Cotton Plant Parts Research Articles

Cry toxin expression in different plant parts of Bt cotton at different phenological stages

BackgroundCompared to Bollgard-I, the utilization of Cry2Ab protein in Bollgard-II cotton cultivars enhances insect control. Field and laboratory studies demonstrated reduction in the numbers of bollworm-infested terminals, squares, and bolls in Bollgard-II cotton lines when compared to both Bollgard-I and non-Bollgard cotton cultivars. This indicates that the combination of Cry2Ab with Cry1Ac increased the overall expression of proteins. The expression of Cry protein varied across different plant parts, such as leaves, bracts, squares, and bolls. As the season progresses, the expression of Cry protein decreased in these plant parts. Leaves exhibited the highest levels of Cry protein expression, followed by squares, flowers, and bolls. Variation in the expression levels of delta endotoxins in different plant parts was one of the contributing factors to the survival of pest populations on Bt cotton.ResultsUsing a commercially available QL 96 ELISA plate kit, the concentration of delta endotoxin in various plant parts at different phenological stages was determined in twelve BG-II cotton hybrids, namely Ajeet-155, JKCH-2245, RCH-3863, NCS-866, MRC-7373, JKCH-99, MRC-7387, NCEH-21, ANKR-3324, NCSI-1904, and NCHB 9902. Cry1Ac and Cry2Ab protein levels were determined from samples of flowers and fruiting parts (Rind, locule, seed, locule wall and seed) at 40, 75, 100 and 125 days after sowing (DAS) over two consecutive years 2018–2019 and 2019–2020. Cry1Ac protein content and expression was the highest at 100DAS in locule, seed and rind; followed by rind and locule wall and seed in green bolls at 125 DAS; followed by seed, locule, rind and flowers at 75 DAS; followed by flowers at 40 DAS in all the tested twelve Bollgard-II hybrids. Cry2Ab protein content and expression was the highest at 125DAS in locule wall and seed and rind, followed by seed, locule and rind in green bolls at 100 DAS, followed by seed, locule, rind and flowers at 75 DAS, then by flowers at 40 DAS in all the tested twelve Bollgard-II hybrids. Cry1Ac protein expression was less in comparison with Cry2Ab.ConclusionsThe research findings indicate that the locule of BG-II cotton plants exhibited the highest expression levels of Cry1Ac and Cry2Ab proteins, followed by the seeds, rind, locule wall, and flowers. These results provide valuable insights into the distribution of Cry protein expression in different plant parts, which can contribute to a better understanding of insect control in Bt cotton cultivars.

Cotton plant part 3D segmentation and architectural trait extraction using point voxel convolutional neural networks

BackgroundPlant architecture can influence crop yield and quality. Manual extraction of architectural traits is, however, time-consuming, tedious, and error prone. The trait estimation from 3D data addresses occlusion issues with the availability of depth information while deep learning approaches enable learning features without manual design. The goal of this study was to develop a data processing workflow by leveraging 3D deep learning models and a novel 3D data annotation tool to segment cotton plant parts and derive important architectural traits.ResultsThe Point Voxel Convolutional Neural Network (PVCNN) combining both point- and voxel-based representations of 3D data shows less time consumption and better segmentation performance than point-based networks. Results indicate that the best mIoU (89.12%) and accuracy (96.19%) with average inference time of 0.88 s were achieved through PVCNN, compared to Pointnet and Pointnet++. On the seven derived architectural traits from segmented parts, an R2 value of more than 0.8 and mean absolute percentage error of less than 10% were attained.ConclusionThis plant part segmentation method based on 3D deep learning enables effective and efficient architectural trait measurement from point clouds, which could be useful to advance plant breeding programs and characterization of in-season developmental traits. The plant part segmentation code is available at https://github.com/UGA-BSAIL/plant_3d_deep_learning.

