JCR| The effect of time and type of stress moderators on yield and yield components of cotton on conventional and double-cropping systems under saline conditions

[Background] Today, stress moderators are employed to mitigate crop loss due to the adverse effects of environmental stress. The current research aimed to investigate the impacts of time and stress moderator types on agro-physiological responses of cotton on conventional and double-cropping systems during 2017 and 2018 under saline conditions. A split-plot factorial experiment was carried out in a randomized complete block design with three replications. Cultivation system [conventional (recommended planting date) and double-cropping systems (sowing after harvest of wheat)] were considered as the main plots, and stress moderator type at four levels [water control, 2 mmol·L–1 Salicylic acid (SA), 100 mmol·L–1 Glycine betaine (GB), and 100 μmol·L–1 sodium nitroprusside (SNP)] and application time (flowering and flowering + bolling stages) were regarded as subplots.

[Result] Plant height, reproductive branch number, the number of bolls, 10-boll weight, 1 000-seed weight, biological yield, seed cotton yield, lint yield, chlorophyll a, chlorophyll b, carotenoids, total chlorophyll, sodium, potassium, and proline content were less in double-cropping system comparing with conventional system. Spraying with the stress moderators alleviated soil salinity effects on yield, yield components, and biochemical traits of cotton. SNP spraying led to maximum plant height, branch number, the number of bolls per plant, 10-boll weight and seed cotton yield. SA spraying yielded the highest 1 000-seed weight, biological yield, lint percentage and lint yield. The highest chlorophyll a, chlorophyll b, carotenoids, and total chlorophyll content resulted from SNP spraying. Yield, yield components, and biochemical traits did not respond to the stress moderator types in double-cropping system. However, the highest chlorophyll a, carotenoids, proline content, the number of bolls per plant, and seed cotton yield resulted from SNP spraying in conventional system. No statistically significant differences were observed between spraying with SNP and SA in most studied traits.

[Conclusion] The results suggest that the optimum cotton planting time and SNP spraying could be recommended for producing the most suitable yield under saline conditions.

[Title] The effect of time and type of stress moderators on yield and yield components of cotton on conventional and double-cropping systems under saline conditions

[Authors] BORZOUYI Zeinab, ARMIN Mohammad & MARVI Hamid

Journal of Cotton Research 2021, 428

https://doi.org/10.1186/s42397-021-00103-6

JCR| Knockdown of 60S ribosomal protein L14-2 reveals their potential regulatory roles to enhance drought and salt tolerance in cotton

[Background] Cotton is a valuable economic crop and the main significant source of natural fiber for textile industries globally. The effects of drought and salt stress pose a challenge to strong fiber and large-scale production due to the ever-changing climatic conditions. However, plants have evolved a number of survival strategies, among them is the induction of various stress-responsive genes such as the ribosomal protein large (RPL) gene. The RPL gene families encode critical proteins, which alleviate the effects of drought and salt stress in plants. In this study, comprehensive and functional analysis of the cotton RPL genes was carried out under drought and salt stresses.

[Result] Based on the genome-wide evaluation, 26, 8, and 5 proteins containing the RPL14B domain were identified in Gossypium hirsutumG. raimondii, and G. arboreum, respectively. Furthermore, through bioinformatics analysis, key cis-regulatory elements related to RPL14B genes were discovered. The Myb binding sites (MBS), abscisic acid-responsive element (ABRE), CAAT-box, TATA box, TGACG-motif, and CGTCA-motif responsive to methyl jasmonate, as well as the TCA-motif responsive to salicylic acid, were identified. Expression analysis revealed a key gene, Gh_D01G0234 (RPL14B), with significantly higher induction levels was further evaluated through a reverse genetic approach. The knockdown of Gh_D01G0234 (RPL14B) significantly affected the performance of cotton seedlings under drought/salt stress conditions, as evidenced by a substantial reduction in various morphological and physiological traits. Moreover, the level of the antioxidant enzyme was significantly reduced in VIGS-plants, while oxidant enzyme levels increased significantly, as demonstrated by the higher malondialdehyde concentration level.

[Conclusion] The results revealed the potential role of the RPL14B gene in promoting the induction of antioxidant enzymes, which are key in oxidizing the various oxidants. The key pathways need to be investigated and even as we exploit these genes in the developing of more stress-resilient cotton germplasms.

