Cotton Cultivars Research Articles

A DNA Extraction Method for Nondestructive Testing and Evaluation of Cotton Seeds (Gossypium L.).

Kernels of cotton provide lint and linter for textiles, oil and protein for food and feed. Cotton seed is formed following fertilization between an ovule and a pollen grain. The seed coat is maternal in origin, whereas the embryo and attached cotyledonary leaves are hybrids of parental lines. The extraction of genomic DNA from an ungerminated whole, a portion or mixed seeds are prerequisite in genetic and genomic studies of cotton. As far as our knowledge, there is only one method of nondescriptive DNA extraction from ungerminated cotton seeds without affecting the seed germination capability, but it has technical difficulties and requires special equipment. Furthermore, the amount of DNA extracted using the published method is low and, therefore, it is only suitable for routine marker assisted selection studies. In this study, a DNA extraction protocol referred to as the CTAB-LiCl was developed for single whole cotton seed, a portion of cotton seed and bulked cotton seeds. This protocol uses a combination of CTAB and LiCl to lyse cells and deplete RNAs simultaneously. The CTAB-LiCl DNA extraction method was evaluated in ninety-six individuals of six different cotton cultivars along with two genetic standards of cotton, TM-1 (G. hirsutum L.), Pima 3-79 (G. barbadense L.), and several other plant species of different plant genera. Results revealed that this method produced high quality and amounts of DNA as confirmed by spectrophotometry, agarose gel, restriction enzyme digestion, polymerase chain reaction, and library production for next generation sequencing studies of whole genome bisulfite sequencing. It does not require the use of liquid nitrogen, RNase, proteinase K, or beta-mercaptoethanol and can be completed in approximately 2h. Small tissues of the chalaza ends of ungerminated cotton seeds could be used to obtain high quality and quantity of DNA ranging from 14 to 28µg without affecting the seeds' germination ability, allowing marker-assisted selection before planting and flowering.

Low soil available phosphorus level reduces cotton fiber length via osmoregulation.

Phosphorus (P) deficiency hinders cotton (Gossypium hirustum L.) growth and development, seriously affecting lint yield and fiber quality. However, it is still unclear how P fertilizer affects fiber length. Therefore, a two-year (2019-2020) pool-culture experiment was conducted using the split-plot design, with two cotton cultivars (CCRI-79; low-P tolerant and SCRC-28; low-P sensitive) as the main plot. Three soil available phosphorus (AP) contents (P0: 3 ± 0.5, P1: 6 ± 0.5, and P2 (control) with 15 ± 0.5 mg kg-1) were applied to the plots, as the subplot, to investigate the impact of soil AP content on cotton fiber elongation and length. Low soil AP (P0 and P1) decreased the contents of the osmotically active solutes in the cotton fibers, including potassium ions (K+), malate, soluble sugar, and sucrose, by 2.2-10.2%, 14.4-47.3%, 8.7-24.5%, and 10.1-23.4%, respectively, inhibiting the vacuoles from facilitating fiber elongation through osmoregulation. Moreover, soil AP deficiency also reduced the activities of enzymes participated in fiber elongation (plasma membrane H+-ATPase (PM-H+-ATPase), vacuole membrane H+-ATPase (V-H+-ATPase), vacuole membrane H+-translocating inorganic pyrophosphatase (V-H+-PPase), and phosphoenolpyruvate carboxylase (PEPC)). The PM-H+-ATPase, V-H+-ATPase, V-H+-PPase, and PEPC were reduced by 8.4-33.0%, 7.0-33.8%, 14.1-38.4%, and 16.9-40.2%, respectively, inhibiting the transmembrane transport of the osmotically active solutes and acidified conditions for fiber cell wall, thus limiting the fiber elongation. Similarly, soil AP deficiency reduced the fiber length by 0.6-3.0 mm, mainly due to the 3.8-16.3% reduction of the maximum velocity of fiber elongation (VLmax). Additionally, the upper fruiting branch positions (FB10-11) had higher VLmax and longer fiber lengths under low soil AP. Cotton fibers with higher malate content and V-H+-ATPase and V-H+-PPase activities yielded longer fibers. And the malate and soluble sugar contents and V-H+-ATPase and PEPC activities in the SCRC-28's fiber were more sensitive to soil AP deficiency in contrast to those of CCRI-79, possibly explaining the SCRC-28 fiber length sensitivity to low soil AP.

