Boll Formation Research Articles

Pink bollworm (Pectinophora gossypiella) movement with respect to rosette flowers in cotton: Novel insights for integrated pest management

Aim: This preliminary study aimed to investigate the movement patterns of Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) larvae in the rosette flowers. Methodology: Field experiments conducted on the migration behavior of pink bollworm larvae with respect to rosette flowers in cotton fields. Observations included monitoring infested flowers, larval stage duration within rosette flowers, and larval movement to soil for pupation, larval mortality post-drop, and larval migration to early bolls, all conducted without insecticide application to reflect natural conditions. Results: The movement of the larvae was tracked and recorded from the start of flowering to the boll formation stage. Nearly, 44.88% of the larvae present on the infested flowers had moved to the soil for pupation, while 14.29% had moved to newly formed bolls on the same rosette flower. Additionally, 30.90% of the larvae had moved to dry leaf debris on the soil, and the remaining 9.93% either escaped or died due to environmental factors such as damp soil. Notably, the study showed that dry soils or light debris accumulation were the most favorable environments for pink bollworm larvae. Interpretation: The present study has generated useful information regarding the movement of PBWs larvae from rosette flowers to bolls that contribute to infestation. Hence, by implementing integrated pest management strategies during the early crop periods between 60 and 100 DAS, green boll infestations can be avoided and economic yields improved. Key words: Larval movement, Pest carryover, Pest management, Rosette flower

Assessment of land configuration techniques on in-situ soil moisture conservation and productivity of rainfed Bt. Cotton in semi-arid production systems

Rainfed agriculture is proving to be a significant contributor to cotton production. However, recent climate change characterizes a substantial threat to current rainfed agricultural production, and consequently to farmers’ livelihoods in semi-arid regions. Typical features of these areas are erratic rainfall to frequent dry spells that lead to frequent crop failure and lasting poverty. In-situ soil moisture conservation is an important climate resilience agricultural practice to enhance the productivity of crops in these regions including rainfed Bt cotton. It comprises agronomical land configuration techniques with several local modifications. The experiments were conducted in a field at Okkarai village (11o 22’ N latitude and 78o 53’ E longitudes), Thuraiyur Block, Tiruchirapallai District in the Northwestern Agro-climatic Zone of Tamil Nadu. It was undertaken during the Rabi season (North-East monsoon) of 2022 and 2023. The experiments were laid out in randomized block design (RBD) with 7 treatments with three replications. The treatments consist of different land configuration techniques viz., flat-bed, ridges and furrows, broad bed and furrows (BBF), raised bed, tied ridges, tied ridges (alternate rows) and tied broad beds (TBB). An analysis of pooled mean data of two years showed significant differences between the treatments. Among the land configuration techniques tested, tied ridges (alternate rows) registered the maximum soil moisture content during flowering and boll formation (90 DAS), boll development (120 DAS) and boll and fibre maturation (140 DAS) stages, and the increase was 34.4%, 31.8% and 15.74%, respectively over flat-bed method. Likewise, tied ridges (alternate rows) significantly enhanced the cotton growth characters viz., plant height (128.92 cm), leaf area index (4.52), dry matter production (5.19 t/ha), and yield attributes viz., number of squares (44.50/plant), number of bolls (43.73/plant), boll weight (4.76 g) and seed cotton yield (20.86 q/ha) and cost-benefit ratio (3.07). Tied ridges in alternative row served as low-cost micro catchment approach for trapping and holding water and its practice in semi-arid rainfed region has beneficial effects of reducing runoff and soil loss, increasing soil moisture and augment crop yield.

