Hirsutum Var Research Articles

N6-methyladenosine RNA modification regulates photoperiod sensitivity in cotton.

The methylation of N6-methyladenosine (m6A) involves writers, erasers, and readers, acting synergistically in posttranscriptional regulation. These processes influence various biological processes, including plant floral transition. However, the specific role of m6A modifications in photoperiod sensitivity in cotton (Gossypium hirsutum) remains obscure. To elucidate this, in this study, we conducted transcriptome-wide m6A sequencing during critical flowering transition stages in the photoperiod-sensitive wild G. hirsutum var. yucatanense (yucatanense) and the photoperiod-insensitive cultivated cotton G. hirsutum acc. TM-1 (TM-1). Our results revealed significant variations in m6A methylation of 2 cotton varieties, with yucatanense exhibiting elevated m6A modification levels compared with TM-1 under long-day conditions. Notably, distinct m6A peaks between TM-1 and yucatanense correlated significantly with photoperiod sensitivity. Moreover, our study highlighted the role of the demethylase G. hirsutum ALKB homolog 5 (GhALKBH5) in modulating m6A modification levels. Silencing GhALKBH5 led to a decreased mRNA level of key photoperiodic flowering genes (GhADO3, GhAGL24, and GhFT1), resulting in delayed bud emergence and flowering. Reverse transcription quantitative PCR analyses confirmed that silencing GhADO3 and GhAGL24 significantly downregulated the expression of the floral integrator GhFT1. Collectively, our findings unveiled a transcriptional regulatory mechanism in which GhALKBH5-mediated m6A demethylation of crucial photoperiodic flowering transcripts modulated photoperiod sensitivity in cotton.

Source of antibiosis to Spodoptera frugiperda (Lepidoptera: Noctuidae) in mocó cotton genotypes (Gossypium hirsutum raça marie galante L. Hutch)

Spodoptera frugiperda (Lepidoptera: Noctuidae) cause damage in cotton plants since the plant emergence until maturation. The objective of this work was to evaluate antibiosis in mocó cotton genotypes (Gossypium hirsutum var marie galante L. Hutch) to S. frugiperda. Newly hatched larvae were individualized in plastic containers (100 mL) sealed with polyethylene film to prevent the insect scape, where they were fed with cotton leaves. The treatments were 27 cotton genotypes, with 40 replications for antibiosis and 20 for nutritional parameters, using a completely randomized design. The biological parameters evaluated were: larval period and viability, weight of caterpillars at ten days, pre-pupal period and viability and pupal weight at 24 hours, life cycle and total viability, adult longevity and sex ratio. Additionally, cotton genotypes were characterized by four microsatellite markers linked blue disease resistance, angular leaf spot, root-knot nematode and reniform nematode. There was high initial mortality of S. frugiperda larvae in genotypes BA0512, MA0423, PI0438, PI0432, CE0461, CE0507, RN0512, MA0425, MA0438, PI0429, MA0430, PI0440, PI0467, AC0602, PI0416, BA0477, MA0409 and MA0409 CE0467. The cotton genotypes presented antibiosis and SSR resistance markers for nematode and blue disease, highlighting that the germplasm of this species is an important source of multiple resistance for insect resistant genotype selection programs

Recycling of gas-to-liquid sludge as a potential organic amendment: Effect on soil and cotton properties under hyperarid conditions

