Cotton Season Research Articles

Влияние на вегетационния хербицид Енвоке върху някои структурни елементи на продуктивността и добива от памук (Gossypium hirsutum L.)

Weeding during the growing season of cotton suppresses and slows down the growth and development of plants, and can lead to a significant reduction in yield and deterioration of fiber quality. The aim of this research was to study the effect of vegetation applied herbicide Envoke on the yield of cotton and some structural elements of productivity such as percent of boll opening and boll weight, under different agro-meteorological conditions. The research was conducted during the period 2020-2022 in the experimental field of the Field Crops Institute in Chirpan. In a three-factor field experiment, the effect of vegetation applied herbicide Envoke, containing 75% trifloxysulforon-sodium, was tested on two cotton varieties. Factor A included the three years of study. Factor B included the cultivars Chirpan-539 and Helius. Factor C included the herbicide Envoke applied in 3 doses - 10 g.ha-1, 15 g.ha-1 and 20 g.ha-1, once and twice during the 4-5 leaf and budding stages of cotton. It was established that when treated with the herbicide Envoke, the highest yield was obtained with the single treatment in the budding phase at a dose of 20 g.ha-1 for the cultivar Chirpan-539 and at a dose of 15 g.ha-1 for the cultivar Helius. Technologically valuable were found all variants with the herbicide Envoke in the cultivar Chirpan-539 and the variants in doses of 15 g.ha-1 and 20 g.ha-1 in the cultivar Helius. These options combined high yield values and high stability of this indicator in different years. The untreated controls in both cultivars were the only ones that received negative scores. This was due to the high number of weeds and self-sown sunflower (Helianthus annuus L.) plants. The vegetation herbicide Envoke, applied in three doses, once and twice during the 4-5 leaf and budding stages of cotton, had little influence on the percentage of boll opening and did not affect the boll weight at the treated variants of the two cotton cultivars - Chirpan-539 and Helius.

Improving soil water storage with no‐till cover cropping in the Mississippi River Alluvial Basin

AbstractExcessive tillage reduces soil water storage and increases surface runoff. Cover crops can modify the effect of tillage on soil water dynamics, but limited information is available for the Mississippi River Alluvial Basin. This study was conducted to determine whether soil–water dynamics could be manipulated through conservation production systems affecting surface residue management. Effects of tillage (conventional tillage [CT] vs. no‐tillage [NT]) and cover cropping (no cover crop and Austrian pea [Pisum sativum L.] cover crop [CC]) on soil water balance during the CC season in sorghum (Sorghum bicolor L.) and cotton (Gossypium hirsutum L.) crops were modeled using the root zone water quality model for a site near Stoneville, MS, on “Commerce” silty‐loam soil. Capacitance sensors measured soil volumetric water content to 120 cm during CC growth in 2019 and 2020. Field calibration of sensors reduced root mean square error from 0.05 to 0.03 m3 m−3. Pooled across years, NT increased volumetric water content in the 0–40 and 40–120 soil layers by 8.5% and 6.8%, respectively, compared to CT. Regardless of the CC treatment and cropping system, NT reduced surface runoff by 24.5% over its conventional counterpart, while soil water storage increased from 2.35 to 5.23 cm within the 1.2‐m profile, resulting in a 17% increase in consumptive use of water (evapotranspiration). CC treatments did not impact soil water storage and consumptive water use. The results demonstrate that NT systems can affect water dynamics by increasing infiltration and soil water storage in the humid subtropical region of the United States.

Investigating the second whitefly population outbreak within a decade in the cotton growing zone of North India.

The whitefly, Bemisia tabaci (Gennadius), is a polyphagous and major pest of cotton worldwide. Both adults and nymphs of B. tabaci affect the crop by causing direct and indirect damage. A severe whitefly outbreak was experienced during 2015 on cotton in North India and this was followed by a profound infestation during 2022. The present research rigorously examined whether the proliferation in the whitefly population was an outbreak or the result of a multi factor resurgence. During 2015, whitefly counts remained above the economic threshold level (ETL) between 28th and 35th Standard Meteorological Week (SMW). However, during 2022 above ETL population was observed in 27th SMW and it persisted until 36th SMW. The peak incidence of the whitefly was noticed during 31st and 29th SMW in 2015 and 2022, respectively. The early pest build up in 2022 and longer persistence (≥10 weeks) over the cotton season resulted in more damage to cotton crop. Additionally, pest survillence across the zone on the farmers' fields during 2022 revealed 44.4 per cent spots (585 out of 1,317 locations) above ETL while the corresponding locations in 2015 was 57% (620 out of 1,089). Thus, in 2022 infestation was not uniform in the entire zone wherein only few blocks of Punjab, Haryana and Rajasthan states of India experienced severe infestations of the whitefly. This study reports the complex of factors including weather, delayed sowing, use of tank mixtures/ subleathal doses of insecticides, pest resurgence etc. that might have possibly contributed to these upsurges in whitefly on cotton in north India.

