors for lower cotton productivity in Southern Punjab, Pakistan. Hence, a two-year study was conducted in Central Cotton Research Institute (CCRI), Multan, Pakistan, to examine the effects of various P rates and application methods on cotton crop output during the growing seasons of 2014 and 2015. Phosphorus was applied in four rates (0, 40, 80, and 120 kg ha−1 P2O5) using broadcast, band application, and fertigation methods. Results indicated that the impact of P rates was statistically significant on plant height, the number of nodes, monopodial and sympodial branches, leaf area index, harvest index, and seed cotton yield. The greater P application (120 kg P2O5 ha−1) had a better effect on cotton productivity than the lower application rates (0, 40, and 80 kg P2O5 ha−1). The band application responded better on nodes plant−1, sympodial branches plant−1, boll weight, leaf area index, lint yield, and harvest during the growing season 2015. Therefore, by adopting the band application coupled with 120 kg P2O5 ha−1 rather than the conventional method of broadcast, productivity of cotton crops could be increased.

Rational optimization of irrigation regimes for drip-irrigated cotton fields without mulch can alleviate the problem of residual film contamination in arid zones

The serious problem of residual film pollution in the arid region of northwestern China has a severe negative impact on both the farmland environment and the benefits of cotton planting. Drip irrigation without mulch (DIWM) has the potential to serve as an effective alternative to mulch drip irrigation and address the issue of residual film pollution. However, there are few studies on how to formulate a rational irrigation regime under DIWM conditions and achieve water savings and productivity gains. Consequently, from 2020 to 2021, we established three DIWM treatments: W4, W6, and W8. None of the treatments were irrigated at the seedling stage, and the irrigation regime was the same for all the treatments at the squaring stage (2 irrigations at an irrigation quota of 45 mm). From the initial flowering stage, the frequency of irrigation was once every 6 d, 8 d, and 12 d for W4, W6, and W8, respectively, and the corresponding total numbers of watering times were 8, 6, and 4, respectively. The irrigation amount was 69 mm at each time point during the flowering and boll-forming stages in all the treatments, and the final irrigation amount was 52.2 mm in W8. The total irrigation amounts were 366 mm, 504 mm and 625.2 mm for W4, W6 and W8, respectively. This study explored the spatiotemporal characteristics of soil moisture via sensors combined with the spatial grid method. Additionally, the growth indices, biomass accumulation, yield components, and water use efficiency (WUE) of cotton were assessed across various treatments. The results revealed that, in 2020 and 2021, the W8 treatment resulted in the highest soil water content (SWC) in the 70–110 cm soil layer and soil water consumption (WC) in the 10–110 cm layer, with the WC in the 10 cm layer being 20 % and 44 % greater than that in W6, respectively. The excessive total irrigation amount (IA) in the W8 treatment led to high vegetative growth of cotton, diminishing the positive impact on yield. Across both years, the WUE observed in the W6 treatment significantly exceeded that of W8, while the seed cotton yield demonstrated only marginal decreases of 5 % and 0.9 % compared with that of W8. The irrigation amount and average WC in the 10–40 cm soil layer were 19 % and 29 % lower in W6 than in W8, respectively, but the economic benefits were only 2 % lower than those in W8. There was a significant positive correlation between the SWC and WC in all the different soil layers, and the effect of the SWC on the WC gradually decreased with increasing soil depth. Overall, the irrigation regime employed in the W6 treatment within the arid zone, devoid of mulch cover, proves to be an effective water-saving strategy, ensuring a consistent cotton yield and enhancing WUE. This study serves as a reference for developing an efficient irrigation system tailored to the DIWM cotton industry in arid zones, contributing to the promotion of green and sustainable agricultural development in this region.

Optimizing type, date, and dose of compost fertilization of organic cotton under climate change in Mali: A modeling study.

