Bacterial blight, caused by Xanthomonas campestris pv. malvacearum (Smith) Dye (Xcm), can be a serious disease in most Uplandcotton (Gossypium hirsutum L.) growing areas of the world. While blight outbreaks in the USA are in- frequent, serious epidemics can occur wherever susceptible cultivars are grown. The purpose of this study was to determine the bacterial blight reactions of 61 Uplandcotton cultivars. This in- formation should be useful to breeders interested in incorporating blight resistance into future cotton cultivars. Varying numbers of cultivars (including four checks) were planted each year near Perkins, Oklahoma, over a 3-yr period. The experimental design used each year was a randomized complete block with four replica- tions. Two of the replications were used for test- ing cultivar reactions to Xcm Race 1. The other two replications were used for testing responses to a mixture of races. Significant differences in blight reactions were detected among cultivars each year for both Race 1 and the race mixture. Mean reactions among cultivars varied from immune to fully susceptible. Cultivars included in this study were developed in seven states. The only cultivars among them with resistance or immunity to the array of races used in this study were from Texas and Oklahoma. Cultivars developed elsewhere were moderately to fully susceptible. Large areas of the Cotton Belt will remain vulnerable to outbreaks of bacterial blight unless higher levels of resistance are more widely incorporated into breeding programs than have been in the past.
parent. Considering the importance of Uplandcotton, the present investigation was undertaken with a view to study heterosis and dominance estimates with the following objectives: a) to study the extent of heterosis over better parent and standard check hybrid G. Cot. Hy. 12 for yield, yield attributes along with other matricate characters and b) to study the average degree of dominance based on potence ratio of twelve different characters.
Cotton is one of the most important economic crops in some developed and developing countries of the world. Production of U.S. cotton results in revenues exceeding $6 billion annually, with an additional $120 billion being generated by industries using cotton as raw materials. Two major economic forces driving the global cotton market are competition from synthetic fibers and technological changes in the textile industry that re- quire improved fiber quality. The exceptional fiber length, strength, and fineness of Pima and Sea Island cotton (G. barbadense L.) give it a 30–50% price ad- vantage over the more widely grown Uplandcotton (G. hirsutum L.) because of its superior spinning and ma- nufacturing performance. However, Uplandcotton occupies .90% of the cotton growing area because of superior agronomic properties and yield potential. The genetic base that cotton breeders use in applied Uplandcotton breeding programs to develop new varieties is narrow. The need to improve fiber quality while main- taining the superior agronomic and yield properties of Upland cottons requires innovative research ap- proaches and a greater understanding of the genetics of fiber quality. The quality of cotton fibers comes from several traits including length, fineness, and strength. Our results showed that controlled interspecific in- trogression of G. hirsutum with G. barbadense through chromosome substitution provided a scope to demon- strate that fiber qualities in G. hirsutum can be improved without genetic drag effect of poor agronomic qualities of G. barbadense. It is the only method that allows in- trogression of a complete chromosome or chromo- some segment, and it complements other methods of introgression.
Uplandcotton is naturally white, with its yellowness (+b) rating highly influencing its eco - nomic value. Field conditions, microorganisms, and growth problems can cause cotton to become discolored at harvest, which has historically been thought to indicate a decrease in product quality. Previous research has suggested that some reac- tions between amino acids and carbohydrates on the surface of cotton fibers may lead to color development after harvest during certain storage and shipping conditions. There has been a lack of research evidence to understand how initial amounts of those surface constituents present at harvest may indicate the propensity for potential future changes in +b ratings. Due to the monetary implications, it is important for those in the cot- ton industry to better understand exactly how detrimental the +b value is on the functionality of the cotton. This study aimed to identify potential relationships between the post-harvest surface amino acids and carbohydrates content with color rating values to gain insight using High Volume Instrument (HVI), a portable spectrophotometer, ion chromatography, and a ninhydrin test to compare amino acid and carbohydrate content of 45 uplandcotton samples with their color mea- surements: +b, Rd, and L*a*b*. A correlational statistical analysis found a quadratic relationship between amino acid content and +b; and highly positive correlations between amino acids and +b ratings: 0.8607; and b* values: 0.820 (p<0.05).
