Upland Cotton Cultivars Research Articles

Reduced Glutathione Protects Subcellular Compartments From Pb-Induced ROS Injury in Leaves and Roots of Upland Cotton (Gossypium hirsutum L.).

Heavy metals-based changes in the plants and their alleviation through eco-friendly agents including reduced glutathione (GSH) have been widely studied. In the present experiment, we tested the alleviatory role of reduced glutathione (GSH) in seedlings of upland cotton cultivar, TM-1 under lead (Pb) toxicity. Plants were grown in the Hoagland solution containing Pb (0 μM), Pb (500 μM), GSH (50 μM), and GSH + Pb (50 μM + 500 μM). Lead exposure exacerbated hydrogen peroxide (H2O2) and hydroxyl radical (OH•) levels, induced lipid peroxidation (MDA), and decreased the activities of catalase (CAT) and ascorbate peroxidase (APX) in the terminal and median leaves of 28-days old cotton seedlings stressed for 10 days. However, in the primary and secondary roots, CAT activity was increased but APX decreased. Similarly, peroxidase (POD) and superoxide dismutase (SOD) activities were enhanced in the median leaves but a declining trend was observed in the terminal leaves, primary roots and secondary roots. Glutathione reductase (GR) activity, ascorbic acid (AsA) contents and GSH concentrations were increased in all parts except AsA in the median leaves. Transmission electron micrographs of Pb-treated plants exhibited deformed cell wall and cell membrane, disfigured chloroplasts and irregularly shaped mitochondria in the terminal and median leaves. Further, cell membrane, mitochondria, nucleus and other cell organelles in root cells were severely affected by the Pb. Thus their identification was little bit difficult through ultramicroscopy. External GSH stabilized leaf and root ultramorphology by stabilizing cell membranes, stimulating formation of multivesicular body vesicles, and by maintaining structural integrity of other organelles. Evidently, GSH played major alleviatory role against Pb toxicity in upland cotton.

Gossypium hirsutum Salt Tolerance Is Enhanced by Overexpression of G. arboreum JAZ1

Gossypium arboreum possesses many favorable traits including robust defense against biotic and abiotic stress although it has been withdrawn from the market because of lower yield and fiber quality compared to G. hirsutum (upland cotton). It is therefore important to explore and utilize the beneficial genes of G. arboretum for G. hirsutum cultivar breeding. Here, the function of G. arboreum JAZ1 in tolerance to salt stress was determined through loss-of-function analysis. GaJAZ1can interact with GaMYC2 to repress expression of downstream genes whose promoters contain a G-box cis element, affecting plant tolerance to salinity stress. The experimental data from NaCl treatments and a 2 year continuous field trial with natural saline-alkaline soil showed that the ectopically overexpressed GaJAZ1 significantly increased salt tolerance in upland cotton compared to the wild type, showing higher growth vigor with taller plants, increased fresh weight, and more bolls, which is due to reprogrammed expression of tolerance-related genes and promotion of root development. High-throughput RNA sequencing of GaJAZ1 transgenic and wild-type plants showed many differentially expressed genes involved in JA signaling and biosynthesis, salt stress-related genes, and hormone-related genes, suggesting that overexpressing GaJAZ1 can reprogram the expression of defense-related genes in G. hirsutum plants to increase tolerance to salt stress. The research provides a foundation to explore and utilize favorable genes from Gossypium species for upland cotton cultivar breeding.

Genomic signatures and candidate genes of lint yield and fibre quality improvement in Upland cotton in Xinjiang.