Adapting organic farming to climate change is a major issue. Cotton yields in Mali are declining due to deteriorating climatic conditions, soil fertility, and poor management. This study aimed to improve organic cotton yield in Mali in the future climate with the optimal choice of compost type, date, and dose of application. Experimental data collected in 2021 from the Sotuba research station in Mali was used for calibration and evaluation of the crop model DSSAT CSM-CROPGRO-Cotton model using phenology, leaf area index, and seed cotton yield. Climate data from the RCP4.5 and RCP8.5 scenarios of the GFDL-ESM2M model were used for future weather datasets for 2020-2039, 2040-2059, and 2060-2079. The model was able to simulate anthesis and maturity with excellent results, with nRMSE < 4%, and seed cotton yields moderately well, an nRMSE of 26% during calibration and 20.3% in evaluation. The scenario RCP8.5 from 2060 to 2079 gave the best seed cotton yields. Seed cotton yields with RCP4.5 and RCP8.5 were all better with the mid-May application period of small ruminant silo compost at 7.5 t/ha. In such conditions, more than 75% of the cases would produce more than 2000 kg/ha of seed cotton.

Phosphorus application under continuous wheat-cotton straw retention enhanced cotton root productivity and seedcotton yield by improving the carbohydrate metabolism of root

ContextStraw retention could reduce phosphorus (P) application without decreasing seedcotton yield but related physiological mechanisms were unclear. Cotton root is the first organ to sense the changes in soil environment, and its growth and development, especially carbohydrate metabolism, significantly affected the formation of seedcotton yield. Therefore, it is necessary to explore the responses of cotton root carbohydrate metabolism to straw retention combined with P application. ObjectiveThis study was to investigate the effects of straw retention combined with P application on root carbohydrate metabolism and its relationship with seedcotton yield. MethodsA field experiment (2020–2022) was conducted to evaluate the changes in seedcotton yield, cotton canopy apparent photosynthesis rate (CAP), biomass, root productivity, root carbohydrate contents and related enzyme activities under different straw management [removal (S0), retention (S1)] and P rates (0, 100, 200 kg P2O5 ha−1). ResultsStraw retention and P application both increased seedcotton yield and had a significant interaction effect on it. In the 5th-7th year of straw retention, straw retention reduced 24 %-26 % P application to reach a similar yield of S0 with 100 kg P2O5 ha−1. Analyzing the reasons: (1) Straw retention combined with P application increased cotton CAP, providing adequate assimilates for cotton development; (2) Straw retention combined with P application promoted the utilization of root carbohydrates, thereby increasing root productivity and seedcotton yield. Specifically, compared with S0 without P, S1 combined with P application increased the enzyme activities related to carbohydrate metabolism, especially sucrose synthase (7.6 %-59.4 %) and acid invertase (3.9 %-58.6 %), which reduced sucrose (3.3 %-32.2 %) and starch (4.3 %-28.7 %) contents at the peak boll setting stage. Efficient utilization of sucrose and starch enhanced root productivity, the ratio of root to shoot (R/S) reduced by 2.7 %-21.6 %, while the boll loading of root system (BLR) and boll capacity of root system (BCR) increased by 0.6 %-39.2 % and 3.1 %-50.6 % at the boll opening stage, respectively, favoring the formation of seedcotton yield. Furthermore, when the R/S, BLR, and BCR reached 0.12, 0.81 boll g−1, and 4.33 g g−1, cotton harvested the maximum theoretical yield of 3780, 3774, and 4069 kg ha−1, respectively. ConclusionsStraw retention combined with P application increased root productivity and seedcotton yield by promoting the utilization of root carbohydrates. ImplicationsThis study revealed the internal mechanism for straw retention combined with P application to affect seedcotton yield from the angle of root carbohydrate metabolism and provided a theoretical basis for rationally reducing P fertilizer under straw retention.

