Conventional Cotton Varieties Research Articles

Supressão de acasalamentos e redução de danos de Spodoptera frugiperda (J. E. Smith, 1797) no algodoeiro

The control of Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) in cotton (Gossypium hirsutum L.) has been limited by the rapid development of resistance to insecticides and Bt toxins. The fall armyworm has become increasingly present in cotton fields, becoming a major problem for growers. Therefore, the demand for new and more sustainable tools for managing this pest has increased in recent years. Ideally, the new tool should be compatible with other available control tactics, such as the use of Bt plants, and it should be implemented following IPM principles. In this study, we tested the efficacy of a liquid pheromone formulation for the Fall armyworm control in Bt and conventional cotton varieties in the Brazilian Midwest. Our results showed that the capture of insects in traps has been reduced by 85% in areas treated with pheromone compared to control suggesting high levels of mating suppression. Pheromone treatment also resulted in 70% less damage to cotton reproductive structures when compared to areas not treated with the pheromone in conventional cotton. Moreover, applying pheromone provided an additional benefit to Bt cotton, resulting in 85% damage reduction. Our results show the effectiveness and feasibility of mating disruption with pheromone as an important management tactic for Lepidopterans in cotton. However, no significant differences were found in yield in the conditions tested. These results represent a potential key step toward developing more sustainable tools for pest management in Brazil.

Sulfur Fertilization and Sulfur Sufficiency Range for Contemporary Cotton Cultivars with High Yielding Potentials

Information is lacking on sulfur (S) nutrition characteristics of contemporary cotton (Gossypium hirsutum L.) cultivars and their responses to S fertilization in the United States. The objective of this study was to develop S fertilizer recommendations and S sufficiency ranges for contemporary cotton cultivars with high yielding potentials. Sixteen field trials were conducted on cotton across west Tennessee during 2014–2016. Five S application rates of 0, 11.2, 22.4, 33.6, 44.8 kg ha−1 were examined in a randomized complete block design with four replicates at each location-year. Lint yield was significantly increased by 8.5–9.8% with S applications of 11.2, 22.4, 33.6, 44.8 kg ha−1 in the soils with low S. Soil residual S level after harvest was significantly enhanced only at the highest rate of 44.8 kg S ha−1. However, lint yield or soil residual S did not respond to S application in the medium S soils. Leaf S concentrations of 3.9–8.2 g kg−1 at late bloom were needed for 95–100% of the highest yield in the low S soils, which were different from the current S sufficiency range of 3.0–9.0 g kg−1 being used in diagnosing cotton S nutrition. In conclusion, application of 11.2 kg S ha−1 is beneficial and adequate for cotton grown on low S soils. The S sufficiency range at late bloom was narrower for contemporary cotton cultivars than conventional cotton varieties. Sulfur management needs to be more accurate for contemporary cotton cultivars due to their narrower S sufficiency range.

Constitutive and induced insect resistance in RNAi-mediated ultra-low gossypol cottonseed cotton

BackgroundBesides fibers, cotton plants also produce a large amount of seeds with a high oil and protein content. The use of these seeds is restricted by their high contents of the terpenoid gossypol, which is harmful to humans and livestock. Using a genetic engineering approach, “Ultra-low gossypol cottonseed” (ULGCS) plants were produced by knocking down an enzyme that catalyzes the formation of a precursor of gossypol. This was accomplished via RNAi-mediated silencing of the target gene using a seed-specific α-globulin promotor. Since gossypol is also a crucial defense mechanism against leaf-feeding herbivores, ULGCS plants might possess lower herbivore resistance than non-engineered plants. Therefore, we tested the constitutive and inducible direct insect resistance of two ULGCS cotton lines against the African cotton leafworm, Spodoptera littoralis.ResultThe herbivore was equally affected by both ULGCS lines and the control (Coker 312) line when feeding on fully expanded true leaves from undamaged plants and plants induced by jasmonic acid. When plants were induced by caterpillar-damage, however, S. littoralis larvae performed better on the ULGCS plants. Terpenoid analyses revealed that the ULGCS lines were equally inducible as the control plants. Levels of terpenoids were always lower in one of the two lines. In the case of cotyledons, caterpillars performed better on ULGCS cotton than on conventional cotton. This was likely caused by reduced levels of gossypol in ULGCS cotyledons.ConclusionDespite those effects, the insect resistance of ULGSC cotton can be considered as largely intact and the plants may, therefore, be an interesting alternative to conventional cotton varieties.