Energy budgeting and productivity response of cotton-wheat cropping system to mechanical sub-soiling

ABSTRACT In North India, sub-soiling is required to alleviate the problem of soil compaction raised due to the use of heavy machinery. We have emphasized energy auditing to understand the practical feasibility of sub-soiling in cotton-wheat cropping system. Four sub-soiling treatments (cross and single side sub-soiling at 1.0 m, 1.5 m under both cases) in addition to conventional tillage were compared with conventional tillage alone at two sites. Sub-soiling improved crop yield by 13.5–33.7% in cotton and 13.0–22.0% in wheat as compared to control. Net monetary returns earned with sub-soiling were 98–408 and 159–287 US$/ha higher under cotton and wheat, respectively over control. Energy auditing suggested that sub-soiling treatments consumed 489–1504 MJ/ha extra energy in cotton season, however, net energy gain was higher in cotton (by 11,518–29,715 MJ/ha) and wheat (by 19,861–32,594 MJ/ha) over control. Energy use efficiency was higher under sub-soiling treatments in cotton (5.36–7.25) and wheat (9.55–10.46), whereas corresponding values under control were 4.64–6.18 and 8.18–8.36. Similarly, lesser specific energy was observed under sub-soiling treatments as compared to control. The present study concluded that sub-soiling increased cotton productivity and energetic returns as well as had the significant residual effect on wheat crop. These results clearly suggest that sub-soiling is a sustainable practice for cotton-wheat system in north-western India.

Amplicon Sequencing of Plant Material Links Cotton Fleahopper to Host Plants

The cotton fleahopper (CFH), Pseudatomoscelis seriatus (Reuter), is an early season cotton pest that feeds on cotton terminals resulting in flower abortion, irregular plant growth, and delayed plant maturity. The CFH has been documented on over 160 host plants across 35 families. Identification of host plants was accomplished through observed presence on a plant in the field and/or controlled feeding studies under lab conditions. Because the CFH is a generalist, these results may not accurately represent the plants used by the CFH under natural conditions. We used amplicon sequencing to identify plant material potentially ingested by CFH nymphs. Control samples consisted of CFHs fed in the laboratory on horsemint, Monarda spp. Nymphs were also collected using a sweep net from fields dense with horsemint, croton (Croton spp.), or fields of mixed plant composition. We detected the correct plant family in control samples. BLAST (https://blast.ncbi.nlm.nih.gov/Blast.cgi) results from the sweep net samples categorized hits into seven different plant families, one of which may be a new feeding host for CFH. Based on these findings, amplicon sequencing may be useful to further understand the complex ecology of the CFH, which may ultimately improve management strategies for CFH.

Field evaluation of automated site-specific irrigation for cotton and perennial ryegrass using soil-water sensors and Model Predictive Control