Development and evaluation of triple gene transgenic cotton lines expressing three genes (Cry1Ac-Cry2Ab-EPSPS) for lepidopteran insect pests and herbicide tolerance

Cotton is an international agricultural commodity and the main cash crop of Pakistan of which quality and quantity are subject to various whims of nature. Climate change, insect pest complex, and weeds are reducing its productivity. Here, we have developed triple gene cotton containing EPSPS gene along with two Bt toxin genes Cry1Ac and Cry2Ab using a strategy where all three genes are cloned in the same T-DNA, followed by successful cotton transformation via Agrobacterium-mediated transformation. This strategy has been developed to help cotton breeders in developing new cultivars by incorporating these genes into the non-transgenic or single Bt (Cry1Ac) gene cotton background where all three genes will inherit together. The expression of all three proteins was confirmed through immunostrips and was quantified through enzyme-linked immunosorbent assay (ELISA). The spatio-temporal expression of Bt protein in different parts of triple gene NIBGE cotton plants was determined. Maximum expression was found in leaves followed by seeds and boll rinds. Insect bioassays with cotton bollworms (Helicoverpa armigera), armyworms (Spodoptera litura), and pink bollworms (Pectinophora gossypiella) showed more than 90% mortality. The best performing line (NIBGE-E2) on the basis of spatiotemporal expression, glyphosate assays, and insect mortality data, was used for event characterization by using the genome sequencing approach. The event was successfully characterized and named NIBGE 20-01. A diagnostics test based on event-specific PCR was developed and its ability to distinguish NIBGE 20-01 event from other commercial transgenic cotton events was confirmed. To confirm stable expression of all three proteins in the field conditions, homozygous transgenic lines were grown in the field and the expression was confirmed through immunostrip assays. It was found that all three genes are expressed under field conditions. To show that all three genes are inherited together upon crossing with local elite cotton lines, the F1 generation was grown under glasshouse and field conditions. The expression of all three genes was confirmed under field conditions. Our results showed that transgenic cotton with three genes cloned in the same T-DNA can express all genes and can be conveniently transferred into elite cotton lines through a single cross.

Susceptibility of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) on detached plant parts of transgenic and non-transgenic cotton

Susceptibility of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) on detached plant parts of transgenic and non-transgenic cotton

Colonization on Cotton Plants with a GFP Labeled Strain of Bacillus axarquiensis.

Verticillium dahliae was one of the most important diseases caused Verticilliumwiltofcotton. In our previous study, Bacillus axarquiensis TUBP1 was screened and found to be an antagonistic strain against V. dahliae with 43% biocontrol effect in the cotton field. In order to uncover the functional mechanism of B. axarquiensis against Verticillium wilt in cotton, the colonization of B. axarquiensis labeled with a green fluorescent protein (GFP) was investigated in cotton plants and the rhizosphere soil. Firstly, a plasmid (pHT-315) containing gfp gene was successfully transformed into wild B. axarquiensis TUBP1 and labeled a green fluorescence by electroporation, which didn't change the bioactivity in vitro. In gnotobiotic conditions, cotton seeds were then inoculated with the gfp-labeled strain and grown in green house. Observation with a confocal laser scanning microscope and a scanning electron microscope showed that GFP-labeled B. axarquiensis TUBP1 infected cotton roots and widely distributed in epidermis, cortical parenchyma, intercellular spaces, the xylem vessels, and pith cells as well as root hair cells through cracks formed at the lateral root junctions, followed by a slow migration from roots to stems and leaves. Quantitative fluorescence and flow cytometry (FACS) approaches showed a gradual decrease in the number of TUBP1-315gfp with increasing inoculation time. However, TUBP1-315gfp levels were detectable till 45days after planting. In contrast, no fluorescence signal was detected in the non-inoculated groups. Therefore, GFP-labeled B. axarquiensis TUBP1 exhibited colonization in different parts of cotton plants from the rhizosphere soil.