SummaryXinjiang has been the largest and highest yield cotton production region not only in China, but also in the world. Improvements in Upland cotton cultivars in Xinjiang have occurred via pedigree selection and/or crossing of elite alleles from the former Soviet Union and other cotton producing regions of China. But it is unclear how genomic constitutions from foundation parents have been selected and inherited. Here, we deep‐sequenced seven historic foundation parents, comprising four cultivars introduced from the former Soviet Union (108Ф, C1470, 611Б and KK1543) and three from United States and Africa (DPL15, STV2B and UGDM), and re‐sequenced sixty‐nine Xinjiang modern cultivars. Phylogenetic analysis of more than 2 million high‐quality single nucleotide polymorphisms allowed their classification two groups, suggesting that Xinjiang Upland cotton cultivars were not only spawned from 108Ф, C1470, 611Б and KK1543, but also had a close kinship with DPL15, STV2B and UGDM. Notably, identity‐by‐descent (IBD) tracking demonstrated that the former Soviet Union cultivars have made a huge contribution to modern cultivar improvement in Xinjiang. A total of 156 selective sweeps were identified. Among them, apoptosis‐antagonizing transcription factor gene (GhAATF1) and mitochondrial transcription termination factor family protein gene (GhmTERF1) were highly involved in the determination of lint percentage. Additionally, the auxin response factor gene (GhARF3) located in inherited IBD segments from 108Ф and 611Б was highly correlated with fibre quality. These results provide an insight into the genomics of artificial selection for improving cotton production and facilitate next‐generation precision breeding of cotton and other crops.

Transcriptomic analysis of gene expression of Verticillium dahliae upon treatment of the cotton root exudates

BackgroundCotton Verticillium wilt is one of the most devastating diseases for cotton production in the world. Although this diseases have been widely studied at the molecular level from pathogens, the molecular basis of V. dahliae interacted with cotton has not been well examined.ResultsIn this study, RNA-seq analysis was carried out on V. dahliae samples cultured by different root exudates from three cotton cultivars (a susceptible upland cotton cultivar, a tolerant upland cotton cultivar and a resistant island cotton cultivar) and water for 0 h, 6 h, 12 h, 24 h and 48 h. Statistical analysis of differentially expressed genes revealed that V. dahliae responded to all kinds of root exudates but more strongly to susceptible cultivar than to tolerant and resistant cultivars. Go analysis indicated that ‘hydrolase activity, hydrolyzing O-glycosyl compounds’ related genes were highly enriched in V. dahliae cultured by root exudates from susceptible cotton at early stage of interaction, suggesting genes related to this term were closely related to the pathogenicity of V. dahliae. Additionally, ‘transmembrane transport’, ‘coenzyme binding’, ‘NADP binding’, ‘cofactor binding’, ‘oxidoreductase activity’, ‘flavin adenine dinucleotide binding’, ‘extracellular region’ were commonly enriched in V. dahliae cultured by all kinds of root exudates at early stage of interaction (6 h and 12 h), suggesting that genes related to these terms were required for the initial steps of the roots infections.ConclusionsBased on the GO analysis results, the early stage of interaction (6 h and 12 h) were considered as the critical stage of V. dahliae-cotton interaction. Comparative transcriptomic analysis detected that 31 candidate genes response to root exudates from cotton cultivars with different level of V. dahliae resistance, 68 response to only susceptible cotton cultivar, and 26 genes required for development of V. dahliae. Collectively, these expression data have advanced our understanding of key molecular events in the V. dahliae interacted with cotton, and provided a framework for further functional studies of candidate genes to develop better control strategies for the cotton wilt disease.

CORRELATION COEFFICIENTS BETWEEN PHYSIOLOGY, BIOCHEMISTRY, COMMON ECONOMIC TRAITS AND YIELD OF COTTON CULTIVARS UNDER FULL AND DEFICIT IRRIGATED CONDITIONS.

Drought is a common abiotic stress that considerably limits crop production. The objective of this study is to explore the influence of water deficiency on the yield and physiologic-biochemical in upland cotton cultivars (Gossypium hirsutum L). Cotton cultivars, 'Ishonch', 'Navbakhor-2','C-6524' and 'Tashkent-6' were selected to study the relationships among their physiologic, biochemical and yield attributes during water deficiency. Deficit irrigation was designed by modifying the traditional watering protocol to reduce water use. Results indicate that cotton cultivars respond differently to water deficit stress. Water deficit significantly influenced plant valuable economic traits and yield in four cultivars. However, yield components such as the number of bolls per plant, seed number per boll, mass of boll per plant and productivity plant yield were significantly reduced only in and C-6524 and Tashkent-6. The malondialdehyde decreased and total chlorophyll, chlorophyll “a” increased in 'Ishonch' and Navbakhar-2 under deficit irrigation conditions. The direct relationship between physiology, biochemistry, valuable economic traits, and yield may be a useful selection criterion for determining candidate parents for cotton drought tolerance breeding.