Gas-to-liquid (GTL) sludge is a specific wastewater treatment by-product, which is generated during the industrial process of natural gas conversion to transportation fuels. This least studied sludge is pathogen-free and rich in organic carbon and plant nutrients. Therefore, it can be reused for soil enhancement as a sustainable management strategy to mitigate landfill gas emissions. In this field study, we compared the performance of soil treatments with GTL sludge to the more conventional chemical fertilizers and cow manure compost for the cultivation of cotton under hyperarid conditions. After a complete growing season, GTL sludge application resulted in the enhancement of soil properties and plant growth compared to conventional inputs. As such, there was a significant dose-dependent increase of soil organic matter (4.01% and 4.54%), phosphorus (534 and 1090 mg kg−1), and cumulative lint yield (4.68 and 5.67 t ha−1) for GTL sludge application rates of 1.5% and 3%, respectively. The produced fiber quality was adequate for an upland cotton variety (Gossypium hirsutum var. MAY 344) and appeared more dependent on the prevailing climate conditions than soil treatments. On the other hand, the adverse effects generally related to industrial sludge reuse were not significant and did not affect the designed agro-environmental system. Accordingly, plants grown on GTL sludge-amended soils showed lower antioxidant activity despite significant salinity increase. In addition, the concentrations of detected heavy metals in soil were within the standards’ limits, which did not pose environmental issues under the described experimental conditions. Leachate analysis revealed no risks for groundwater contamination with phytotoxic metals, which were mostly retained by the soil matrix. Therefore, recycling GTL sludge as an organic amendment can be a sustainable solution to improve soil quality and lower carbon footprint. To reduce any environmental concerns, an application rate of 1.5% could be provisionally recommended since a two-fold increase in sludge dose did not result in a significant yield improvement.

Genome-wide chromatin accessibility analysis unveils open chromatin convergent evolution during polyploidization in cotton

Allopolyploidization, resulting in divergent genomes in the same cell, is believed to trigger a "genome shock", leading to broad genetic and epigenetic changes. However, little is understood about chromatin and gene-expression dynamics as underlying driving forces during allopolyploidization. Here, we examined the genome-wide DNase I-hypersensitive site (DHS) and its variations in domesticated allotetraploid cotton (Gossypium hirsutum and Gossypium barbadense, AADD) and its extant AA (Gossypium arboreum) and DD (Gossypium raimondii) progenitors. We observed distinct DHS distributions between G. arboreum and G. raimondii. In contrast, the DHSs of the two subgenomes of G. hirsutum and G. barbadense showed a convergent distribution. This convergent distribution of DHS was also present in the wild allotetraploids Gossypium darwinii and G. hirsutum var. yucatanense, but absent from a resynthesized hybrid of G. arboreum and G. raimondii, suggesting that it may be a common feature in polyploids, and not a consequence of domestication after polyploidization. We revealed that putative cis-regulatory elements (CREs) derived from polyploidization-related DHSs were dominated by several families, including Dof, ERF48, and BPC1. Strikingly, 56.6% of polyploidization-related DHSs were derived from transposable elements (TEs). Moreover, we observed positive correlations between DHS accessibility and the histone marks H3K4me3, H3K27me3, H3K36me3, H3K27ac, and H3K9ac, indicating that coordinated interplay among histone modifications, TEs, and CREs drives the DHS landscape dynamics under polyploidization. Collectively, these findings advance our understanding of the regulatory architecture in plants and underscore the complexity of regulome evolution during polyploidization.

Identification and validation of SSRS linked to fiber quality traits in cotton using RILs derived from Gossypium hirsutum var. MCU5 and TCH 1218

In order to increase the fiber productivity in cotton, it is imperative to genetically improve the fiber component traits and such effort can be quickened by use of molecular markers. Totally, seventy-four simple sequence repeat (SSR) markers that were previously shown to be linked to fibre strength, boll weight, and fibre elongation were used to differentiate Gossypium hirsutum var. MCU5 and TCH1218 and among them two were found to be polymorphic markers. These two polymorphic markers viz., TMB 0409 and CGR 6889 were used to genotype 220 F13 recombinant inbred lines (RILs) derived from MCU5 and TCH1218 and single marker analysis was used to confirm their linkage with target traits using the phenotypic data collected on cotton fiber yield component traits such as plant height, days to 50 percent flowering data, boll weight, number of monopodial and sympodial branches and bolls. These identified and validated markers across genetic background can be employed to genetically improve cotton through marker assisted selection.

Identification of Stable and Multiple Environment Interaction QTLs and Candidate Genes for Fiber Productive Traits Under Irrigated and Water Stress Conditions Using Intraspecific RILs of Gossypium hirsutum var. MCU5 X TCH1218.

