Combining ability of Egyptian cotton(Gossypium barbadense L.)reveals genetic potential for improved yield and fiber quality

Background As the most widely cultivated fiber crop,cotton production depends on hybridization to unlock the yield potential of current varieties.A deep understanding of genetic dissection is crucial for the cultivation of enhanced hybrid plants with desired traits,such as high yield and fine fiber quality.In this study,the general combining ability(GCA)and specific combining ability(SCA)of yield and fiber quality of nine cotton parents(six lines and three testers)and eighteen F1 crosses produced using a line×tester mating design were analyzed.Results The results revealed significant effects of genotypes,parents,crosses,and interactions between parents and crosses for most of the studied traits.Moreover,the effects of both additive and non-additive gene actions played a notably significant role in the inheritance of most of the yield and fiber quality attributes.The F1 hybrids of(Giza 90×Aust)×Giza 86,Uzbekistan 1×Giza 97,and Giza 96×Giza 97 demonstrated superior performance due to their favorable integration of high yield attributes and premium fiber quality characteristics.Path analysis revealed that lint yield has the highest positive direct effect on seed cotton yield,while lint percentage showed the highest negative direct effect on seed cotton yield.Principal component analysis identified specific parents and hybrids associated with higher cotton yield,fiber quality,and other agronomic traits.Conclusion This study provides insights into identifying potential single-and three-way cross hybrids with superior cotton yield and fiber quality characteristics,laying a foundation for future research on improving fiber quality in cotton.

Assessing genetic variation in Gossypium barbadense L.germplasm based on fibre characters

Background Gossypium barbadense L.has specific fibre in terms of its length,strength,and fineness,and known as extra-long staple(ELS) cotton,Sea–Island cotton,or Egyptian cotton.Narrow genetic base with less genetic variability is observed in G.barbadense germplasm.Hence,this study was aimed to evaluate the genetic variability present in 108 germplasm accessions of G.barbadense and to identify the superior genotypes based on the fibre traits.Results We evaluated 108 accessions for five fibre quality traits along with three checks in augmented block design.All fibre traits showed significant differences among genotypes,indicating that there is genetic potential for improvement.Fibre strength and micronaire(MIC) showed high phenotypic and genotypic coefficients of variation.High heritability combined with high genetic advance as percentage of mean(GAM) was recorded for fibre length,strength,and micronaire.Fibre strength and fibre length were significantly correlated with each other,while both showed negative correlation with micronaire.Principal component analysis and Biplot analysis showed that uniformity index discriminated all the genotypes in higher level,while fibre length and strength were medium in discrimination power.Biplot revealed genotypes DB 16,EC959191,GSB 39,ARBB 20,5746U,EA 203,and EA 201 were genetically diverse.Hierarchal cluster analysis based on unweighted paired group method using arithmetic average(UPGMA) grouped the genotypes into four clusters,with each cluster consisting of 4,18,48,and 38 genotypes,respectively.Conclusion Among the genotypes,34 for fibre length(> 35 mm),18 for fibre strength(> 40.4 g·tex^(-1)) and 66 for micronaire(3.7-4.2,A grade) were identified as potential accessions based on their superiority.The superior fibre genotypes identified in this study are potential lines for the ELS cotton breeding program.

Genetic variation in LBL1 contributes to depth of leaf blades lobes between cotton subspecies, Gossypium barbadense and Gossypium hirsutum

Leaf is a essential part of the plants for photosynthetic activities which mainly economize the resources for boll heath. Significant variations of leaf shapes across the Gossypium sp. considerably influence the infiltration of sunlight for photosynthesis. To understand the genetic variants and molecular processes underlying for cotton leaf shape, we used F2 population derived from upland cotton genotype P30A （shallow-lobed leaf） and sea-island cotton genotype ISR （deep-lobed leaf） to map leaf deep lobed phenotype controlling genes LBL1 and LBL2. Genetic analysis and localization results have unmasked the position and interaction between both loci of LBL1 and LBL2, and revealed the co-dominance impact of the genes in regulating depth of leaf blades lobes in cotton. LBL1 had been described as a main gene and member of transcription factor family leucine zipper （HD-ZIPI） from a class I homologous domain factor Gorai.OO2G244000. The qRT-PCR results elaborated the continuous change in expression level of LBL1 at different growth stages and leaf parts of cotton. Higher expression level was observed in mature large leaves followed by medium and young leaves respectively. For further confirmation, plants were tested from hormonal induction treatments, which explained that LBL 1 expression was influenced by hormonal signaling. Moreover, the highest expression level was detected in brassinolides （BR） treatment as compared to other hormones, and this hormone plays an important role in the process of leaf blade lobed formation.