The response of dominant and rare taxa for fungal diversity within different root environments to the cultivation of Bt and conventional cotton varieties

BackgroundBacillus thuringiensis (Bt) crops have been cultivated at a large scale over the past several decades, which have raised concern about unintended effects on natural environments. Microbial communities typically contain numerous rare taxa that make up the majority of community populations. However, the response of dominant and rare taxa for fungal diversity to the different root environments of Bt plants remains unclear.ResultsWe quantified fungal population sizes and community composition via quantitative PCR of ITS genes and 18S rRNA gene sequencing of, respectively, that were associated with Bt and conventional cotton variety rhizosphere soils from different plant growth stages. qPCR analyses indicated that fungal abundances reached their peak at the seedling stage and that the taproots and lateral root rhizospheres of the Bt cotton SGK321 were significantly different. However, no significant differences in population sizes were detected between the same root zones from Bt and the conventional cotton varieties. The overall patterns of fungal genera abundances followed that of the dominant genera, whereas overall patterns of fungal genera richness followed those of the rare genera. These results suggest that the dominant and rare taxa play different roles in the maintenance of rhizosphere microhabitat ecosystems. Cluster analyses indicated a separation of fungal communities based on the lateral roots or taproots from the three cotton varieties at the seedling stage, suggesting that root microhabitats had marked effects on fungal community composition. Redundancy analyses indicated that pH was more correlated to soil fungal community composition than Bt protein content.ConclusionsIn conclusion, these results indicate that dominant and rare fungal taxa differentially contribute to community dynamics in different root microhabitats of both Bt and conventional cotton varieties. Moreover, these results showed that the rhizosphere fungal community of Bt cotton did not respond significantly to the presence of Bt protein when compared to the two conventional cotton varieties.

Impact of transgenic Cry1Ac + CpTI cotton on diversity and dynamics of rhizosphere bacterial community of different root environments

The objective of this study was to characterize the diversity and dynamics of rhizosphere bacterial community, especially the response of dominant and rare bacterial taxa to the cultivation of Bt cotton for different root environments at different growth stages. qPCR analyses indicated that bacterial abundances of the taproots and lateral root rhizospheres of the Bt cotton SGK321 were significantly different at seedling and bolling stages. But no significant differences were detected between the same root zones from Bt and the conventional cotton varieties. Total bacterial genera had similar pattern with dominant genera in abundance, and with rare genera in richness to the changes of bacterial community, respectively. Although the rhizosphere bacterial diversity of the three cotton varieties changed in taproot and lateral root, no significant differences were detected in the same root environments between Bt and conventional cotton. Moreover, Soil pH was more correlated with variations in the bacterial community composition than Bt proteins. In conclusion, these results revealed no indication that rhizosphere bacterial community of Bt cotton had different response to increased Bt protein regarding the same root environment. In particular, dominant and rare bacterial taxa showed the variation in diversity and community composition in different root microhabitats.

Field trial of insect-resistant and herbicide-tolerant genetically modified cotton (Gossypium hirsutum L.) for environmental risk assessment in Japan

ABSTRACTJapan imports cottonseed mainly from Australia and the USA where more than 96% of all cotton varieties grown are genetically modified (GM). GM crops undergo an environmental risk assessment (ERA) under the Law Concerning the Conservation and Sustainable Use of Biological Diversity before import into Japan. Potential adverse effects on biodiversity are comprehensively assessed based on competitiveness, production of harmful substances and outcrossing ability. Even though imported cottonseed is intended for food and feed uses and not for cultivation, the potential risks from seed spillage during transport must be evaluated. In most cases, the ERA requires data collected from in-country field trials to demonstrate how the GM crop behaves in Japan's environment. Confined field trials in Japan were conducted for the ERA of Lepidoptera-resistant and glufosinate-tolerant GM cotton (Gossypium hirsutum L.) lines GHB119 and T304-40. These lines were compared with conventional varieties for growth habit, morphological characteristics, seed dormancy, and allelopathic activity associated with competitiveness and production of harmful substances. Outcrossing ability was not a concern due to the absence of sexually compatible wild relatives in Japan. Although slight statistical differences were observed between the GM line and its conventional comparator for some morphological characteristics, transgenes or transformation were not considered to be responsible for these differences. The trial demonstrated that competitiveness and production of harmful substances by these GM cotton lines were equivalent to conventional cotton varieties that have a long history of safe use, and no potential adverse effects to biosafety in Japan were observed.

