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Naturally colored cotton fiber is environment-friendly but has monotonous color and poor fiber quality. Identification of green fiber or fuzz genes would aid in investigating the biosynthesis of green pigments in cotton fibers. In this study, we established a mapping population and found that the Lgf trait (white lint and green fuzz) from Gossypium hirsutum race latifolium is controlled by an incompletely dominant gene. The Lgf locus was mapped to a 71-kb interval on chromosome 21 containing seven genes, including a transcription factor with similarity to Arabidopsis MYB9. Harboring 13 SNPs and a 4-bp insertion/deletion in its promoter, GhMYB9 was highly up-regulated in the critical period for green pigment development in fuzz. Virus-induced gene silencing of GhMYB9 in a green-fuzz accession of G. hirsutum race latifolium TX-41 conferred white or light green fuzz. These results suggest that GhMYB9 is an important contributor to green pigments in cotton fiber and shed light on the regulatory mechanism controlling green pigmentation.

Cotton (Gossypium spp.) is a major source of fibre for the textile industry and naturally coloured cotton fibre does not require the use of synthetic dyes making it an eco‐friendly option for textile production. Coloured cotton cultivars are however associated with lower fibre yields and reduced lint quality. A greater understanding of the genetic mechanisms underlying fibre colouration will aid in the development of improved cultivars. The brown‐fibred Gossypium arboreum L. accession PI 615733 was identified from the United States Department of Agriculture germplasm collection and crossed with three white‐fibred accessions PI 529712, PI 529729 and PI 615740 to develop F₂ populations for genetic evaluation. Population data indicated a single dominant gene conferred the brown fibre phenotype. Variation in the intensity of fibre colouration was observed within populations. These data failed to support an incomplete dominance model suggesting genetic modifiers may also play a role in fibre colouration. Additionally, chimeras were frequently observed in the PI 615733 × PI 615740 population. These data will be useful to further characterize the brown fibre trait.

The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is an important insect pest in cotton that feeds on reproductive fruit, contributing to yield loss. Economically damaging infestations of L. lineolaris have doubled in Virginia since 2013. Escalation of L. lineolaris abundance may increase Fusarium hardlock disease observed in this region, compounding economic losses. Research has linked Fusarium hardlock with fungal species Fusarium verticillioides and F. proliferatum. Field and greenhouse experiments were performed to investigate (i) Fusarium hardlock occurrence in field plots managed and unmanaged for L. lineolaris, (ii) severity of F. verticillioides infection of cotton bolls with and without the presence of L. lineolaris feeding in a greenhouse setting, and (iii) Fusarium species composition and prevalence within field-collected L. lineolaris and cotton lint with and without insect feeding injury and hardlock symptoms present. Nearly twice the amount of hardlock (i.e., proportion of hardlocked locules) occurred in field-collected bolls with L. lineolaris feeding symptoms (0.40 ± 0.02) compared with bolls without (0.21 ± 0.01). Based on real-time quantitative PCR, cotton bolls exposed to F. verticillioides inoculum and caged with L. lineolaris adults had greater levels of F. verticillioides DNA compared with untreated bolls. F. proliferatum, F. verticillioides, and F. fujikuroi were isolated from field-collected L. lineolaris and hardlocked cotton lint at harvest. These findings suggest that the presence of L. lineolaris is associated with an increased risk of Fusarium hardlock in Southeastern cotton, and both should be carefully managed using timely insecticide applications and cultural control practices to minimize yield loss.

Cotton (Gossypium hirsutum L.) production in Oklahoma has more than tripled in the last ten years. This increase in cotton acreage in Oklahoma, a region that traditionally produces winter wheat, has led to increased incidences of 2,4 D contamination in sprayers that are used to spray cotton crops. Cotton is extremely sensitive to 2,4 D, with losses of yield and ultimately profit to the cotton producer in cases of drift or tank carryover. In this study, six cotton cultivars (three 2,4 D susceptible and three 2,4 D tolerant) were grown in combination with four N treatments to determine the benefits or drawbacks of using a green manure as N source. Seedcotton, seed, and lint yield were all negatively impacted by 2,4 D in the susceptible cultivars. Additionally, water use was increased in the susceptible cultivars compared to the tolerant cultivars. The negative effects of 2,4 D on cotton growth were partially mitigated by grasspea, though the supply of too much nitrogen increased the negative effects of 2,4 D. Applying nitrogen to a susceptible cultivar of cotton contaminated by 2,4 D is not recommended for short season environments like Oklahoma.

In the present investigation, 39 desi (Gossypium arboreum L.) genotypes along with three checks viz., AKA-7, PA-08 and JLA-794 were studied to observe genetic variability, heritability and genetic advance for fifteen yield contributing and fiber quality characters. Analysis of variance showed significant differences for all the characters among genotypes indicating the presence of wide range of genetic variability in the experimental materials. The high GCV and PCV were observed for number of boll per plant, seed cotton yield per plant, number of sympodia per plant, lint index and plant height. High heritability estimates coupled with high expected genetic advance were observed for the characters number of boll per plant, seed cotton yield per plant, number of sympodia per plant, lint index, plant height and micronaire. It indicates the presence of additive gene action and phenotypic selection may be more fruitful and effective for desired genetic improvement.

Oxycarenus hyalinipennis Costa (Lygaeidae: Hemiptera) has attained the status of major insect pest drastically affecting the value and production of the cotton crop. The main objective of the study is to estimate losses caused by O. hyalinipennis (10, 20, 30, 40, 50, 60 pairs release / boll) identified on boll weight, fiber characteristics (mike, staple length, staple strength, lint index and Ginning Out Turn), seed index and seed germination, under semi opened bolls of two Bt genotypes (MNH-886 and MNH-456). The offered O. hyalinipennis density is directly proportional to GOT while inversely proportional to boll weight, seed index, germination, lint index, mike, staple length and staple strength. All morphological parameters revealed highly significant but negative correlation with offered densities of O. hyalinipennis. Linear regression model showed that fiber characteristics affected significantly by O. hyalinipennis. Thus, a long term sustainable IPM strategy must be implemented to curtail this bug population under check.

Gossypium genus is the main source of natural fiber all over the world. Limitations in conventional breeding program for genetic improvement are due to the complexity and limited knowledge about economically important traits. A diverse germplasm was screened at East Mediterranean Transitional Zone Agricultural Research Institute of Kahramanmaras and at farmer field in Diyarbakir Turkey during 2016 to assess variation for ginning outturn and fiber quality. The gene pool was consisted of global collections namely Acala Maxa, Fibermax810 and Stoneville-453 derived from USA, Delcerro (Venezuela), Carmen (Australia), Taskent-6, Samarkand Uzbek (Uzbekistan), Allepo-40 (Syria), Albania-6172 (Albania), Lachata, Nata (Spain), NSCH777 (India) and elite cultivars from Turkey including Carla, Nazilli84S, Ozbek142 and Fantom. Analysis of variance showed highly significant differences among genotypes for all traits on pooled data basis. Correlation analysis showed significant relationship among fiber traits such as fiber length, fiber strength and micronaire. It was concluded that some genotypes can be used as potential parents in breeding such as AB-80 and BA440 for increasing lint percentage, YB-230 and Flora for fiber length, and Delcerro and Menderes for fiber strength.

The objective of this study was to test the effects of N rates and tillage radish (Raphanus sativus var. longipinnatus) cover crop (TRCC) on soil water and cotton (Gossypium hirsutum L) yield. In three years of the investigation, the treatments were N rates at 84 kg ha−1 and 140 kg ha−1 with and without TRCC. Soil water contents were measured using soil water sensors. Results showed that cotton yield was not significantly (p &gt, 0.05) influenced by TRCC. Compared to N rate at 84 kg ha−1, 140 kg N ha−1 increased lint yield by 2.0%, 7.4%, 18.4% in 2017, 2018, and 2019, respectively, but the increase was significant only in 2019 (p &lt, 0.02). Interactions between TRCC and nitrogen rate on yield were significant (p &lt, 0.03) only in 2017. TRCC increased soil water infiltration capacity, resulting in higher soil water content. Use of TRCC did not affect the cotton yield, which could be due to the high inputs of water and high rates of N neutralizing the positive contributions to the cotton growth expected from the TRCC. Sub-optimum winter temperatures hampered the establishment and subsequent growth of TRCC, which also possibly contributed to its minimum impacts on cotton crop performance in the following season.