Variable-rate irrigation technology can reduce water use in centre pivot and lateral move irrigation systems through application of irrigation according to spatially varied soil-water profiles. However, filling the profile may not maximise yield because of variations in crop response and water requirements with crop stage. For example, cotton crops produce optimal yield under slight water stress during early stages. An irrigation strategy ‘Model Predictive Control’ has been implemented that accounts for changes in crop water requirements at different growth stages using biophysical crop models. This strategy involves automatically and iteratively executing the biophysical crop model APSIM parameterised with local soil and weather information, with different irrigation depths, to identify which combination maximises yield with the minimum depth of water application. This strategy has potential to address spatial and temporal variations in crop water requirements but has not previously been evaluated for variable-rate irrigation in the field. This paper reports field trials conducted over four cotton (Gossypium hirsutum L.) seasons and two perennial ryegrass (Lolium. perenne L.) seasons to evaluate the accuracy of the yield prediction of the biophysical model and compare field performance of irrigation strategies: uniform irrigation and variable-rate irrigation using a fixed underlying map, soil-water sensors and Model Predictive Control. Yield was most accurately predicted using on-site weather data and field soil core information, with R² = 0.733 and RMSE = 153.9 kg/ha for cotton, and R² = 0.336 and RMSE = 295.3 kg/ha for ryegrass. For cotton, Model Predictive Control led to 4.9% more yield with 5.6% reduction in water application, mainly through reduced water after peak bloom and/or open boll physiological stages. For grazed ryegrass, the Model Predictive Control strategy led to 8.5% more yield with 5.4% reduction in water application, potentially caused by reduced applications after grazing events. Further work includes evaluating the Model Predictive Control strategy with control of irrigation event timing under a broader range of field conditions to identify parameters to provide greatest economic return, and to refine biophysical models for improved performance of optimisation in the strategy.

Combining remote sensing-derived management zones and an auto-calibrated crop simulation model to determine optimal nitrogen fertilizer rates

CONTEXTCotton is an economically important crop in Australia that requires high resource application, particularly that of nitrogen (N) fertilizers. Determining optimal N fertilizer rates that reach both economic and environmental objectives is a key challenge in cotton systems because of the inherent within-field variability and relatively low N fertilizer use efficiency (NFUE). OBJECTIVEThis study aimed to model optimal N fertilizer rates by accounting for within-field variability through management zone (MZ) delineation across a cotton field in Queensland, Australia. METHODSMZs were delineated using satellite-derived normalized difference vegetation index (NDVI) and the crop simulation model, Decision Support System for Agrotechnology Transfer (DSSAT), was automatically calibrated with a grid-search optimization algorithm and validated across two cotton seasons. A total of 336 different N fertilizer scenarios were subsequently evaluated at pre-planting and top-dressing to observe the effect on profit margin and NFUE. RESULTS AND CONCLUSIONSThe MZ delineation analysis determined that within-field variability could be best represented by two MZs, one of which displaying subsoil constraints due to high carbonate concentrations. The use of the auto-calibration algorithm led to a successful validation of the model with a Wilmott d-index of agreement ranging between 0.75 (soil nitrate) and 0.96 (aboveground biomass and plant N), respectively. The subsequent N scenario simulations indicated that by reducing N fertilizer rates by 80 and 30 kg N ha−1 across the two MZs, respectively, compared to the current industry average, profits could be maximized through maintaining yields while reducing N inputs. SIGNIFICANCEOverall, these results demonstrate the potential of combining remote sensing-derived MZs and crop model auto-calibration techniques to support the cotton industry in achieving improved resource efficiency and profit margins.

Early Season Growth Responses of Resistant and Susceptible Cotton Genotypes to Reniform Nematode and Soil Potassium Application

A greenhouse study was conducted to investigate the roles that host plant resistance and soil potassium (K) levels play in affecting Rotylenchulus reniformis Linford and Oliveira (Tylenchida: Hoplolaimidae) (RN) populations and early season cotton (Gossypium hirsutum L.) growth. Two upland, RN-resistant cotton lines (G. barbadense introgressions: 08SS110-NE06.OP and 08SS100), a genetic standard (Deltapine 16) and a commercially available susceptible cultivar (PHY 490 W3FE) were evaluated at four different levels of K [100% of recommended rate, 150% of recommended, 50% of recommended, and a base level] from seeding until harvesting, 60 days after sowing (DAS). Quadratic functions (r2 = 0.82 to 0.95) best described the early season growth response of cotton genotypes to soil K. The base K level was associated with the lowest values for most morphological variables, including plant height (PH), mainstem nodes (MSN), leaf area, and dry weight at 30 DAS and 60 DAS. However, soil K did not affect RN population counts (RC). Additionally, soil K did not influence the rate of change in growth variables among genotypes. The resistant genotype 08SS110-NE06.OP showed greater growth in terms of time to first true leaf, PH, MSN, and above-ground dry weights compared to the commercially available susceptible genotype. No interaction between K and RN or genotype and RN was found in early season cotton growth. However, RC in pots of resistant genotypes was less than in pots of susceptible genotypes. Our research on the early season growth response to soil K by novel, RN-resistant genotypes and susceptible genotypes contributes to the development of improved RN resistance and fertilization management in cotton.