Carbohydrate and Amino Acid Profiles of Cotton Plant Biomass Products

To achieve the optimal and diverse utilization of cotton (Gossypium hirsutum) plant residues in various agricultural, industrial, and environmental applications, the chemical composition of cotton biomass tissues across different plant parts (e.g., seed, boll, bur, leaves, stalk, stem, and root) is of essential information. Thus, in this work, we collected field-grown whole mature cotton plants and separated them into distinct biomass fractions including main stems, leaf blades, branches, petioles, roots, and reproductive parts (mid-season growth stage) or bur, peduncles/bract, and seed cotton (pre-defoliation stage). The contents of selected carbohydrates and amino acids in these cotton biomass materials were determined. Both essential and nonessential amino acids were enriched in cotton leaf blades and reproductive parts. The distribution pattern of the selected carbohydrates differed from that of amino acids—higher contents of carbohydrate were found in roots, main stems, and branches. Although glucose was the most abundant non-structural carbohydrate in cotton plant parts at mid-season, xylose was the most abundant in most plant parts at the pre-defoliation stage. Nutritional carbohydrates and amino acids were further accumulated in seeds at pre-defoliation. The information reported in this work would be helpful in exploring and optimizing management practices and processing strategies for utilizing cotton crop biomass materials as valuable and renewable natural resources.

Distribution, Dissipation, and Metabolism of Neonicotinoid Insecticides in the Cotton Ecosystem under Foliar Spray and Root Irrigation

The uptake, distribution, metabolism, and degradation of three neonicotinoid insecticides (NIs)-imidacloprid (IMI), acetamiprid (ACE), and thiamethoxam (THI) in different parts of cotton plants were investigated under field conditions. Insecticides were either applied by foliar spraying or root irrigation. Foliar application resulted in high tissue concentration (average tissue concentration ratio, TCR: 46.78-68.61% for leaves and 12.2-31.40% for flowers). The flowers showed high NI residual. The metabolism and trends of NIs in different parts of cotton were reported here for the first time. Metabolites, toxic to bees, were detected in the flowers. The translocation factor was around 0.004 for the spray treatment and 0.2-0.7 for the root irrigation treatment. The average root concentration factors of IMI, ACE, and THI were 0.838, 8.027, and 1.014, respectively, indicating that the three NIs can be transported from the soil to the plant. The high concentrations of NIs and their metabolites in flowers indicate exposure risk to pollinators, such as bees.

Stay or move: how Bt‐susceptibleHelicoverpa armigeraneonates behave on Bt cotton plants

AbstractHelicoverpa armigera(Hübner) (Lepidoptera: Noctuidae) larvae occasionally have been reported to survive at management threshold levels in fields of Bollgard II®cotton,Gossypium hirsutumL. (Malvaceae). The pattern and degree of larval survival is not easily predicted but depends on the ability of first instars to establish on host plants. Experiments were conducted withBacillus thuringiensisBerliner (Bt)‐susceptible and Bt‐resistant larvae ofH. armigerato understand how physiologically Bt‐susceptibleH. armigerasurvive on Bt cotton plants, and examine how their first meal influences survival rates. In assays using cotton plant parts, both strains of larvae displayed similar tendencies to drop‐off specific plant parts of Bt and non‐Bt cotton. However, significantly more Bt‐susceptible larvae dropped off young leaves, mature leaves, and squares of Bt cotton compared to non‐Bt cotton plants. Egg cannibalism significantly improved the survival of Bt‐susceptibleH. armigeralarvae on Bt cotton plants. Larvae were more likely to eat live aged eggs, than newly laid or dead eggs. Survival significantly improved when larvae cannibalized eggs before feeding on Bt leaves. The behavior of Bt‐susceptible larvae with respect to drop‐off and egg cannibalism may help enhance their survival on Bt cotton plants.