Cotton productivity under water-stressed conditions is controlled by multiple quantitative trait loci (QTL). Enhancement of these productivity traits under water deficit stress is crucial for the genetic improvement of upland cotton, Gossypium hirsutum. In the present study, we constructed a genetic map with 504 single nucleotide polymorphisms (SNPs) covering a total span length of 4,416 cM with an average inter-marker distance of 8.76 cM. A total of 181 intra-specific recombinant inbred lines (RILs) were derived from a cross between G. hirsutum var. MCU5 and TCH1218 were used. Although 2,457 polymorphic SNPs were detected between the parents using the CottonSNP50K assay, only 504 SNPs were found to be useful for the construction of the genetic map. In the SNP genotyping, a large number of SNPs showed either >20% missing data, duplication, or segregation distortion. However, the mapped SNPs of this study showed collinearity with the physical map of the reference genome (G. hirsutum var.TM-1), indicating that there was no chromosomal rearrangement within the studied mapping population. RILs were evaluated under multi-environments and seasons for which the phenotypic data were acquired. A total of 53 QTL controlling plant height (PH), number of sympodial branches, boll number (BN), and boll weight (BW) were dissected by QTL analysis under irrigated and water stress conditions. Additionally, it was found that nine QTL hot spots not only co-localized for more than one investigated trait but were also stable with major QTL, i.e., with > 10% of phenotypic variation. One QTL hotspot on chromosome 22 flanked by AX-182254626–AX-182264770 with a span length of 89.4 cM co-localized with seven major and stable QTL linked to a number of sympodial branches both under irrigated and water stress conditions. In addition, putative candidate genes associated with water stress in the QTL hotspots were identified. Besides, few QTL from the hotspots were previously reported across various genetic architects in cotton validating the potential applications of these identified QTL for cotton breeding and improvement. Thus, the major and stable QTL identified in the present study would improve the cotton productivity under water-limited environments through marker-assisted selection.

Co-treatment of cotton (Gossypium hirsutum var R405 2000) with methyl jasmonate and ethephon: Impact on the production of phenolic compounds

Co-treatment of cotton (Gossypium hirsutum var R405 2000) with methyl jasmonate and ethephon: Impact on the production of phenolic compounds

Co-treatment of cotton (Gossypium hirsutum var R405 2000) with methyl jasmonate and ethephon: Impact on the production of phenolic compounds

The objective of this study is to show the real impact of methyl jasmonate and ethephon in combination on the production of phenolic compounds in cultivar R405-2000 of the cotton plant Gossypium hirsutum. As well, cotton plants were treated in the field by methyl jasmonate (MeJA), ethephon (ETH) and the association of methyl jasmonate and ethephon (MeJA + ETH). The effect of these treatments was appreciated thanks to a qualitative analysis of total phenols by High Performance Liquid Chromatography. The results showed that ethephon, the metabolic precursor of ethylene, has properties identical to those of MeJA. However, the treatment of cotton leaves with ethephon induces less phenolic compounds than MeJA. On the other hand, the co-treatment of the leaves with MeJA and ethephon leads to an induction of phenolic compounds, which accumulate in greater quantities in the plant the phenols synthesized are more important with an activation of the biosynthetic pathway of stilbenoids because trans-resveratrol and transpiceide, two compounds belonging to the group of stilbenoids were synthesized de novo by the joint application of MeJA and ethephon on cotton leaves when they could not be synthesized when these two elicitors are applied alone.

Assessing Cotton Genotypes for Resistance to Aphis gossypii (Hemiptera: Aphididae).