Registration of glandless ‘NuMex COT 17 GLS’ upland cotton cultivar with Fusarium wilt race 4 resistance

AbstractThe New Mexico Agricultural Experiment Station announces the release of a glandless ‘NuMex COT 17 GLS’ cotton (Gossypium hirsutum L.) (Reg. no. CV‐141, PI 691837), which carries the incomplete dominant glandless allele Gl2e. NuMex COT 17 GLS was derived from an advanced backcross progeny of a cross between the Gl2e allele donor ‘Bahtim 110’ (G. barbadense L.) and glanded upland cotton ‘CRI 12’, followed by five backcrosses with glanded upland ‘CRI 35’ as the recurrent parent. It is resistant to Fusarium wilt (FW) race 4, with a level of resistance similar to the resistant checks ‘PHY 802RF’ and ‘PHY 811RF’, when evaluated in two naturally infected fields in California, and it is more resistant than ‘Acala 1517‐08’ when evaluated in the greenhouse in New Mexico. This new cultivar was tested in seven replicated field trials in New Mexico in 2013–2017 and in 11 tests across nine states in 2014. Compared with glandless ‘Acala GLS’, ‘Acala 1517‐18 GLS’, and ‘NuMex COT 15 GLS’, NuMex COT 17 GLS yielded 26, 16, and 13% more lint, respectively, and produced 93% of glanded Acala 1517‐08 yield. It had significantly higher lint percentage than all the check cultivars. It is classified as a medium staple with fiber quality inferior to long‐staple Acala cotton cultivars. NuMex COT 17 GLS is especially adapted to the Mississippi Delta and was the top yielder in the region. It is resistant to four races of bacterial blight and less susceptible to Alternaria leaf spot than Acala 1517‐08. The release of NuMex COT 17 GLS represents one of the first successful introgressions from G. barbadense germplasm with FW race 4 resistance.

Registration of upland cotton cultivar ‘Acala 1517‐20’ resistant to Fusarium wilt race 4

AbstractThe New Mexico Agricultural Experiment Station announces the release of an upland cotton (Gossypium hirsutum L.) cultivar ‘Acala 1517‐20’ (Reg. no. CV‐142, PI 691836). Acala 1517‐20 was derived from a single plant selection in a biparental cross between an unreleased upland line NM 010368 and a Chinese cultivar ‘Jimian 958’ that is resistant to Fusarium wilt (Fusarium oxysporum f. sp. vasinfectum, FOV) race 7. Acala 1517‐20 is moderately resistant to FOV race 4 (FOV4), similar to ‘Pima DP 358 RF’, based on vascular root staining and growth vigor in the field in California and foliar disease severity ratings in the greenhouse in New Mexico. This new cultivar was tested in nine replicated field trials in New Mexico in 2008–2017 and in 20 tests in 14 locations across 12 states in 2016–2017. Acala 1517‐20 yielded similarly to the high‐yielding Acala cotton cultivars, including ‘Acala 1517‐99W’, ‘Acala 1517‐16 B2RF’, and ‘Acala 1517‐08’, and the Acala‐type transgenic commercial cultivars, including ‘PHY 725 RF’, ‘PHY 755 WRF’, ‘PHY 764 WRF’, and ‘FM 2322 GL’, but yielded lower than ‘FM 1830 GLT’. Compared with Acala 1517‐08, Acala 1517‐20 had higher lint percentage, lower boll and seed weight, and lower short fiber content. Acala 1517‐20 was susceptible to four races of bacterial blight and Alternaria leaf spot. It is recommended for regions where Acala cotton is grown in the presence of FOV4. It will also provide a new source of resistance to FOV4.

Changes in the Lint Yield and Associated Traits of Upland Cotton in China

This study reviewed data from 1950 to 2014 on 1,257 upland cotton (Gossypium hirsutum L.) cultivars from three agroecological regions in China: Yellow River Valley, Yangtze River Valley, and Northwest Inland. The main aim was to establish future breeding and cultivation strategies. Lint yields significantly increased linearly in the three regions over time. Yield improvement in the new cultivars was due to: the decrease in planting density and increase in lint percentage and single boll mass in Yellow River Valley, the decrease in planting density and increase in lint percentage and bolls per plant in Yangtze River Valley, and the increase in planting density and lint percentage and decrease in bolls per plant in Northwest Inland. Planting density had significant effects on bolls per plant, single boll weight, lint percentage, growing period, and plant height in the three ecological regions. Our results suggest that different regions require different breeding strategies, and the evaluation of the genetic improvement process of cotton should not ignore the effects of planting density.