[Title] Knockdown of 60S ribosomal protein L14-2 reveals their potential regulatory roles to enhance drought and salt tolerance in cotton

[Authors] SHIRAKU Margaret Linyerera, MAGWANGA Richard Odongo, CAI Xiaoyan, KIRUNGU Joy Nyangasi, XU Yanchao, MEHARI Teame Gereziher, HOU Yuqing, WANG Yuhong, WANG Kunbo, PENG Renhai, ZHOU Zhongli & LIU Fang

Journal of Cotton Research 2021, 427

https://doi.org/10.1186/s42397-021-00102-7

JCR | Genetic variability for yield and fiber related traits in genetically modified cotton

[Background] Cotton (Gossypium hirsutum L.) is grown for fiber and oil purposes in tropical and sub-tropical areas of the world. Pakistan is the 4th largest producer of cotton. It has a significant contribution in the GDP of Pakistan. Therefore, the present study was performed to assess the genetic variations and genetic diversity of yield and fiber quality traits in cotton and to analyze the associations present among them.

[Results] Analysis of variance exhibited significant variation for all studied traits except total number of nodes and the height to node ratio. The phenotypic coefficient of variation was higher than the genotypic coefficient of variation for all studied traits. Plant height, monopodial branches, total number of bolls, lint index, seed index, and seed cotton yield displayed high heritabilities in a broad sense with maximum genetic advance. Correlation analysis revealed that seed cotton yield had a significant positive association with plant height, the number of monopodial branches, the number of sympodial branches, ginning outturn (GOT), the number of bolls, seed per boll, seed index, uniformity index, the number of sympodial branches, reflectance, and seed index at the genotypic level while a significant positive relationship was observed with plant height, the number of sympodial branches, boll number, and GOT. Plant height, monopodial branches, GOT, boll weight, seeds per boll, and short fiber index exerted direct positive effects on seed cotton yield. The first 6 principal component analysis (PCs) out of the total fourteen PCs displayed eigenvalues (> 1) and had maximum share to total variability (82.79%). The attributes that had maximum share to total divergence included plant height, uniformity index, the number of sympodial branches, seed per boll, GOT, seed cotton yield, and short fiber index.

[Conclusion] The genotype AA-802, IUB-13, FH-159, FH-458, and CIM-595 were genetically diverse for most of the yield and fiber quality traits and could be utilized for the selection of better performing genotypes for further improvement.

[Title] Genetic variability for yield and fiber related traits in genetically modified cotton

[Authors] SAHAR Adeela, ZAFAR Muhammad Mubashar, RAZZAQ Abdul, MANAN Abdul, HAROON Muhammad, SAJID Sunaina, REHMAN Abdul, MO Huijuan, ASHRAF Muhammad, REN Maozhi, SHAKEE AmirL & YUAN Youlu

Journal of Cotton Research 2021, 419

https://doi.org/10.1186/s42397-021-00094-4

Increasing plant density increases Bt toxin concentration of boll wall in cotton by decreasing boll setting speed

[Background] In order to uncover the mechanism of significantly reduced insect resistance at the late developmental stage in cotton (Gossypium hirsutum L.), the relationship between boll setting rate under different planting densities and Bacillus thuringiensis (Bt) insecticidal concentrations in the boll wall were investigated in the present study. Two studies were arranged at Yangzhou, China during the 2017–2018 cotton growth seasons. Five planting densities (15 000, 25 000, 45 000, 60 000 and 75 000 plants per hectare) and the flower-removal treatment were imposed separately on Bt cotton cultivar Sikang3 to arrange different boll setting rates, and the boll setting rates and Bt toxin content were compared.

[Results] Higher boll setting rate together with lower Bt toxin contents in boll wall was observed under low planting density, whereas lower boll setting rate and higher Bt toxin contents were found under high planting density. Also, higher Bt protein concentration was associated with higher soluble protein content, glutamic-pyruvic transaminase (GPT), and glutamic oxaloacetate transaminase (GOT) activities, but lower amino acid content, and protease and peptidase activities. It was further confirmed that a higher boll setting rate with lower Bt protein content under flower-removal.

[Conclusion] This study demonstrated that the insecticidal efficacy of boll walls was significantly impacted by boll formation. Reduced protein synthesis and enhanced protein degradation were related to the reduced Bt toxin concentration.

[Title] Increasing plant density increases Bt toxin concentration of boll wall in cotton by decreasing boll setting speed

[Authors] ZHOU Mingyuan, CHEN Chen, TAMBEL Leila I. M., CHEN Yuan, ZHANG Xiang, CHEN Yuan & CHEN Dehua

Journal of Cotton Research 2021, 412

https://doi.org/10.1186/s42397-021-00084-6

Integrated transcriptome and proteome analysis reveals complex regulatory mechanism of cotton in response to salt stress

[Background] Soil salt stress seriously restricts the yield and quality of cotton worldwide. To investigate the molecular mechanism of cotton response to salt stress, a main cultivated variety Gossypium hirsutum L. acc. Xinluzhong 54 was used to perform transcriptome and proteome integrated analysis.