Satellite-based measurements of temporal and spatial variations in C fluxes of irrigated and rainfed cotton grown in India

The small number of carbon dioxide (CO2) observation networks and the prohibitively high equipment cost restrict the estimation of net ecosystem CO2 exchange (NEE). Satellite-based remote sensing techniques have made it possible to obtain NEE and component carbon (C) fluxes. One-third of the world's cotton area is in India, but the information on NEE is limited. We used the Level 4 Carbon (L4_C) product from the Soil Moisture Active Passive (SMAP) mission to estimate C fluxes based on satellite-derived soil moisture, weather, and vegetation data. For our study (2018-19 to 2020-21), we chose two ecosystems (rainfed central India vs. irrigated northern India). Seasonal variations were observed in C fluxes. Gross primary productivity was the highest during the boll formation phase. This phase was the strongest sink and coincided with the highest CO2 uptake, followed by the flowering and square formation phases. The cotton crop was a C source during the initial vegetative phase and after the boll opening. Overall, the cotton crop was a sink for atmospheric CO2 with an average NEE value of −189.6 g C m−2 under irrigated and −245.6 g C m−2 in rainfed cotton. Higher ecosystem respiration in irrigated cotton resulted in lower C sink strength than rainfed cotton. Our studies indicate that the SMAP L4_C product model estimates can be used to obtain information on C fluxes in real-world situations. Moreover, such satellite-based remote sensing techniques will enable large-scale environmental monitoring with different cropping systems and support policymaking.

Abundance and diversity of cotton insect pests under repeatedly cultivated cotton fields of Tanzania.

Cotton production in Tanzania is facing significant challenges due to insect pests that cause extensive damages to the crop. The most notable pests include the African bollworm (Heliothis armigera Hubner), Spiny bollworm (Earias biplaga Walker), Cotton stainers (Dysdercus sidae (Herrich-Schaeffer), Cotton Aphids (Aphis gossypii Glover), Thrips (Thrips tabaci Lindeman), Jassids (Amrasca biguttula, Bigutula), Leafhoppers (Cicadellidae jassidae), and Whiteflies (Bemisia tabaci Genn). If left uncontrolled, these pests can cause up to 60% damage to the crop. Despite the importance of cotton and the fact that most of these pests are endemic, there are scanty knowledge on the dynamics and distribution of cotton pests across the seasons of the year and crop's phenological growth stages (germination, vegetative growth, flowering and boll formation) in areas under repeated cultivation of the crop in Tanzania. Here we report on the influence of seasons and cotton's phenological stages on the abundance, diversity, distribution and richness of cotton insect pests. The study was conducted in the Misungwi district for two cotton-growing seasons, using the UKM08 cotton variety. Stick traps and handpicking methods were deployed in catching the cotton insect pests. On average, a total of 8,500 insect specimen of diverse families and species were collected every season. The four dominant species among the collected were Aphis gossypii (17.37%), Amrasca biguttula (11.42%), Nezara viridura (10.7%), and Bemisia tabacci (10.68%). Both cotton phenological growth stages and seasons significantly (p<0.05) influenced the abundance, diversity, distribution and richness of cotton insect pests. In particular, the phenological growth stage 3 exhibited greater diversity of insect pests. The pests' distribution patterns remained relatively uniform across the crop growth stages. Findings from the present study could contribute to developing sustainable pest management strategies in areas under repeated cotton production in Tanzania and elsewhere.

SCREENING OF COTTON (GOSSYPIUM HIRSUTUM L.) GERMPLASM AGAINST COTTON LEAF CURL VIRUS (CLCUV)

Cotton Leaf Curl Virus (CLCuV) is a devastating disease affecting cotton production worldwide, particularly in South Asia and Africa transmitted by the whitefly (Bemisia tabaci). CLCuV infection leads to severe symptoms, including leaf curling, vein thickening, stunted growth, and significant yield losses. Developing resistant cotton varieties is the most suitable strategy for managing CLCuV, given the limitations and environmental concerns associated with chemical controls. This study aimed to evaluate the resistance and susceptibility of different cotton varieties to CLCuV under natural field conditions and artificially infected condition using a disease severity scale ranging from 0 (highly resistant) to 5 (susceptible). A total of five cotton varieties, were assessed at three critical growth stages: vegetative, flowering, and boll formation. Disease severity, and yield components were recorded to determine extent of resistance of each variety. The results indicated that genotypes and treatments had significant variation in control compared to T1. According to DSI, NIAB-852 was scored as resistant with 10% infected leaves. FH-142 and CIM-496 were scored as tolerant according to DSI with 10-25% infection in leaves. NIAB Karishma and CIM-448 were scored as moderately susceptible with 50-75% infection. All genotypes had significant reduction in number of bolls, boll weight and seed cotton yield in T1 than control. These findings provide valuable insights into the effectiveness of existing cotton germplasm against CLCuV and highlight the need for continuous evaluation and development of resistant varieties. The study highlights the importance of generating resistant cultivars, thereby ensuring sustainable cotton production.