RNA-seq reveals hormone-regulated synthesis of non-cellulose polysaccharides associated with fiber strength in a single-chromosomal-fragment-substituted upland cotton line

Cotton fibers are the main raw materials of the textile industry. Exogenous superior fiber genes have been introduced into upland cotton to develop high-yield cultivars with excellent fiber quality. We used a single chromosomal segment on the chromosome A07 substitution line SL7, with high fiber strength, to investigate the molecular mechanism underlying its fiber quality. RNA-seq and KEGG analysis showed that 70 differentially expressed genes were enriched in plant hormone transduction pathways, including auxin, ethylene and abscisic acid, in fibers at 10 days post-anthesis (DPA). Among these, fiber-development related transcription factors MYB and NAC, including Gh_A11G0981 (MYB108), Gh_A03G0887 (NAC029), and Gh_A08G1691 (NAC021), were significantly upregulated in SL7, as were numerous cellulose synthase-like (CSL) genes involved in non-cellulose polysaccharide and cell wall synthesis. The hemicellulose content of SL7 was significantly higher than that of L22, an upland cotton cultivar. These results suggest that key genes in the introgressed chromosomal segment of SL7 regulate the expression of transcription-factor genes via hormone-transduction pathways, thereby inducing the expression of genes involved in secondary wall synthesis and ultimately improving fiber quality. This study has shed light on the molecular mechanism of fiber development and will contribute to the improvement of fiber quality of upland cotton by molecular breeding.

Genetic Basis of Fiber Improvement and Decreased Stress Tolerance in Cultivated Versus Semi-Domesticated Upland Cotton.

Crop domestication from wild ancestors has resulted in the wide adaptation coupled with improved yield and quality traits. However, the genetic basis of many domesticated characteristics remains to be explored. Upland cotton (Gossypium hirsutum) is the most important tetraploid cotton species, accounting for about 90% of world cotton commerce. Here, we reveal the effects of domestication on fiber and stress traits through comprehensive analyses of semi-domesticated races and cultivated cotton accessions. A total of 416 cotton accessions were genotyped, and a decrease in genetic diversity from races to landraces and modern cultivars was detected. Furthermore, 71 domestication selective sweeps (DSS) and 14 improvement selective sweeps (ISS) were identified, with the Dt sub-genome experiencing stronger selection than the At sub-genome during the both selection types. The more expressed genes and a delay in the expression peak of genes related to secondary cell wall (SCW) development in modern cultivars compared to semi-domesticated cotton races, may have contributed to long fibers in these plants. However, down-regulation of genes related to stress response was responsible for decreasing stress tolerance in modern cultivars. We further experimentally confirmed that silencing of PR1 and WRKY20, genes that showed higher expression in the semi-domesticated races, drastically compromised cotton resistance to V. dahliae. Our results reveal fiber improvement and decreased stress tolerance as a result of the domestication of modern upland cotton cultivars.

High Temperature Reduces the Viability of Pollen from Upland Cotton in China

The viability of pollen grains from upland cotton (Gossypium hirsutum L.) has an important influence on fertilization and fiber yield and quality, and high temperature adversely affects cotton pollen grain development. However, the effects of high temperature on the vigor of pollen grains and cultivars having pollen grains resistant to high temperature in different regions have not been reported. The purpose of this study was to evaluate how high temperatures influence the viability of pollen from upland cotton and determine the high‐temperature risk to pollen vigor in upland cotton cultivars in major cotton‐producing regions in China. In this study, pollen grain germination was performed in vitro by culturing pollen grains in medium to detect cotton pollen grain viability. Pollen germination rates decreased significantly when the maximum daily temperature was ≥35°C for three consecutive days. The resistance of pollen vigor to high temperatures significantly differed among cultivars. According to the average annual number of days with temperatures ≥35°C from June to August in the main cotton‐producing areas in China within a 10‐yr period, the risk of high temperature affecting pollen vigor can be divided into five levels. Seventeen cultivars (lines) resistant to high temperatures were selected from 206 upland cotton cultivars, and four simple sequence repeat (SSR) markers were found to be associated with pollen germination rates under high temperature. This study clarified the degree of high‐temperature risk in major cotton‐producing areas in China and provided guidance for the selection of suitable heat‐resistant cultivars.Core Ideas Pollen germination rates decreased significantly when the maximum daily temperature was ≥35°C for three consecutive days. The heat resistance index was calculated to evaluate the differences in the heat resistance among the different cultivars. Resistance of pollen vigor to high temperature significantly differed among cultivars. Four simple sequence repeat markers associated with pollen germination rates under high temperature were identified.