Comparative Economics Analysis of the Bt. Cotton V/S Conventional Cotton Production in Khairpur District, Sindh, Pakistan

Cotton is an important cash crop which covers 35 million hectares of land. Major objectives of the study were to examine the role of determinants of cotton yield to asses’ financial gain from Bt.cotton comparing with conventional Cotton. District Khairpur was selected for the present study where both Bt.cotton and conventional cotton varieties are grown primary data on Bt. cotton and conventional cotton was collected from the farmers through personal interviews with the help of specially designed questionnaire. A simple random sampling technique was used to collect the data. Cobb-Douglas production function was used for yield analysis. Logit model was used to find the probability of Bt.cotton. Farmers growing Bt. cotton who had used seed rate (6-8) kg per acre were 46.66 percent, while 53.33 percent had used seed rate (9-10) kg per acre. Conventional cotton who had used seed rate (6-8) kg per acre was 66.66 percent while 33.33 percent had used seed rate (9-10) kg per acre. Total costs per acre in Bt.cotton sown were greater than the conventional Cotton activities, total costs incurred in the conventional cotton were far lower (about 26 percent lower) than Bt.cotton. On an average higher yield (40 mounds per acre) was obtained in Bt.cotton sown than conventional cotton yield (25 mounds per acre). Price gained per mounds was almost the same in two cotton activities. Higher profit was observed in Bt. cotton and very low profit was obtained in conventional cotton.

<b>Behavior of <i>Orius insidiosus</i> preying on <i>Aphis gossypii</i> reared on transgenic and conventional cotton varieties

The objective of this study was to evaluate the functional response of Orius insidiosus preying on the third and fourth instars of Aphis gossypii nymphs that were reared on transgenic NuOPAL (Bollgard I Event 531) and conventional Buriti cotton varieties. Fifty O. insidiosus female bugs aged 12-24h were distributed into five different Petri dishes with different densities of A. gossypii (2, 4, 8, 16, and 32 nymphs per plate) for each cotton variety. The number of prey consumed was evaluated over the course of 12h, with a final assessment at 24h. The handling times (Th) and attack rates (a) were 0.0697h and 1.1862h -1 , respectively, for the Buriti variety and 0.0713h and 0.3030h -1 , respectively, for the NuOPAL variety. The average number of prey consumed by O. insidiosus was similar for both varieties at 24h and at higher densities; the attack rate was higher for the Buriti-reared aphid prey than for the NuOPAL-reared aphids.

EVALUATION OF INSECTICIDE SPRAY/NO SPRAY ON CONVENTIONAL AND DOUBLE-GENE INSECT RESISTANT COTTON AGAINST BOLLWORM, 2013

Thirteen double-gene insect resistant and two conventional cotton varieties were evaluated for control of BW in Virginia cotton at the Virginia Tech Tidewater Agric. Res. & Ext. Ctr., Suffolk, VA. Each variety was treated with insecticides targeting BW, or not treated for BW. In the treated plots, double-gene insect resistant varieties received one spray of Brigade @ 6.4 oz/acre plus Belt @ 2 oz/acre on 14 Aug 6 day after BW egg threshold. Conventional varieties received two sprays for BW, Brigade @ 6.4 oz/acre at BW egg threshold on 8 Aug, and Brigade @ 6.4 oz/acre plus Belt @ 2 oz/acre on 14 Aug. Treatments were applied with a Spider Spray Trac-mounted CO2-pressurized sprayer at 16.5 gpa and 30 psi through 8002VS nozzles spaced 18 inches apart on the spray boom. Cotton was planted 17 May using 36-inch row spacing. A split-plot experimental design was used with 4 replicates; plots were 4 rows by 40 ft. Plant population was determined on 24 Jun by counting all plants in two rows per plot. External boll injury was determined by visually inspecting 25 bolls per plot for evidence of BW feeding on three dates. Yield was determined by harvesting 2 rows of each plot (80 row ft) on 13 Nov using a commercial 2-row cotton picker. Samples from each variety were ginned to determine lint versus seed and trash weight. Data were analyzed using ANOVA and LSD statistical procedures.