The qualitative side of reaction norm of eight promising cotton lines and of standard cultivar was studied. The lines were obtained by intra-specific and remote hybridization of the G. hirsutum L. species with some wild diploid species of the genus Gossypium L. The type of their dynamic regression (of their regression curve) and the structure of ecological environments in their dynamic rows were determined in order to characterize the reaction norm. The years of the study (2014-2017) appeared to be as different ecological environments. Four qualitative characters - seed cotton yield, boll weight, fiber length and fiber lint percentage were analyzed. It was found that in most cases the studied lines had reaction norm which considerably differed from that of the standard cultivar. The specificity of the lines reaction was less pronounced in its type (in ½ of cases) and stronger (in more than 7/8 of cases) in the structure of ecological environments in its dynamic row. By the index type of reaction line № 457 was closest to the standard cultivar, while line № 449 was furthest from it. For the individual characters, the line reaction norm was manifested to varying degrees, from very high - for the boll weight, where similarity with the standard cultivar was missing, to average - for the seed cotton yield, where for this character half of the lines were similar to the standard cultivar.

Red cotton bugs [Dysdercus spp. (Hemiptera: Pyrrhocoridae] are among the most destructive pests of cotton and many other crops. Red cotton bugs (RCBs hereafter) damage cotton plants by sucking sap and deteriorate lint by staining. The incidence of RCBs causes boll injury along the field margins neighboring with various peripheral areas. The adjacent habitat/crops strongly mediate the population dynamics of RCBs. However, limited is known about the impact of adjacent habitat on population dynamics of RCBs and lint quality. This two-year field study evaluated the impact of adjacent habitat (okra, unpaved road, water channel and Eucalyptus trees) on population dynamics of RCBs and lint quality of cotton. The RCBs were sampled weekly from margins to 4 meter inside the cotton field. The RCBs’ populations were monitored and plucked cotton bolls were examined for internal damage. The highest incidence of RCBs was recorded for cotton field adjacent to okra and water channel. Similarly, the highest number of damaged bolls were observed for the field side neighboring with okra and water channel. Furthermore, the highest number of unopened bolls were recorded for okra and water channel sides with higher percentage of yellowish lint. Field sides bordering with Eucalyptus trees and unpaved road had lower RCBs incidence and lint staining. Nonetheless, RCBs incidence was higher at field margins compared to field center indicating that population was strongly affected by adjacent habitat. It is concluded that sowing okra and weedy water channels adjacent to cotton would support RCBs population and subsequent lint staining. Therefore, water channels must be kept weed-free and okra should not be sown adjacent to cotton. Nonetheless, detailed studies are needed to compute monetary damages caused by cotton pests to the crop. Furthermore, effective management strategies must be developed to manage RCBs in cotton to avoid lint-staining problem.

The cotton agroecosystem is one of the most intensely managed, economically and culturally important cropping systems worldwide. Native pollinators are essential in providing pollination services to a diverse array of crops, including those which have the ability to self-pollinate. Cotton, which is autogamous, can potentially benefit from insect-mediated pollination services provided by native bees within the agroecosystem. Examined through two replicated experiments over two years, we hypothesized that native bees facilitated cross-pollination, which resulted in increased lint of harvested bolls produced by flowers exposed to bees and overall lint weight yield of the plant. Cotton bolls from flowers that were caged and exposed to bees, flowers that were hand-crossed, and bolls from flowers on uncaged plants exposed to pollinators had higher pre-gin weights and post-gin weights than bolls from flowers of caged plants excluded from pollinators. When cotton plants were caged with the local native bee Melissodes tepaneca, seed cotton weight was 0.8 g higher on average in 2018 and 1.18 g higher on average in 2019 than when cotton plants were excluded from bees. Cotton production gains from flowers exposed to M. tepaneca were similar when measuring lint and seed separately. Cotton flowers exposed over two weeks around the middle of the blooming period resulted in an overall yield gain of 12% to 15% on a whole plant basis and up to 24% from bolls produced from flowers exposed directly to M. tepaneca. This information complements cotton-mediated conservation benefits provided to native pollinators by substantiating native bee-mediated pollination services provided to the cotton agroecosystem.

Verticillium wilt, caused by Verticillium dahliae Kleb., leads to significant losses in cotton yield and fiber quality worldwide. To investigate Verticillium wilt impact on photosynthesis rate, yield, and fiber quality, six upland cotton genotypes, namely Verticillium susceptible (DP 1612 B2XF) and partially resistant (FM 2484B2F) commercial cultivars and four breeding lines, were grown to maturity under greenhouse conditions in soil either infested or not infested with V. dahliae microsclerotia. Photosynthetic rate, lint, and seed yield were all higher (p &lt, 0.05) for FM 2484B2F than DP 1612 B2XF when infected with V. dahliae. When comparing healthy (H) to Verticillium wilt (VW) affected plants, fiber properties were greatly impacted. Micronaire decreased from 5.0 (H) to 3.6 (VW) with DP 1612 B2XF and 4.4 (H) to 4.1 (VW) with FM 2484B2F. The maturity ratio decreased from 0.90 (H) to 0.83 (VW) for DP 1612 B2XF and was unchanged for FM 2484B2F (0.90). Fiber properties such as short fiber content, nep count, fineness, and immature fiber content were also significantly affected under Verticillium wilt pressure. With Verticillium wilt affected plants, lines 16-13-601V and 17-17-206V performed similarly to FM 2484B2F for photosynthetic rate, yield, and all fiber properties measured. When selecting for improved cultivars in the presence of Verticillium wilt, it is important to select for relatively unchanged fiber properties under disease pressure in addition to reduced disease severity and increased yield.

Managers, scientists, planners and designers of landscapes are interested in systematic investigations, to predict the reconstruction of disturbed soil resources for optimum vegetation productivity. In this study, a predictive equation for estimating neo-soil plant growth in Coryell County, Texas was developed. The equation predicts the vegetation growth for wheat (Triticum aestivum L.), oats [Avena sativa L. (1753)], sorghum [Sorghum bicolor (L.) Moench], cotton lint (Gossypium hirsutum L.), Bermuda grass [Cynodon dactylon (L.) Pers.], and rangeland production in general. The results suggest that an all-vegetation predictive model was highly significant (p &le, 0.0001), explaining over 80% of the variance. The equation employed hydraulic conductivity as a main-effect variable, bulk density and hydraulic conductivity as squared terms, and percent clay times bulk density, bulk density times soil reaction, hydraulic conductivity times available water holding capacity, and hydraulic conductivity times soil reactions as first order interaction terms, with each predicting variable containing a p-value equal to or less than 0.05. The results suggest that an annual crop equation and a plant-specific cotton lint equation also have merit.

Cotton known as king of fibers or white gold, belongs to the order Malvales and family Malvaceae. The four cultivated species namely, Gossypium arboreum, G. herbaceum, G. hirsutum, and G. barbadense contain almost all the varieties of cotton cultivated in India. The most important part of the cotton plant is the fiber or lint, which is used in making cotton cloth. Root rot disease of cotton occurs in several countries including Egypt, Greece, India, Israel, Pakistan, Sudan, Trinidad, Uganda, USA, Venezuela, and Republic of Congo. Seedling disease of cotton is important in almost all cotton growing areas. Anthracnose of cotton is widespread in different cotton growing tracts of India. However, it is occasionally noticed in Eastern Maharashtra and summer cotton growing areas in South India. The disease occurs in different cotton growing areas of the world. The disease has been reported from Argentina, Brazil, China, Fiji, India, Nigeria, Sri Lanka, USA, and West Indies.