[Results] Through transcriptome analysis in cotton leaves under salt stress for 0 h (T0), 3 h (T3) and 12 h (T12), we identified 8 436, 11 628 and 6 311 differentially expressed genes (DEGs) in T3 vs. T0, T12 vs. T0 and T12 vs. T3, respectively. A total of 459 differentially expressed proteins (DEPs) were identified by proteomic analysis, of which 273, 99 and 260 DEPs were identified in T3 vs. T0, T12 vs. T0 and T12 vs. T3, respectively. Metabolic pathways, biosynthesis of secondary metabolites, photosynthesis and plant hormone signal transduction were enriched among the identified DEGs or DEPs. Detail analysis of the DEGs or DEPs revealed that complex signaling pathways, such as abscisic acid (ABA) and jasmonic acid (JA) signaling, calcium signaling, mitogen-activated protein kinase (MAPK) signaling cascade, transcription factors, activation of antioxidant and ion transporters, were participated in regulating salt response in cotton.

[Conclusion] Our research not only contributed to understand the mechanism of cotton response to salt stress, but also identified nine candidate genes, which might be useful for molecular breeding to improve salt-tolerance in cotton.

[Title] Integrated transcriptome and proteome analysis reveals complex regulatory mechanism of cotton in response to salt stress

[Authors] CHEN Lin, SUN Heng, KONG Jie, XU Haijiang & YANG Xiyan

Journal of Cotton Research 2021, 411

https://doi.org/10.1186/s42397-021-00085-5

Review of oxidative stress and antioxidative defense mechanisms in Gossypium hirsutum L. in response to extreme abiotic conditions

[Abstract] Oxidative stress occurs when crop plants are exposed to extreme abiotic conditions that lead to the excessive production and accumulation of reactive oxygen species (ROS). Those extreme abiotic conditions or stresses include drought, high temperature, heavy metals, salinity, and ultraviolet radiation, and they cause yield and quality losses in crops. ROS are highly reactive species found in nature that can attack plant organelles, metabolites, and molecules by interrupting various metabolic pathways until cell death occurs. Plants have evolved defense mechanisms for the production of antioxidants to detoxify the ROS and to protect the plant against oxidative damage. Modern researches in crop plants revealed that low levels of ROS act as a signal which induces tolerance to environmental extremes by altering the expression of defensive genes. In this review, we summarized the processes involved in ROS production in response to several types of abiotic stress in cotton plants. Furthermore, we discussed the achievements in the understanding and improving oxidative stress tolerance in cotton in recent years. Researches related to plant oxidative stresses have shown excellent potential for the development of stress-tolerant crops.

[Title]Review of oxidative stress and antioxidative defense mechanisms in Gossypium hirsutum L. in response to extreme abiotic conditions

[Authors]QAMER Zainab, CHAUDHARY Muhammad Tanees, DU Xiongming, HINZE Lori & AZHAR Muhammad Tehseen

Journal of Cotton Research 2021, 48

https://doi.org/10.1186/s42397-021-00086-4

Cotton N rate could be reduced further under the planting model of late sowing and high-density in the Yangtze River valley

[Background] An optimal N rate is one of the basic determinants for high cotton yield. The purpose of this study was to determine the optimal N rate on a new cotton cropping pattern with late-sowing, high density and one-time fertilization at the first flower period in Yangtze River Valley, China. A 2-year experiment was conducted in 2015 and 2016 with a randomized complete block design. The cotton growth process, yield, and biomass accumulation were examined.

[Result] The results showed that N rates had no effect on cotton growing progress or periods. Cotton yield was increased with N rates increasing from 120 to 180 kg·hm−2, while the yield was not increased when the N rate was beyond 180 kg·hm−2, or even decreased (929%). Cotton had the highest biomass at the N rate of 180 kg·hm−2 is due to its highest accumulation speed during the fast accumulation period.

[Conclusion] The result suggests that the N rate for cotton could be reduced further to be 180 kg·hm− 2 under the new cropping pattern in the Yangtze River Valley, China.

[Title] Cotton N rate could be reduced further under the planting model of late sowing and high-density in the Yangtze River valley

[Authors] SONG Xinghu, HUANG Ying, YUAN Yuan, SHAHBAZ Atta Tung, BIANGKHAM Souliyanonh & YANG Guozheng

Journal of Cotton Research 2020, 328

https://doi.org/10.1186/s42397-020-00065-1

Heritability and correlation analysis of morphological and yield traits in genetically modified cotton

[Background] Cotton is known for fiber extraction and it is grown in tropical and sub-tropical areas of the world due to having hot weather. Cotton crop has a significant role in GDP of Pakistan. Therefore, the two-years research was conducted to estimate heritability and association among various yield contributing parameters of cotton, i.e., plant height, number of bolls per plant, number of sympodial branches per plant, seed cotton yield, boll weight, seed index, ginning outturn (GOT), fiber length, fiber strength, and fiber fineness.