Study on the Mitochondrial Genome of Sea Island Cotton(Gossypium barbadense) by BAC Library Screening

The plant mitochondrial genome displays complex features, particularly in terms of cytoplasmic male sterility （CMS）. Therefore, research on the cotton mitochondrial genome may provide important information for analyzing genome evolution and exploring the molecular mechanism of CMS. In this paper, we present a preliminary study on the mitochondrial genome of sea island cotton （Gossypium barbadense） based on positive clones from the bacterial artificial chromosome （BAC） library. Thirty-five primers designed with the conserved sequences of functional genes and exons of mitochondria were used to screen positive clones in the genome library of the sea island cotton variety called Pima 90-53. Ten BAC clones were obtained and verified for further study. A contig was obtained based on six overlapping clones and subsequently laid out primarily on the mitochondrial genome. One BAC clone, clone 6 harbored with the inserter of approximate 115 kb mtDNA sequence, in which more than 10 primers fragments could be amplified, was sequenced and assembled using the Solexa strategy. Fifteen mitochondrial functional genes were revealed in clone 6 by gene annotation. The characteristics of the syntenic gene/exon of the sequences and RNA editing were preliminarily predicted.

Construction of Molecular Linkage Map of Cultivated Allotetraploid Cotton (Gossypium hirsutum L.×G. barbadense L. )with SSR and RAPD Markers

A permanent doubled haploid population fromthe crossing of G.hirsutum × G.barbadensewere developed by means of Vsg,virescentlymarked semigamy line in sea island cotton,which was characterized by a cytologicalmechanism for developing haploids with certainconvenience,and thus constructed

Genetic Dissection of Net Effects Between Yield and Its Components in Sea Island Cotton (Gossypium barbadense L.)

The number of bolls, individual boll weight, and lint percentage are three important yield components of lint yield of cotton. In the present study, nine parents, twenty F1, and twenty F2 crosses of intraspecific hybrids of sea island cotton （Gossypium barbadense L.） were grown at Tarim University, Alar, Xinjiang, China, in 2000 and 2001. Lint yield and its three component traits were measured and analyzed by an extended conditional mixed linear model approach. Lint percentage made the largest contribution to additive, additive x environment, and dominance x environment variations for lint yield. The contribution ratios of number of bolls, individual boll weight, and combined contribution of these two traits to additive x environment and dominance x environment variations for lint yield were not statistically significant. Lint yield of different parents could be affected differently by lint percentage. Lint yield of some parents was closely correlated with lint percentage, whereas for other parents, the behavior of individual boll weight and number of bolls played much more important roles on lint yield than that of lint percentage. It was shown by the conditional and conventional predicted additive x environment interaction effects of parents that the environment condition could influence different parents with varied effects.

Molecular Cloning and Characterization of Genes Involved in Cotton(Gossypium barbadense L.) Response to Verticillium dahliae

Verticillium dahliae Kleb.is a necrotrophic plant pathogen which causes serious soil borne vascular disease in cotton.The molecular basis the defense response of cotton to this pathogen is

Isolation and Analysis of Expansins from the Gossypium barbadense Cotton Elongating Fiber

Gossypium barbadense L.is one of the most valuable cotton species due to its silkiness,luster,long staple,and high strength.Transferring the excellent fiber traits from G.barbadense as the secondary gene pool to the widely cultivated G.hirsutum via traditional and molecular-aided selection

基因枪介导的海岛棉(Gossypium barbadense L.)茎尖遗传转化体系的建立

以新疆海岛棉品种新海13号的茎尖为转化受体,采用基因枪介导法,研究DNA包裹浓度、微载体种类、前渗处理时间、轰击条件、筛选方法等对茎尖转化的影响,建立了基因枪法介导的海岛棉茎尖转化体系。研究结果表明,采用1.5μg·μL-1的质粒DNA包裹1.0μm金粉微载体,前渗处理12 h,轰击压力为7.584 MPa(1100 psi),轰击距离为6 cm,后渗处理16 h,恢复处理24 h,在120 mg·L-1卡那霉素浓度下直接筛选35 d。在添加4g·L-1活性炭粒的生根培养基中诱导抗性幼苗生根,获得抗性再生植株。通过PCR和RT-PCR检测,共得到5株转抗除草剂基因EPSPS的阳性植株。该研究体系的建立为海岛棉的遗传转化奠定了基础,为海岛棉的育种工作提供了材料。