Different responses of the rhizosphere microbiome to Verticillium dahliae infection in two cotton cultivars.

Verticillium wilt is a disastrous disease caused by Verticillium dahliae that severely damages the production of cotton in China. Even under homogeneous conditions, the same cotton cultivar facing V. dahliae tends to either stay healthy or become seriously ill and die. This binary outcome may be related to the interactions between microbiome assembly and plant health. Understanding how the rhizosphere microbiome responds to V. dahliae infection is vital to controlling Verticillium wilt through the manipulation of the microbiome. In this study, we evaluated the healthy and diseased rhizosphere microbiome of two upland cotton cultivars that are resistant to V. dahliae, Zhong 2 (resistant) and Xin 36 (susceptible), using 16S rRNA and ITS high-throughput sequencing. The results showed that the healthy rhizosphere of both resistant cultivar and susceptible cultivar had more unique bacterial ASVs than the diseased rhizosphere, whereas fewer unique fungal ASVs were found in the healthy rhizosphere of resistant cultivar. There were no significant differences in alpha diversity and beta diversity between the resistant cultivar and susceptible cultivar. In both resistant cultivar and susceptible cultivar, bacterial genera such as Pseudomonas and Acidobacteria bacterium LP6, and fungal genera such as Cephalotrichum and Mortierella were both highly enriched in the diseased rhizosphere, and Pseudomonas abundance in diseased rhizospheres was significantly higher than that in the healthy rhizosphere regardless of the cultivar type. However, cultivar and V. dahliae infection can cause composition changes in the rhizosphere bacterial and fungal communities, especially in the relative abundances of core microbiome members, which varied significantly, with different responses in the two cotton cultivars. Analysis of co-occurrence networks showed that resistant cultivar has a more complex network relationship than susceptible cultivar in the bacterial communities, and V. dahliae has a significant impact on the bacterial community structure. These findings will further broaden the understanding of plant-rhizosphere microbiome interactions and provide an integrative perspective on the cotton rhizosphere microbiome, which is beneficial to cotton health and production.

A bZIP transcription factor GhVIP1 increased drought tolerance in upland cotton

BackgroundCotton is extremely affected by severe natural stresses. Drought is one of the most serious abiotic stress that adversely influences cotton growth, productivity, and fiber quality. Previous studies indicate that basic leucine-zipper (bZIP) transcription factors are involved in the response of plants to various stresses. However, the molecular function and regulatory mechanism of GhVIP1 in response to drought stress are still unknown.ResultsIn this research, GhVIP1 was cloned from a drought-tolerant variety. Expression of GhVIP1 was up-regulated in response to multiple abiotic stresses, especially under drought stress. And GhVIP1 was highly expressed in the root, stem, and 10 days post-anthesis ovule. Inhibiting the expression of GhVIP1 in cotton using the virus-induced gene silencing method resulted in higher electrical conductivity in leaves, but lower water content under drought stress compared with the WT plant. Overexpression of GhVIP1 in Arabidopsis enhanced plant drought tolerance through increasing the seed germination rate and improving the development of root. The exogenous expression of GhVIP1 up-regulated the transcription of genes associated with drought response and proline biosynthesis during drought stress in Arabidopsis.ConclusionIn summary, these results indicated that GhVIP1 played a positive role in plants' response to drought stress. The use of GhVIP1 via modern biotechnology might facilitate the improvement of drought tolerance in cotton cultivars.

Phosphorus uptake mechanisms associated with phosphorus application levels in two cotton cultivars

Poor phosphorus utilization is a common limitation of sustainable cotton production. Even so, the intrinsic potential for efficient phosphorus acquisition of the roots remains unclear. In this study, we aimed to explore if phosphorus acquisition in cotton is affected by interactions that could possibly be associated with root morphology and gene expression, between genotype and application rates. A pot experiment was conducted with seven phosphorus application rates: 0, 12.5, 25, 50, 75, 150, and 300 mg P kg−1. The agronomic characters, root morphology, and expression of the PHT1 gene in the roots of cotton varieties with different phosphorus acquisition efficiencies were measured. According to the results, the phosphorus acquisition efficiency in cultivar XLZ19 was higher than in XLZ13 for phosphorus uptake because of the upregulation of GhPTs gene expression that increased the total root length and proportion of fine roots. The Olsen-P levels in the soil ranged from 20 to 30 mg kg−1 at the seedling stage and from 15 to 25 mg kg−1 at the flowering stage, suggesting better root growth and phosphorus supply. The conversion of phosphorus fertilizers to soil Olsen-P decreased when the phosphorus application rate exceeded 50–75 mg kg−1. The phosphorus acquisition–efficient XLZ19 phenotype owes its efficiency to high GhPTs expression and morphological changes in the roots. Finally, with these crops that are highly efficient in phosphorus acquisition, agricultural practices in sustainable cotton production may consume less phosphorus fertilizers.