Impact of Different Plant Densities and Fertilizer Levels on Yield Attributes, Yield and Fibre Quality Characters of Bt Cotton in HDPS

Adopting a high-density planting system in cotton cultivation has resulted in increased yields compared to traditional methods. Despite the clear benefits, farmers face various challenges throughout the cultivation process, from sowing to harvesting. However, selecting appropriate plant spacings, fertilizer levels and implementing tailored cultivation techniques can significantly enhance productivity. A field experiment was conducted at Siddapur research farm, Regional Agricultural Research Station, Warangal, Telangana, India during kharif 2023 to investigate the “Impact of different plant densities and fertilizer levels on yield attributes, yield and fibre quality characters of cotton in high density planting system (HDPS)”. The experiment was laid out in randomized block design (factorial) and replicated thrice, consisting of 12 treatment combinations comprising of three plant spacings S1: 80 x 20 cm (62,500 plants ha-1), S2: 90 x 15 cm (74,074 plants ha-1), S3: 90 x 60 cm in factor I and four fertilizer levels (F1: 100%RDF, F2: 125%RDF, F3: 100%RDF + Microbial consortia, F4: Control) in factor II. Both the factors significantly influenced the number of bolls per plant, number of bolls m-2 and seed cotton yield per hectare. The results revealed that higher no. of bolls plant-1 were recorded in 90 x 60 cm (18,518 plants ha-1) however, higher no. of bolls m-2, seed cotton yield (2233 kgha-1) obtained from higher plant density (74,074 plants ha-1) with the spacing 90 x 15 cm. Boll weight was not significantly influenced by varied plant spacings and fertilizer levels. Among the different levels of fertilizer, 125%RDF recorded highest no. of bolls per plant, no. of bolls m-2 and seed cotton yield (2362 kgha-1). Fibre quality characters viz., Upper half mean length(mm), micronaire(µginch-1), tenacity(gtex-1) and uniformity index (%) were not significantly influenced by both plant spacings and fertilizer levels as they are primarily governed by genetic makeup of cotton genotypes. For optimum seed cotton yield, cotton should be sown at closer spacing 90 x 15 cm and the application of 125%RDF was economically feasible in high density planting system.

Growth, yield, and fiber quality of cotton plants under drought stress are positively affected by seed priming with potassium nitrate

Growth, productivity, and fiber quality of cotton (Gossypium hirsutum L.), a vital fiber-producing cash crop, are severely affected under drought conditions. Seed priming has a proven role in enhancing crop tolerance to abiotic stress, including drought. The objective of this study was to evaluate the effects of seed priming with KNO3 on cotton productivity and fiber quality under drought stress. A germination experiment was established under laboratory conditions with five treatments of seed priming (non-primed or control treatment, hydropriming, and priming with 2.5, 5.0, and 7.5 g KNO3 L−1). Another experiment under polyhouse conditions based on the same seed priming treatments was conducted under three levels of soil water contents (field capacity [FC] 100%: FC100, 75%: FC75, and 50%: FC50). The results obtained showed that there was a clear reduction in the different parameters tested at FC50 in comparison to FC100 (39–54%, 32–44%, 6–12%, and 7–12% reduction for boll number per plant, seed cotton yield, fiber strength, and leaf relative water content, respectively, across all priming treatments). Seed priming with KNO3 at 5 g L−1 effectively alleviated the detrimental effects originated from drought stress and caused 61–73%, 13–16%, and 16–23% increase in seed cotton yield, fiber length, and fiber strength, respectively, across soil moisture levels when compared with the control treatment. The same KNO3 dose caused an increase of 78% in water productivity in comparison to the control plants at FC50. Priming cotton seeds with 5 g KNO3 L−1 holds promise to obtain synchronized germination, enhance fiber quality, and increase yield, especially under water-limited conditions, thereby promoting economic viability and environmental sustainability. Additionally, this practice enhances water productivity, leading to significant water savings and reduced irrigation costs for cotton farmers. This method could be used as potential technology in advancing sustainable agriculture in water-constraint conditions.