Optimizing the Bacillus thuringiensis(Bt)protein concentration in cotton:Coordinated application of exogenous amino acids and EDTA to reduce spatiotemporal variability in boll and leaf toxins

During the boll formation stage,cotton bolls exhibit the lowest expression of Bacillus thuringiensis(Bt)insecticidal proteins.Resistance to insects varies notably among different organs,which poses challenges for controlling cotton bollworms.Consequently,an experimental strategy was designed in the 2020-2021 cotton growing season to coordinate the enhancement of protein synthesis and the attenuation of degradation.Two Bt cultivars of Gossypium hirsutum,namely the hybrid Sikang 3 and the conventional Sikang 1,were used as test materials.Three treatments were applied at the peak flowering period:CK(the control),T1(amino acids),and T2(amino acids and EDTA).The results show that,in comparison to the CK group,the Bt protein contents were significantly increased in both cotton bolls and their subtending leaves under the T1 and T2 treatments.The maximum levels of increase observed were 67.5%in cotton bolls and 21.7%in leaves.Moreover,the disparity in Bt protein content between cotton bolls and their subtending leaves notably decreased by 31.2%.Correlation analysis suggested that the primary physiological mechanisms for augmenting Bt protein content involve increased protein synthesis and reduced protein catabolism,which are independent of Bt gene expression levels.Stepwise regression and path analysis revealed that elevating the soluble protein content and transaminase activity,while reducing the catabolic enzyme activities,are instrumental in enhancing the Bt protein content.Consequently,the coordinated application of amino acids and EDTA emerges as a strategy that can improve the overall resistance of Bt cotton and mitigate the spatiotemporal variations in Bt toxin concentrations in both cotton bolls and leaves.

Inheritance of Fertility Restoration for Cytoplasmic Male Sterility in a New Gossypium barbadense Restorer

In order to clarify inheritance mechanism of fertility restoration for cytoplasmic male sterility （CMS） in a new Gossypium barbadense restorer line Hai R which was found in the fertility test crossing of G. hirsutum CMS lines with G. barbadense germplasms. 23 fertility segregation populations of F2 and backcross were used to analyze the inheritance of fertility restoring gene（s） of Hai R. The result showed that Hai R had one major dominant gene （RfB） to control the CMS fertility restoration and this fertility restoration gene functioned at the sporophytic level. The sterile cytoplasm background might not only influence the transmission rate of male gamete but also that of female gamete when the restorer gene was recessive. It could be deduced that this fertility restoration gene might come from G. harknessii cotton, Hai R is of value in the application of cotton interspecific hybrid breeding.

The BEL1-like transcription factor GhBLH5-A05 participates in cotton response to drought stress

Drought stress impairs crop growth and development.BEL1-like family transcription factors may be involved in plant response to drought stress,but little is known of the molecular mechanism by which these proteins regulate plant response and defense to drought stress.Here we show that the BEL1-like transcription factor GhBLH5-A05 functions in cotton(Gossypium hirsutum)response and defense to drought stress.Expression of GhBLH5-A05 in cotton was induced by drought stress.Overexpression of GhBLH5-A05 in both Arabidopsis and cotton increased drought tolerance,whereas silencing GhBLH5-A05 in cotton resulted in elevated sensitivity to drought stress.GhBLH5-A05 binds to cis elements in the promoters of GhRD20-A09 and GhDREB2C-D05 to activate the expression of these genes.GhBLH5-A05 interacted with the KNOX transcription factor GhKNAT6-A03.Co-expression of GhBLH5-A05 and GhKNAT6-A03 increased the transcription of GhRD20-A09 and GhDREB2C-D05.We conclude that GhBLH5-A05 acts as a regulatory factor with GhKNAT6-A03 functioning in cotton response to drought stress by activating the expression of the drought-responsive genes GhRD20-A09 and GhDREB2C-D05.