Construction of DNA Fingerprinting and Analysis of Genetic Diversity for Xinluzao Cotton Varieties

Fifty-one Xinluzao conventional cotton varieties authorized before 2013 were detected with 75 pairs of primers with high polymorphism, good repeatability, and even distribution on 26 chromosomes(2–3 pairs from each chromosome) selected from 5000 pairs of SSR primers. A total of 226 polymorphic loci were obtained, and each marker detected 2–12 polymorphic loci with an average of 3.01; the polymorphism information content ranged from 0.0799 to 0.8752, with an average of 0.6624. The results showed that 21 varieties were differentiated by characteristic primers, and the rest 30 varieties could be identified by primer conbinations. In the end, 40 specific primers and combinated primers could completely differentiate the 51 Xinluzao cotton varieties from each other. DNA fingerprinting of the 51 Xinluzao conventional varieties were constructed with the 40 pairs of SSR markers. NTSYS-pc V2.10 software was used to analyze genetic diversity of the 51 conventional varieties, the results indicated that genetic similarity coefficient for the varieties ranged from 0.4269 to 0.9873, with an average of 0.7071, showing the narrow genetic diversity in Xinluzao cotton varieties. The 51 Xinluzao cotton varieties were divided into four types with the genetic similarity coefficient matrix and cluster analysis, which were strongly consistent with their pedigrees.

Scientific Opinion on application EFSA‐GMO‐RX‐MON531 for renewal of the authorisation for continued marketing of existing cottonseed oil, food additives, feed materials and feed additives produced from MON 531 cotton that were notified under Articles 8(1)(a), 8(1)(b) and 20(1)(b) of Regulation (EC) No 1829/2003 from Monsanto

This scientific opinion evaluates the risk assessment for the authorisation for continued marketing of genetically modified insect resistant cotton MON531 for food and feed produced from it. MON531 was transformed via Agrobacterium. It contains single copies of functional Cry1Ac and NPTII expression cassettes; two fragments of the Cry1Ac cassette and aadA as non-functional elements. Stability of the inserted DNA was confirmed over several generations. Bioinformatic analyses and the levels of recombinant proteins did not reveal safety concerns. Analysis of compositional, phenotypic and agronomic characteristics indicated that MON531 is not different from its conventional counterpart and is compositionally within the range observed among conventional cotton varieties, except for Cry1Ac and NPTII. Safety assessment of Cry1Ac and NPTII proteins and cotton MON531 identified no concerns regarding potential toxicity and allergenicity. Products from MON531 do not contain viable plant parts. The aadA and oriV sequences in MON531 may facilitate the stabilisation of nptII through double homologous recombination in plasmid sequences in the environment. However, considering the expected low frequency of gene transfer from MON531 to bacteria compared to that between bacteria, and the very low exposure to MON531 DNA, the GMO Panel concludes that gene transfer from MON531 to bacteria does not indicate a risk to human or animal health or to the environment in the context of its intended uses. The exposure of potentially sensitive non-target organisms to Cry1Ac protein is likely to be low and of no biological relevance. A PMEM plan is not required. The EFSA GMO Panel considers that information available for cotton MON531 addresses the questions raised by the Member States and that cotton MON531, as described in this application, is as safe as its conventional counterpart and is unlikely to have adverse effects on human and animal health and the environment in the context of its intended uses.