Population Dynamics of Dysdercus volkeri F. (Heteroptera: Pyrrhocoridae) at Different Stages of Cotton Development in Northeastern Nigeria

Two-location field trials were conducted at the Teaching and Research Farm of the Department of Crop Protection, Modibbo Adama University of Technology Yola and at the School Farm Government Girls Secondary School Kaltungo, Gombe state, in 2022 cropping season. The study was carried out to determine the population dynamics of Dysdercus volkeri at different stages of cotton development in North-Eastern Nigeria. The experiments were laid-out using randomize complete block design (RCBD) and the treatments consisting of five cotton varieties (SAMCOT 8, SAMCOT 9, SAMCOT 10, SAMCOT 11, SAMCOT 12) were replicated four (4) times. The week that had the highest population of D. volkeri in a combined analysis was 18 Weeks After Sowing (WAS), 66.30 in Yola and 16WAS, 20.70 in Kaltungo, per 10 cotton plants. The least population of the insect in both locations was obtained on 12WAS with 27.70 in Yola and 12WAS with 2.83 in Kaltungo, per 10 cotton plants. SAMCOT 10 had the highest population of the insect in both location with 54.71 and 32.70 (per 10 cotton plants) with the least on SAMCOT 11 and 12 with a population of 37.17 and 7.57 (per 10 cotton plants). Boll maturation stage supported the highest population of D. volkeri at Yola and Kaltungo with 89.23, the least at the beginning of boll formation 48.34 in both locations

Heterosis and combining ability for phenological yield and fiber traits of cotton (Gossypium hirsutum L.) genotypes

The seeds of 4 lines, 3 testers, and their 12 F1 hybrids were sown in a randomized complete block design (RCBD) with 3 replications at Botanical Garden, Department of Plant Breeding and Genetics, Sindh Agriculture University, Tandojam during Kharif 2019. F1 hybrids were raised for the estimation of heterotic effects, GCA and SCA for days to 1st squaring, days to 1st boll formation Bolls opened at 90 days after sowing, Sympodial branches plant-1, Bolls plant-1, Boll weight (g), Seed cotton yield plant-1 (g), 100-seed weight (g), Ginning outturn (%) and staple length (mm). Genotypes, parents, crosses, parent's v/s crosses, lines, testers and line × testers were significant for days to 1st squaring and days to 1st boll forming. Bolls unveiled their fissures precisely 90 days post-sowing, while parameters including sympodial branches per plant, bolls per plant, individual boll weight, seed cotton yield per plant, 100-seed weight, ginning outturn, and staple length underwent meticulous evaluation. The statistical scrutiny unveiled the insignificance of both lines and testers concerning the 90-day boll dehiscence. Similarly, the parental influence on boll weight, 100-seed weight, and staple length exhibited a lack of statistical significance. Line CRIS-134, Sindh, and tester FH-901 gave a higher mean performance for all the traits. Among the hybrids, Mehran × FH-901, Sindh-1 × CIM-602, CRIS-134 × CIM-602, CRIS-342 × Koonj, and CRIS-342 × CIM-602 gave a desirable mean performance and heterotic effect for all the traits. CRIS-342 × Koonj produced maximum SCA effects for bolls per plant. Mehran × FH-901 recorded higher SCA effects for seed cotton yield plant-1 and 100-seed weight, CRIS-342 × CIM-602 for lint percentage, and CRIS-342 × FH-901 for staple length. It is suggested that these lines and testers should be utilized in the breeding program to improve these traits.