Small plot cotton cultivar trials (12 trials) were conducted from 2016 to 2019 in fields infested with Meloidogyne incognita. Entries in these trials included commercial cultivars with partial and high resistance to M. incognita, as well as cultivars with no known resistance. Different resistant groups were created based on different cotton seed companies and their descriptions of the M. incognita resistant cultivars. Groups were none (susceptible); partial resistance found in Stoneville or Fibermax cultivars (PR-FM/ST); partial resistance found in PhytoGen cultivars (PR-PHY); resistance (unknown gene(s)) in Deltapine cultivars (NR-DP); and highly resistant cultivars homozygous for RK1 and RK2 resistant genes in PhytoGen cultivars (HR-PHY). The highest lint yields using a mixed model analysis were found in the PR-FM/ST (1,396 kg lint/ha), HR-PHY (1,327 kg lint/ha), and PR-PHY (1,314 kg lint/ha) groups. Yield for NR-DP (1,234 kg lint/ha) was not different (p > 0.05) than yield for susceptible cultivars (1,243 kg lint/ha). If the older resistant cultivars from Deltapine and PhytoGen (those with only Roundup Ready® herbicide technology) were removed from the analysis, then HR-PHY yields increased by 133 kg of lint/ha to 1,460 kg lint/ha and NR-DP yields remained approximately unchanged (1,227 kg lint/ha). Newer HR-PHY had much improved yield over the first HR-PHY cultivars. Newer HR-PHY averaged 17% higher yield than the susceptible group. LOG10 (M. incognita eggs/500 cm3 soil + 1) were highest for the susceptible cultivars (3.2), followed by PR-FM/ST (2.6), NR-DP (2.4), PR-PHY (2.1), and lowest with HR-PHY (1.4). The newer HR-PHY cultivars (those with ENLIST® herbicide technology) combine excellent yields (17% higher than susceptible cultivars) with high (96%) suppression of M. incognita. Small plot cotton cultivar trials (12 trials) were conducted from 2016 to 2019 in fields infested with Meloidogyne incognita. Entries in these trials included commercial cultivars with partial and high resistance to M. incognita, as well as cultivars with no known resistance. Different resistant groups were created based on different cotton seed companies and their descriptions of the M. incognita resistant cultivars. Groups were none (susceptible); partial resistance found in Stoneville or Fibermax cultivars (PR-FM/ST); partial resistance found in PhytoGen cultivars (PR-PHY); resistance (unknown gene(s)) in Deltapine cultivars (NR-DP); and highly resistant cultivars homozygous for RK1 and RK2 resistant genes in PhytoGen cultivars (HR-PHY). The highest lint yields using a mixed model analysis were found in the PR-FM/ST (1,396 kg lint/ha), HR-PHY (1,327 kg lint/ha), and PR-PHY (1,314 kg lint/ha) groups. Yield for NR-DP (1,234 kg lint/ha) was not different (p > 0.05) than yield for susceptible cultivars (1,243 kg lint/ha). If the older resistant cultivars from Deltapine and PhytoGen (those with only Roundup Ready® herbicide technology) were removed from the analysis, then HR-PHY yields increased by 133 kg of lint/ha to 1,460 kg lint/ha and NR-DP yields remained approximately unchanged (1,227 kg lint/ha). Newer HR-PHY had much improved yield over the first HR-PHY cultivars. Newer HR-PHY averaged 17% higher yield than the susceptible group. LOG10 (M. incognita eggs/500 cm3 soil + 1) were highest for the susceptible cultivars (3.2), followed by PR-FM/ST (2.6), NR-DP (2.4), PR-PHY (2.1), and lowest with HR-PHY (1.4). The newer HR-PHY cultivars (those with ENLIST® herbicide technology) combine excellent yields (17% higher than susceptible cultivars) with high (96%) suppression of M. incognita.

Extreme elongation distinguishes about one-fourth of cotton (Gossypium sp.) seed epidermal cells as “lint” fibers, useful for the textile industry, from “fuzz” fibers (

Economically damaging infestations of Lygus lineolaris (Palisot de Beauvois), tarnished plant bug, were sporadic in Virginia and North Carolina cotton before 2010. Given the sudden rise of L. lineolaris as an economic pest in these states, regionally specific management practices (i.e., chemical and cultural control) are needed to help producers protect yield potential while minimizing input costs. Field experiments were conducted in Virginia and North Carolina in 2018 and 2019 to 1) determine the effects of various management practices on L. lineolaris density, plant injury (i.e., square retention, internal boll injury), and lint yield, 2) calculate the economic trade-offs between integrated pest management (IPM) systems approach and current management practices for L. lineolaris in these states, and 3) evaluate economic benefits associated with various sampling thresholds. Lygus lineolaris populations peaked mid-season (i.e., August) during cotton flowering in both states. Weekly scouting and applying foliar insecticides when the current University Extension recommended economic threshold was reached was the most critical management treatment in maximizing economic returns. Additional costs among various IPM practices did not translate into significant yield protection and economic gains. Moreover, there were additional economic benefits associated with protecting glabrous and longer maturing varieties in Virginia. Lygus lineolaris density varied significantly between states; therefore, management recommendations should be modified based on the growing region. Results from this study will be used to create an IPM strategy to help cotton producers effectively manage this insect pest in the Southeast.

Cotton fibres, as single cells arising from the seed coat, can be classified as lint and fuzz according to their final length. Gossypium arboreum is a cultivated diploid cotton species and a potential donor of the A subgenome of the more widely grown tetraploid cottons. In this study, we performed genetic studies on one lintless and seven fuzzless G. arboreum accessions. Through association and genetic linkage analyses, a recessive locus on Chr06 containing GaHD-1 was found to be the likely gene underlying the lintless trait. GaHD-1 carried a mutation at a splicing acceptor site that resulted in alternative splicing and a deletion of 247 amino acid from the protein. The regions containing GaGIR1 and GaMYB25-like were found to be associated with fuzz development in G. arboreum, with the former being the major contributor. Comparative transcriptome analyses using 0-5 days post-anthesis (dpa) ovules from lintless, fuzzless, and normal fuzzy seed G. arboreum accessions revealed gene modules and hub genes potentially important for lint and fuzz initiation and development. Three significant modules and 26 hub genes associated with lint fibre initiation were detected by weighted gene co-expression network analysis. Similar analyses identified three vital modules and 10 hub genes to be associated with fuzz development. The findings in this study contribute to understanding the complex molecular mechanism(s) regulating fibre initiation and development and indicate that G. arboreum may have fibre developmental pathways different from tetraploid cotton. It also provides candidate genes for further investigation into modifying fibre development in G. arboreum.

Lint and fuzz are the two types of fiber that develop on cotton seeds. Lint is an economically important fiber used in the textile industry. Fuzz fibers remain attached to seeds, and reducing the amount of fuzz could improve ginning efficiency. The Gossypium arboreum accession PI 615733 from the United States Department of Agriculture cotton germplasm collection showed the fuzzless trait, where no fuzz fibers were observed on seeds. Accession PI 615733 was crossed with the fuzzy seeded G. arboreum accession PI 529729 to develop an F2 population. Seeds from F1 plants showed no fuzz fiber. For the F2 population of 409 plants, 239 plants were classified as fuzzless and 170 were classified as fuzzy. These data support a two-gene model with incomplete dominance. A greater understanding of the genetic mechanisms controlling fiber development on cotton seeds could contribute to breeding efforts to improve lint fiber yields and quality.

BRS 372 and BRS 416 are cotton cultivars with high lint yield and genetic resistance to the main cotton diseases in Brazil, particularly to Ramularia Leaf Spot. They have stable yields, good fiber quality and can contribute to a sustainable cotton disease management in tropical environments.

Sixteen cotton genotypes representing a wide range of cotton characteristics, were used in two concurrent trials (laboratory and field) at Sakha Agric. Res. Station under well-watered and water-limited regimes during 2016 and 2017 seasons. The objectives were to determine genotypic variability among cotton varieties in their response to deficit water stress and to detect the most suitable genotypes, traits and selection procedure for water stress condition. The genotypes were evaluated for water deficit stress in laboratory by the simulation of water potentials with polyethylene glycol-6000 (0.0 and -0.4 MPa), at 25oC using aerated hydroponic culture box. After 18 days the following seedling traits were measured, root length (cm) (RL), root fresh weight (g) (RFW), root dry weight (g) (RDW), shoot length (cm) (SHL), shoot fresh weight (g) (SHFW) and shoot dry weight (g) (SHDW). Field trail conducted to measure vegetative traits, yield and yield components and fiber traits. Analysis of variance for the growing seasons 2016 and 2017 revealed significant differences with respect to water regimes, genotypes and water regimes x genotypes for most of the studied traits, confirming the presence of genotypic variability among the studied cotton genotypes. Mean values exhibited decreasing in traits from normal to water deficit conditions in all traits except for maturity (M). The relative reduction (RD%) varied from 1.25% for pressley index(PI) to 51.6% for lint yield/plant (LY/P). Fiber traits were the lowest affected traits by water stress. G. 88, G. 93 and Suvin were less affected by water stress for seedling traits. For vegetative traits, G.77, G.94, G.89xG.86, Ashmouni, Menoufi and Suvin showed higher values under water deficit. Regarding to yield and yield components traits G.89xG.86, Menoufi, Suvin and G.86 showed the highest water deficit tolerance with acceptable production under limited water regime. On the other hand, most of extra-long staple cotton varieties G.87, G.88 and G.93 were most susceptible to water deficit stress in production term. Drought susceptibility index (DSI) showed significant negative correlation with yield under water deficit regime suggesting DSI as a useful predictor of drought tolerance in cotton and confirming the need of performing genotype evaluation under water stress in case of breeding for water deficit tolerance. Generally, the extra-long genotypes were more susceptible to water deficit stress than long staple genotypes for fiber traits. Correlation coefficients between all the studied traits under well watered and limited water regimes over two years revealed that, yield was positively correlated with yield components traits and plant height (PH); and negatively correlated with most fiber traits. The path coefficient analysis revealed positive and negative direct effect of traits on seed cotton yield (SCY/P). The highest direct effect on SCY/P was exhibited by bolls/plant (B/P) (1.36) followed by boll weight (BW) (0.91) and lint percentage (L%) (0.53). The highest indirect effect of most of yield and vegetative traits were through B/P and BW. These results confirming that, selection to improve productivity under water deficit stress could be more effective throughout direct selection for B/P and BW. Factor analysis revealed that first three components accounted for about 88.51% % of the total variation among the studied traits. Results exhibited the importance of LI, SI, L%, BW, LY/P, SCY/P and PH traits in factor 1 and B/P, SCY/P and LY/P in factor 2 confirming the importance of these traits in the total variance to improve productivity under deficit water stress.