Rainfed cotton crop in central India is a strong net CO2 sink: An eddy covariance-based analysis of ecosystem fluxes

The present study reports ecosystem CO2, H2O exchanges (at diurnal, daily, and seasonal-scale) from a rainfed (dryland) cotton crop (Gossypium sp) grown in deep black soil of tropical central India during 2019–20 and 2020–21, using an Eddy Covariance (EC) system. The half-hourly CO2 fluxes were found to vary significantly across the growth stages of cotton crop with peak values during first boll opening to first picking stage [mean Net Ecosystem CO2 Exchange (NEE), −16 to −18 µmol m-2 s-1; mean Gross Primary production (GPP), 20–22 µmol m-2 s-1; and mean Ecosystem Respiration (Reco), 5–6 µmol m-2 s-1]. The response of daytime GPP to Photosynthetic Photon Flux Density (PPFD) was found to be poor during 1–30 days after sowing (DAS) with R2∼0.4. It improved during 30–150 DAS (R2∼0.6), while deteriorating further as the crop started senescing. The rainfed cotton crop was found to be a strong net CO2 sink, with seasonal NEE, GPP, Reco, and evapotranspiration (ET) of − 333.66 gC m-2, 990.16 gC m-2, 656.50 gC m-2 and 468.32 mm during 2019–20, respectively. The cotton season of 2020–21 had seasonal NEE, GPP, Reco, and ET of − 391.85 gC m-2, 1063.89 gC m-2, 672.04 gC m-2, and 545.25 mm respectively. The seasonal Ecosystem Water Use Efficiency (EWUE) was estimated to be 1.9 and 2.1 gC kg-1 H2O during 2019–20 and 2020–21, respectively. Maximum values of crop coefficient (Kc) were observed to be 1–1.2 during 30–75 DAS, signifying favourable conditions for crop growth. The inter-seasonal differences in the CO2 and H2O exchanges were mainly driven by the differences in incoming PPFD due to cloudiness. Results of the present study will help in understanding the ecosystem processes and exchanges from a rainfed cotton-based cropping system, which in turn can significantly contribute to the global carbon and moisture budget.

Efficacy of Biopesticides in the Management of the Cotton Bollworm, Helicoverpa armigera (Noctuidae), under Field Conditions.

Simple SummaryCotton remains the most important cash crop in the world. The key insect pests of cotton include the African bollworm Helicoverpa armigera. This pest causes damage to crops estimated at greater than USD 2 billion per year worldwide. Excessive use of insecticides to control this pest has a negative effect on the environment, and is expensive for the farmers. The aim of this study is to explore the field efficacy of different biopesticides as an alternative to control H. armigera. Four biopesticides—namely, Eco-Bb® (Beauveria bassiana), Bb endophyte (Beauveria bassiana), Bolldex® (nucleopolyhedrovirus), and Delfin® (Bacillus thuringiensis)—were evaluated and compared with the pyrethroid Karate® (lambda-cyhalothrin) and an untreated control. Plots treated with Karate® had significantly lower numbers of H. armigera larvae compared to the untreated control, and were comparable to the plots treated with Bolldex®. On average, plots treated with Bolldex® had a high seed cotton yield compared to the other treatments. Biopesticides showed a moderate reduction in the numbers of H. armigera larvae, and could thus be used within an integrated pest management programme.Cotton is one of the most valuable materials in the world, popularly used in the clothing industry and other products. However, its production is limited by the high infestation of insect pests. A study was conducted to evaluate the effects of different biopesticides on the control of the African bollworm (Helicoverpa armigera) under cotton field conditions. Four biopesticides—namely, Eco-Bb® (Beauveria bassiana), Bb endophyte (Beauveria bassiana), Bolldex® (Nucleopolyhedrovirus), and Delfin® (Bacillus thuringiensis)—were evaluated and compared with the pyrethroid Karate® (lambda-cyhalothrin) and an untreated control against H. armigera. Field trials were conducted at the Agriculture Research Council, Rustenburg, in the North West Province of South Africa during the 2017 and 2018 cotton seasons. The results revealed that in plots sprayed with Karate® and Bolldex®, the numbers of H. armigera were significantly reduced compared to the untreated controls. Plots treated with Bolldex® had the lowest number of damaged bolls in 2017, while those treated with Karate® had the lowest number of damaged bolls in 2018. All treated plots had significantly fewer damaged bolls when compared to the controls. A seed cotton yield of 5987 kg/ha was recorded in the plots that were treated with Bolldex®—significantly higher than the yields from plots treated with Eco-Bb®, Delfin®, and Bb endophyte—in 2017. However, the yield in treatments with Eco-Bb®, Delfin®, and Bb endophyte was lower than that from the untreated controls during this season. In 2018, plots treated with Bolldex® had the highest yield, at 6818 kg/ha, which was not different from the other treatments. The highest average seed cotton yield of 6400 kg/ha was recorded in the plots treated with Bolldex®, followed by Karate®. In summary, the efficacy of different biopesticides against H. armigera varied significantly, while the synthetic pesticide (Karate®) and Bolldex® resulted in more consistent control of this pest. The results suggest that biopesticides may, however, have the potential for use in the sustainable control of cotton bollworms as part of integrated pest management programmes, although further work is required to support this hypothesis.