Genetic Diversity in the Environmental Conditioning of <i>Gossypium hirsutum</i>and <i>Gossypium barbadense</i>Cultivars

Enzyme adaptations to temperature occur constantly as temperature patterns modulate diurnally and seasonally. These adaptations entail qualitative and/or quantitative metabolic changes that often provide a competitive advantage, impact adjustment to new environments, and effect the survival of the species. Changes in isozymes or allozymes, changes in enzyme concentration, modification by substrate and effectors, and metabolic regulation of enzyme function without changing enzyme composition are all possible strategies for adaptation to changes in temperature. The degree of adaptation among cotton cultivars to a specific thermal regime may be difficult to determine from phenotypic responses of the plants. The present study evaluated the thermal sensitivity of Gossypium hirsutum L. and Gossypium barbadense L. cultivars following growth under distinct thermal environments. The metabolic fitness of Gossypium hirsutum L. and Gossypium barbadense L. cultivars showed that the Gossypium hirsutum L. cultivars grown in a 28&deg;C/20&deg;C day/night cycle tended to be better equipped to cope with a 16 h - 38&deg;C treatment than the same cultivars grown in a 38&deg;C/32&deg;C day/night cycle. The Gossypium barbadense L. cultivars, on the other hand, grown in a 38&deg;C/32&deg;C day/night cycle tended to be equipped to cope with a 16 h - 38&deg;C treatment than the same cultivars grown in a 28&deg;C/20&deg;C day/night cycle. The Gossypium hirsutum L. line TX 303 is an exception to these general trends as its responses were similar to the Gossypium barbadense L. St. Vincent and Pima S-7 cottons.

Molecular Cloning and Characterization of the Actin-depolymerizing Factor Gene in Gossypium barbadense

Sea Island cotton(Gossypium barbadense L.) has been highly valued in Verticillium wilt resistance and many fiber qualities including fiber length,strength,and fineness.To identify whether

Genomic Differentiation Between Gossypium barbadense and G.hirsutum

Sea Island cotton(Gossypium barbadense L.) has superior fiber quality properties,while Upland cotton(G.hirsutum L.) is characterized by its high yield.Although these two species are

Mapping of QTL for Fiber Length Using Interspecific Gossypium hirsutum × G.barbadense F_2 Population

Cotton occupies a pre-eminent place among cash crops as it guides the destiny of a large section of the farming community as well as that of a flourishing textile industry.As the yarn manufacturing industry has undergone a technological revolution,more emphasis is given to quality of the raw

GbAt11 gene cloned from Gossypium barbadense mediates resistance to Verticillium wilt in Gossypium hirsutum

Background:Gossypium hirsutum is highly susceptible to Verticillium wilt,and once infected Verticillium wilt,its yield is greatly reduced.But G.barbadense is highly resistant to Verticillium wilt.It is possible that transferring some disease-resistant genes from G.barbadense to G.hirsutum may contribute to G.hirsutum resistance to Verticillium wilt.Result:Here,we described a new gene in G.barbadense encoding AXMN Toxin Induced Protein-11,Gb At11,which is specifically induced by Verticillium dahliae in G.barbadense and enhances Verticillium wilt resistance in G.hirsutum.Overexpression in G.hirsutum not only significantly improves resistance to Verticillium wilt,but also increases the boll number per plant.Transcriptome analysis and real-time polymerase chain reaction showed that Gb At11 overexpression can simultaneously activate FLS2,BAK1 and other genes,which are involved in ETI and PTI pathways in G.hirsutum.Conclusion:These data suggest that Gb At11 plays a very important role in resistance to Verticillium wilt in cotton.And it is significant for improving resistance to Verticillium wilt and breeding high-yield cotton cultivars.

Bioinformatics Analysis of PHYB Gene in Upland Cotton(Gossypium hirsutum)