Copy numbers were evaluated by real-time quantitative PCR, and 149 junctions of T-DNA were isolated by thermal asymmetric interlaced PCR from 92 independent transgenic cotton lines transformed by Agrobacterium tumefaciens strain LBA4404. Real-time quantitative PCR results showed that 46% had integration of one or two T-DNA copies, 54% had three or more copies. Among 63 amplified products at LB junctions, 51% showed co- transformation of the vector backbone, 30% retained a portion of LB ranging from 3 to 23 bp, and 19% showed deletions ranging from 1 to 148 bp from the LB inner end. In contrast, all of the cleavage sites were located in the inner region of RB. The distribution of T-DNA insertions in uplandcotton genome included coding sequences, transposons, plastid-derived sequences and microsatellites.
A successful cotton breeding program depends upon the choice and use of best parental lines for crossing and selection of favorable gene combinations. Improvements in cotton yields can be made by applying dependable tools to cotton breeders regarding to heterotic studies and inbreeding depression. For enhancement of production per unit area by proper availability of environment, identification and selection of genotypes with best genetic potential is a regular requirement. In view of economic importance of hybrid cotton cultivation and importance of selected hybrids in segregating generations, the current research was undertaken to study the genetic potential, heterotic effects and inbreeding depression for yield related traits in 6 × 6 F 2 diallel populations of uplandcotton.
was also documented, based on field observations, in Phytogen Seed Company’s (Dow Chemical Company, Midland, MI) elite Upland germplasms PHY 98M-2983, PHY x1, PHY x2, and PHY x3 (T. Anderson, personal communication). However, the genotypes of FOV to which these lines are resistant are unknown. The purpose of this study was to evaluate the response of eight Uplandcotton and two Pima cultivars against seven genotypes of FOV (races 1, 2, 3, 4, and 8 and genotypes LA108 and LA140). The susceptibility or resistance of MD25-26ne, MD25-27, PHY 98M-2983, PHY x1, PHY x2, and PHY x3 was evaluated. Phytogen 800 was used as a resistant check against all genotypes of FOV; Rowden was used as a susceptible check against all genotypes of FOV. Delta Pine 744 (DP 744) was used as a susceptible check for FOV race 4. In addition, Phytogen 72 was used as a susceptible control for FOV race 1 and 2 and LA108 and LA140 (Holmes et al., 2009).
Neither of the F2 populations exceeded the high parental value for any economically beneficial trait (i.e., lint yield and fiber quality). The value of these populations likely will be derived from IPSs in a pedigreed breeding program. Ideally breeders would create segregating populations with considerable variation which would increase the odds of finding beneficial transgressive segregating plants. Smith et al. (2009a) suggested that transgressive segregates for UHML in uplandcotton can be expected at low frequencies when crossing contrasting parents or similar parents. Yield performance and fiber quality of F2 progeny demonstrated the high degree of penetrance of the ELS germplasm. Capturing the ELS trait in high-yielding germplasm will speed the development of cultivars with improved fiber quality.
Bourland and Hornbeck (2007) indicated that density of marginal bract trichomes tended to be greater on younger bracts and on genotypes with greater leaf trichome density. However, they did not find any Uplandcotton genotype to have glabrous bracts. Marginal bract trichome density varied among smooth leaf, semi-smooth, and hairy leaf genotypes. Additionally, trichome density on bract margins was positively related to trichome density on abaxial leaves, leaf margins, and stems. The low magnitude of these correlations (ranged from 0.29 to 0.41) indicated that the traits were not pleiotropic, and could likely be modified independently. However, selection for reduced trichomes on one plant part might be associated with lower trichome density on other plant parts, including fibers on seed.
Sixty eight diverse genotypes of American cotton Gossypium hirsutum L. were evaluated for 13 quantitative and fibre quality traits. The variability studies indicated that high PCV and GCV was observed in case of seed cotton yield/ plant and number of bolls/plant while moderate PCV and GCV was observed in case of days to first flower, plant height and boll weight. Seed cotton yield /plant, days to first flower, plant height, number of bolls/plant and boll weight shows high heritability with high genetic advance over mean. The correlation study revealed that seed cotton yield was found to be positively and significantly correlated with traits like days to first flower, plant height, number of monopodial branches, number of bolls/plant, seed index, lint index, ginning out turn, and uniformity ratio, whereas it had negative association with boll weight, 2.5% span length, fibre fineness, and bundle strength. Path analysis revealed that days to first flower, number of monopodial branches, number of bolls/plant, boll weight, seed index, lint index, ginning out turn and uniformity ratio showed positive direct effect on seed cotton yield. Hence selection for these traits would be quite effective to improve the seed cotton yield in uplandcotton.