Effect of different agro-techniques on yield of Bt cotton

A field experiment was conducted during the 2 consecutive kharif seasons of 2019 and 2020 at Agronomy Instructional Farm, Chimanbhai Patel College of Agriculture, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar, to study the yield maximization of Bt cotton through agro-techniques in loamy sand. The experiment consisted of four factors viz; spacing, detopping, intercropping and sowing time with two levels in each treatment. The results of pooled data of 2 years indicated that Bt cotton sown at spacing of 60 cm × 45 cm recorded significantly higher plant height, crop growth rate as well as seed cotton (3077 kg/ha) and stalk yields (5930 kg/ha), seed cotton equivalent yield (3512 kg/ha) and oil yield (335 kg/ha). However, wider spacing of 120 cm × 60 cm produced remarkably higher number of sympodial branches per plant, relative growth rate, number of open bolls per plant, weight of seed cotton per boll and seed cotton yield per plant. Topping carried out at 75 DAS remarkably improved growth and yield attributes, seed cotton and stalk yields, seed cotton equivalent yield, oil yield. All growth and yield attributes as well as seed cotton yield were recorded significantly higher without intercrop in Bt cotton. Though intercropping of greengram (additive series) in Bt cotton produced significantly higher seed cotton equivalent yield than no intercropping in pooled mean. Advance sowing of Bt cotton in last week of May produced significantly higher seed cotton yield and seed cotton equivalent S1 T2I2 D1 [Advance sowing (Last week of May)] at plant spacing of 60 cm × 45 cm along with detopping at 75 DAS and intercropping with greengram] gave significantly higher seed cotton equivalent yield as well as net returns and B: C ratio of Bt cotton.

ROLE OF PHOTOSYNTHETIC STABILITY AND PHYSIO-CHEMICAL ATTRIBUTES IN THE SELECTION OF IMPROVED COTTON GENOTYPES IN ACTUAL FIELD CONDITIONS

The current experimental study was conducted at Cotton Research Station, Bahawalpur during the cotton growing in 2022. The study was designed to evaluate the elite cotton genotypes based on their photosynthetic sustainability and other physiochemical attributes which could help in framing a selection criterion for the development of improved carton genotypes. The results revealed that highly significant variations were present among the elite cotton genotypes for studied morpho-physiological, photosynthetic and biochemical traits i.e., CLCV incidence percentage, number of bolls, sympodia per plant, boll weight, net photosynthetic rate, total chlorophyll contents, transpiration rate, stomatal conductance, sugar contents, total phenolic contents, ascorbic acid and seed cotton yield, which could be used in devising selection criteria for this election of parental material to be used in the hybridization program. Furthermore, the correlation coefficient analysis unveiled the strong correlation of seed cotton yield with transpiration rate, sugar contents, stomatal conductance, net photosynthetic rate, ginning out turn and sympodia per plant whereas a strong negative correlation was found for total phenolic contents. These results were also verified through the mean bar graphs and biplot graphs which show that these traits have the highest influence on seed cotton yield under the optimal condition.

Heterosis and combining ability for phenological yield and fiber traits of cotton (Gossypium hirsutum L.) genotypes

The seeds of 4 lines, 3 testers, and their 12 F1 hybrids were sown in a randomized complete block design (RCBD) with 3 replications at Botanical Garden, Department of Plant Breeding and Genetics, Sindh Agriculture University, Tandojam during Kharif 2019. F1 hybrids were raised for the estimation of heterotic effects, GCA and SCA for days to 1st squaring, days to 1st boll formation Bolls opened at 90 days after sowing, Sympodial branches plant-1, Bolls plant-1, Boll weight (g), Seed cotton yield plant-1 (g), 100-seed weight (g), Ginning outturn (%) and staple length (mm). Genotypes, parents, crosses, parent's v/s crosses, lines, testers and line × testers were significant for days to 1st squaring and days to 1st boll forming. Bolls unveiled their fissures precisely 90 days post-sowing, while parameters including sympodial branches per plant, bolls per plant, individual boll weight, seed cotton yield per plant, 100-seed weight, ginning outturn, and staple length underwent meticulous evaluation. The statistical scrutiny unveiled the insignificance of both lines and testers concerning the 90-day boll dehiscence. Similarly, the parental influence on boll weight, 100-seed weight, and staple length exhibited a lack of statistical significance. Line CRIS-134, Sindh, and tester FH-901 gave a higher mean performance for all the traits. Among the hybrids, Mehran × FH-901, Sindh-1 × CIM-602, CRIS-134 × CIM-602, CRIS-342 × Koonj, and CRIS-342 × CIM-602 gave a desirable mean performance and heterotic effect for all the traits. CRIS-342 × Koonj produced maximum SCA effects for bolls per plant. Mehran × FH-901 recorded higher SCA effects for seed cotton yield plant-1 and 100-seed weight, CRIS-342 × CIM-602 for lint percentage, and CRIS-342 × FH-901 for staple length. It is suggested that these lines and testers should be utilized in the breeding program to improve these traits.