Survival of Helicoverpa armigera larvae on and Bt toxin expression in various parts of transgenic Bt cotton (Bollgard II) plants

AbstractThere is no conclusive evidence that Helicoverpa spp. (Lepidoptera: Noctuidae) in Australia have evolved significant levels of resistance to Bollgard II® cotton (which expresses two Bt toxin genes, cry1Ac and cry2Ab). However, there is evidence of surviving larvae on Bollgard II cotton in the field. The distribution and survival of early‐instar Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) larvae were examined on whole Bollgard II and non‐Bt cotton plants in greenhouse bioassays. The expression of Cry toxins in various parts of Bollgard II plants was compared to the survival of larvae in those locations. Only 1% of larvae survived after 6 days on greenhouse‐grown Bollgard II plants compared to 31% on non‐Bt cotton plants. Overall, and across all time intervals, more larvae survived on reproductive parts (squares, flowers, and bolls) than on vegetative parts (leaves, stems, and petioles) on Bollgard II plants. The concentration of Cry1Ac toxin did not differ between plant structures, whereas Cry2Ab toxin differed significantly, but there was no relationship between the level of expression and the location of larvae. This study provides no evidence that lower expression of Cry toxins in the reproductive parts of plants explains the survival of H. armigera larvae on Bollgard II cotton.

Susceptibility of Cotton Boll Weevil (Coleoptera: Curculionidae) to Spinosyns.

The control of boll weevil, Anthonomus grandis grandis Boh., relies primarily on synthetic insecticides. Although insecticides are registered to spray cotton fields against boll weevils, only a few offer satisfactory control and most have broad-spectrum action. Alternatively, spinosyns have been recommended against lepidopteran pest species in cotton and are considered comparatively of reduced risk to nontargets. The susceptibility of nine populations of boll weevil to spinosad and spinetoram was determined through dried residue on squares and cotton leaves. Furthermore, control efficacy of spinosad and spinetoram compared with the standard organophosphate malathion was determined for caged adults at two different positions within the plant canopy or treated cotton leaves after different spray intervals. Boll weevil susceptibility varied across the nine populations and tested spinosyns. The lethal concentrations (LC50s and LC90s) varied from 8.62 to 32.25 and 49.86 to 281.70 mg a.i./l for spinosad and from 2.17 to 15.36 and 8.58 to 69.36 mg a.i./l for spinetoram. The location of boll weevil within the plant canopy affected the insecticide efficacy with higher mortality when caged on upper parts rather than on lower parts of cotton plants (>85% vs <45% of control) across all three insecticides. In addition, dried residues of spinosyns resulted in adult mortality >80% until the end of the evaluation period (8 d), while the standard malathion caused only 10% at this last evaluation time. Thus, we can conclude that both spinosyns promoted prolonged adult mortality using recommended field rates compared with the standard malathion.

Phytoremediation of Heavy Metals Using Cotton Plant: A Field Analysis.

Phytoremediation, a technique dependent on the heavy metal bioaccumulation and translocation in different parts of plants, is an efficient and environment friendly method for decontamination of soils from metals. In the present study, the bioaccumulation and translocation of heavy metals was analyzed in different parts of cotton plant grown in intensively cultivated agricultural fields of Malwa region of Punjab, India. The soils were found to be alkaline in nature with very high sand contents which resulted in low retention of metals (As, Cr, Cu, Mn, Sr and Zn) in soils. But, the bioaccumulation factor and translocation factor calculated for metal accumulation analysis in cotton plant parts were found to be above 1 (maximum 9.13 for Sr) which indicated that the cotton plant (a non-edible fibre crop) can prove to be a significant system for phytoremediation and an efficient green tool for decontamination of soils from heavy metals.