Dynamic infection of Verticillium dahliae in upland cotton.

Verticillium wilt, an infection caused by the soilborne fungus Verticillium dahliae, is one of the most serious diseases in cotton. No effective control method against V.dahliae has been established, and the infection mechanism of V.dahliae in upland cotton remains unknown. GFP-tagged V.dahliae isolates with different pathogenic abilities were used to analyse the colonisation and infection of V.dahliae in the roots and leaves of different upland cotton cultivars, the relationships among infection processes, the immune responses and the resistance ability of different cultivars against V.dahliae. Here, we report a new infection model for V.dahliae in upland cotton plants. V.dahliae can colonise and infect any organ of upland cotton plants and then spread to the entire plant from the infected organ through the surface and interior of the organ. Vascular tissue was found to not be the sole transmission route of V. dahliae in cotton plants. In addition, the rate of infection of a V. dahliae isolate with strong pathogenicity was notably faster than that of an isolate with weak pathogenicity. The resistance of upland cotton to Verticillium wilt was related to the degree of the immune response induced in plants infected with V. dahliae. These results provide a theoretical basis for studying the mechanism underlying the interaction between V. dahliae and upland cotton. These results provide a theoretical basis for studying the mechanism underlying the interaction between V.dahliae and upland cotton.

Screening of abiotic stress-responsive cotton genes using a cotton full-length cDNA overexpressing Arabidopsis library.

Cotton (Gossypium hirsutum L.) is a major crop and the main source of natural fiber worldwide. Because various abiotic and biotic stresses strongly influence cotton fiber yield and quality, improved stress resistance of this crop plant is urgently needed. In this study, we used Gateway technology to construct a normalized full-length cDNA overexpressing (FOX) library from upland cotton cultivar ZM12 under various stress conditions. The library was transformed into Arabidopsis to produce a cotton-FOX-Arabidopsis library. Screening of this library yielded 6,830 transgenic Arabidopsis lines, of which 757 were selected for sequencing to ultimately obtain 659 cotton ESTs. GO and KEGG analyses mapped most of the cotton ESTs to plant biological process, cellular component, and molecular function categories. Next, 156 potential stress-responsive cotton genes were identified from the cotton-FOX-Arabidopsis library under drought, salt, ABA, and other stress conditions. Four stress-related genes identified from the library, designated as GhCAS, GhAPX, GhSDH, and GhPOD, were cloned from cotton complementary DNA, and their expression patterns under stress were analyzed. Phenotypic experiments indicated that overexpression of these cotton genes in Arabidopsis affected the response to abiotic stress. The method developed in this study lays a foundation for high-throughput cloning and rapid identification of cotton functional genes.

Extensive intraspecific gene order and gene structural variations in upland cotton cultivars

Multiple cotton genomes (diploid and tetraploid) have been assembled. However, genomic variations between cultivars of allotetraploid upland cotton (Gossypium hirsutum L.), the most widely planted cotton species in the world, remain unexplored. Here, we use single-molecule long read and Hi-C sequencing technologies to assemble genomes of the two upland cotton cultivars TM-1 and zhongmiansuo24 (ZM24). Comparisons among TM-1 and ZM24 assemblies and the genomes of the diploid ancestors reveal a large amount of genetic variations. Among them, the top three longest structural variations are located on chromosome A08 of the tetraploid upland cotton, which account for ~30% total length of this chromosome. Haplotype analyses of the mapping population derived from these two cultivars and the germplasm panel show suppressed recombination rates in this region. This study provides additional genomic resources for the community, and the identified genetic variations, especially the reduced meiotic recombination on chromosome A08, will help future breeding.