Enhancing stand establishment and yield formation of cotton with multiple drip irrigation during emergence in saline fields of Southern Xinjiang

ContextFlooding irrigation prior to sowing during the winter or spring seasons has been widely employed to mitigate soil salinity and generate adequate soil moisture for cotton seedling emergence in saline fields. In an effort to conserve water, a technique known as "dry sowing and wet emergence" has been utilized in arid regions of Northern Xinjiang, China, where the soil is not irrigated before sowing, and a single drip irrigation is applied to facilitate cotton emergence immediately after sowing. However, the successful implementation of this technique has not been achieved due to high soil salinity in Southern Xinjiang, China. In light of these challenges, we hypothesize that modifying the traditional "dry sowing and wet emergence" technique from a one-time irrigation to multiple irrigations during the seedling stage could improve the microenvironment of the root-zone soil, thereby mitigating salinity stress and promoting seedling emergence and stand establishment. MethodWe conducted a two-year field experiment employing a randomized block experimental design to assess the impacts of various irrigation methods during the seedling stage on soil microenvironment, seedling emergence, stand establishment, plant physiological response to salinity stress, and yield formation of cotton. The experiment encompassed three treatments, including pre-sowing flood irrigation (flood irrigation), the traditional single drip irrigation for dry sowing and wet emergence (single drip irrigation), and the modified dry sowing and wet emergence with three rounds of drip irrigation (multiple drip irrigation). ResultsMultiple drip irrigation resulted in consistently higher soil temperatures during the period of 5–30 days after sowing (DAS), lower soil salinity from 15 to 30 DAS, and also maintained relatively higher soil moisture levels than single drip irrigation between 20 and 30 DAS. In contrast to flood irrigation, multiple drip irrigation led to an increase in soil temperature from 5 to 30 DAS and a reduction in soil salinity levels during the period of 15–30 DAS. Conversely, single drip irrigation led to a decrease in soil salinity during 5–10 DAS, but a substantial increase in soil salinity and decrease in soil moisture from 20 to 30 DAS. Multiple drip irrigations used only 40 % of the irrigation amount needed for flood irrigation but achieved comparable seedling emergence and stand establishment rates. Compared to single drip irrigation, multiple drip irrigations decreased Na+ and malondialdehyde (MDA) content in the leaves by 21.7 % and 15.6 %, and increased photosynthetic (Pn) rate and stand establishment rate by 22.0 % and 36.3 %, respectively. Moreover, multiple drip irrigation produced seedcotton yields equal to those of flood irrigation, with an increase of 24.2 % compared to single drip irrigation. ConclusionsThe results demonstrate that multiple drip irrigations enhance seedcotton yield through improving stand establishment compared to single drip irrigation. This improvement is attributed to reduced salinity stress, as evidenced by the decreased soil salinity, Na+ content, and MDA content in the leaves when using multiple drip irrigation during seedling emergence. Therefore, multiple drip irrigation is a promising technique for promoting cotton seedling emergence and stand establishment in saline fields of Southern Xinjiang and other cotton-growing areas with similar ecological conditions.