Whitefly has assumed the status of a serious pest of cotton in north India in recent past due to its severe attack on cotton crop. The productivity of cotton crop has fallen substantially from 574 kg ha-1 of lint in the year 2014 -15 to 197 kg ha-1 in the year 2015-16 in Punjab. During extensive epidemiological surveillance of whitefly on cotton crop in the month of September 2016, mummified whiteflies with fungus were noticed on both abaxial and adaxial surfaces of leaves of the infested cotton plant at village, Mandi Khurd, Mansa District of Punjab, India and at Punjab Agricultural University, Regional Research Station, Bathinda, India. The fungus was isolated and purified from the mummified white fly and characterized at molecular level by sequencing 633 bp D2 region of Large Subunit (LSU) rRNA gene and identified as Penicillium oxalicum spg1. The gene sequence has been submitted to NCBI, USA with accession no. KY214238. The microscopic studies (stereo- and scanning electron) of the cotton leaves with mummified whitefly further strengthen the entomopathogenic potential of P. oxalicum spg1. There are few reports of entomopathogenic potential of P. oxalicum spg1 against other insects and pests. To our knowledge, this is the first report of isolation and identification of P. oxalicum spg1 from mummified white fly. It’s potential as a biocontrol agent against white fly can be exploited in a promising way with nominal interference with biological equilibrium.

The present investigation entitled “Study on heterosis and combining ability for yield, its components and fibre characters in Desi cotton ( Gossypium arboreum L.)” was undertaken to estimate general combining ability effects (GCA) of the parents and specific combining ability effects (SCA) of the crosses. The experimental material comprised of 24 F 1 hybrids obtained by crossing 4 lines with 6 testers in line x tester mating system. Sum total of 36 treatments consisting of 24 crosses, 10 parents and three standard checks were sown in Randomized Complete Block Design. The analysis of variance for combining ability revealed significant general combining ability effects (GCA) and specific combining ability effects (SCA) for all the traits. Among ten parental lines, most of the lines were found to be best general combiner, which had significant general combining ability (GCA)effect for seed cotton yield and its contributing characters including fibre quality traits. Analysis of variance for means revealed significant differences for all the eighteen characters studied. Among females, PA 741 was found to be the best general combiner for 3 characters viz ., days to 50 per cent flowering, days to 50 per cent boll bursting and days to maturity had significant GCA effects. The female PAIG 77 was the best general combiner for three characters viz ., number of bolls per plant, number of seeds per plant and boll weight. The female PA 809 was the best general combiner for 2.5 per cent span length, fibre fineness/micronaire, fibre strength, uniformity ratio and short fibre index. Among males, AKA 2004-29 found to be best general combiner for days to 50 per cent flowering, days to 50 per cent boll bursting, days to maturity and ginning outturn. Male parent ARBAS 1301 was also found to be best general combiner for number of sympodia per plant, number of bolls per plant,number of seeds per boll, seed cotton yield per plant, lint index, seed index, plant height, 2.5 per cent span length, fibre fineness, short fibre index and fibre strength. Male parent GAM 162 found to be best genral combiner for ginning outturn, 2.5 per cent span length and short fibre index whereas, CNA 1016 for boll weight. There was close agreement between per se performance and GCA as well as SCA effects for most of the characters. Observations on various characters indicated that the crosses showing high heterosis and high SCA effects had high per se performance and they involved at least one high combining parent. The combinations PAIG 77 x ARBAS 1301, PA 734 x ARBAS 1301, PA734 x CNA 1016, PA 809 x ARBAS 1301 and PA 741 x JLA 0614 showed significant and desirable SCA effects for most of the yield and fibre quality traits studied, indicating potential for exploiting hybrid vigor in breeding programme.

Target spot, caused by Corynespora cassiicola, prematurely defoliates and occasionally reduces cotton yield across the southeastern United States. Reaction of the cultivars Deltapine 1137 B2RF, Deltapine 1252 B2RF, Fibermax 1944 GLB2, PhytoGen 499 WRF, PhytoGen 575 WRF, and Stoneville 6448 GLB2 to target spot and lint yield as influenced by a full-season Headline + Bravo Ultrex fungicide program was assessed for 3 years in southwest Alabama. Significantly greater final % and relative area under the disease curve (relAUC) season-long defoliation was recorded for PhytoGen 499 WRF than the other cultivars, which had similarly lower defoliation values. A significant yield gain of 92 kg of lint/ha valued at $142/ha across all cultivars was obtained with the fungicide program. In addition, PhytoGen 499 WRF and Fibermax 1944 GLB2 had significantly lower defoliation and greater yield gains (189 and 263 kg of lint/ha, respectively) with the fungicide than no fungicide program. Hardlock incidence was greater in 2016 than in preceding years and did not differ by fungicide program. Open and unopen boll counts were similar across all cultivars and fungicide programs. Study results indicate that partially resistant cultivars may be an effective tool for managing target spot in cotton.

Cotton (Gossypium hirustum L.) as well as other crops are asking for an effective production with cost reduction and environment stewardship globally, especially in the developing countries. A new cotton planting strategy should be possible by shortening the growth season (less than six months rather than seven to eight months by late sowing and early harvesting) with low nitrogen (N) and high density. Therefore, a two-year (2018–2019) field experiment was conducted with a split plot design, two planting densities (D1, 6 plants m−2; D2, 8 plants m−2) as the main plot and three N rates (150, 180 and 210 kg ha-1 referred as N1, N2, and N3, respectively) as the subplot, to determine the effects of planting density and N rate on cotton yield and biomass accumulation. Results showed that, averaged across years, cotton yield was greater for treatment D2 as compared with that in D1, and N3 did not differ from that in N2 but was greater than that in N1. The highest lint yield (1271.2 kg ha-1) was achieved in D2N2 which no differ from that in D2N3 and D1N3. The maximal biomass (K) was achieved in treatment D2N2 (1032.4 g m−2) with the average speed (VT) of 21.2 g m−2 d-1 during the fast accumulation period, and the maximal growth rate (Rm, 20.5 g m−2 d-1) of sink during the cotton growth and development. Seedcotton yield was positively correlated (r = 0.72) to the plant biomass during flowering and boll-setting period, and the yield was contributed directly by sink with a coefficient as high as 0.70, while it was contributed indirectly by flow and source with coefficients of 0.63 and 0.59, respectively. The results suggest that N reduction is feasible due to a quicker bulk sink biomass accumulation under a higher planting density, which benefits efficient cotton production in the Yangtze River Valley, China, and areas with similar ecology.

Neonicotinoid insecticides are currently one of two classes of chemicals available as a seed treatment for growers to manage early season insect pests of cotton, Gossypium hirsutum L. (Malvales: Malvaceae), and they are used on nearly 100% of cotton hectares in the midsouthern states. An analysis was performed on 100 seed-treatment trials from Arkansas, Louisiana, Mississippi, and Tennessee to determine the value of neonicotinoid seed treatments in cotton production systems. The analysis compared seed treated with neonicotinoid insecticides seed treatments plus a fungicide with seed only treated with fungicide. When analyzed by state, cotton yields were significantly greater when neonicotinoid seed treatments were used compared with fungicide-only treatments. Cotton treated with neonicotinoid seed treatments yielded 123, 142, 95, and 104 kg ha-1, higher than fungicide only treatments for Arkansas, Louisiana, Mississippi, and Tennessee, respectively. Across all states, neonicotinoid seed treatments provided an additional 115 kg lint ha-1 comparedwith fungicide only treated seed. Average net returns from cotton with a neonicotinoid seed treatment were $1,801 per ha-1 compared with $1,660 per ha-1 for cottonseed treated with fungicide only. Economic returns for cotton with neonicotinoid seed treatments were significantly greater than cottonseed treated with fungicide only in 8 out of 15 yr representing every state. These data show that neonicotinoid seed treatments provide significant yield and economic benefits in Mid-South cotton compared with fungicide only treated seed.