Optimal choice of cotton cultivar for rainfed conditions in Sahelo-Sudanian climate with late planting: a case study in Senegal

AbstractLate planting due to erratic onset of the rainy season is becoming more frequent in the Sahelo-Sudanian climate where cotton is grown, causing seed cotton yield (SCY) loss and higher risk of drought at the end of the crop cycle. Therefore, cultivars should be adapted to late (from July 10) planting date (PD) in Senegal. The aim of this study was to analyse the interaction between genotypes and PD on SCY in Senegal under rainfed conditions. Field experiments were conducted in 2018 and 2019 using a split-plot design (two PDs, eight cultivars) at three experimental stations. Robust analysis of SCY was used to moderate the effect of potential outliers. The average SCY was 1404 kg/ha under early planting, and 714 kg/ha under late planting. The best SCY was obtained under early planting conditions, in environments with good rainfall. The loss due to late planting was significantly affected by cultivar choice. None of the cultivars performed best under both early and late PD. Under early PD, cultivar CS 50 gave the best SCY, while under late PD it was cultivar IRMA Q302. The best performing cultivar on average depended on the proportion of early plantings. A model was developed to identify the best overall cultivar based on the expected proportion of early planting, as a decision support tool for the cotton development company, if only one cultivar is released. The benefit of releasing a second cultivar for late-planted fields is considered.

Cotton ethylene response factor GhERF91 is involved in the defense against Verticillium dahliae

Verticillium dahliae causes significant losses in cotton production. To reveal the mechanism of the defense response to V. dahliae in cotton, transcriptomic analyses were performed using cotton cultivars M138 (V. dahliae-resistant) and P2 (V. dahliae-susceptible). The results revealed 11,076 and 6,640 differentially expressed genes (DEGs) in response to V. dahliae, respectively. The weighted gene co-expression network analysis of 4,633 transcription factors (TFs) indicated a “MEblue” module containing 654 TFs that strongly correlate with resistance to V. dahliae. Among these TFs, the ethylene response factor Ghi_A05G10166 (GhERF91) was identified as a putative hub gene with a defense response against V. dahliae. A virus-induced gene silencing assay and exogenous application of ethephon showed that GhERF91 is activated by ethylene and positively regulates the response to V. dahliae exposure in cotton. This study provides fundamental transcriptome data and a putative causal gene (GhERF91) associated with resistance to V. dahliae, as well as genetic resources for breeding V. dahliae-resistant cotton.

65 years of cotton lint yield progress in the USA: Uncovering key influential yield components

Context or problemCotton is an essential cash crop with significant importance in industries related to fiber, feed, and oil. However, achieving further improvements in cotton lint yield requires a more comprehensive understanding of different biomass components and the development of targeted management strategies. Objective or research questionThe objective of this study was to assess the biomass partitioning of 20 cotton cultivars released between 1953 and 2018, determine the rate of gain for lint yield, and identify the contribution of biomass components to yield performance. MethodsA two-year field experiment was conducted to evaluate the biomass partitioning of the 20 cotton cultivars released between 1953 and 2018. Correlation, linear, and path analyses were performed to estimate the effects of various biomass components (such as leaf, stem, bolls, burs, seed, and lint harvest index) on lint yield. ResultsThe study found that lint percentage, lint harvest index, seed biomass, and total aboveground biomass and its components exhibited a linear increase with the year of release. However, improving total aboveground biomass alone without enhancing reproductive partitioning could lead to a decrease in lint yield. Furthermore it was observed that the efficiency of modern cultivars in partitioning aboveground biomass into different plant parts, except for lint, has remained unchanged over the past 65 years of breeding. ConclusionsThe results suggest that future research should prioritize improving the lint harvest index to further enhance the potential lint yield of cotton. Merely increasing total aboveground biomass may not yield the desired improvements in lint yield. Optimizing reproductive partitioning is crucial for achieving enhanced lint yield. Implications or significanceThis study provides valuable insights into the biomass partitioning and yield performance of cotton cultivars spanning several decades. The findings emphasize the importance of focusing on improving the lint harvest index as a key factor in increasing lint yield. The results have implications for the development of targeted management strategies in cotton production and breeding programs, contributing to the overall sustainability and productivity of the cotton industry. Data AvailabilityThe datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