Straw-derived biochar incorporation improves seedcotton yield and fiber quality by optimizing photosynthetic carbon and nutrients partitioning and boll formation patterns

Synergistic improvement of cotton (Gossypium hirsutum L.) yield and quality is necessary to meet the demands of the textile industry. Straw or biochar addition has been shown to increase boll number and hence yield, while optimizing reproductive growth processes (e.g., accelerating boll formation during the effective boll-setting period) is essential for improving fiber quality. However, it remains unclear how straw and biochar affect boll formation dynamics and whether they can simultaneously improve cotton yield and fiber quality. In order to reveal the mechanism of simultaneous improvement of cotton yield and quality, this study investigated the responses of plant photosynthetic carbon allocation, bud and boll dynamics, seedcotton yield, and fiber quality to different straw returning modes. A 7- year field experiment was performed with four straw treatments: no straw or biochar addition (CK); straw-derived biochar incorporation (SBI); straw incorporation (SI); and straw mulching (SM). The results suggested that SBI, SI and SM remarkably increased the seedcotton yield (24.5–30.7 %, 12.6–20.4 % and 4.7 %-11.0 %), fiber length (3.6–6.7 %, 4.0–9.5 % and 2.4–7.1 %) and fiber strength (8.0–13.0 %, 6.2–10.7 % and 4.4–5.7 %) from 2019 to 2021, compared with CK. There was a strong consistency between seedcotton yield and fiber strength among straw returning modes, and were highest under SBI, followed by SI and SM. Compared with CK, SBI significantly increased nutrients and photosynthetic carbon accumulation in cotton plant, and enhanced their distribution proportion in reproductive organs. This increased the number of fruiting branches, number of fruiting sites and ratio of fruiting sites to fruiting branches, accelerated budding and reduced the shedding rate of buds and bolls. Finally, SBI obtained the highest boll forming rate during the boll formation stage, as well as the highest effective boll number at the harvest stage. Overall, returning straw-derived biochar into soils optimized the allocation of nutrients and photosynthetic carbon in cotton plant, and accelerated the formation of cotton bolls from peak flowering stage to peak boll setting stage, thereby improving seedcotton yield and fiber quality. This work provides practical guidance for improving seedcotton yield, fiber quality, and the utilization of straw resources.

Enhancement of Growth and Yield of Cotton by Organic and Inorganic Nutrients with Phytohormone

Cotton is an important fibre and cash crop in India, contributing significantly to the country's industrial and agricultural economies. It provides the textile industry with its main raw material (cotton fibre). Cotton in India is a direct source of income for 6 million farmers, while the cotton trade and processing employs approximately 40-50 million people. Agriculture in the twenty-first century has encountered numerous hurdles in meeting the expanding population's food and fibre needs. Humans will confront greater challenges in meeting their requirements as the population grows to reach nine billion by 2050. A field experiment was conducted in Farmer’s Field at Jayapuram Village, Natrampalli Taluk in Thirupathur District during Aug-Jan (2021-22) to investigate the effect of soil application of NPK fertilizers, Zn-enriched compost and foliar spray of ZnO2 and NAA on enhancement of cotton yield and quality in sandy loam soil. Fertilizers (N: P2O5: K2O) were sprayed at the appropriate dose (60:30:30 kg ha-1) using Urea, SSP, and MOP. Zn-enriched compost (Zn-EC) was treated at 1.0 t ha-1 as a basal one week before sowing. As per treatment. ZnO2 at 0.1% was applied twice during the vegetative and blooming periods of the crop. The treatment included spraying NAA at 40 ppm twice during flowering and boll formation. Cotton cv. Sabari was cultivated as a test crop using suggested cultural methods. The highest seed cotton yield of 1813.73 kg ha-1 was observed with application of 75% RDF + Zn EC @ 1.0 t ha-1 + ZnO2 @ 0.1%+ NAA @ 40 ppm (T9). the present investigation clearly concluded that 75% RDF + Zn EC @ 1.0 t ha-1 + ZnO2 @ 0.1%+ NAA @ 40 ppm (T9) was the best treatment for enhancing growth, yield, quality and nutrient uptake by cotton cv. Sabari. The study examined how different treatments affected growth, yield characteristics, quality, and soil health.