Aphis gossypii Glover (Hemiptera: Aphididae) is a polyphagous species frequently associated with the presence of sooty mold and viruses lethal to plants. The purpose of this work was to characterize possible resistance categories of cotton genotypes against A. gossypii. Initially, a preliminary test was carried out with 78 genotypes, 15 of which were selected for infestation ability assays and the determination of the cumulative aphid-day rates. Posteriorly, these genotypes were also evaluated through antixenosis and antibiosis assays. The genotypes FM 910, FM 966 LL, Mocó, Gossypium hirsutum var. punctatum L. (Malvaceae), Variedade Reba = BTK-12, Deltapine, Hi-Bred, Acala 4-42, IAC PV010-1664, IAC 21, Reba B-50 PR and FMT 709 inhibited the aphid colonization. In the infestation ability assay, G. hirsutum punctatum, IAC PV010-1664 and Acala 4-42 were the least infested. In a multiple-choice assay, Deltapine Smooth Leaf and Variedade Reba = BTK-12 were significantly less infested, suggesting antixenosis. In the antibiosis assay, Gossypium arboreum L. (Malvaceae) 1 showed the lowest number of nymphs, number of nymphs per adult per day and, number of nymphs at 10 d after the birth of the first nymph in addition to reducing the reproductive period, nymphal survival, adult longevity and, developmental time. In the FM 910, the number of nymphs produced per day and, at 10 d after the birth of the first nymph decreased, which also indicated resistance. The results obtained here are unprecedented and can be explored in breeding programs to develop insect-resistant cotton cultivars.

Systematic Contributions to Taxa Dorycnium hirsutum (Fabaceae) in Turkey

Some interesting plant samples collected from Samandağ district of Hatay province were examined and it was determined that these specimens belong to Dorycnium hirsutum var. syriacum . Its status in the Flora of Turkey is mentioned as suspicious. In this study, it is stated that the Dorycnium hirsutum species should be divided into two distinct varieties as Dorycnium hirsutum var. hirsutum and Dorycnium hirsutum var. syriacum to investigate the morphological, taxonomic and palynological features of these taxa. Diagnostic characters and detailed descriptions of taxa and species identification key are given and IUCN categories are proposed.

Genetic Analysis of the Transition from Wild to Domesticated Cotton (Gossypium hirsutum L.).

The evolution and domestication of cotton is of great interest from both economic and evolutionary standpoints. Although many genetic and genomic resources have been generated for cotton, the genetic underpinnings of the transition from wild to domesticated cotton remain poorly known. Here we generated an intraspecific QTL mapping population specifically targeting domesticated cotton phenotypes. We used 466 F2 individuals derived from an intraspecific cross between the wild Gossypium hirsutum var. yucatanense (TX2094) and the elite cultivar G. hirsutum cv. Acala Maxxa, in two environments, to identify 120 QTL associated with phenotypic changes under domestication. While the number of QTL recovered in each subpopulation was similar, only 22 QTL were considered coincident (i.e., shared) between the two locations, eight of which shared peak markers. Although approximately half of QTL were located in the A-subgenome, many key fiber QTL were detected in the D-subgenome, which was derived from a species with unspinnable fiber. We found that many QTL are environment-specific, with few shared between the two environments, indicating that QTL associated with G. hirsutum domestication are genomically clustered but environmentally labile. Possible candidate genes were recovered and are discussed in the context of the phenotype. We conclude that the evolutionary forces that shape intraspecific divergence and domestication in cotton are complex, and that phenotypic transformations likely involved multiple interacting and environmentally responsive factors.

Evaluation of fungi-toxicants against root rot of cotton caused by Macrophomina phaseolina under screen house conditions

Cotton (Gossypium spp.) is one of the most important and extensively grown cash crops in India. It contributes significantly to our national economy. However, root rot disease caused by Macrophomina phaseolina is one of the major soil-borne diseases of this crop which is responsible for poor crop stand and lower yield in northern cotton growing states. The disease causes total loss in patches in the field Therefore, keeping in view the importance of this disease, the present investigation was carried out to find out the effective management of this disease with fungicides. Six fungi toxicants were evaluated as seed treatment to test their efficacy in pre and post emergence mortality due to root rot on American cotton (Gossypium hirsutum var. HS 6) and desi cotton (Gossypium arboreum var. HD 432). For fungicidal control in screen house condition, seed treatment with carbendazim was found superior than other fungicides in controlling this disease as it exhibited 68–78.3% disease control in American cotton and 75.5–82.8% disease control in Desi cotton. Besides carbendazim, MEMC and carboxin + thiram were found effective against root rot of cotton.