English

An evaluation was made of upland cotton cultivar fiber quality, when subjected to water deficit periods, on the phenological stages. The experiment was carried out at the Campina Grande Federal University, Pombal county Campus, Paraíba State, Brazil, between June and December 2015. Treatments were formed using a split-plot arrangement, in which the plots were 6 water deficit periods (P) (P1 = No deficit; P2 = Deficit in the initial growth stage; P3 = Deficit in the flower bud stage; P4 = Deficit in the flower stage; P5 = Deficit in the boll stage; and P6 = Deficit in the open boll stage) and the subplots, 2 upland cotton cultivars (C) (C1 = Brazil Seeds 286 and C2 = BRS 336), in randomized block design, with 4 replicates. The water deficits applied affected cultivars fiber quality, except maturity, reflectance and yellowness. The treatment without water deficit promoted the best fiber values, except of short fiber index, elongation and micronaire. Tested upland cotton cultivars were more tolerant to water deficit in the initial growth and boll stages. In general, BRS 336 was more tolerant to water deficits than BRS 286. Key words: Gossypium hirsutum L. r. latifolium H., stress, cotton lint industry technological characteristics. &nbsp

English

Aiming to evaluate the gas exchange of upland cotton cultivars cultivated in the Brazilian semiarid, subject to water deficit periods on the phenological stages, an experiment was carried out at the Campina Grande Federal University, Pombal county campus, Paraíba State, Brazil, between June and December 2015. Treatments were formed from a split-plot arrangement, in which the plots were 6 water deficit periods (P) (P1 = No deficit, P2 = Deficit in the initial growth stage, P3 = Deficit in the flower bud stage, P4 = Deficit in the flower stage, P5 = Deficit in the boll stage and P6 = Deficit in the open boll stage) and the subplots, 2 upland cotton cultivars (C) (C1 = Brazil Seeds 286 and C2 = BRS 336), in randomized block design, with 4 replicates. Water deficits reduced the gas exchange of the upland cotton plants, mainly stomatal conductance, transpiration and photosynthesis. The cotton cultivars BRS 286 and BRS 336 presented similar behavior in the different water deficits applied on different phenological stages. Cotton was less tolerant to water deficits in the boll formation stage and more tolerant in the initial growth and flower bud stages. Key words: Gossypium hirsutum L. r. latifolium H., water stress, physiology. &nbsp

Genetic characterization of Gossypium arboreum accession PI 529740 for reniform nematode resistance

AbstractBreeding for reniform nematode (Rotylenchulus reniformis) resistance is hindered by the lack of resistance in upland cotton (Gossypium hirsutum) cultivars. Resistance has been frequently identified in accessions from the Gossypium arboreum germplasm collection with accession PI 529740 rated as highly resistant. Accession PI 529740 was crossed with the susceptible G. arboreum accession PI 529729 to develop an F2 population for genetic characterization. The population showed quantitative variation suggesting multiple genes conferred the resistant phenotype. Thirteen of the 216 F2 plants showed resistance similar to the resistant parent and these data supported a two recessive gene model. Sixty plants were classified as resistant or moderately resistant, indicating a single recessive gene conferred the moderately resistant phenotype. The classification of 24 F2:3 families for nematode resistance generally supported the classification of the corresponding F2 plants; however, most families were highly variable for infection with no families rated as resistant. This information will aid in the introgression of resistance into upland cotton as larger populations will be required to successfully recover resistance conferred by multiple recessive genes.

Production components and water efficiency of upland cotton cultivars under water deficit strategies

The objective of this work was to study water deficits effect on different phenological phases in the production components and water efficiency of upland cotton cultivars. For this, an experiment was carried out at the Federal University of Campina Grande - UFCG, Pombal county Campus, Paraiba State, Brazil. Treatments were formed from a split-plot arrangement in which plots were 6 water deficit periods (P): (P1 = No deficit; P2 = Deficit in the initial growth stage; P3 = Deficit in the flower bud stage; P4 = Deficit in the flower stage; P5 = Deficit in the boll stage; and, P6 = Deficit in the open boll stage) and, the subplots, 2 upland cotton cultivars (C): (C1 = Brazil Seeds 286 and C2 = BRS 336), in randomized block design, with 4 replicates. Cultivars studied were more tolerant to water deficit in stages of initial growth, flower bud and open boll. Water deficit during flowers and bolls stages in upland cotton cultivars was the most detrimental to production components. Between cultivars tested, their behavior was similar only in cotton seed yield and water-use efficiency being BRS 286 higher than BRS 336 in other analyzed variables, except for mean open boll weight. Key words: Gossypium hirsutum L. r. latifolium H., Hydric stress, agronomic variables.