The trade-off between root growth redundancy and premature senescence under different straw returning modes affects boll formation and seedcotton yield

The indeterminate growth habit of cotton (Gossypium hirsutum L.) makes a coordinated rootshoot relationship critical for increasing yield, which requires comprehensive consideration of root growth redundancy and premature senescence. Although recent evidence suggests that straw management affects root growth and thus seedcotton yield, there is limited documentation on the dynamics of root physiological activity and the rootshoot relationship of cotton under different straw returning modes. The present study compared four treatments: straw removal (CK), straw mulching (SM), straw incorporation (SI), and strawderived biochar incorporation (SBI) in an 8year field experiment. The growth dynamics of roots, shoots and reproductive organs, root physiological activity and seedcotton yield were investigated. The results showed that longterm straw application significantly enhanced seedcotton yield, but the effect varied significantly with straw returning modes. The seedcotton yield increased by 30.5%, 17.8% and 1.8% under SBI, SI and SM respectively in the 8th year of straw management, compared to CK. SBI and SI significantly enhanced the biomass of cotton roots and shoots while had higher growth rate of shoots relative to roots from peak squaring stage to peak bollsetting stage. This reduced root growth redundancy and increased the boll loading and boll capacity of root system. Besides, SBI increased the root activity, soluble protein content and antioxidant enzyme activities, and reduced the root malondialdehyde content from peak bollsetting stage to boll opening stage. These resulted in the greatest increase in boll number (53.862.1%) and boll biomass (39.480.4%) at the boll opening stage under SBI compared to CK. Overall, strawderived biochar improved the boll retention capacity of cotton roots by balancing the growth redundancy and premature senescence of the root system, and was a more suitable straw returning strategy to promote boll formation and increase cotton yield.

Optimizing the Bacillus thuringiensis (Bt) protein concentration in cotton: Coordinated application of exogenous amino acids and EDTA to reduce spatiotemporal variability in boll and leaf toxins

During the boll formation stage, cotton bolls exhibit the lowest expression of Bacillus thuringiensis (Bt) insecticidal proteins. Resistance to insects varies notably among different organs, which poses challenges for controlling cotton bollworms. Consequently, an experimental strategy was designed in the 2020–2021 cotton growing season to coordinate the enhancement of protein synthesis and the attenuation of degradation. Two Bt cultivars of Gossypium hirsutum, namely the hybrid Sikang 3 and the conventional Sikang 1, were used as test materials. Three treatments were applied at the peak flowering period: CK (the control), T1 (amino acids), and T2 (amino acids and EDTA). The results show that, in comparison to the CK group, the Bt protein contents were significantly increased in both cotton bolls and their subtending leaves under the T1 and T2 treatments. The maximum levels of increase observed were 67.5% in cotton bolls and 21.7% in leaves. Moreover, the disparity in Bt protein content between cotton bolls and their subtending leaves notably decreased by 31.2%. Correlation analysis suggested that the primary physiological mechanisms for augmenting Bt protein content involve increased protein synthesis and reduced protein catabolism, which are independent of Bt gene expression levels. Stepwise regression and path analysis revealed that elevating the soluble protein content and transaminase activity, while reducing the catabolic enzyme activities, are instrumental in enhancing the Bt protein content. Consequently, the coordinated application of amino acids and EDTA emerges as a strategy that can improve the overall resistance of Bt cotton and mitigate the spatiotemporal variations in Bt toxin concentrations in both cotton bolls and leaves.

Infestation of Anthonomus grandis grandis (Coleoptera: Curculionidae) contributes to forming shelter structures in cotton plants

AbstractHerbivorous arthropods can induce their host to form structures where they shelter during unfavourable periods. The boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), can spend the off‐season inside cotton plant structures, known as dry bolls, protected from pesticides, natural enemies and heat and desiccation on the soil surface, thereby increasing its survival and preserving its reproductive capacity. However, the relationship between the boll weevil and dry boll formation is not fully understood and requires further study. The formation and external and internal characteristics of dry bolls on cotton plants infested with different densities of boll weevils, and the emergence and survival of this insect from these structures, were evaluated. Compared with non‐infested control plants, plants infested with boll weevil formed almost twice as many dry bolls, which were 2.3 times heavier and with a diameter 1.7 times larger than those on non‐infested plants. Boll weevil infestation reduces the number of bolls and commercial mass of fibre + seeds, reducing productivity and increasing cotton harvest contaminants. However, dry bolls on non‐infested plants demonstrate that other factors are involved in their formation.