Biocontrol Potential of Trichoderma and Bacillus Species on Fusarium oxysporum f. sp vasinfectum

Fusarium wilt, caused by Fusarium oxysporum f. sp. vasinfectum, is one of the major diseases of cotton. Preventive methods to manage this disease should be adopted what includes the seed treatment with biocontrol agents as a good alternative. This work aimed to evaluate the efficiency of biological products based on Trichoderma spp. and Bacillus subtilis in the control of Fusarium oxysporum f. sp. vasinfectum (Fov) applied in seeds and seedlings of cotton. The experiment was carried out at the Laboratório de Fitopatologia of the Centro de Ciências Agrárias, of the Universidade Federal de Paraíba (CCA-UFPB), located in the city of Areia, Paraíba - Brazil. The disease transmission of the seeds to the seedlings was evaluated. After the transmission test, cotton seeds of the variety Mocó (Gossypium hirsutum var. Marie-gallante (Watt) Hutch.), BRS 286 and Topázio cultivar (Gossypium hirsutum L.) were submitted to the treatments T1 - Control, T2 - Trichodel® (0,5 mL); T3-Trichodel® (1.0 mL); T4-Trichodel® (1.5 mL); T5-Trichodel® (2.0 mL); T6-Bactel® (2.0 mL); T7-Bactel® (2.5 mL); T8-Bactel® (3.0 mL); T9-Bactel® (3.5 mL) diluted in 100 mL SDW; T10 - Fungicide Captana (240 g / 100 kg of seeds) and inoculated with Fov. The pathogen incidence of the seeds was evaluated seven days after the inoculation (DAI). To evaluate the biological control of Fov in the seedlings, the treated seeds were submitted to the following inoculation methods: 1 - inoculation of the substrate with a pathogen conidia suspension; 2 - immersion of the seeds in the conidia suspension and 3 - direct contact of the seeds with the pathogen mycelium. Twenty-one DAI the disease severity and percentage of seedlings with vascular darkening were evaluated. It was observed a transmission rate of 64.0 to 89.0% of the seeds to the seedlings. Trichodel® reduced the incidence and severity of Fov in the cotton seedlings and was the most efficient product.

Abundant Small Genetic Alterations after Upland Cotton Domestication.

Domestication has long been recognized as the most direct and effective way to intentionally influence morphological and physiological phenotypes in plants and animals. Consequently, understanding how small genetic alterations contribute to domestication is of considerable importance. In this study, we resequenced the genome of the wild upland cotton variety Gossypium hirsutum var. yucatanense, the putative wild ancestor of cultivated upland cotton, and then compared single nucleotide polymorphism (SNP) and short insertion and deletion (InDel) variations of the genome with the cultivated accession (TM-1) of G. hirsutum. We found approximately 6.6 million SNPs and 0.7 million InDels between the two genomes. Most of the small genetic variations were anchored in the noncoding regions. With regard to potential coding genes, we found 24,035 genes with nonsynonymous SNPs. Interestingly, 2603 genes in domesticated cotton are found that have changed the positions of stop codons or shifted reading frames from that in G. hirsutum var. yucatanense. This suggests that domestication may have been selected for mutations that restored gene function or that wild cotton has undergone a number of gene inactivation events since its divergence from cultivated cotton. The former scenario seems most likely due to the intense selective pressure applied during the domestication process. These results demonstrate that, within a relatively short period of time, the cotton genome has been readjusted through small genetic changes. The current study provides useful clues for seeking interesting genes for cotton improvement.

Saponin synthesis and cotton growth is antagonistically regulated by solar UV-B radiation