SUMMARYThe number of replications and locations used in a cultivar evaluation scheme is an important factor affecting the trial heritability (H) and optimum resource allocation. The aim of the present study was to calculate the required number of replications and locations for realizing an optimumHof 0·75 and to identify the most effective test locations for cotton (Gossypium hirsutumL.) in Greece. The data for lint yield, plant height, verticillium wilt (Verticillium dahliaeKleb.) and fibre quality were derived from an 8-year experiment (2000–2007) conducted under irrigated, Mediterranean conditions at 14 locations along the Greek mega-environment. Analysis of variance was performed to calculateHas well as genotype plus genotype × environment (GGE) biplot analysis to determine the location's desirability. It was determined that the four replications currently used in the evaluation of lint yield were sufficient, whereas four locations were proposed as optimum in lieu of the current 8–14 locations used in the evaluation. Two locations excelled as the most effective for lint yield evaluation and one for selection of genotypes tolerant to verticillium wilt using as criteria: the high and consistent across yearsH(0·75), GGE biplot representativeness and discriminating ability. Moreover, one location was selected as a backup based on average trial failures. Plant height was sufficiently evaluated by four replications and two locations, while verticillium required four replications for realizing lowerH(0·60) and three locations for even lowerH(0·40). Regarding quality, an increase of replications from the two currently used to four was sufficient for evaluation of all the traits. The advantage of reducing the number of locations for evaluation of lint yield to just four casts no doubt on the evaluation precision of lint percentage, length, strength and elongation but does for micronaire, short fibre index and uniformity, which realized lowerH(0·60 or 0·50).

This study assesses the effects of plant population density (PPD) and sowing date (SD) on growth, physiology and lint yield of a cotton crop. Seedling transplanting is one of the most dominant cotton production systems in China. But on the other hand, the net benefit is decreasing because the system is labor intensive. Therefore, a shorter cotton growing season is urgently needed to reduce the production costs through management practices such as adjusting sowing date and PPD. The following hypothesis was tested; would cotton yield and physiology from a late sowing be compensated by plant density? Field experiments were conducted with two sowing dates (S1, May 20; S2, June 04) as the main plot and three PPDs (D1, low; 7.5 × 104; D2, moderate; 9.0 × 104 and D3, high; 10.5 × 104 ha−1) as the sub-plot. Early-sown plants produced 23%, 32%, 55%, 77% and 14%, taller stems more nodes, leaves and fruits, respectively, than the late-sown plants. Consequently, S1 produced 26% higher lint yield than S2. This increase in lint yield was mainly attributed to a relatively longer cropping season, which allowed utilization of available resources. Growth and fruit production in S1 plants were further increased by an increased photosynthetic rate (Pn) and N acquisition. Across the plant densities, 13% and 6% more lint yield was achieved under D2 than the D3 and D1, respectively. Moderate PPD increased lint yield by 13% and 6% over high and low, respectively. Nitrogen (N) acquisition was 45%, 33%, higher for S1 sown crop compared with S2, respectively. S1D2 had higher average (3.5 VT kg ha−1 d−1) and maximum (4.5 VM kg ha−1 d−1) rates of N accumulation in reproductive organs at the fastest accumulation point among other treatments. Our data suggest that for both sowing dates moderate PPD is a promising option, which allows light interception and penetration to the lower canopy, efficient N utilization and assimilate distribution to reproductive structures.

The cotton stainer, Dysdercus koenigii Fabricius (Hemiptera: Pyrrhcoridae), has become a major threat to transgenic cotton as it causes warts on the internal carpel wall of cotton boll, severe lint staining, lint locks, and lint lesions. Thus, keeping in view the importance of this pest on cotton, in the present study, screening of 13 transgenic cotton genotypes was performed and the population of D. koenigii was determined on these genotypes during 2012–13. Furthermore, among these genotypes, a high yielding advanced cultivar (FH-114) was selected for further experiments. A number of five different densities of D. koenigii (5, 10, 15, 20, and 25) at adult stage with well-developed proboscis were released in the cages along with a control treatment. Cotton genotypes FH-312, FH-2073, FH-Lalazar, FH-142, and MNH-886 possessed minimum population (1.33 D. koenigii per plant) compared to FH-324 and FH-444 (6.0 D. koenigii per plant). The number of bolls per plant and boll weight decreased as a result of increased densities. The increased density of D. koenigii resulted in fewer bolls per plant (12.1 bolls), reduced boll weight (2.1 g), germination (39.1%), ginning out turn (38.3%), staple length (27.8 mm), and staple fineness (4.0 μg/in.) when compared with un-infested plants (30.6, 3.2 g, 77.3%, 41.5%, 28.8 mm, and 4.4 μg/in.), respectively. Correlation analysis revealed that bolls per plant, boll weight, germination, ginning out turn, and staple fineness resulted in negative and significant correlation with density of D. koenigii with r-values of −0.95, −0.98, −0.98, −0.8, and −0.85, respectively. Coefficient of determination (R2) demonstrated that bolls per plant, boll weight, germination, ginning out turn, staple length, and staple fineness contributed with 91, 96, 96, 79, 43 and 73%, respectively, to the total variability at different densities of D. koenigii. Our findings demonstrated that D. koenigii has become potential major pest and causes quantitative and qualitative losses to transgenic cotton, hence, there is a need to develop appropriate control measures for controlling its population to avoid further losses.

Genetic diversity provides the foundation for crop improvement. Genetic variation and associations among Cotton Leaf Curl Disease (CLCuD), fiber and yield related traits were investigated in exotic lines of Gossypium arboreum L. in an experimental field at the Central Cotton Research Institute (CCRI), Multan, Pakistan during the crop season 2011-12. One hundred and nineteen (119) accessions imported from USA through the Pakistan and US “Cotton Productivity Enhancement Program” (CPEP), were evaluated in this study. Various statistical approaches including descriptive statistics, correlation and principal component analysis was performed to evaluate and identify desirable genotypes. Results revealed that seed cotton yield was significantly and positively correlated with boll weight and number of bolls plant-1. Similarly, plant height was also significantly correlated with sympodial branches, lint percentage and micronaire value. Lint percentage showed a highly significant and positive correlation with plant height, sympodial branches and micronaire value. With respect to fiber traits, negative and significant relationships were observed between the micronaire value (MIC) and fiber strength. CLCuD showed no relationship with any of the studied traits, as all the G. arboreum L. lines evaluated were scored resistant to CLCuD. Principal component analysis (PCA) showed that the first four out of 11 components contributed about 65.88% of the total variation having an eigen value greater than 1. Based on PCA, the genotypes GS-4, GS-9, GS-8, GS-55 and GS-50 could be utilized successfully in a future breeding program based on having the highest positive loading factor for staple length (0.135) in PC1 and seed cotton yield (0.625), number of bolls plant-1, boll weight, first sympodial nod, staple length and fiber strength in PC2 respectively.

Interactive effects of multiple environmental stresses are predicted to have a negative effect on cotton growth and development and these effects will be exacerbated in the future climate. The objectives of this study were to test the hypothesis that cotton cultivars differ in their responses to multiple environmental factors of (CO2) [400 and 750 µmol·mol–1 (+(CO2)], temperature [28/20 and 20/12°C (–T)], and UV–B radiation [0 and 10 kJ·m–2·d–1 (+ UV–B)]. A genetic and molecular standard (TM-1) and three modern cotton cultivars (DP1522B2XF, PHY496W3R, and ST4747GLB2) were grown in eight sunlit, controlled environment chambers with control treatment 400 µmol·mol–1 [CO2], 28/21°C temperature, and 0 kJ UV–B. The results showed significant differences among the cultivars for most of the shoot and root parameters. Plants grown under low temperature alone or as a combination with + UV–B treatment caused more detrimental effects on root and shoot vigor. Although the elevated CO2 treatments weakened the damaging effects of higher UV–B levels on cotton growth on all cultivars, increased CO2 could not mask the negative effects of low temperature. When comparing all cultivars, genetic standard TM-1 produced the smallest values for the majority of traits under CO2, UV–B, and low temperature either alone or in combination with other treatments. Based on principal component analysis, the four cultivars were classified as tolerant (DP1522B2XF), intermediate (PHY496W3R and ST4747GLB2) and sensitive (TM-1) to multiple environmental stresses.Low temperature was identified as the most damaging treatment to cotton early seedling vigor while elevated CO2 caused the least. Existing variability of cotton cultivars in response to multiple environmental stresses could allow for selection of cultivars with the best coping ability and higher lint yield for future climate change environments.