Material culture of the ethnic aboriginal Jarawa folk in Andaman Islands, India

Traditional knowledge is structured on the basis of practical utility and it is an experiential aptitude developed which is scripted down or transmitted orally from one generation to other. Jarawas are hunter-gatherer nomadic negritoid tribe leading a contented life with forest resources thereby justifying themselves as ‘ecosystem people’. Jarawas are eco-friendly people as they extract only that much of natural resources from the surrounding forests as they require for their survival. Awareness of the Jarawas about nature comprises of their knowledge of flora, fauna, land, sea, cosmic phenomena and especially their knowledge of flora is astounding. Nevertheless, ethnobotanical studies of Jarawas provide ample scope to generate interesting floristic data as the tribe belongs to a unique racial group inhabiting the remote geographically isolated islands with varied vegetation. They make different artefacts using materials that are available from their forest habitat except iron. Material culture of Jarawa’s is not utilitarian as they make the artefacts aesthetically pleasant by engraving geometric designs on them. Customarily, Jarawas were observed crafting criss-cross wavy designs on their faces and bodies with clay soil, besides wearing girdles of red cotton and wool which clearly exemplifies their aesthetic sense. These artefacts are mostly function oriented and their preparation is gender specific. However, no gender restrictions exist in using the artefacts. Always men make the hunting implements like bow (aav), arrow (patho) and chest guard (kekad). Conversely, the women make fishing net (botho) and cane basket (taiga) which is used for collecting and gathering food materials. Women also make head, neck and waist girdles using red wool, cotton and different plant parts like flowers and leaves etc. and decorate their bodies. Ethnobotanical information of Jarawa tribe pertaining to artefacts used in shelter, hunting, fishing, food gathering, ornamentation and dressing purposes are presented in detail besides highlighting their subsistence activities and cultural influences.

Droplet deposition characteristics of plant protection UAV spraying at night

Abstract: The spraying technology of plant protection UAVs is developing rapidly. Although they can spray autonomously at night, the application performance under meteorological conditions at night still needs to be evaluated. In this research, the droplet deposition characteristics of nighttime and daytime spray of a P20 UAV with different operating parameters were compared. Specifically, the number of droplets deposited in different parts of the plant was evaluated. The results showed that under the same operating parameters the application time had a significant effect on the number of droplets deposited and coverage rate, the droplets number and coverage rate for the nighttime application were 43.47% and 37.21% higher than that by the daytime application. In terms of the droplets deposition in different parts of cotton plants, for the nighttime application, the proportions of the droplets on the upper, middle and lower layer to the total droplet number in the vertical direction of the plant were 41.24%, 35.71% and 23.05%, respectively and those were 43.09%, 33.99% and 22.91% for the daytime application. There were more droplets deposited on the middle and lower layer of the plants when spraying at night than those in the day. Additionally, the deposited droplets on the backside of the leaf account for 21.92% of the total droplets on a leaf for the nighttime application on average, while it was 20.23% for the daytime application, this proportion did not exceed 25% within all treatments. In the daytime, the droplet deposition effect was better at the flight speed of 3.0 ~3.5 m/s and flight height of 1.5~2.0 m, while for the nighttime application the best parameters were the flight speed of 3.0~4.5 m/s and the flight height of2 m. The deposition amount and penetration of droplets of the nighttime application were better than that during the daytime, and the optimal operating speed at night is also faster, so spray at night can help to improve UAV operating efficiency. Keywords: plant protection UAV, spraying at night, droplet distribution, parameters optimization DOI: 10.33440/j.ijpaa.20200304.103 Citation: Tian Z W, Xue X Y, Cui L F, Chen C, Peng B. Droplet deposition characteristics of plant protection UAV spraying at night. Int J Precis Agric Aviat, 2020; 3(4): 18–23.

Biological Importance of Cotton By-Products Relative to Chemical Constituents of the Cotton Plant.

Although cultivated for over 7000 years, mainly for production of cotton fibre, the cotton plant has not been fully explored for potential uses of its other parts. Despite cotton containing many important chemical compounds, limited understanding of its phytochemical composition still exists. In order to add value to waste products of the cotton industry, such as cotton gin trash, this review focuses on phytochemicals associated with different parts of cotton plants and their biological activities. Three major classes of compounds and some primary metabolites have been previously identified in the plant. Among these compounds, most terpenoids and their derivatives (51), fatty acids (four), and phenolics (six), were found in the leaves, bolls, stalks, and stems. Biological activities, such as anti-microbial and anti-inflammatory activities, are associated with some of these phytochemicals. For example, β-bisabolol, a sesquiterpenoid enriched in the flowers of cotton plants, may have anti-inflammatory product application. Considering the abundance of biologically active compounds in the cotton plant, there is scope to develop a novel process within the current cotton fibre production system to separate these valuable phytochemicals, developing them into potentially high-value products. This scenario may present the cotton processing industry with an innovative pathway towards a waste-to-profit solution.