[Objective] This study was conducted to clarify the biological information of PHYB genes in upland cotton （Gossypium hirsutum）. [Method] Two PHYB genes were identified from the genome database of allotetraploid cotton （G. hirsutum L. acc. TM-1）, and were found to be distributed on subgenomes A10 and D10. And then bioinformatic analysis on these two genes were performed. [Result] The PHYB genes of upland cotton had the same motifs and domains with the PHYB genes in other plant species, and even the number and location of the motifs and domains of these PHYB genes were consistent. The PHYB amino acid sequence alignment and the phylogenetic tree constructed based on PHYB amino acid sequence of these plant species indicated that the two PHYB genes in upland cotton had higher homology and closer evolutionary relationships with cocoa （Theobroma cacao）, but lower similarity to PHYB genes in monocotyledonous plants, such as rice （Oryza saitva） and corn （Zea mays）. The comparison of PHYB gene structure also revealed that plant PHYB gene was more conserved during evolution. The autophosphorylation of dozens of phosphorylation sites in upland cotton PHYB gene may be essential for the functions of phytochromes and plays a significant role in regulating phytochrome-mediated signal transduction pathways. [Conclusion] The results of this paper will provide a theoretical basis for the cloning and functional research of PHYB genes.

Screening of drought resistance indices and evaluation of drought resistance in cotton(Gossypium hirsutum L.)

Sixteen cotton cultivars widely planted in China were sowed under five different drought concentrations(0,2.5,5,7.5,and 10%)using PEG6000 to screen the indices of drought resistance identification and explore the drought resistance of different cotton cultivars.Eighteen physiological indices including root,stem,and leaf water contents(RWC,SWC,and LWC),net photosynthetic rate(Pn),the maximum photochemical quantum yield(Fv/Fm),the actual photochemical quantum yield(ΦPSII),non-photochemical quenching coefficient(NPQ),leaf water potential(LWP),osmotic potential(Ψs),leaf relative conductivity(REC),leaf proline content(Pro),leaf and root soluble protein contents(LSPC and RSPC),leaf and root malondialdehyde(MDA)contents(LMDA and RMDA),root superoxide dismutase,peroxidase,and catalase activities(RSOD,RPOD,and RCAT)were measured.Results indicated the 18 physiological indices can be converted into five or six independent comprehensive indices by principal component analysis,and nine typical indices(Fv/Fm,SWC,LWP,Pro,LMDA,RSPC,RMDA,RSOD,and RCAT)screened out by a stepwise regression method could be utilized to evaluate the drought resistance.Moreover,the 16 cotton cultivars were divided into four types:drought sensitive,drought weak sensitive,moderate drought resistant,and drought resistant types.The resistance ability of two selected cotton cultivars(drought resistant cultivar,Dexiamian 1;drought sensitive cultivar,Yuzaomian 9110)with contrasting drought sensitivities were further verified by pot experiment.Results showed that the responses of final cotton biomass,yield,and yield composition to drought were significantly different between the two cultivars.In conclusion,drought resistant cultivar Dexiamian 1 and drought sensitive cultivar Yuzaomian 9110 were screened through hydroponics experiment,which can be used as ideal experimental materials to study the mechanism of different cotton cultivars with contrasting drought sensitivities in response to drought stress.

Ameliorative effects of potassium on drought-induced decreases in fiber length of cotton(Gossypium hirsutum L.) are associated with osmolyte dynamics during fiber development

Fiber length of cotton(Gossypium hirsutum L.)decreases under drought stress,potassium(K)could diminish the decreased caused by drought,but the mechanism associated with this alleviation effect is not clear.We evaluated the effect of K on fiber elongation using two cotton cultivars,Simian 3 and Siza 3,grown in well-watered and drought-stressed conditions.Potassium fertilizer(K2O)was applied 0,150,or 300 kg ha?1 in each growing condition.Drought stress reduced the final fiber length due to a decline in the maximum rate of rapid elongation(Vmax,mmday?1).The application of K alleviated the droughtinduced fiber length reduction by increasing Vmax.At 10 and 15 days post-anthesis(DPA),drought significantly reduced osmotic potential(OP)and increased K+and malate contents at all K rates,relative to well-watered conditions,which was associated with increased activities of phosphoenolpyruvate carboxylase(PEPC),V-ATPase,PPase,and PM H+-ATPase in cotton fiber.However,the relative contribution of K+and malate to OP declined under drought in comparison with well-watered condition.Compared with control without K,K application decreased OP and increased the accumulation of osmolytes(K+,malate and soluble sugar)as well as the activities of related enzymes in fiber irrespective of water treatments.Moreover,K application increased osmotic adjustment during drought,and improved the contribution of K+and malate to OP,especially under drought stress.This study showed that drought decreased fiber length by reducing Vmax,and K application ameliorates the decline in fiber elongation due to drought by enhancing osmolytes accumulation and their contribution to OP in fiber cells.