Aphis gossypii Glover is a major pest of cotton and can severely affect cotton yield and lint quality. In this study, the efficacy of sulfoxaflor applied via drip irrigation and foliar spray on controlling cotton aphids was evaluated in 2016 and 2017 in Xinjiang, China. The distribution of sulfoxaflor in cotton roots, stems, leaves, and aphids, as well as its effects on two natural enemies of aphids, were also investigated. Results showed that sulfoxaflor applied through drip irrigation mainly concentrated in leaves and provided effective control of cotton aphids for 40 days, compared to 20 days when applied through foliar spray. Furthermore, drip application resulted in much lower sulfoxaflor concentrations in aphids than foliar spray. As a result, ladybird beetle and lacewing populations were higher in drip applied plants than in foliar sprayed plants. Additionally, the cost of drip irrigation was lower than foliar spray as cotton plants are commonly irrigated via drip irrigation in Xinjiang. Our results showed that application of sulfoxaflor through drip irrigation is an effective way of controlling cotton aphids in Xinjiang due to a prolonged control period, safety to two natural enemies, and lower cost of application.

Combined application of nitrogen (N), phosphorus (P), and potassium (K) is a valuable practice to improve the growth and physiological activities of cotton, especially during a boll setting. The main purpose of this research was to investigate the effects of the different combined ratios of nitrogen (N), phosphorus (P), and K (potassium) on morpho-physiological activities of Bacillus thuringiensis (Bt) cotton genotypes Siza 1 and Sikang 1 during the cotton boll development stage. A two-year (2016&ndash, 2017) field experiment was performed in which the total amount of combined N, P, and K were applied at different levels, B1 = 150 N, 0 P2O5, and 0 K2O kg ha&minus, 1 (control), B2 = 150 N, 45 P2O5, and 90 K2O kg ha&minus, 1, B3 = 150 N, 90 P2O5, and 135 K2O kg ha&minus, 1, and B4 = 150 N, 135 P2O5, and 180 K2O kg ha&minus, 1. Results revealed that combined application of N, P, and K significantly increased boll length by 5.8% and 2.3%, fresh boll weight by 12.2% and 16.4%, dry lint weight by 15.2% and 1.7%, number of seeds boll&minus, 1 by 15.2% and 2.5% as well as dry boll shell weight by 11.0% and 4.9% as compared with the treatment without P and K (1:0:0) across two growing seasons. Furthermore, superoxide dismutase activity was improved by 2.3% and 15.6% and soluble protein by 5.1% and 14.1% as compared with the control, respectively. Our study indicated that combined application of N, P, and K at appropriate ratios enhanced morpho-physiological activities (boll length, boll width, boll weight, protein content, sugar content, and superoxide dismutase) of cotton during boll development and generally the ratio of 150:135:180 considerably performed best amongst all treatments during two growing seasons in this study.

Since the summer of 2006, bacterial boll rot of cotton has been observed on fruits of ‘Xinluzao 31’ (Xinluzao 6 × Acala) in Xinjiang Province. It resulted in as much as 20% yield loss in several fields. Symptoms do not appear on the outer carpel. In the infected cotton bolls, fibers do not mature completely and seed tissue exhibits brown necrotic coloration. Lint and seeds from 24 surface-disinfested cotton bolls were triturated and plated onto King's medium B (KB). Plates were incubated at 28°C for 48 h. Forty eight strains with yellow pigmentation on KB were characterized. All were nonfluorescent on KB, gram negative, facultatively anaerobic, unable to produce indole from tryptophan, able to reduce nitrate to nitrite, and produce acid from glucose, cellobiose, lactose, melibiose, and melonate. In addition, 16S rDNA in seven strains was amplified with universal primers (1). The PCR products were cloned into pGEM-T easy vector and sequenced. A BLAST search of the seven sequences against the GenBank nucleotide library indicated 100% identity with the 16S rDNA sequence of Enterobacter agglomerans strain A80. Then an additional primer pair, pagF and pagR (3), was used for more specific amplification of Pantoea agglomerans 16S rDNA, which resulted in single highly specific fragments of approximately 1 kb. On the basis of morphological, physiological, biochemical characteristics, and 16S rRNA gene sequence analysis, we identified the bacterium to be P. agglomerans. To confirm pathogenicity, cell suspensions (1 × 108 CFU/ml) of eight representative strains were used to inoculate cotton at peak bolling stage in the field. Cell suspensions, or water as the control, were applied to stigma scars, wall sutures, and scratch wounds on bracts, calyxes, and bolls. Alternatively, a needle was used to puncture through a drop of suspension placed on the boll wall suture and bracts. At least 20 bolls or flowers were inoculated with each bacterial strain per inoculation method. Infection occurred only when bacterial injections breached the endocarp of the boll either through the carpel wall or a suture between carpel sections. Disease symptoms developed 1 week postinoculation. The inoculated organism was reisolated from the diseased tissues. P. agglomerans is generally regarded to be a soil saprophyte or leaf epiphyte, but strains can opportunistically infect plants triggering gall formations or human wounds causing septic arthritis. The disease symptoms and pathogen characteristics observed in this study are identical to those reported in the United States (2). To our knowledge, this is the first report of P. agglomerans causing boll rot of cotton in China. References: (1) S. Manulisi and I. Barash. Mol. Plant Pathol. 4:307, 2003. (2) E. G. Medrano et al. J. Appl. Microbiol. 103:436, 2007. (3) S. Vorwerk et al. Agric. For. Entomol. 9:57, 2007.

Investigating the population dynamic of important cotton pests on new cotton varieties is important. Cotton cultivars have important pests such as thrips, aphids, whitefly and bollworm. Considering the premature cultivars with proper yield for second cultivation in cotton-growing Golestan province at the north of Iran, this study seems necessary. This genotypes was cultivated with 9 treatments in 4 replicates. A completely randomized block design was carried out in Hashem Abad research station in a spray-free plot with the dimensions of 30 × 80 cm in 2018-2019 years. According to the results of this study, analysis of variance of two years showed that the yield of N2G80 with 1538 g in the plot with 41.7% lint percentage had the highest yield, and M13 with 685 g in the plot and 35.8% lint percentage in the lowest yield they had. The infestation rate of the genotypes tested in the population of green aphid of cotton in K880-2 and Golestan® cultivars was 48.88 and 40.31 in aphid with the highest density, and the SKT-133 and TBL-60 genotype respectively with 27.15 and 29.11 aphids per leaf had the least infestation. The amount of infestation of the genotypes tested to the population of whitefly cotton on the N2G80 and TBL-60 genotype was 90.76 and 68.86 whitefly in the leaf with the highest infestation and N2G80 and TBL-60 genotype respectively with 40.05 and 75.51 white fly in leaf were the least infested. Correlation coefficient between traits was equal to 0.55. The number of bolls per plant was not correlated with other traits including boll weight, lint percentage, aphid and white fly.

Tumble dryer lint has been employed as a surrogate for synthetic and processed (microplastic) fibres discharged to the environment from laundering activities and exposed to marine mussels (Mytilus galloprovinciallis) in controlled experiments for a period of 7 d. A range of biological responses at different levels of organisation were subsequently determined, with copper employed concurrently as a positive control. Physiological changes were assessed from measurements of clearance rate, histopathological effects were evaluated from abnormalities in (or injuries to) gill and digestive gland tissues, and genetic damage was determined by measuring DNA strand breaks using the comet assay. With increasing lint concentration (over the range 56–180 mg L−1) we observed a reduction in mean clearance rate, increasing extents of abnormality in both gills (e.g. deciliation and hypertrophy) and digestive gland (e.g. atrophy and necrosis), and an increase in damage to DNA. The precise causes of these effects are unclear but likely arise from both the fibrous material itself and from chemicals (e.g. additives and metals) that are mobilised from the polymers into seawater or the digestive tract. The latter assertion is consistent with an observed increase in the release of certain trace elements (e.g. zinc) into the exposure medium with increasing lint concentration. Although microfibre concentrations we employed are significantly greater than those typically encountered in the environment, the results indicate the potential for this type of material to exert a range of adverse effects on exposed marine animals.