Population Dynamics of Sucking Pests in Dual Season Cotton Ecosystem and Its Correlation with Weather Factors

Population dynamics of sucking pests in cotton ecosystem were studied at Tamil Nadu Agricultural University, Coimbatore during winter (2021) and summer (2022) seasons. Weekly observations were recorded on 20 randomly selected plants representing top, middle and bottom canopy of the crop which was raised in regular planting dates of winter and summer and were maintained as per the recommended regular agronomic practices except insect management interventions. During winter season, sucking pests viz., leafhopper, aphids, thrips, and whitefly were first observed in field from 39th SMW i.e. one month after sowing. Mealybugs were first observed during 41st SMW i.e. 43 days after sowing (DAS) of crop. The highest population of leafhopper, aphids, thrips, whitefly and mealybug recorded was 4.7, 18.7, 4.6, 2.45 no. per 3 leaves and 13.7 no. per 3 twigs, respectively. The mean population of sucking pests was high in October, 2021 and coincided with square formation to flowering stage except mealybug, which attained peak during January, at the boll bursting stage of crop. During summer season, the sucking pests were found to colonize from 8th SMW, corresponded to 20 DAS crop, while the mealybug occurred at 11th SMW, 40 DAS crop. The peak population of leafhopper, aphids, thrips, whitefly and mealybug registered was 5.4, 38.4, 4.9, 7.07 no./ 3 leaves and 2.4 no./ 3 twigs, respectively. The mean population of sucking pests was high from mid march to first fortnight of april 2022, and by that time the crop was at square formation to flowering stage. On comparison of both the season, summer season crop was infested by intensive level of sucking pests. Correlation results revealed that maximum temperature (0C) showed positive correlation, whereas rainfall (mm) showed negative correlation with population growth of sucking pests. Results of multiple linear regression analysis revealed that all the weather parameters collectively caused 51.1% – 88.4% influence on the population fluctuation of sucking pests.

Management of Sucking Pests of early Season Cotton by Application of different Seed and Soil Insecticides in Pakistan

Cotton is cash crop of Pakistan and sucking insect pests are serious issue especially in early cotton season. To cope with the issue, a field experiment was conducted to investigate the post emergence effectiveness of two seed and two soil applied insecticides on populations’ development of sucking insect pests in cotton. The seed applied insecticides i.e. Imidacloprid (Confidor 70 WS) and Thiamethoxam (Actara 70 WS) were applied to the seed before sowing. Two granular insecticides i.e. Aldicarb (Temik 10 G) and Carbaryl (Sevin 10 D) were applied in furrows with a modified applicator that was calibrated to deliver the desired rate. The results showed that all the tested insecticides were very effective in controlling the targeted sucking insect pests i.e. thrips, whiteflies and jassids as compared to untreated cotton. Conversely, the seed applied insecticides i.e. Imidacloprid and Thiamethoxam showed more effectiveness compared to soil applied granular insecticides i.e. Aldicarb and Carbaryl in reducing sucking pests’ populations. Such systemic insecticides applied as treated seed can be present in sufficient quantity in germinating plants leading to toxicity to pests, and helpful for safety of natural enemies. The population trends of the three principal sucking insect pests namely thrip, whitefly and jassid were varied significantly over the study months thereby indicating that the population build up was favoured by certain factors. Consequently, the use of seed applied insecticides can be a major component to put into practice in the integrated pest management technology of cotton.