Growth and antioxidant defence in hypocotyl-derived calli of two cotton cultivars with contrasting salt tolerance

Growth and antioxidant defence in hypocotyl-derived calli of two cotton cultivars with contrasting salt tolerance

Increasing root-lower characteristics improves drought tolerance in cotton cultivars at the seedling stage

Drought is an important abiotic stress factor in cotton production. The root system architecture (RSA) of cotton shows high plasticity which can alleviate drought-related stress under drought stress (DS) conditions; however, this alleviation is cultivar dependent. Therefore, this study estimated the genetic variability of RSA in cotton under DS. Using the paper-based growth system, we assessed the RSA variability in 80 cotton cultivars at the seedling stage, with 0 and 10% polyethylene glycol 6000 (PEG6000) as the control (CK) and DS treatment, respectively. An analysis of 23 above-ground and root traits in the 80 cotton cultivars revealed different responses to DS. On the 10th day after DS treatment, the degree of variation in the RSA traits under DS (5–55%) was greater than that of CK (5–49%). The 80 cultivars were divided into drought-tolerant cultivars (group 1), intermediate drought-tolerant cultivars (group 2), and drought-sensitive cultivars (group 3) based on their comprehensive evaluation values of drought resistance. Under DS, the root length-lower, root area-lower, root volume-lower, and root length density-lower were significantly reduced by 63, 71, 76, and 4% in the drought-sensitive cultivars compared to CK. Notably, the drought-tolerant cultivars maintained their root length-lower, root area-lower, root volume-lower, and root length density–lower attributes. Compared to CK, the root diameter (0–2 mm)-lower increased by 21% in group 1 but decreased by 3 and 64% in groups 2 and 3, respectively, under DS. Additionally, the drought-tolerant cultivars displayed a plastic response under DS that was characterized by an increase in the root-lower characteristics. Drought resistance was positively correlated with the root area-lower and root length density-lower. Overall, the RSA of the different cotton cultivars varied greatly under DS. Therefore, important root traits, such as the root-lower traits, provide great insights for exploring whether drought-tolerant cotton cultivars can effectively withstand adverse environments.

Effect of Melatonin Spraying on some Growth Characters of Several Cotton Cultivars

To investigate the role of melatonin on the development of certain cotton cultivars, an experiment was set up in a farmer’s fields during the summer of 2022 in the Al Karma district of the Anbar Governorate. The experiment had three replications and was set up in split plots per the RCBD protocol. The four types of cotton (Back Coat, Lachata, Coker 310, and Montana) and the four melatonin concentrations (0, 50, 100, and 150 mg L-1) were randomly distributed over the main plots. The results showed that the plants of the Coker 310 cultivar were characterized by the lowest number of nodes for the first fruiting branch on the stem and the lowest number of days to flowering, in addition to the superiority of the leaves content of chlorophyll and the highest average number of vegetative and fruiting branches, which reached 5.54 and 63.18 days and 27.26 mg 100 gm−1 fresh weight, and 3.42 and 13.51 branch plant−1 respectively. On the other hand, Back Coat plants outperformed with the highest average plant height of 170.75 cm. The cotton plants that were sprayed with a concentration of 150 mg L−1 were characterized by the lowest number of days to flowering stage (63.00 days), highest chlorophyll content in their leaves, plant height, and the number of vegetative and fruiting branches amounted to 28.50 mg, 100 gm−1 fresh weight, 185.91 cm, 3.95, and 14.70 branches. Plant−1 respectively.

Effects of exogenous abscisic acid on antioxidant system of salt tolerant and salt sensitive cotton cultivars

Summary Salinity is one of the most imperative global problems that affect crop productivity on a large scale. Salinity impairs plant growth and development by imposing various stresses. Therefore it is vital to decode those stress factors and identify possible solutions to improve agriculture productivity. However, the adaptive mechanisms under saline conditions of glycophytes have not been studied. The present study was undertaken to determine the effects of exogenous abscisic acid (ABA) on salinity tolerance in cotton plants. Some patterns of resistance development were revealed on the seedlings of two cotton cultivars, a salt-tolerant (Gulistan) and a salt-sensitive one (C-4727). Moreover, the antioxidant potentials of these cultivars were compared. The activities of ascorbate peroxidase (APX), super-oxide dismutase (SOD), as well as the quantity of endogenous ABA, malondialdehyde (MDA), and free proline (Pro) were determined in control and post treatment. Our results demonstrate significant differences between the salt- tolerant and sensitive cotton seedlings in response to saline stress, i.e., high levels of Pro and endogenous ABA, but lower MDA concentrations, and higher activity of APX and SOD for the salt-tolerant cultivar, Gulistan, as compared to the salt stress-sensitive cultivar C-4727.