A large plot experiment was conducted in a field infested with Verticillium dahliae. The test area of the field was divided into three different cropping systems. Within each cropping system, the treatments were conventional tillage (CT) and reduced tillage (RT) at three irrigation rates (base rate = 1.0B designed to meet 60% of the crop evapotranspiration [ET] needs, and 50% above [1.5B] and below [0.5B] the base rate). Higher microsclerotia densities occurred with CT at the 1.5B rate than with RT at that rate, though densities were similar between tillage treatments at the 1.0B and 0.5B irrigation rates. Wilt incidence and defoliation were not affected by tillage treatment. Yield was higher with RT than CT in the area of the field with a sorghum/cotton rotation (RT lint yield = 1411 kg/ha and CT was 1261 kg/ha) and with a winter wheat/summer fallow/cotton rotation (RT lint yield = 1490 kg/ha and CT was 1306 kg/ha). The continuous cotton with a terminated wheat cover crop had no tillage differences (RT lint yield = 1422 kg/ha and CT was 1380 kg/ha for CT), but the CT treatment with this cropping system had little to no cultivation because of the terminated cover crop. Irrigation rate was more impactful than tillage treatment on Verticillium wilt. The 1.5B rate had higher densities of microsclerotia and incidence of Verticillium wilt than the 1.0B and 0.5B rates. Yield in a semi-arid environment is often a function of irrigation rate, but in a Verticillium wilt field, the severity of wilt at the high irrigation rate affected yield. The highest yield occurred with the 1.0B rate, though it was not significantly (P

Verticillium wilt is responsible for substantial yield losses in cotton. The use of cultivars with partial resistance to Verticillium wilt is a preferred management strategy. Cotton breeders utilize rating scales based on severity of foliar symptom expression and/or defoliation when making cultivar selections. The objective of this research was to determine the yield relationship with cultivars grouped by both incidence of Verticillium wilt during the boll filling stage, and late season defoliation in fields with a history of Verticillium wilt. Small plot, replicated cultivar trials were conducted over an 11 year period in west Texas. Cultivars were divided into four classes (A–D) based on normalized wilt incidence (NW) and four classes based on normalized defoliation ratings (ND). Classes were determined through a mixed model analysis of cultivars, with T-test comparisons between a partially resistant check (Fibermax 2484B2F) and a susceptible check (Deltapine 0912B2RF). The A and C classes did not differ (P = 0.05) from the partially resistant and susceptible checks, respectively. Classes were used in a mixed model analysis with lint yield. In a model with only NW classes, lint yield decreased significantly as NW increased with least square mean values of 1421, 1385, 1284 and 1204 kg/ha, for classes A, B, C and D, respectively. In a model with both NW and ND classes, the A/A class combination of NW and ND had a significantly (P ≤ 0.05) higher lint yield (1776 kg/ha) than any other combination. NW/ND class combinations of A/B, B/A, B/B, and C/A had intermediate yields, and ND classes of C or D had the lowest yields. Cultivars with both low wilt and defoliation incidences should result in higher yields in fields infested with Verticillium dahliae. Furthermore, these two rating criteria could be used to standardize the process for developing resistant cultivars.

The study was to determine the long-term effects of subtropical monoculture and rotational cropping systems and fertilization on soil enzyme activities and soil C, N, and P levels. Cropping systems included continuous sorghum ( Sorghum bicolor L.), cotton ( Gossypium hirsutum L.), corn ( Zea mays L.), and cotton/sorghum rotations after 26 years of treatment imposition. Soil under continuous sorghum and continuous corn had 15% and 11%, respectively, greater C concentrations than soil under continuous cotton. Organic C was 10% higher at 0–7.5 cm than at 7.5–15 cm. Total N followed similar trends with soil depth as organic C. Continuous sorghum had 19% higher total N than other crop species and rotations. With fertilization, continuous cotton had the highest total P at 0–7.5 cm and sorghum had the highest at 7.5–15 cm. Soil total P was 14% higher at 0–7.5 than at 7.5–15 cm, and fertilization increased 15% total P compared to unfertilized soil. Arylsulfatase, alkaline phosphatase, and β-d-glucosidase activity were the highest for sorghum and the lowest for cotton. Rotation increased enzyme activities compared to continuous cotton but not for continuous sorghum. Of all crop species and rotations, continuous cotton generally showed the lowest levels of organic matter and enzyme activities after 26 years. Fertilization significantly increased the yields for all cropping systems, but rotation had no significant effect on either sorghum or cotton lint yield compared to each crop grown in monoculture. Long-term cropping did not increase soil organic matter levels beyond short-term gains, indicating the difficulty in promoting C sequestration in subtropical soils.

The five cotton cultivars viz., CB1, CB3, CB5, CB8, and C12 were evaluated under field conditions to compare their resistance levels against the aphid species Aphis gossypii (Hemiptera: Aphididae) and the jassid species Amrasca devastans (Hemiptera: Cicadellidae). The effects of plant characteristics that could explain some of the varietal resistance levels were tested by measuring infestation levels, biochemical content, leaf trichome density, agronomic traits, yield, and quality of seed and fiber. In comparison with other varieties, CB1 and CB3 showed the least leaf and boll infestation, and possessed higher numbers of trichomes. CB12 had the lowest number of trichomes and exhibited the highest percentages of leaf and boll infestation. Biochemical analyses indicated that the highest percentage of starch occurred in CB8, and that of protein in CB5. Both starch and protein content were lowest in CB12. Aphid and jassid infestation reduced the starch and protein content of all cultivars. CB3 was the best performing variety in terms of size and weight of bolls; ginning out-turn (GOT); number of branches, leaves, and bolls per plant; and number of locules per boll. Seed cotton yields and lint indices were highest in CB1 and CB3 and lowest in CB12. CB12 was also the worst performing variety in terms of plant height, micronaire value, percentage of GOT and germination, number of leaves and bolls per plant, and boll length, width and weight. The findings of this study clearly demonstrate that, among the cultivars evaluated, CB12 is the most susceptible to aphid and jassid infestation.SAARC J. Agri., 14(1): 11-23 (2016)

Trees are the dominant species in agroforestry systems, profoundly affecting the performance of understory crops. Proximity to trees is a key factor in crop performance, but rather little information is available on the spatial distribution of yield and yield components of crop species under the influence of trees in agroforestry systems. Also, little information is available on how crop density may be exploited to optimize the yield in such systems. Here we studied the performance of cotton in jujube/cotton agroforestry. Field experiments were conducted in 2012 and 2013 in Hetian, Xinjiang, China. Cotton was grown at a row distance of 60 cm in three densities, 13.5, 18.0 and 22.5 plants m−2 in six m wide paths between tree lines in a jujube plantation. Plant density affected both cotton aboveground dry matter and yield significantly. The highest yield was attained at the intermediate density of 18.0 plants m−2 (20.0 plants m−2 corresponding in sole cotton), lower than the optimal density in sole cotton (25.0 plants m−2). Yield at the lower density was constrained by the low number of bolls per m2 as a direct consequence of the low density, whereas at the high plant density yield was constrained by a lower allocation of assimilates to cotton seed and lint, as a consequence of intraspecific and interspecific competitions. There were strong gradients in yield and yield components in relation to the distance from the tree rows. Leaf area and total dry matter of cotton in rows close to the tree lines were reduced, especially in the rows next to the trees. Moreover, biomass allocation to cotton fruits was reduced in these rows. Competitive influences from the trees on cotton performance extended two rows deep in a six-year old jujube stand, and even three rows deep in a seven-year old stand. Shading effects on cotton yield were compensated by increasing plant density as a result of greater boll numbers per unit ground area. Data from this study help guide the design of optimal plant density of cotton in jujube plantations and give insight in the spatial distribution and dynamics of competitive effects in agroforestry systems in general.