Effects of Defoliation at Different Fertility Stages on Material Accumulation, Physiological Indices and Yield of Cotton

In recent years, severe hailstorms have caused damage to cotton leaves and stalks. In order to identify the effects of cotton leaf damage on its dry matter accumulation, protective enzyme activity and yield in different periods, in this experiment, different intensities of hail were simulated by manual leaf cutting. In this study, the effects of leaf damage on dry matter accumulation, chlorophyll fluorescence, POD (peroxidase), SOD (superoxide dismutase) and MDA levels (malondialdehyde), and yield of cotton were studied in field experiments at three stages (bud, full bud and flower boll stages) and in sub-plots with different artificial defoliation intensities (0%, 25%, 50%, 75% and 100%). Removing the leaf sources had differently sized effects on the “sink” at each stage, and these are ordered as follows: flowering and boll stage &gt; full bud stage &gt; pregnancy stage. The greater the intensity of leaf removal, the greater the impact on the “sink”. Among them, after removing 50% of the leaves at the full bud stage, the total dry matter of the cotton plant increased by 12.46% compared to that of the control, and the boll formation rate per plant increased by 14.99%, resulting in overcompensation. Mo, Vj and φDo all showed a tendency to decrease and then increase with the increase in defoliation intensity at different periods of the treatment, and the lowest values of Mo, Vj and φDo, and the largest values of φpo, ψo and φEo were found in the 50% defoliation treatment at the gestational bud stage. The values of ψo and φEo were at the maximum in the 25% defoliation treatment at the full bud stage. The values of Mo and Vj in the different defoliation treatments at the bolling stage showed a tendency to increase and then decrease with the increase in defoliation intensity, with the highest values in the 25% treatment and the smallest values of φpo, ψo and φEo in the 25% defoliation treatment. The POD enzyme activity level was elevated in the defoliation treatments at the three different periods, and the highest value was observed in the 50% defoliation group at the full bud and boll stages, which is a reflection of supercompensation. The SOD enzyme activity level tended to increase with the intensity of defoliation, and defoliation at the gestational and full bud stages first enhanced and then weakened the stress on the cotton plants. The differences between treatments decreased after 12 weeks. The stress of defoliation on cotton plants was weakened at the boll stage. With the increase in defoliation intensity, the content of MDA showed a gradual increasing trend. The cotton MDA content was higher than that of the other treatments at 75% defoliation at both the post-fertilized bud and full bud stage.

EFFECT OF SOWING TIME IN COTTON (GOSSYPIUM HIRSUTUM L.) ON BOLL DISTRIBUTION, CELLULOSE RATIO AND FIBER QUALITY

The growth, flowering, square, and boll formation of the cotton plant are significantly affected by sowing time and fruiting distributions. This study was carried out in order to determine the effect of sowing time, varieties and boll distribution on fiber yield and fiber quality of cotton, under the GAP region ecological conditions of Türkiye during 2017 and 2018 cotton growing seasons. In this study, Candia and Lima cotton varieties were used as plant material. Cotton seeds were sown on 5 May (normal sowing) and 10 June (late sowing) using a pneumatic seeder in both years. In the study, the number of bolls (per plant-1), yield per plant (g plant-1), boll weight (g), ginning outturn (%), holocellulose, cellulose, scan viscosity, and polymerization degree were studied. According to the research, the number of bolls, boll weight, and fiber yield were higher in normal planting than in late planting. The low positional sympodial branch (1-5 fruit branches) boll position was better in the number of bolls, and the middle positional sympodial branch (6-10 fruit branches) was better in boll weight compared to other positions. The fiber yield obtained in a low positional sympodial branch (1-5 fruit branches) and middle positional sympodial branch (6-10 fruit branches) positions was higher than the upper positional sympodial branch position (11 and higher fruit branches). The effects of sowing times and cultivars on cellulose and holocellulose rations were statistically insignificant. The cellulose ratio (94.40) obtained in the upper positional sympodial branch position (11 and higher fruit branches) in the first year was higher than the other sympodial positions, while the effect of the boll position was statistically insignificant in the second year of the experiment. In conclusion, the planting time had a significant effect on boll positions and fiber quality of cotton. Late sowing had negative impact on boll maturation, cellulose synthesis, yield and fiber quality. Hence, the delay in cotton planting caused a decrease in yield; so, cotton should be sown as early as possible in the region. Keywords: Cotton, sowing date, boll position, boll weight, fiber quality