Seed Hull Fracture Resistance of Upland and Pima Cotton Cultivars

Seed durability is a current issue of cotton ginners, who have noted smaller and weaker seed, lower seed grades, and increased seed coat fragments within ginned cotton fiber. To better understand the differences in the seed hull properties of Upland (Gossypium hirsutum L.) and Pima (G. barbadense L) seed, compression testing was conducted to determine the seed hull fracture resistance of both species. Plants were grown in Five Points, CA, U.S., for two years. After roller ginning, seed were conditioned to standard environmental conditions and were compressed until rupture on a material strength tester. Seed of the Pima cultivars generally required greater maximum compressive force and energy to rupture than did the seed of the Upland cultivars. However, when the seed were compressed in a vertical orientation, a few individual Upland cultivars did have compression properties within the range of values observed for the Pima cultivars. Hence, it is possible to find Upland seed with compression properties comparable to or slightly greater than those of some Pima seed. Differences in the data for the two years showed that growing environment affects seed hull strength properties. The results should help clarify some conflicting literature regarding the relative strength attributes of Gossypium species seed.

INHERITANCE OF MORPHO-ECONOMIC TRAITS AND COMBINING ABILITY ANALYSIS IN INTRASPECIFIC HYBRIDS OF GOSSYPIUM BARBADENSE L.

In intraspecific F1 diallel hybrids of Gossypium barbadense L., the inheritance study of traits plant height, boll weight, plant productivity, and 1000-seed weight, with combining ability analysis took place in 2020–2022 at the Institute of Genetics and Plant Experimental Biology, Academy of Sciences, Uzbekistan. These polygenic traits’ inheritance showed different ways in the fine-fiber cotton F1 hybrids. The plant height trait’s inheritance with overdominance and intermediate level of the high/low-performance cultivars. The boll weight trait was mainly in negative overdominance with incomplete dominance of the low-performance cultivar. The inheritance of seed cotton yield had the positive overdominance main control, while the 1000-seed weight had negative and positive overdominance. According to combining ability analysis, the highest positive general combining ability effects resulted in fine-fiber cotton cultivars Surkhan-14 (ĝi = 8.71) and Bo'ston (ĝi =1.86) for plant height, Guzor (ĝi = 0.12) for boll weight, in genotypes Marvarid (ĝi = 2.44) and Surkhan-14 (ĝi = 2.95) for plant productivity, and in cultivars Marvarid (ĝi = 2.3) and Guzor (ĝi = 2.8) for 1000-seed weight. The F1 hybrids Guzor × Surkhan-14, Marvarid × Bo'ston, and Bo'ston × Surkhan-14 showed the highest positive and desirable specific combining ability effects for 1000-seed weight and seed cotton yield. Results concluded that fine-fiber cotton cultivars Marvarid, Surkhan-14, and Guzor can benefit as initial breeding material in selecting high-yielding cotton cultivars.

FH-444: A HIGH YIELDING AND SUPERIOR FIBER QUALITY UPLAND COTTON VARIETY SUITABLE FOR COTTON GROWING AREAS OF PUNJAB, PAKISTAN