Results of these studies and others (Butler and Henneberry, 1984; Flint and Parks, 1990; Leigh et al., 1994; Natwick et al., 1995; Watson et al., 1994) indicate a wide range of susceptibility of uplandcotton cultivars to whiteflies in the field. Leaf morphology (Chu et al., 1995b) and hairiness (Norman and Sparks, 1997) may be related to cultivar susceptibility. LA 887 and ST 474 were the two most susceptible cultivars in our studies and both have hairy leaves. All the Deltapine cultivars tested are smooth leaf cotton types (Larry Burdett, Delta and Pine Land Co., Yuma, AZ, 1995, personal communication) which may partially explain the lower whitefly populations. Butler et al. (1991) suggested that glabrous, small leaf area, and open
Genetic divergence of sixty genotypes of uplandcotton for 15 characters was estimated using D 2 statistic. The genotypes were grouped into 11 clusters based on D 2 values and PCA identified seven principal components which explained 78.6 per cent of the total variability. Divergence results indicated that geographical diversity is not necessarily associated with the genetic diversity. Multivariate analysis revealed maximum divergence among genotypes HYPS 152, GISV 267, MCU 5, L 389 and TCH 1741 signifying their role in possible exploitation of heterosis.
Results: We developed a transient transformation system for gene characterization in uplandcotton. Using β‑glucuronidase as a reporter for Agrobacterium‑mediated transformation assays, we evaluated multiple transforma‑ tion parameters such as Agrobacterium strain, bacterial density, length of co‑cultivation, chemicals and surfactants, which can affect transformation efficiency. After the initial characterization, the Agrobacterium EHA105 strain was selected and a number of binary constructs used to perform gene characterization studies. 7‑days‑old cotton seed‑ lings were co‑cultivated with Agrobacterium and transient gene expression was observed 5 days after infection of the plants. Transcript levels of two different transgenes under the control of the cauliflower mosaic virus (CaMV) 35S pro‑ moter were quantified by real‑time reverse transcription PCR (qRT‑PCR) showing a 3–10 times increase over the levels observed in non‑infected controls. The expression patterns driven by the promoters of two G. hirsutum genes as well as the subcellular localization of their corresponding proteins were studied using the new transient expression system and our observations were consistent with previously published results using Arabidopsis as a heterologous system. Conclusions: The Agrobacterium‑mediated transient transformation method is a fast and easy transient expression system enabling high transient expression and transformation efficiency in uplandcotton seedlings. Our method can be used for gene functional studies such as promoter characterization and protein subcellular localization in cotton, obviating the need to perform such studies in a heterologous system such as Arabidopsis.
(Punitha and Raveendran, 2004; Akter et al. 2009). The precise inform- ation on the nature and magnitude of genotypic variation depends upon the various procedures exploited for its estimation like characterization based on agronomical, morpholo- gical and physiological traits (Bajracharya et al., 2006). As the morphological traits of uplandcotton cultivars revealed significant varia- bility (Copur, 2006) and seed cotton yield have significant differences for first and last pick (Soomro et al., 2005). Keeping in view the import- ance of cotton as a major industrial crop, the study was carried out to estimate heritability and genetic potential in nine different uplandcotton cultivars for yield related attributes in the agro-ecological environment of D.I.Khan.
Since uplandcotton is an allotetraploid crop with two different genomes it is possible that some markers could produce amplicons from both genomes giving rise to multilocus data. We employed two criterions for separating such multilocus data into different loci. First, if one of the amplicons was monomorphic across all entries it was considered to be an individual locus. Second, because all entries were selfed for three generations we did not expect high residual heterozygosity, so ampliconss were separated into two different loci to reduce overall heterozygosity for the marker. Basic summary statistics for biallelic data were calculated using POWERMARKER software package version 3.25 (Liu and Muse, 2005). The polymorphism information content (PIC) of SSR marker was determined according to the method described by Botstein et al. (1980). A PIC value of 1 indicates that the marker can differentiate each line, and 0 indicates a monomorphic marker. Informative potential of a marker is high if its PIC value is more than 0.5, moderate if PIC is between 0.5 and 0.25 and only slightly informative if PIC value is below 0.25. Other statistics calculated were number of alleles, allele diversity and heterozygosity for each marker.