Performance of Cotton (Gossipium hirsutum L.) Varieties under High Density Planting System in Alfisols of Telangana, India

Aims: Cotton productivity is lower in India than the global average due to inadequate soil moisture during boll formation stage due to cessation of south west monsoon. Cotton is mainly grown under rainfed conditions in marginal and shallow soils, cultivating short duration cotton varieties with high density could improve productivity in the rainfed regions. So, this experiment was conducted to evaluate the three cotton varieties and a hybrid under four high density spacings.&#x0D; Study Design: The experiment was laid out in split plot design and replicated thrice.&#x0D; Place and Duration of Study: The field experiment was conducted for three years during Kharif 2014, 2015 and 2016 at Regional Agricultural Research Station, Palem, Nagarkurnool District of Telangana state, India. The experimental site was located at 16.51703° North latitude and 78.2469° East longitude and an altitude of 478 m above mean sea level.&#x0D; Methodology: Treatments consisted of 4 spacings (45×10 cm, 60×10 cm, 75×10 cm and 90×10 cm) under main plots and 3 non bt cotton varieties (Suraj, WGCV-48 and ADB-39) and 1 Bt Cotton hybrid Jadoo was included as 4th treatment under subplots during 2015 and 2016. The soil at the site was Alfisol with low organic carbon (0.24%) and N (210 kg ha-1), high in available P (75 kg P2O5 ha-1) and available K (455 kg K2O ha-1). The crop was cultivated under rainfed conditions. Intercultivation and hand weeding was done and kept weed free. Gross plot size of 9 m × 3 m was maintained for each treatment. Nitrogen dose of 40 kg N ha-1, 20 kg P2O5 ha-1 and 20 kg K2O ha-1 was applied. The single plant data was collected on five tagged plants in each plot of each treatment and yield data was collected from the net plot area.&#x0D; Results: Seed cotton yield was significantly influenced by the spacing and the varieties. The pooled data of 3 years revealed that cotton crop under 90×10 cm spacing (2054 kg ha-1) recorded significantly higher seed cotton yield than the crop under 75×10 cm (1854 kg ha-1), 60×10 cm (1723 kg ha-1) and 45×10 cm (1603 kg ha-1). The pooled data of 3 years revealed that the seed cotton yield in hybrid Jadoo (2189 kg ha-1) was significantly higher than the three varieties. The seed cotton yield in all the three varieties (Suraj, WGCV-48 and ADB-39) was on par with each other during all the years under study.&#x0D; Conclusion: High density spacing of 90×10 cm, recorded significantly higher seed cotton yield than the other tested spacing. Among the varieties and the hybrid, cotton Jadoo outperformed all the cotton varieties and seed cotton yield of cotton varieties (Suraj, WGCV-48 and ADB-39) was on par with each other.