Performance of drip fertigation and foliar nutrition on cotton-black gram sequence in subtropics

Field experiments were conducted over two seasons to study the effect of drip fertigation levels and foliar nutrition on the growth and yield of cotton-black gram cropping sequences. The treatments comprised three levels of fertigation viz., 50, 75, and 100% recommended dose of fertilizers (RDF) and nitrogen, phosphorus, and potassium (NPK), combined with and without two levels of foliar spray, drip irrigation with soil surface application of 100% RDF, and surface irrigation with soil surface application of 100% RDF as a control. Drip-irrigated cotton and black gram registered higher yields during both seasons as compared to the surface methods of irrigation. Application of 100% RDF as drip fertigation combined with a foliar spray of 1% urea phosphate registered the highest seed cotton yield of 3598 kg ha−1 and black gram grain yield of 856 kg ha−1, which was significantly superior over the control. Application of nutrients through drip fertigation improved seed cotton yield by 45.2% and blackgram grain yield by 49.8% compared with conventional surface irrigation with soil application of fertilizers. From the results, it could be concluded that drip fertigation at 100% RDF with foliar spray of 1% urea phosphate can be recommended for higher productivity in the cotton-black gram cropping sequence.

Deep vertical rotary tillage reduced soil salinity and improved seed cotton yield and water productivity under limited irrigation in saline-alkaline fields

Water scarcity and soil salinization severely limit cotton production in arid areas on the globe. A two-season (2020 and 2021) field experiment was performed on cotton under film-mulched drip irrigation in south Xinjiang of China to explore the responses of soil moisture, soil salinity, root growth, seed cotton yield and water productivity to deep vertical rotary tillage (DVRT) depth (T20: 20 cm, T40: 40 cm, T60: 60 cm, Tck: 20 cm, traditional rotary tillage) in saline-alkaline fields under two irrigation amounts (W1:360 mm, W2: 480 mm, local irrigation amount). It was found that the soil moisture storage (0–120 cm) increased with as irrigation amount increased and decreased with increasing DVRT depth. Soil electrical conductivity in the root zone (0–60 cm) and 0–120 cm soil layer declined as irrigation amount and DVRT depth increased. Irrigation amount and DVRT depth had significant effects on root length density, root mass density, root/shoot ratio, and seed cotton yield, all of which increased with increasing irrigation amount and DVRT depth. Under W2, T20, T40 and T60 increased seed cotton yield by 23.3 %, 45.3 %, 65.6 % in 2020, and by 38.9 %, 62.0 % and 84.1 % in 2021 compared with TCK, respectively. Both water productivity and irrigation water productivity increased with increasing DVRT depth. There were significant positive correlations among seed cotton yield and leaf area index, dry matter accumulation, harvest index, root length density, root mass density, root/shoot ratio, water productivity and irrigation water productivity. W1T60 was suggested for cotton production in the saline regions of southern Xinjiang. The DVRT offset the decrease in seed cotton yield under limited irrigation, which indicates that DVRT is promising to reduce soil salinity and improve seed cotton yield and water productivity in saline-alkaline fields for coping with water scarcity and soil salinization.

GENETIC INSIGHTS AND BREEDING IMPLICATIONS: ENHANCING COTTON YIELD AND QUALITY THROUGH BIPARENTAL SELECTION

This study was performed in Egypt's Sakha Agriculture Research Station during the seasons 2015–2018 to study the efficiency of biparental progenies derived from inter-population random mating in F2 generation in a cotton cross. Intercrossing is allowed in cotton breeding populations. Although the best lines may include harmful alleles, thus early segregating generation recombination and hybridization are required. The F2 generation of the cotton cross (Giza70 TNB1), which obtained from Agriculture Research Center, Egypt, consisted of five male and eight female plants, was used to test biparental progeny from random interpopulation mating. About 28 and 24 families in BIPS1 and BIPS2 had their original parents were examined. All genotypes were assessed for agricultural and fiber qualities. The mean of families (BIPs2) was higher than BIPs1 for all measured metrics except lint yield, percentage, and uniformity ratio. BIPS2 families had more genotypic coefficients of variation (GCV) for features than BIPS1. Intercrossing affected correlation coefficients of BIPS1 and BIPS2 genotypes. Seed cotton yield and lint index genotypic correlations became considerable. Seed cotton yield estimated by seed index and first fruiting node location were altered from negative to positive. Among them, No.5, No.7, No.8, No.18, and No.19 had large yields and early ripening, as shown by their components. The top five families chosen for fiber length had gain values of 3.373% to 8.961% and 5.919 to 7.781% for fiber strength. The No.18 family exhibited good seed cotton production and fiber length. Intermating and self-pollination (BIPS2) may utilize non-additive gene effects and accumulate trait-influencing alleles. Continuing to select and evaluate families based on their large-scale reproductive performance will enhance the likelihood of producing genotypes with desired features. In conclusion, this study underscores the utility of continued selection based on discerned genetic parameters, genotypic correlations, and observed gains in facilitating the ongoing improvement of cotton breeding programs. By providing valuable insights into the intricacies of genetic variability and trait associations, this research holds implications not only for the advancement of cotton breeding practices but also for the broader agricultural landscape on both national and global scales. Keywords: Biparental, selection efficiency, correlated response, hybridization, self-pollination