Cotton may suffer from waterlogging from seedling to boll-setting stage, but little is known of how it responds to temporal waterlogging. In this study, cotton was grown in a rain-shelter and subjected to 0 (control)-, 10-, 15- and 20-d waterlogging at squaring (WLS), flowering (WLF) and boll-setting (WLB) stages. The effects of timing (growth stage) and duration of waterlogging on the growth, yield and yield components as well as some physiological and molecular features of cotton were examined. The lint yield was significantly affected by timing and duration of waterlogging as well as their interaction. On average, the 10-, 15-, and 20-d waterlogging reduced lint yield by 53, 59 and 63% at squaring; 27, 37 and 55% at flowering, and 13, 15 and 24% at boll-setting. The more pronounced yield reduction under WLS than later waterlogging (under WLF and WLB) was attributed to greater reductions in biological yield, harvest index, and the resulting boll density and boll weight. Variations in yield loss due to temporal waterlogging was associated with some physiological and molecular changes: a) the chlorophyll synthesis associated gene (GhLHCB) in the main-stem leaves was down-regulated under WLS to a larger extent, leading to lower leaf photosynthesis than that under WLF or WLB; b) cotton alcohol dehydrogenase (GhADH) and pyruvate decarboxylase (PDC) genes were better up-regulated, resulting to greater activity of lactate dehydrogenase (LDH), alcohol dehydrogenase (ADH) and PDC plus lower activity of SOD, POD and CAT and higher accumulation of malondialdehyde (MDA) and H2O2 under WLS than under WLF and WLB; c) more pronounced reductions in GA and IAA content were observed under WLS than WLF and WLB. Higher sensitivity to earlier waterlogging than later waterlogging in cotton was attributed to the greater reductions in biological yield and harvest index resulting from differences in physiological and molecular adjustments of the plants.

AIM To determine the capacity of the brown stink bug (BSB) (Euschistus servus) to transmit an infective Pantoea agglomerans strain Sc 1-R into cotton (Gossypium hirsutum) bolls. METHODS AND RESULTS A laboratory colony of BSB was maintained on fresh green beans. Either sterile or Sc 1-R contaminated beans were offered to adult insects. Strain Sc 1-R holds rifampicin resistance (Rif(r) ). Insects were then caged with unopened greenhouse-grown bolls. After 2 days, BSB were surface sterilized, ground, and then plated on media with and without Rif. Two weeks later, seed with lint were ground and plated on media with and without Rif. Microbes were recovered on nonselective media from all BSBs and from seed/lint at concentrations reaching 10(9) CFU g(-1) tissue. Rif(r) bacteria were recovered strictly from insects exposed to Sc1-R and from diseased seed/lint of respective bolls. CONCLUSIONS Euschistus servus was capable of transmitting strain Sc 1-R into bolls resulting in disease. Insects not exposed to the pathogen deposited bacteria yet the nonpathogenic microbes produced insignificant damage to the boll tissue. SIGNIFICANCE AND IMPACT OF STUDY This is the first study to concretely show the capacity of the BSB to transmit an infective P. agglomerans strain resulting in boll disease.

Seed mass and oil content of the quiescent cotton seed are positively associated with seedling vigor. In contrast, seed size has been negatively associated with lint yield due to selection for cultivars with greater lint percent. The current study addressed the hypothesis that planting seed mass and total oil + protein calorie content of the quiescent cotton seed would be strongly predictive of seedling vigor across most field conditions and that the impact of seed traits on yield would be dependent upon yield environment. When considered in each yield environment, seedling vigor was positively associated with seed size and the total oil + protein calorie content per seed in four out five environments tested. Regression analysis of cultivar mean oil + protein kcal content per seed versus seedling vigor across all environments indicated a strong, positive relationship between the two parameters (r2 = 0.65). Although lint percent was positively correlated with lint yield in every environment, planting seed mass and calorie content were not correlated with lint yield in four of the five environments tested or when cultivar means for lint yield and seed characteristics were averaged across all environments. Thus, it is concluded that individual planting seed mass and total energy content for oil + protein are strong predictors of early seedling vigor. Furthermore, selecting commercially available cultivars with characteristics indicative of seedling vigor does not appear to limit lint yield in most environments tested.

Yield and fiber quality of cotton even varies within locules in a boll, but it is not clear how yield components and quality parameters are altered across seed positions of a locule (SPL). A field experiment was arranged in a split plot design with transgenic insect resistant Bt (Bacillus thuringiensis) cotton hybrid cultivar CRI75 and conventional cultivar SCRC28 as the main plots, and three plant densities (15 000, 51 000 and 87 000 plants ha−1) as the subplots in 2012 and 2013 at Anyang, Henan Province, China. Cotton was hand harvested by node and fruiting position, and then seeds of the first fruiting position bolls from nodes 6–10 were separated by SPL. The effects of plant density on lint yield, fiber quality, especially across SPL were determined. It was showed that plant densities of 51 000 and 87 000 plants ha−1 increased lint yield by 61.3 and 65.3% in 2012 and 17.8 and 15.5% in 2013 relative to low plant density (15 000 plants ha−1), however, no significant difference was observed between 51 000 and 87 000 plants ha−1. The number of bolls (boll density) increased while boll weight decreased as plant density raised, and no significant changes occured in lint percentage in 2013 but increased with plant density in 2012. The number of bolls in upper nodes and distal fruiting positions, the number of seeds per boll, seed area (SA) and seed vigor index increased with decreasing plant density. Seed area was found to be greater from the base to the middle compared to the apex of a locule. Mote frequency (MF) increased as plant density increased, and fiber quality was the best at the middle of the locule regardless of plant density. As the number of fibers per seed area is genetically determined, adjusting plant density to produce more seeds and greater seed area can be a potentially promising alternative to improve lint yield in cotton. These findings might be of great importantance to cotton breeding and filed management.

Fertilizer trees, the nitrogen-fixing legumes, such as gliricidia (Gliricidia sepium) and tephrosia (Tephrosia spp.) have been used to improve soil fertility for higher crop yields in nitrogen deficient soils. Many studies have focused on how these fertilizer trees improve maize yield, but there has been a dearth of information on the effect of fertilizer tree species on cotton growth and yield. A study was undertaken for two cropping seasons (2012/13 and 2013/14) with the objective of assessing IRM 81 cotton growth and yield responses to tephrosia and/or gliricidia biomass with or without inorganic fertilizer application. Boll opening significantly varied (P

Field experiments were conducted in 2013 and 2014 to determine the influence of velvetleaf densities of 0, 0.125, 0.25, 0.5, 1, 2, 4, and 8 plants m−1of row on cotton growth and yield. The relationship between velvetleaf density and seed cotton yield was described by the hyperbolic decay regression model, which estimated that a density of 0.44 to 0.48 velvetleaf m−1of row would result in a seed cotton yield loss of 50%. Velvetleaf remained taller and thicker than cotton throughout the growing season. Both cotton height and stem diameter reduced with increasing velvetleaf density. Moreover, velvetleaf interference delayed cotton maturity, especially at velvetleaf densities of 1 to 8 plants m−1of row, and cotton boll number and weight, seed numbers per boll, and lint percentage were also reduced. Fiber quality was not influenced by weed density when analyzed over 2 yr; however, fiber length uniformity and micronaire were adversely affected in 2014. Velvetleaf intraspecific competition resulted in density-dependent effects on weed biomass, ranging from 97 to 204 g plant−1dry weight. Velvetleaf seed production per plant or per square meter was indicated by a logarithmic response. At a density of 1 plant m−1of cotton row, velvetleaf produced approximately 20,000 seeds m−2. The adverse impact of velvetleaf on cotton growth and development identified in this study have indicated the need for effective management of this species when the weed density is greater than 0.25 to 0.5 plant m−1of row and before the weed seed maturity.

Whole-plant cage field experiments were conducted in 2014, 2015, and 2016 to characterize cotton injury from a species complex of boll-feeding sucking bugs represented by the verde plant bug, Creontiades signatus (Distant) (Hemiptera: Miridae), brown stink bug, Euschistus servus (Say), green stink bug, Acrosternum hilare (Say), and redbanded stink bug, Piezodorus guildinii (Westwood) (Hemiptera: Pentatomidae). Field-collected adult bugs were used to infest cotton plants previously maintained free of insect injury. Plants caged in groups of four were infested at mid-bloom and late-bloom for 7 d with four insect densities: 0 (control), 0.25 bugs per plant, 1 bug per plant, and 2 bugs per plant. Species and water stress conditions varied across years, allowing selective within-year comparisons. Response to feeding resulted in boll injury in the form of lint deterioration and cotton boll rot at mid- and late-bloom stages, and in water limiting and non-water limiting conditions. Although plant injury was apparent across a wide range of conditions, subsequent yield decline attributed to insect feeding was seen primarily under water limiting conditions when plants were infested at mid-bloom. For these conditions, significant yield-insect density relationships were used to calculate economic injury levels (EILs) for each species. EILs expressed as bugs per plant from lowest to highest were the brown stink bug (0.29-0.31 bugs per plant), redbanded stink bug (0.33), verde plant bug (0.49), and green stink bug (0.50). Given the variability observed among species, species-specific EILs may be used where the injurious species is known and combined for stink bugs (a common EIL of 0.34 bugs per plant) where multiple species occur. Verde plant bug was less damaging and can be considered separately, but its EIL was generally within a range of values for the boll-feeders encountered.