Relative abundance and damage by target and non-target insects on Bollgard and BollgardII cotton cultivars

Bollgard ® and BollgardII ® cotton cultivars were evaluated for their efficacy for control of bollworms and their effects on sucking insects and the abundance of natural enemies under bollworm insecticide protected and non-insecticide protected field conditions during the 2004 and 2005 cropping seasons. Bollgard cultivars are genetic transforms that produce Cry1Ac toxins from Bacillus thuringiensis (Bt) to control American bollworm, Helicoverpa armigera. Second generation BollgardII cultivars contain 2 toxins, Cry1Ac and Cry2Ab, and are more effective in controlling a broader range of caterpillar species. Bollgard cultivars were free of H. armigera damage until harvest under insecticide protected as well as non-protected conditions. Both BollgardII and Bollgard cultivars were infested with larvae of spotted bollworm, Earias vitella, and spiny bollworm, Earias insulana, at later crop growth stages. Neither BollgardII nor Bollgard cultivars were free of square (fruiting body), open boll and loculi damage. Bollworm damage did not reach economic threshold levels up to harvest. Densities of sucking insects ( Amrasca biguttula biguttula, Bemisia tabaci, Aphis gossypi, and Thrips tabaci), of the foliage feeder Myllocerus undecimpustulatus and of predators ( Chrysoperla spp., Orius spp., Coccinella spp., Brumus spp., Vespa spp., Lycosa spp., and Aranews spp.) were similar on Bollgard, BollgardII and conventional cultivars. The time of the first appearance of bollworms, sucking insects and predators on Bt cotton did not vary from conventional cotton varieties. Insecticidal protection based on economic threshold levels resulted in significant reductions in bollworm damage on conventional cultivars.

Evaluation of cottonseed meal derived from genetically modified cotton as feed ingredients for channel catfish,Ictalurus punctatus

Three laboratory experiments were conducted to assess nutritional quality of cottonseed meals from genetically modified (GM) cotton crops, Roundup Ready® Flex, Bollgard® × Roundup Ready, Bollgard II® × Roundup Ready, and Bollgard II × Roundup Ready Flex for channel catfish, Ictalurus punctatus using Good Laboratory Practices. Growth, feed efficiency, survival, and fillet composition of catfish fed diets containing 20% cottonseed meal from these cotton products were compared with that of catfish fed diets containing cottonseed meals from the near-isogenic, non-GM control and non-GM commercial varieties. Juvenile catfish (mean weights of 4.1, 5.0, and 0.6 g per fish for Experiments 1, 2, and 3, respectively) were stocked in each of 80-L aquaria and fed experimental diets for 8 weeks. Although there were slight variations in proximate composition, amino acids, and gossypol concentrations, the GM cottonseed meals were not significantly different from the conventional control and the reference cottonseed meals. Weight gain, feed conversion, survival, and fillet composition of catfish fed GM cottonseed meals appeared similar to that of either the control or the commercial cottonseed meals. Results from the present study demonstrate that these GM cottonseed meals are nutritionally equivalent to conventional non-GM cotton varieties when fed to catfish at 20% of the diet.

Impact of Bt cotton adoption on pesticide use by smallholders: A 2-year survey in Makhatini Flats (South Africa)

This paper explores insecticide use in fields cropped with conventional or Bt cotton varieties in a smallholder farming area (Makhathini Flats, KwaZulu Natal, South Africa). The study was carried out during the 2002–2003 and 2003–2004 growing seasons as part of a broader survey based on daily monitoring of a sample of smallholdings. The adoption of Bt cotton led to a decrease in pyrethroid use, but the level of insect resistance of this cultivar was not sufficient to completely drop this pesticide from the spraying programme. On the other hand, organophosphates were still being applied in substantial amounts, thus raising questions as to the impact of Bt cotton adoption on farmers’ health. The overall economic results obtained with Bt cotton were slightly positive despite the low cotton yields obtained in the Flats during our survey. Bt cotton adoption did lead to labour savings, but the extent of this gain was not as high as expected. In conclusion, cropping Bt cotton in Makhathini Flats did not generate sufficient income to expect a tangible and sustainable socioeconomic improvement due to the way the crop is currently managed. Adoption of an innovation like Bt cotton seems to pay only in an agro-system with a sufficient level of intensification.