Bisexual Attract-and-Kill: A Novel Component of Resistance Management for Transgenic Cotton in Australia.

In Australia, destruction of overwintering pupae of Helicoverpa armigera (Hübner) and Helicoverpa punctigera (Wallengren) (Lepidoptera: Noctuidae) has been a key component of mandatory resistance management schemes to constrain development of resistance to Bt toxins in transgenic cotton. This has been accomplished by tillage (‘pupae busting’), but it is expensive and can interfere with farming operations. Bisexual attract-and-kill technology based on plant volatile formulations offers a potential alternative in some circumstances. We discuss strategies for using such products and describe two trials in which three applications of an attract-and-kill formulation substantially reduced the numbers of Helicoverpa spp. moths and the numbers of potentially overwintering eggs they laid. One trial tested a curative strategy in which the last generation of moths emerging from transgenic cotton was targeted. The other tested a preventive strategy which aimed to reduce the numbers of eggs in the last generation. The preventive strategy reduced egg numbers by about 90% and is now included as an optional alternative to pupae busting in resistance management strategies for Australian cotton. It is limited to fields which have not been defoliated prior to 31 March and was developed to be used primarily in southern New South Wales. In the 2020–2021 cotton season, it was adopted on approximately 60% of the eligible cotton area. We describe the process whereby the strategy was developed in collaboration with the transgenic technology provider, supported by the cotton industry, and approved by the regulatory authority.

Comparative Analysis of Infection Process in Pima Cotton Differing in Resistance to Fusarium Wilt Caused by Fusarium oxysporum f. sp. vasinfectum Race 4.

Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4) causes an early season cotton disease including seedling deaths. This study compared two Pima cottons (Gossypium barbadense) in the infection process of FOV4 using a confocal and a scanning electron microscope. Seedlings were grown in a hydroponic system and inoculated with a virulent local FOV4 isolate. As compared with the susceptible Pima S-7, the resistant Pima PHY 841 RF had significantly fewer conidia attached and germinated on the root surface. FOV4 penetration into the root epidermis of PHY 841 RF was delayed until 24 h postinoculation (hpi) as compared with 8 hpi in Pima S-7. In Pima S-7, hyphae progressed to the xylem through the cortex between 5 and 7 days postinoculation. However, hyphae grew much slower in the cortex with no apparent hyphae observed in the xylem of PHY 841 RF. At plant maturity, no FOV4 was detected through fungal isolation and PCR in the stem of PHY 841 RF and its resistance donor parents PHY 800 and Pima S-6, as compared with Pima S-7 and DP 744 with positive results. The results demonstrate that PHY 841 RF is resistant to FOV4, due to delayed infection, reduced fungal growth and reproduction, and prevention of the fungus from invading the xylem.

ON THE SIGNIFICANCE OF THE SQUARE-NESTING METHOD OF COTTON SOWING

The article considers the advantages of square-nest sowing compared to other methods of sowing cotton seeds. Square-nest sowing, along with increasing the area of cotton seed nutrition, reduces seed consumption and makes it possible to conduct cross-cultivation during the growing season of cotton. For this purpose, the issue of constructing a new mechanism in the seeder is being considered in the future.

Lowering soil greenhouse gas emissions without sacrificing yields by increasing crop rotation diversity in the North China Plain