Chemical Characterization of Cotton Plant Parts for Multiple Uses

Core Ideas Cotton plant parts can be used for multiple purposes depending on their compositions. Cotton stems with less ash are better suited for lignocellulosic feedstock of bioenergy and bio‐products. Feed quality characteristics of cottonseed are comparable to those of forage crops. Cotton (Gossypium hirsutum L.) is an important crop in the southern and southeastern parts of the United States, but cotton plant biomass residues are underutilized because the high‐value lint receives the most attention. In this study, whole cotton plants were collected at midseason and just before harvest and were chemically characterized to explore multiple uses. The plant samples were separated into six (midseason) or eight (pre‐defoliation for harvest) biomass fractions. We determined the macro‐ and trace elements, protein, fiber, and lignin contents in the biomass materials. Growth stages affected the relative contents of some, but not all, of the measured parameters. Correlation coefficient analysis of the measured data revealed that some of the parameters were well related to each other, whereas some were quite independent. The information reported in this work will be helpful in exploring and optimizing management practices and processing strategies for best utilization of these types of cotton crop biomass materials as renewable natural resources.

Inhibitory effect of aqueous extract of different parts of Gossypium herbaceum on key enzymes linked with type 2 diabetes and oxidative stress in rat pancreas in vitro

This study sought to determine the inhibitory effect of aqueous extract of different parts (bark, leaf, and flower) of cotton plant (Gossypium herbaceum) on key enzymes linked with type 2 diabetes and oxidative stress in rat pancreas in vitro. The aqueous extract (1:10 w/v) of Gossypium herbaceum was prepared and the ability of the extract to inhibit the activity of α-amylase and α-glucosidase as well as activities of pro-oxidant Fe2+-induced lipid peroxidation was determined spectrophotometrically. The results revealed that the three varieties were able to inhibit the activity of α-amylase and α-glucosidase in rat's pancreas in a dose dependent manner (0–88.8 mg/ml). Also, the incubation of pancreas tissue homogenate in the presence of Fe2+ caused a significant increase (233.3%) in the malondialdehyde (MDA) content of pancreas homogenate, nevertheless, the introduction of the aqueous extract inhibited MDA production dose dependently (0–33.33 mg/ml) and also exhibited further antioxidant properties as represented by their high radical scavenging and Fe2+ chelating abilities. Inhibition of α-amylase and α-glucosidase activities has been the primary treatment for the management/prevention of type 2 diabetes. Therefore, the α-amylase and α-glucosidase inhibitory activities of aqueous extracts of different parts of Gossypium herbaceum in rat pancreas and prevention of lipid peroxidation in the tissue may be attributed to the presence of polyphenol content of the plant.

Compositional features of cotton plant biomass fractions characterized by attenuated total reflection Fourier transform infrared spectroscopy

Cotton is one of the most important and widely grown crops in the world. In addition to natural textile fiber production as a primary purpose, it yields a high grade vegetable oil for human consumption and also carbohydrate fiber and protein byproducts for animal feed. In this work, attenuated total reflection (ATR)-Fourier transform infrared (FTIR) spectroscopy was applied to characterize the cotton plant biomass fractions. Furthermore, principal component analysis (PCA) of these ATR-FTIR spectra were performed to evaluate the similarity or dissimilarity of these biomass fractions from different parts of cotton plants, and the same plant parts collected between mid-season and pre-defoliation stages. These data revealed the more rapid accumulation of major carbohydrate components in main stems, roots, and branches than in petioles and leaf blades, increased our understanding of the cotton growth mechanism. PCA revealed that the ATR-FTIR spectra of cotton biomass fractions fell into two distinct clusters representing two types of cotton plant parts: Stem cluster (main stems, roots, branches, and petioles) and Leaf cluster (leaf blades, bracts, bur, and/or reproductive parts). Such clustering information could be helpful in selecting the FT-IR measurement parameters for assessing cotton plant growth, nutrition management, and biomass production.