[Result] Association analysis revealed that seed cotton yield had a significant positive correlation with plant height, number of bolls per plant, number of sympodial branches per plant, GOT, staple length and fiber strength. Staple length and fiber strength were negatively linked with each other. Estimates of heritability were high for all of the traits except the number of sympodial branches per plant and boll weight.

[Conclusion] The parent IUB-222 was found to be the best for plant height, the number of bolls per plant, boll weight, GOT, seed cotton yield, and seed index. The genotypes namely, NIAB-414 and VH-367 were identified as the best parents for fiber length, strength, and fineness. Among the crosses NIAB-414 × IUB-222 was the best for the number of bolls per plant, seed index, seed cotton yield and fiber fineness, whereas, the cross of NIAB-414 × CIM-632 was good for plant height. The combination of A555 × CIM-632 was the best for the number of sympodial branches per plant, boll weight, fiber length, and strength, and VH-367 × CIM-632 proved the best for GOT.
[Title] Heritability and correlation analysis of morphological and yield traits in genetically modified cotton

[Authors] REHMAN Abdul, MUSTAFA Nida, DU Xiongming & AZHAR Muhammad Tehsee

Journal of Cotton Research 2020, 323

https://doi.org/10.1186/s42397-020-00067-z

The impact of plant density and spatial arrangement on light interception on cotton crop and seed cotton yield: an overview

[Abstract] Light attenuation within a row of crops such as cotton is influenced by canopy architecture, which is defined by size, shape and orientation of shoot components. Level of light interception causes an array of morpho-anatomical, physiological and biochemical changes. Physiological determinants of growth include light interception, light use efficiency, dry matter accumulation, duration of growth and dry matter partitioning. Maximum light utilization in cotton production can be attained by adopting cultural practices that yields optimum plant populations as they affect canopy arrangement by modifying the plant canopy components. This paper highlights the extent to which spatial arrangement and density affect light interception in cotton crops. The cotton crop branches tend to grow into the inter-row space to avoid shade. The modification of canopy components suggests a shade avoidance and competition for light. Maximum leaf area index is obtained especially at flowering stage with higher populations which depicts better yields in cotton production.
[Keywords] Light interception, Plant populations, Spatial arrangement, Canopy architecture

[Title] The impact of plant density and spatial arrangement on light interception on cotton crop and seed cotton yield: an overview

[Authors] CHAPEPA Blessing, MUDADA Nhamo & MAPURANGA Rangarirai

Journal of Cotton Research 2020, 318

https://doi.org/10.1186/s42397-020-00059-z

Applying plant-based irrigation scheduling to assess water use efficiency of cotton following a high-biomass rye cover crop

[Background] This study addressed the potential of combining a high biomass rye winter cover crop with predawn leaf water potential (ΨPD) irrigation thresholds to increase agricultural water use efficiency (WUE) in cotton. To this end, a study was conducted near Tifton, Georgia under a manually-controlled, variable-rate lateral irrigation system using a Scholander pressure chamber approach to measure leaf water potential and impose varying irrigation scheduling treatments during the growing season. ΨPD thresholds were − 0.4 MPa (T1), − 0.5 MPa (T2), and − 0.7 MPa (T3). A winter rye cover crop or conventional tillage were utilized for T1-T3 as well.

[Results] Reductions in irrigation of up to 10% were noted in this study for the driest threshold (− 0.7 MPa) with no reduction in lint yield relative to the − 0.4 MPa and − 0.5 MPa thresholds. Drier conditions during flowering (2014) limited plant growth and node production, hastened cutout, and decreased yield and WUE relative to 2015.

[Conclusions] We conclude that ΨPD irrigation thresholds between − 0.5 MPa and − 0.7 MPa appear to be viable for use in a ΨPD scheduling system with adequate yield and WUE for cotton production in the southeastern U.S. Rye cover positively impacted water potential at certain points throughout the growing season but not yield or WUE indicating the potential for rye cover crops to improve water use efficiency should be tested under longer-term production scenarios.

[Title] Applying plant-based irrigation scheduling to assess water use efficiency of cotton following a high-biomass rye cover crop

[Authors] MEEKS Calvin D., SNIDER John L., CULPEPPER Stanley and HAWKINS Gary
Journal of Cotton Research 3, Article number: 16 (2020)

https://doi.org/10.1186/s42397-020-00057-1