Viability of cotton and canola pollen on the proboscis of Helicoverpa armigera: implications for spread of transgenes and pollination ecology

Abstract. 1. Pollen can be transported thousands of kilometres by insects but its viability after long‐distance transport is not known. Knowing the potential for this mechanism to cause outcrossing of transgenes from genetically modified (GM) plants is important for risk assessments.2. The viability of pollen from cotton (Gossypium hirsutum L.) and canola (Brassica napus L.) was determined after placing it on the proboscis of Helicoverpa armigera moths for intervals of up to 32 h. Viability of both cotton and canola pollen declined at a much greater rate when in contact with the moth proboscis. Most was non‐viable by 8 h compared with 16 h for control cotton pollen or 32 h for canola pollen.3. There was no significant difference in the rate of decline of pollen viability between the five conventional cotton varieties, or between these and the one GM cotton variety used in these experiments.4. The number of canola pollen grains remaining on the proboscis declined over time. Very few cotton pollen grains were retained on the proboscis.5. The reduction in pollen viability during contact with the proboscis might indicate partial ingestion of the pollen via the proboscis.6. The points above suggest that pollen is unlikely to remain attached or remain viable when carried over large distances by H. armigera. The implications for spread of pollen from transgenic plants and for pollination ecology in general are discussed.

Bollgard II Cotton: Compositional Analysis and Feeding Studies of Cottonseed from Insect-Protected Cotton (Gossypium hirsutumL.) Producing the Cry1Ac and Cry2Ab2 Proteins

Bollgard II cotton event 15985 producing the Cry1Ac and Cry2Ab2 proteins has been developed by genetic modification to broaden the spectrum of insects to which the plant is tolerant and to provide an insect resistance management tool to impede the onset of resistance. The purpose of this study was to evaluate the composition and nutrition of Bollgard II cotton, relative to the use for food and animal feed, compared to that of conventional cotton varieties. Compositional analyses were conducted to measure proximate, fiber, amino acid, fatty acid, gossypol, and mineral contents of cottonseed from a total of 14 U.S. field sites over two years. Compositional analysis results showed that the cottonseed and cottonseed oil from Bollgard II cotton were comparable in their composition to those of the conventional control cotton line and other commercial varieties. The composition data are supported by nutritional safety studies conducted with dairy cows, catfish, and quail. Results from these studies showed that Bollgard II performed similarly to the conventional control cotton varieties. These data demonstrate that Bollgard II cotton is compositionally and nutritionally equivalent to conventional cotton varieties. These data support the conclusion that Bollgard II cotton is as safe and nutritious as conventional cotton for food and feed use.

Glyphosate and Water‐Stress Effects on Fruiting and Carbohydrates in Glyphosate‐Resistant Cotton

Water stress and glyphosate treatments to glyphosate‐resistant (GR) cotton (Gossypium hirsutum L.) can cause abscission of young bolls although the interaction of these factors is not well defined. Studies were conducted to quantify the effects of water stress and glyphosate treatments on fruit retention, fruit placement, and carbohydrate partitioning in GR and conventional cotton varieties grown in a phytotron environment. Glyphosate‐resistant plants treated with glyphosate at the four‐leaf stage, postemergence (POST), and at the eight‐leaf stage, POST‐directed (PDIR), had fewer first‐position bolls after 0 and 1 d of water stress than nontreated GR and conventional plants but did not differ after 2 and 3 d of water stress. Glyphosate‐treated GR plants reached first bloom 3 to 4 d later than nontreated plants. Five‐day‐old bolls from plants of one genotype, SG 125RR, treated with glyphosate had lower fructose content than bolls from nontreated plants. Subtending leaf carbohydrates and boll sucrose, glucose, and starch content did not differ after glyphosate treatments. Increasing water stress caused reductions in subtending leaf glucose, sucrose, and starch content, as well as reductions in boll starch and sucrose content. Reductions in boll starch and sucrose content in response to water stress may indicate the potential for abscission. Water stress and glyphosate treatments to GR cotton do not alter carbohydrate profiles in boll or leaf tissues in a like manner. Differences in carbohydrate profiles of young bolls and leaves from glyphosate‐treated and water‐stressed cotton plants suggest that water stress and glyphosate treatments may promote fruit abscission in different manners.