BackgroundEarlier we have reported that the exclusion of solar UV-B increased the growth and yield of cotton plants as compared with ambient UV-B. The UV-B radiation effects on the saponins and the impact of ambient and reduced UV-B on the accumulation of saponins has not been investigated yet. Thus a field experiment was conducted to study the influence of solar UV-B on the growth response and saponin synthesis in cotton (Gossypium hirsutum) var. Vikram plants by the exclusion of UV-B. The cotton plants were grown in specially designed iron chambers, wrapped with filters that excluded UV-B (<315 nm), or transmitted ambient UV-B.ResultsExclusion of ambient UV-B enhanced the growth of cotton plants in terms of plant height and leaf area. Greater plant height in UV-B excluded plants was due to elongated internode and more number of nodes. Enhancement in growth was accompanied by a decrease in the accumulation of saponins, which was quantified by the spectrophotometric, TLC and HPLC methods. Solvent extraction of saponins from the internodes and leaves were used for the bioassay of Amaranthus hypocotyl growth and expansion of cucumber cotyledons. Extracts obtained from the UV-B excluded plants (leaves and internodes) promoted the growth to a larger extent as compared with the extracts obtained from ambient grown plants.ConclusionsThe result indicates that solar UV-B may possibly suppress the plant growth by regulating the synthesis of natural growth inhibitor’s like saponin.

Suppression of cotton leaf curl disease symptoms in Gossypium hirsutum through over expression of host-encoded miRNAs

Cotton leaf curl disease (CLCuD), a major factor resulting in the enormous yield losses in cotton crop, is caused by a distinct monopartite begomovirus in association with Cotton leaf curl Multan betasatellite (CLCuMB). Micro(mi)RNAs are known to regulate gene expression in eukaryotes, including antiviral defense in plants. In a previous study, we had computationally identified a set of cotton miRNAs, which were shown to have potential targets in the genomes of Cotton leaf curl Multan virus (CLCuMuV) and CLCuMB at multiple loci. In the current study, effect of Gossypium arboreum-encoded miRNAs on the genome of CLCuMuV and CLCuMB was investigated in planta. Two computationally predicted cotton-encoded miRNAs (miR398 and miR2950) that showed potential to bind multiple Open Reading Frames (ORFs; C1, C4, V1, and non- coding intergenic region) of CLCuMuV, and (βC1) of CLCuMB were selected. Functional validation of miR398 and miR2950 was done by overexpression approach in G. hirsutum var. HS6. A total of ten in vitro cotton plants were generated from independent events and subjected to biological and molecular analyses. Presence of the respective Precursor (pre)-miRNA was confirmed through PCR and Southern blotting, and their expression level was assessed by semi quantitative RT-PCR, Real Time quantitative PCR and northern hybridization in the PCR-positive lines. Southern hybridization revealed 2–4 copy integration of T-DNA in the genome of the transformed lines. Remarkably, expression of pre-miRNAs was shown up to 5.8-fold higher in the transgenic (T0) lines as revealed by Real Time PCR. The virus resistance was monitored following inoculation of the transgenic cotton lines with viruliferous whitefly (Bemisia tabaci) insect vector. After inoculation, four of the transgenic lines remained apparently symptom free. While a very low titre of viral DNA could be detected by Rolling circle amplification, betasatellite responsible for symptom induction could not be detected in any of the healthy looking transgenic lines. In this study for the first time, efficacy of the host (G. arboreum)-encoded miRNAs against CLCuD symptoms was experimentally demonstrated through overexpression of miR398 and miR2950 in G. hirsutum var. HS6 plants. Computational prediction of miRNAs targeting virus genome and their subsequent implication in translational inhibition or cleavage based suppression of viral mRNA via overexpression could help in generating virus resistant plants.

Discovery of single nucleotide polymorphism in Gossypium hirsutum and G. barbadense through next generation sequencing approach

Single nucleotide polymorphism was identified using ddRAD and pooled amplicon sequencing between the allotetraploid cotton genotypes of G. hirsutum var. DS-28 (POOL-H) and G. barbadense var. SBYF-425 (POOL-B). The 471270 (470161 SNP and 1109 INDELs), 2723 (2621 SNP and 102 INDELs) and 780 (759 SNP and 21 INDELs) variant calling were predicted at read depth of 10 in the genotypes by using G. raimondii (D5), G. arboreum (A2) and G. hirsutum (AD) as reference genomes, respectively. Further, filtered out false positive homoeologous SNPs between parents (DS-28 and SBYF-425) at read depth of 10, identified 245 and 45 homozygous polymorphic SNPs between parents based on pooled amplicon sequencing and ddRAD sequencing by using G. raimondii, G. arboreum and G. hirsutum as a reference genomes. Based on gene function, 5 SNPs were converted into KASPar markers and genotyped in 21 RILs for fibre quality traits. Identified polymorphic SNPs and INDELs can be used for genotyping and QTL mapping after converting into functional markers.