Intensive double cropping in the North China Plain has been challenged by serious environmental problems. Crop rotation is one of the important strategies for sustainable agriculture, which can reduce production risk and environmental impact. Yet, few studies have assessed enhanced crop rotation diversity on GHG emissions in the North China Plain. Carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O) emissions and yields were measured from four cropping systems: (1) wheat ( Triticum aestivum L.)-maize ( Zea mays L.) double cropping (WM); (2) peanut ( Arachis hypogaea L.) and WM rotation (PWM); (3) ryegrass ( Lolium perenne L.)-cotton ( Gossypium hirsutum L.), peanut and WM rotation (RCPWM); and (4) continuous cotton (C), to determine if enhanced crop rotation diversity can reduce greenhouse gas (GHG) emissions and improve yields. The RCPWM, PWM and WM cropping system produced 11.9%, 15.7% and 32.4% higher net greenhouse gas emissions (GHGE), respectively, than the C cropping system each year by the soil-based method assessing the field productive process. From 2017 to 2018, in the same crop planting seasons, RCPWM had lower cumulative N 2 O and CO 2 emissions, and produced similar peanut, wheat, and maize yields when compared to PWM. In 2018, PWM had higher cumulative N 2 O than WM during the wheat period, and they had similar seasonal cumulative N 2 O emissions during the maize period. Meanwhile, PWM produced lower cumulative CO 2 emissions and higher wheat and maize yields. In 2019, RCPWM did not have significantly different seasonal cumulative N 2 O emissions and yield, but slightly higher soil CO 2 emissions than C during the cotton season. The GHG emission intensity (GHGI) of the same crops was lower in RCPWM than in PWM during the peanut, wheat, and maize period or slightly higher than in the C treatment during cotton period. The results demonstrate that RCPWM could reduce soil N 2 O emissions when the same crops in PWM were compared due to less soil CO 2 emissions that the previous cotton brought about. The RCPWM system did not show a lower soil organic carbon (SOC) sequestration rate than the PWM and C systems. Therefore, increasing cotton into the peanut and wheat-maize rotation system (RCPWM) for more diversified system can help reduce soil GHG emissions without sacrificing yields. • PWM, RCPWM and C cropping systems reduced indirect GWP compared to WM. • PWM did not decrease soil N 2 O emissions but improved wheat and maize yield. • The previous cotton lowered soil CO 2 and N 2 O emissions for next crop growing season. • Increasing crop species in rotation could reduce soil GHG emissions without sacrificing yields.

Study of Genetic Analysis of Physiological Attributes under Normal and Drought Conditions in Gossypium hirsutum L.

The aim of this study was to identify the suprior cotton genotypes with improved physiological characteristics under drought conditions. On the bais of root-shoot charcteristics, five genoypes of G. hirsutum were identified as drought tolerant and three genotypes screened out as drought susceptible. The field screening experiment were carried out to validate the findigs of root-shoot screening sudy on the basis of physiological as well as agronomical chracteristics. Both drought tolerant and susceptible genotypes were grown in glass house in pots and followed line x tester mating desighn to cross these genotyps. Parents with their fiftenn offsprings were grown in field conditions in very next cotton season for further analysis. Analysis of variance showed the existence of significant variations among the accessions for all the physiological parameters i.e, osmotic potential, relative water content, cell injury, leaf water potential, excised leaf water loss, stomatal conductance, photosynthesis rate and transpiration rate. Further, among parents line, MS-64 and tester, BH-176 showed superior performance under water scarce conditions. Among the crosses COOKER-315 x Cyto-62 and GS-444 x MPS-11 were better perfomed for high yielding parametrs. The results showed that these two combinations might be helpful to develop drought resistant germplasm on large scale.

Determining Planting Window for Growing Upland Cotton (Gossypium hirsutum L.) during Dry Season in Bandarban, Bangladesh

Farmers in the Chattogram Hill Tracts, Bangladesh have been growing cotton (Gossypium hirsutum L.) in their traditional system of jhum cultivation which is undergoing transformation. Growing rainfed cotton as a monocrop in the uplands is constrained by farmers’ socio-economic conditions and erratic rainfall. Shifting growing season to post-monsoon dry monthscould be an option to sustain cotton production in hilly areas. An exploratory experiment was conducted for two seasons to explore the possibility of growing cotton in valley lands in Bandarban during dry season. Growth and yield potentials of dry season cotton were evaluated in relation to prevailing environmental conditions. Night temperature dropped to 9oC on several occasions in 2018-2019 season; but it remained higher than 11oC throughout the season in 2019-2020. In 2018-2019, day temperatures surged higher past March 15 occasionally exceeding 38oC. Variability in temperatures was more in 2018-19 while average temperatures were higher in 2019-20 season. Rainfall distribution was almost similar in both the growing seasons receiving total rainfall of 757 mm and 579 mm in two seasons, respectively. Higher seed cotton yield (2,047 kg per ha) was recorded for 15 November planted crop compared with 1 December planted crop (1,186 kg per ha). December 1 planted crop was affected more by low temperatures at seedling stage resulting in poor growth and fewer bolls per plant. Late planted crop was more vulnerable to rain damage at boll opening stage. Crops of both the seasons encountered high temperatures (>32oC) during boll development. Changing climate, shorter winter season and rising temperatures may allow cotton production in valley lands shifting growing season from rainy season to post-monsoon dry months. However, the window of dry season cotton growing in Bandarban, Bangladesh seems narrow. Rainfall pattern restricts planting seeds prior to mid-November. Again, high temperatures stress in March and April synchronizing boll development, and rainfall toward late April and May during boll opening may cause yield loss. Development and adoption of short duration, low temperature tolerant upland cotton varieties might be of advantage for adapting to climate change vulnerabilities. Ann. Bangladesh Agric. (2020) 24(2): 1-14