Tolerance of commercial Upland (Gossypium hirsutum) and Pima (G. barbadense) cotton cultivars, advanced breeding lines and glandless cotton to halosulfuron (Sandea) herbicide under field conditions

Halosulfuron (Sandea) herbicide is recommended to control problem weeds with the use of hood for cotton protection. However, no information is available on genotypic variation in cotton response to Sandea. In this study, 104 entries representing 81 cotton genotypes including 8 Pima (Gossypium barbadense L.) and 73 Upland (G. hirsutum L.) genotypes were divided into four replicated tests for evaluation of Sandea tolerance at the 4–5th true-leaf stage (27 days after planting, DAP) under the same field conditions in 2016. The analysis of variance did not detect a significant genotypic difference among the Pima cotton cultivars and lines tested, while there were significant genotypic variations in the three replicated Upland cotton tests. The broad-sense heritability estimates for Sandea tolerance based on crop injury ratings at 6 days after treatment (DAT) ranged from 72.1 to 82.6%, with an average of 77.9%. When 18 lines were tested in 2–3 tests (or twice in the same test), overall consistent results in crop injury ratings were obtained, which allowed the selection of the tolerant check Acala 1517-08 and the sensitive check glandless Acala 1517-18 GLS for screening cotton for Sandea tolerance. As compared to the tolerant check, no Upland genotype was more tolerant to Sandea, but many of them were as tolerant. However, three glandless cotton lines were the most sensitive to Sandea, which were significantly more sensitive to Sandea than all the glanded cotton tested except for PHY 499 WRF which was equally sensitive. Furthermore, seedlings at the first true-leaf stage (14 DAP) were not sensitive to Sandea, as no apparent crop injury was observed at 6 DAT. This is the first report on genotypic variation for Sandea tolerance in cotton, and the results provide useful information in cotton breeding for cultivar selection for tolerance to Sandea herbicide.

Performance of different upland cotton varieties under the climatic condition of Lasbella Uthal Balochistan

Abstract A trial was conducted at Cotton Research Station Lasbela for testing and evaluating the yield and fiber performance of different commercial cotton varieties so that on the basis of the results best varieties can be recommended for general cultivation in the area. Eight best Bt and non-Bt cotton varieties of different organizations were sown under the climatic condition of Lasbela. It was concluded that CRIS-129 obtained maximum seed cotton yield (3850 kg ha-1) followed by CRIS-342 (3592 kg ha-1) and Sindh-1 (3518 kg ha-1). For bolls per plant CRIS-129 formed maximum number of bolls (43.0) per plant fallowed by CRIS-342 (40.2) and Sindh-1 (39.0). Maximum boll weight (3.7g) was weighted in variety MNH-886. Whereas, CRIS-342 and BH-178 and CEMB-33 were the second which gave (3.5 g) boll weight. CEMB-33 ginned highest lint percentage (41.5) followed by MNH-886 (40.0) and Sadori (38.6). CRIS-342 produced longer staple length (29.0 mm) followed by BH-178 (28.3 mm) and Sadori (28.2 mm). Regarding mike value CRIS-129 and Sadori produced better mike value (4.4 µ inch-1) as compared to other varieties. Among all the varieties CRIS-129 showed maximum fiber strength (35.0 g/tex-1) followed by CRIS-134 (34.2 g/tex-1) and CRIS-342 (32.5 g/tex-1). On the basis of present findings, it was concluded that upland cotton cultivar ‘CRIS-129’ showed promising results for getting higher seed cotton yield followed by CRIS-342 and Sindh-1. The cotton cultivar ‘CRIS-129’ is recommended to cotton growers for cultivation under climatic condition of Lasbella, Uthal Balochistan. Keywords: Fiber strength; Lint (%); Seed cotton yield http://dx.doi.org/10.19045/bspab.2018.700211