FH-444 is a new Bt cotton variety which was released during the year 2020-21 by Cotton Research Station, Ayub Agricultural Research Institute, for irrigated areas of Punjab, Pakistan to maintain fiber quality and production through gradually replacement of existing cotton cultivars to avoid the yield losses caused by insect, pest and unexpected disease attacks. The FH-444 possesses drought tolerance and very good combination of traits to meet the requirements of the farmers, pickers, ginners, spinners and textile industry. The evaluation of this promising line was started during 2011-12 in different yield tests viz: preliminary & advance yield trials, Provincial Coordinated Cotton Trial (PCCT), National Coordinated Varietal Trial (NCVT), Distinctness, Uniformity and Stability (DUS) Trial, Agronomic trials, 1.25 Acre trials etc. In preliminary yield trials, FH-444 showed 45.96% increase in yield (3592 kg/ha) over standard variety FH-113 (2461 kg/ha) during 2011-12 while in advanced yield trials, FH-444 exhibited 23.61% increase in yield (3408 kg/ha) over standard variety FH-113 (2757 kg/ha) during 2013-14. It was also found that the effects of Cotton Leaf Curl Disease (CLCuD) were low (1.7 %) in FH-444 during growing season of 2014-15, while FH-142 showed increased incidence of attack (4.9%). FH444 demonstrated significant resistance with respect to thrips, whitefly, jassid and pink bollworm infestation. In present study it was found that the variety FH-444 possesses higher yield potential and will contribute to improve cotton yield and production under different stress conditions.

Domestication over Speciation in Allopolyploid Cotton Species: A Stronger Transcriptomic Pull.

Cotton has been domesticated independently four times for its fiber, but the genomic targets of selection during each domestication event are mostly unknown. Comparative analysis of the transcriptome during cotton fiber development in wild and cultivated materials holds promise for revealing how independent domestications led to the superficially similar modern cotton fiber phenotype in upland (G. hirsutum) and Pima (G. barbadense) cotton cultivars. Here we examined the fiber transcriptomes of both wild and domesticated G. hirsutum and G. barbadense to compare the effects of speciation versus domestication, performing differential gene expression analysis and coexpression network analysis at four developmental timepoints (5, 10, 15, or 20 days after flowering) spanning primary and secondary wall synthesis. These analyses revealed extensive differential expression between species, timepoints, domestication states, and particularly the intersection of domestication and species. Differential expression was higher when comparing domesticated accessions of the two species than between the wild, indicating that domestication had a greater impact on the transcriptome than speciation. Network analysis showed significant interspecific differences in coexpression network topology, module membership, and connectivity. Despite these differences, some modules or module functions were subject to parallel domestication in both species. Taken together, these results indicate that independent domestication led G. hirsutum and G. barbadense down unique pathways but that it also leveraged similar modules of coexpression to arrive at similar domesticated phenotypes.

The antifungal effect of propolis extract against cotton wild disease (Verticillium dahliae Kleb.)

The aim of this study is to investigate the antifungal activity of propolis against V. dahliae Kleb. under both in vitro and in vivo conditions. Firstly, the inhibitory effect of the propolis on mycelial growth in Potato Dextrose Agar (PDA) media containing its ethanol extract (PE) at various concentrations (0.003, 0.06, 0.125, 0.25, 0.5, and 1 ppm/mL) was investigated under in vitro conditions. Then to assess the effect of PE on non-defoliating (PHCVd3 isolate) and defoliating (PHCVd47 isolate) pathotypes of V. dahliae, the varieties Giza 45 (resistant), Carmen (tolerant), and Acala SJ2 (susceptible) treated with PEE (1 ppm/mL) were observed in the plant growth chamber up to the 4-6 leaf stage. The whole in vitro experiments were carried out with three replicates, and the studies in vivo experiment were with five replicates depending on a completely randomized parcels design. The most effective dose of PEE with1 ppm/mL dose resulted in 75.2% suppression against the PHCVd3 isolate, while the effect of the same dose against the PHCVd47 isolate was 74.4%. The lowest disease severity index (DSI) values against PHCVd3 and PHCVd47 isolates in cotton cultivars treated with PE were 1.34 and 1.64 in the Giza 45, respectively, and the highest DSI values were 3.80 and 3.90 in the Acala SJ2 cultivar in vivo experiment, respectively. The findings indicate that PE treatment has a promising effect against cotton wilt disease that could be combined with known plant protection strategies.

Utilization of primary and secondary biochemical compounds in cotton as diagnostic markers for measuring resistance to cotton leaf curl virus.