Grouping of Bulgarian and foreign cotton varieties by cluster analysis

Abstract. During the period 2016-2019, 21 Bulgarian and 10 foreign cotton varieties were included in a trial set by the block method design in four replicates and a harvest plot of 20 m2. A cluster analysis was applied to the most important economic traits. It was found that based on the clustering by individual years and on average for four years, the varieties were divided into two or three main clusters, mainly on the traits of seed cotton yield, fiber length and lint percentage. The year conditions have influenced the phenotypic manifestation of the studied traits and have had a significant impact on the genotypes clustering by the individual years. The clustering of the varieties based on the average data for four years showed different degrees of genetic similarity and distance between them and with the standard variety – Chirpan-539. The varieties Helius, Trakia, Philipopolis and Plovdiv, which were highly productive, were genetically very similar and it is appropriate to include them in one selection program together with the varieties Natalia, Dorina, Vega, Perla-267, Kolorit, (Bulgarian selection), Stoneville 112, Deltapine 30 (American) and 791-169 (Greek), which were genetically more distant from them and have shown other valuable traits.

Improving cotton productivity and nitrogen use efficiency through late nitrogen fertilization: Evidence from a three-year field experiment in the Xinjiang

ContextPremature senescence is a major concern for crop production especially for high-density cotton in Xinjiang, China, when nitrogen (N) rates are reduced. This study aimed to examine the potential of late N fertilization in mitigating senescence, improving light and N use efficiency, and enhancing cotton productivity under reduced N rate. MethodsA three-year field experiment was conducted from 2019 to 2021, employing a total of 240 kg N ha-1, which was one-third lower than the traditional rate of 360 kg ha-1. Five different N application ratios based on cotton stages were tested, with N064 (0:6:4 ratio at early: middle: late growth stages) representing late N fertilization, and N262 representing traditional ratio in fertilization. The effects of N application timing-based ratios on yield components, N use efficiency, canopy photosynthesis, and root traits were evaluated. ResultsThe results showed that N064 had the highest lint yield 2727–3305 kg ha-1 (2019–2021) among all treatments over the three years. Late N fertilization (N064) resulted in significant increases in boll density (4.6–10.7%), seed cotton yield (5.8–8.1%), and N use efficiency (10.5–14.1%) when compared to traditional N262. During late peak boll-setting to boll opening stages, N064 decreased leaf area index (3.5–6.6%), canopy light interception rate (3.8–11.4%), and boll capacity of root (18.1%) compared to N262, while increasing SPAD (2.3–4.8%), diffuse non-interceptance (3.9–16.6%), canopy apparent photosynthetic rate (13.2–49.4%), root biomass (19.5%), root/shoot ratio (15.0%). N064 also resulted in a higher root surface area density in deep soil than N262. ConclusionsLate N fertigation enhanced post-flowering canopy photosynthetic production by improving the cotton root-shoot relationship and delaying root and canopy senescence, resulting in improved yields and N use efficiency. This N management strategy implemented under reduced N cultivation shows promise for sustainable cotton production in Xinjiang and similar ecological regions.