sion recommended practices under certain envi- ronmental conditions or when specific symptoms are observed. These inputs include enhanced soil fertility, in-furrow foliar fungicides, in-furrow insecticides, foliar applied fungicides, and late foliar applied potassium. In-furrow fungicide pro- vides added protection against the cotton seedling disease complex above what is already achieved with the seed treatment fungicides which are present on the overwhelming majority of planted acres (Keonning and Collins, 2016). An in-furrow insecticide on top of insecticidal seed treatments has been recommended to improve and prolong the management of early season thrips populations in uplandcotton in the southeastern United States (US) Cotton Belt (Reisig, 2016). The application of foliar fungicides is intended to prevent leaf spot and boll rot caused by fungal pathogens in conditions conducive to disease development (Syngenta Crop Protection, 2017). Potassium, is utilized by cotton throughout the growing season (Pettigrew, 2008), but the majority of utilization occurs during boll development and plays a vital role in cotton fiber elongation (Pettigrew, 2008; Snider and Oosterhuis, 2015). These inputs are presented to the growers as inexplicit ways to promote plant health even when the recommended conditions and symptoms are not present. Therefore, research was conducted to observe these representative inputs, regardless of present environmental conditions or plant symp- toms, for effects on cotton growth and yield com- pared to current state extension recommendations. In addition, the monetary impacts of these inputs were analyzed for profitability.
Uplandcotton is a key source of spinnable fiber and culti- vated in more than 61 countries in the world on an area of 29.3 million hectares (ICAC 2018). Cotton and cotton- based industry has a pivoting role in the economy of Pakistan. Pakistan ranks the fourth in terms of area and production in the world after India, China and USA, 3rd in consumption and 2nd in yarn production in the world. Cotton contributes 1% share in GDP, while 55% in total for- eign exchange earnings of Pakistan. Cotton was planted on an area of 2.7 million hectares in 2017, showing an increase of 10% over the previous year. About 8% more cotton pro- duction, i.e., 11.54 million bales was recorded during 2017/ 2018 as compared with 2016/2017 where 10.72 million bales was recorded (PCCC 2017). However, in terms of per acre yield (679 kg·hm − 2 ), Pakistan is lagging far behind from the major cotton producing countries like Australia (1 816 kg·hm − 2 ), China (1 719 kg·hm − 2 ), Turkey (1 826 kg·hm − 2 ) and USA (985 kg·hm − 2 ) (ICAC 2018).
Under the 2014 Farm Bill, cotton producers fall into a unique policy position relative to other crop pro- ducers. The shallow-loss revenue protection and price protection programs under Title I were not available to cotton producers. However, cotton producers can enroll in the Supplemental Coverage Option (SCO) or the Stacked Income Protection Plan (STAX). The STAX program is available only to uplandcotton producers. The SCO and STAX are similar to Group Risk Income Protection. Both programs cover county- wide losses and they are designed to complement an individual’s insurance policy. Thus, producers could simultaneously purchase an individual policy and an SCO or STAX policy. The individual policy would cover deeper losses, whereas the SCO or STAX policy would cover shallow losses (Campiche, 2013a). Be- cause most U.S. cotton producers have coverage levels of 70% or lower on individual policies, they could receive up to 20% STAX coverage (a 10% deductible) (Campiche, 2013b).
Economic Analysis. The economic impact of roller ginning versus saw ginning must be consid- ered. In commercial settings the production rate of high-speed roller ginning is the same as saw ginning on a per unit of width basis. However in the small runs and laboratory conditions of this test the roller ginning was approximately 33% slower due to issues with static electricity and choking up of the reclaimer, which is not representative of normal commercial practice. The roller gin experienced an average of greater than 2.0% increased turnout (Table 2), which would equal an extra 2.86 bales at 37% turnout for every 50 bales produced at 35% turnout. Although both the roller- and saw-ginned cottons had staple lengths that are at the maximum premiums on the Commodity Credit Corporation (CCC) Loan Sched- ule of Premiums for UplandCotton (USDA, 2016b), the improved uniformity index of the roller-ginned cotton provides for an additional 44.4 points/kg (20 points/lb) premium.