Cotton (Gossypium hirsutum L.) is one of the most important staple fibrous crops cultivated in India and globally. However, its production and quality are greatly hampered by cotton leaf curl disease (CLCuD) caused by cotton leaf curl virus (CLCuV). Therefore, the aim of the present study was to investigate the biochemical mechanisms associated with CLCuD resistance in contrasting cotton genotypes. Four commercial cotton varieties with susceptible (HS 6 and RCH-134 BG-II) and resistant (HS 1236 and Bunty) responses were used to analyze the role of primary (sugar, protein, and chlorophyll) and secondary (gossypol, phenol, and tannin) biochemical compounds produced by the plants against infection by CLCuV. The resistant cultivars with increased activity of protein, phenol, and tannin exhibited biochemical barriers against CLCuV infection, imparting resistance in cotton cultivars. Reducing sugar in the healthy plants of the susceptible Bt cultivar RCH 134 BG-II exhibited the highest value of 1.67 mg/g at 90 days. In contrast, the lowest value of 0.07 mg g-1 was observed at 60 DAS in the highly diseased plants of the susceptible hybrid HS 6. Higher phenol content (0.70 mg g-1) was observed at 90 DAS in resistant cultivars, whereas highly susceptible plants exhibited the least phenol (0.25 mg g-1) at 90 DAS. The lowest protein activity was observed at 120 DAS in susceptible cultivars HS 6 (9.4 mg g-1) followed by RCH 134 BG-II (10.5 mg g-1). However, other biochemical compounds, including chlorophyll, sugar, and gossypol, did not show a significant role in resistance against CLCuV. The disease progression analysis in susceptible cultivars revealed non-significant differences between the two susceptible varieties. Nevertheless, these compounds are virtually associated with the basic physiological and metabolic mechanisms of cotton plants. Among the primary biochemical compounds, only protein activity was proposed as the first line of defense in cotton against CLCuV. The secondary level of defense line in resistance showed the activity of secondary biochemical compounds phenol and tannins, which displayed a significant increase in their levels while imparting resistance against CLCuV in cotton.

Function analysis of GhWRKY53 regulating cotton resistance to verticillium wilt by JA and SA signaling pathways.

WRKY transcription factors (TFs) play an important role in regulating the mechanism of plant self-defense. However, the function of most WRKY TFs in upland cotton (Gossypium hirsutum) is still unknown. Hence, studying the molecular mechanism of WRKY TFs in the resistance of cotton to Verticillium dahliae is of great significance to enhancing cotton disease resistance and improving its fiber quality. In this study, Bioinformatics has been used to characterize the cotton WRKY53 gene family. we analyzed the GhWRKY53 expression patterns in different resistant upland cotton cultivars treated with salicylic acid (SA) and methyl jasmonate (MeJA). Additionally, GhWRKY53 was silenced using a virus-induced gene silencing (VIGS) to determine the contribution of GhWRKY53 to V. dahliae resistance in cotton. The result showed that GhWRKY53 mediated SA and MeJA signal transduction pathways. After VIGS of the GhWRKY53, the ability of cotton to resist V. dahliae decreased, indicating that the GhWRKY53 could be involved in the disease resistance mechanism of cotton. Studies on the levels of SA and jasmonic acid (JA) and their related pathway genes demonstrated that the silencing of GhWRKY53 inhibited the SA pathway and activated the JA pathway, thereby reducing the resistance of plants to V. dahliae. In conclusion, GhWRKY53 could change the tolerance of upland cotton to V. dahliae by regulating the expression of SA and JA pathway-related genes. However, the interaction mechanism between JA and SA signaling pathways in cotton in response to V. dahliae requires further study.

Determination of fiber yield and quality in cotton cultivars, applied with biologically reclaimed greywater

Application of recycled municipal wastewater and industrial effluents using biological treatment methods to industrial crops is an ingenious practice to ensure the combined means of adopting sustainable industrial crops production through sustainable freshwater management. An investigation was made to study the effects of recycled greywater treated using the extended form of Effective Microorganisms in the sewage treatment plant, over the growth, biochemical contents, yield and fiber quality of MCU7 and SVPR2 cotton cultivars, grown under experimental conditions. The efficacy of the recycled greywater treatment was compared with ground well water as control and untreated greywater as on another treatment. Improved yield of lint fiber and cotton seeds were obtained with a ginning out turn (GOT) of 71.66% and 66.1% in the SVPR2 and MCU7 cultivars, respectively, when irrigated with recycled greywater. Similarly, both the cotton cultivars, supplied with the recycled greywater was found with a significantly higher (P ≤ 0.01) stable length (SL) and fiber strength, as well as significantly higher spinning consistency index (SCI) (P ≤ 0.05) and uniformity ratio, when compared with the other two treatments. The novelty approach, adopted in the experiment therefore can be concluded using the recycled greywater to the specific cotton cultivars in water-deficit agro-climatic conditions would be beneficial to sustain the cotton production, would be in turn benefiting the industries.