Investigation of salt tolerance in cotton germplasm by analyzing agro-physiological traits and ERF genes expression

The development of genotypes that can tolerate high levels of salt is crucial for the efficient use of salt-affected land and for enhancing crop productivity worldwide. Therefore, incorporating salinity tolerance is a critical trait that crops must possess. Salt resistance is a complex character, controlled by multiple genes both physiologically and genetically. To examine the genetic foundation of salt tolerance, we assessed 16 F1 hybrids and their eight parental lines under normal and salt stress (15 dS/m) conditions. Under salt stress conditions significant reduction was observed for plant height (PH), bolls/plant (NBP), boll weight (BW), seed cotton yield (SCY), lint% (LP), fiber length (FL), fiber strength (FS), potassium to sodium ratio (K+/Na+), potassium contents (K+), total soluble proteins (TSP), carotenoids (Car) and chlorophyll contents. Furthermore, the mean values for hydrogen peroxide (H2O2), sodium contents (Na+), catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and fiber fineness (FF) were increased under salt stress. Moderate to high heritability and genetic advancement was observed for NBP, BW, LP, SCY, K+/Na+, SOD, CAT, POD, Car, TSP, FL, and FS. Mean performance and multivariate analysis of 24 cotton genotypes based on various agro-physiological and biochemical parameters suggested that the genotypes FBS-Falcon, Barani-333, JSQ-White Hold, Ghauri, along with crosses FBS-FALCON × JSQ-White Hold, FBG-222 × FBG-333, FBG-222 × Barani-222, and Barani-333 × FBG-333 achieved the maximum values for K+/Na+, K+, TSP, POD, Chlb, CAT, Car, LP, FS, FL, PH, NBP, BW, and SCY under salt stress and declared as salt resistant genotypes. The above-mentioned genotypes also showed relatively higher expression levels of Ghi-ERF-2D.6 and Ghi-ERF-7A.6 at 15 dS/m and proved the role of these ERF genes in salt tolerance in cotton. These findings suggest that these genotypes have the potential for the development of salt-tolerant cotton varieties with desirable fiber quality traits.

Optimum Plant Density Improved Cotton (Gossypium hirsutum L.) Root Production Capacity and Photosynthesis for High Cotton Yield under Plastic Film Mulching

Optimum Plant Density Improved Cotton (Gossypium hirsutum L.) Root Production Capacity and Photosynthesis for High Cotton Yield under Plastic Film Mulching

Drip fertigation and crop management in Bt cotton (Gossypium hirsutum)

A field experiment was conducted during the rainy season of 2014 and 2015 at Rahuri, Maharashtra, to study the effect of deficit irrigation, fertigation and planting techniques on growth, yield and quality parameters of Bt cotton (Gossypium hirsutum L.). Scheduling of irrigation at 1.0 ETc recorded significantly maximum growth, yield attributes and seed-cotton yield of Bt cotton, being at par with 0.8 ETc irrigation regime. Maximum and significantly higher seed-cotton yield was recorded in 1.0 ETc irrigation regime (3.3 t/ha), being at par with 0.8 ETc irrigation regime (3.1 t/ha) on pooled mean basis. Planting of Bt cotton at 90 cm × 90 cm was found superior to 150 cm × 60 cm in respect of growth, yield attributes and seed-cotton yield of Bt cotton. Planting of Bt cotton at 90 cm × 90 cm resulted in significantly higher seed-cotton yield (3.3 t/ha) than 150 cm × 60 cm planting (2.3 t/ha) on pooled mean basis. Fertigation of 100% GRDF up to 100 days + 20 kg MgSO4 /ha and 25 kg ZnSO4 /ha up to flowering at weekly interval + foliar spray of Fe (1.0 %) and B (0.5 %) at flowering and boll-development stages was found suitable for achieving the maximum growth, yield attributes and seed-cotton yield (3.1 t/ha) of Bt cotton. The maximum water use efficiency was obtained with 0.6 ETc irrigation regime (7.00 kg/ha-cm), followed by 0.8 ETc irrigation regime during both the years.