QTL Mapping for Plant Height Using Chromosome Segment Substitution Lines in Upland Cotton

Chromosome segment substitution lines(CSSLs) were developed using Gossypium hirsutum var. CCRI36 as the recipient parent and G. barbadense var. Hai 1 as the donor parent. For mapping stable QTLs associated with plant height, three CSSL populations were planted in five environments(BC5F3, BC5F3:4, and BC5F3:5 in Anyang, Henan in 2009, 2010, and 2011, respectively, and BC5F3:5 in Shihezi, Xinjiang and Liaoyang, Liaoning in 2011) for phenotypic evaluation. The result showed that the transgressive ratio in different environments ranged from 53.43% to 88.97%. Using SSR data based on 408 individuals from BC5F3 and a linkage map constructed earlier that covers 5088.28 cM of cotton genome with 2280 SSR markers in 26 linkage groups, a total of 16 QTLs associated with plant height were detected, which were mapped on 10 chromosomes. Each QTL explained phenotypic variance from 7.35% to 13.17%. Seven QTLs were detected in at least two environments. Locus qPH-15-19 close to marker MUSS563 was identified in one environment, but the marker has been reported to be linked to a QTL for plant height. These stablly expressed QTLs could be applied in the marker assisted selection, fine QTL mapping and gene cloning.

Interspecific hybridization in Gossypium L.: characterization of progenies with different ploidy‐confirmed multigenomic backgrounds

AbstractCytological and molecular investigations were undertaken for parent and progeny derived from a trispecific line [2(Gossypium arboreum × G. anomalum) × G. hirsutum var. BWR], which was crossed with G. hirsutum var. JLH168. Cytomorphological analysis of the F1 (G. arboreum × G. anomalum), its amphidiploid and progeny from trispecies hybrid showed distorted ploidy segregation with monovalents to hexavalents and high intergenomic (small A2 and large B1) allosynthetic chromosome pairing. Microsatellite analysis identified three fragments associated with G. arboreum and G. anomalum and six fragments associated with G. hirsutum in derivates of the trispecies line × G. hirsutum var. JLH168. Inter‐Retrotransposon Amplified Polymorphism (IRAP) analysis revealed fragments of G. arboreum and G. anomalum, only in F1 and amphidiploid. Chromosomal association and microsatellite analysis of three progeny genotypes (i.e. haploid, hexaploid and tetraploid no. 1) confirmed that they share multigenomic background from the three cotton species (A2, AhDh and B1 genome). The interspecific hybrid cotton genotypes studied are likely to be useful for the introgression of genes from diploid species to commercial upland cultivars.

Assessment of impact of solar UV components on growth and antioxidant enzyme activity in cotton plant.

A field experiment was conducted to study the impact of solar UV-B (280-315nm) and UV-A (315-400nm) components on the growth and antioxidant enzyme activity in cotton plant (Gossypium hirsutum var. Vikram). Solar UV components were excluded by filtering the sunlight through selective UV-B (<315nm) and UV-B/A (<400nm) absorbing polyester films. Plants grown under filters that transmitted solar UV served as controls. Exclusion of UV-B and UV-B/A enhanced plant height, leaf area and total biomass of plants. The activity of antioxidant enzymes superoxide dismutase (SOD), ascorbic acid peroxidase (APX), glutathione reductase (GR) and guaiacol peroxidase (GPx) assayed in the leaves were lesser in the UV excluded plants. The level of ascorbic acid and UV absorbing substances were also decreased by the exclusion of UV. Solar UV components exerted a limitation on the potential growth of cotton plants. Reduction in the antioxidant enzyme activity and ascorbic acid after UV exclusion indicated that ambient UV components exert a significant stress on cotton plants. Reduction in the production of UAS indicated a changed pattern of metabolism leading to improved primary metabolism. Exclusion of UV components is advantageous from the agricultural point to enhance the growth of cotton plants.