Gossypol Content of Cotton Free Commercial Feed for Dairy Cows.

Gossypol is a yellow pigment occurring in all parts of cotton plants, with the highest levels found in seeds, and it exhibits a variety of toxic effects. Few data are available on the content of gossypol in the commercial complementary feed and in feed raw materials. The present study was focused on the investigation of the presence of free gossypol in commercial complementary feed not containing cotton. A total of 50 samples of commercial complementary feed for dairy cows were performed in 29 feed mills both using and not using cotton as feed material. The free gossypol contamination resulted under the detection limit of the technique (4 mg/kg) in 12 out of 50 samples analysed and ranged from 4 to 20 mg/kg in 28 samples. In 10 samples the level of free gossypol ranged from 20 to 29.5 mg/kg. Average contamination of samples was 12.2±9.2 SD mg/kg. No significant difference (P=0.571) was shown in free gossypol concentration between feed produced in cotton free plants and in plants where cotton is used as feed material. Free gossypol content detected in the present study allows considering complementary feed for dairy cows not at risk. On the other hand, the detection of free gossypol in cotton free complementary feed, probably attributable to cross contamination of feed materials upstream of the feed mill, should be further investigated.

Phosphorus use efficiency in pima cotton (Gossypium barbadense L.) genotypes

In the Brazilian Cerrado, P deficiency restricts cotton production, which requires large amounts of phosphate fertilizer. To improve the yield of cotton crops, genotypes with high P use efficiency must be identified and used. The present study evaluated P uptake and use efficiency of different Gossypium barbadense L. genotypes grown in the Cerrado. The experiment was carried out in a greenhouse with a completely randomized design, 15 x 2 factorial treatment structure (15 genotypes x 2 P levels), and four replicates. The genotypes were MT 69, MT 70, MT 87, MT 91, MT 92, MT 94, MT 101, MT 102, MT 103, MT 105, MT 106, MT 110, MT 112, MT 124, and MT 125; P levels were sufficient (1000 mg pot-1, PS treatment) or deficient (PD treatment). Dry matter (DM) and P levels were determined in cotton plant parts and used to calculate plant P content and use efficiency. In general, DM and P content were higher in the PS than in the PD treatment, with the exception of root DM and total DM in some genotypes. Genotypes also differed in terms of P uptake and use capacity. In the PS treatment, genotypes MT 92 and MT 102 had the highest response to phosphate fertilization. Genotype MT 69 exhibited the most efficient P uptake in the PD treatment. Genotype MT 124 showed the best shoot physiological efficiency, apparent recovery efficiency, and utilization efficiency, whereas MT 110 exhibited the highest root physiological efficiency.

Survival and development of american bollworm (Helicoverpa armigerahubner) on transgenicBtcotton

A laboratory bioassay was conducted to study the impact of Cry 1 Ac protein on survival and development of Helicoverpa armigera (Hubner.) by feeding larvae with Bt cotton plant parts. During the study, terminal leaves and squares of two Bt hybrids, their corresponding non Bt hybrids and Bunny as check were fed to larvae. Among the plant parts tested, mortality of H.armigera larvae was higher on leaves compared to squares of both the Bt hybrids. Further, the mortality of early larval instars was higher compared to older instar larvae on both leaves and squares of Bt hybrids. Though, the later instar larvae were able to survive when exposed continuously to Bt cotton plant parts, but reduction larval and pupal weight, increase in larval developmental period, malformations in pupae and adults, reduction in adult emergence, less fecundity, low growth and survival indices was observed on both the Bt hybrids compared to their corresponding non Bt hybrids and check hybrid, Bunny.