TWO APPLICATIONS OF PB-ROPES AS AN EFFECTIVE MANAGEMENT TOOL FOR PECTINOPHORA GOSSYPIELLA (LEPIDOPTERA: GELECHIIDAE)

The experiment was conducted to observe the effectiveness and working duration of PB-Ropes in the cotton season 2018-19. The gossyplure baited traps were installed in the last week of June for monitoring of pink bollworm (PBW) while application of PB-Ropes was done @ 120 ropes / acre at pin head square stage on 30 acres of cotton during 1st week of July. The percent infestation of PBW in green bolls and number of moth catches were recorded from the plots treated with 2 applications of PB-Ropes alone and 1 application of PB-Ropes + insecticide application. The PBropes provide mating disruption for the period of 90 days. The percent infestation ingreen bolls was decreased effectively by two applications of PBropes as compared to one application of PB-Ropes and Control Plot.The number of moth catches were highly reduced in the plot treated with two applications of PB-ropes (6.07 ± 0.70) as compared to one application of PB-ropes (28.05 ± 3.16) and control plot (40.439 ± 3.62). The further application of pesticides was done to decrease the % infestation of pink bollworm in the plots treated with PB-Rope + Triazophos @ 600 ml /acre (9.6061 ± 0.9873), PB-Rope + Bifenthrin 10 % EC@ 250 ml / acre (11.848 ± 1.4921) and PB-Rope + Spintoram 12 % SC (14.273 ± 1.5838). The results of this study also provided best and long term approach to farmers for the effective management of pink bollwormby the two applications of PB-Ropes to cover full cotton season as compared to one application of PB-Ropes. The use of two applications of PB-Ropes proved effective and provides cost benefit to farmer as compared to the use of insecticide for the management of the Pink bollworm.

TWO APPLICATIONS OF PB-ROPES AS AN EFFECTIVE MANAGEMENT TOOL FOR PECTINOPHORA GOSSYPIELLA (LEPIDOPTERA: GELECHIIDAE)

The experiment was conducted to observe the effectiveness and working duration of PB-Ropes in the cotton season 2018-19. The gossyplure baited traps were installed in the last week of June for monitoring of pink bollworm (PBW) while application of PB-Ropes was done @ 120 ropes / acre at pin head square stage on 30 acres of cotton during 1st week of July. The percent infestation of PBW in green bolls and number of moth catches were recorded from the plots treated with 2 applications of PB-Ropes alone and 1 application of PB-Ropes + insecticide application. The PBropes provide mating disruption for the period of 90 days. The percent infestation ingreen bolls was decreased effectively by two applications of PBropes as compared to one application of PB-Ropes and Control Plot.The number of moth catches were highly reduced in the plot treated with two applications of PB-ropes (6.07 ± 0.70) as compared to one application of PB-ropes (28.05 ± 3.16) and control plot (40.439 ± 3.62). The further application of pesticides was done to decrease the % infestation of pink bollworm in the plots treated with PB-Rope + Triazophos @ 600 ml /acre (9.6061 ± 0.9873), PB-Rope + Bifenthrin 10 % EC@ 250 ml / acre (11.848 ± 1.4921) and PB-Rope + Spintoram 12 % SC (14.273 ± 1.5838). The results of this study also provided best and long term approach to farmers for the effective management of pink bollwormby the two applications of PB-Ropes to cover full cotton season as compared to one application of PB-Ropes. The use of two applications of PB-Ropes proved effective and provides cost benefit to farmer as compared to the use of insecticide for the management of the Pink bollworm.