Validation of Bio-stimulant Seed Treatment, Soil and Foliar Application of Nano DAP, Urea, K, Zn, Cu, B Formulations in a Flood Affected Bt Hybrid Cotton

Bt hybrid cotton faced 30-60% excess rains in 70% years since its release and four times water logging in 2021, in a deep and shallow Vertisols with Calcareous sub-strata forced to confirm all the agronomical advices to it. Water logging reduced the biomass, boll number and cotton lint yields to more than 50 percent except the fibre quality. Prevailing runoff and leaching losses of soil applied fertilizer nutrients were accumulated at downstream, which increased the soil test values. Water logging caused reduction of index leaf N, P, K, Zn and B nutrient status below the threshold levels. Soil application of Zn and B once in three years alone or seed treatment formulation with N, P, K Bio-inoculant consortia along with nano ZnO 0.0004% + CuO 0.0001% as seed treatment at the time of sowing with or without foliar application of NPK WSF 2%, Zn 0.5%, B 0.3% or 0.04% nano formulations of DAP alternated with Urea alongwith ZnO and K with common insecticides and fungicidal sprays significantly improved index leaf nutrient status, biomass, boll number and seed cotton yields in both the soils. Validation of these results in station trials during 2022-24 found the need for atleast two foliar application of nano nutrients each DAP + ZnO + K followed by nano Urea+ ZnO + K 0.004% alternately at the mid and end September and October months. This increased N, P, K, Zn, B content in index leaves and seeds with additional cotton lint yield 209 kg ha-1 worth 174 US $ ha-1 net profit by soil application ZnSO4 20 and Borox 5 kg ha-1 yr -3 in Vertisols and three times foliar application at squaring, flowering and boll formation stage with nano ZnO 0.004%+ B 0.3% or ZnSO4 0.36% +Boron 0.2% in Vertisols with calcareous sub-strata.

Effect of foliar nutrition on growth and yield of cotton (Gossypium herbaceum) MCU 5

From the experimental results, it is inferred that cotton crop responds well to the foliar nutrition with zinc and magnesium. Application of these nutrients through foliar spray might be the feasible option to control the yield barrier under rainfed condition. Further the study found that foliar spraying of MgSO4 1.0% along with 0.5% of ZnSO4 three times respectively at squaring, flowering and boll formation stages markedly improved the plant growth and seed cotton yield. Thus, these treatments may be recommended for enhancing the rainfed cotton yield but location specificity verification is required before recommendation.

Foliar melatonin ameliorates drought-induced alterations in enzyme activities of sugar and nitrogen metabolisms in cotton leaves.

Sugar and nitrogen metabolisms help plants maintain cellular homeostasis, stress tolerance, and sustainable growth in drought conditions. Melatonin, a potent antioxidant and signaling molecule, appears to mitigate the negative impacts of drought on plants. This study aimed to investigate the potential role of foliar-applied melatonin in ameliorating drought-induced alterations in leaf sugar and nitrogen metabolisms' enzyme activities during cotton flowering and boll formation. To date, no study has examined drought-induced sugar and nitrogen metabolisms' enzyme activity changes in cotton treated with foliar melatonin. Drought levels (FC1 = 75 ± 5%, FC2 = 60 ± 5%, and FC3 = 45 ± 5%) were maintained between 3 and 35 days after flowering (DAF), and melatonin (M) concentrations (0, 25, 50, and 100 μmol L-1 ) were applied at 3 and 21 DAF in a completely randomized design. M100 concentrations at low FC levels significantly enhanced leaf sugar and N-metabolic enzyme activities, such as sucrose synthase (65.56%) and glutamine synthetase (55.24%), compared to plants not treated with melatonin; peaking between 7 and 21 DAF and declining gradually with crop growth. Moreover, the M100 concentrations at all FC levels, particularly FC3, significantly increased the relative expression of GhSusB, GhSusC, SPS1, and SPS3 genes, indicating that melatonin improves leaf sugar and N-metabolism enzymatic activities under drought stress. Therefore, applying M100 concentrations to cotton foliage under FC3 conditions during reproductive stages improves leaf water status, sugar, and N-metabolism enzyme activities, demonstrating melatonin's potent anti-stress, osmoregulatory, and growth-promoting properties in overcoming drought stress in cotton crops. Future research into the molecular mechanisms of melatonin-mediated sugar and nitrogen metabolism enzyme activities in cotton leaves may lead to biotechnological methods to improve drought resilience in cotton and other crops.

Influence of Plant Density vis-à-vis Architecture on Growth Parameters Bt Cotton (Gossypium hirsutum L.)

A field experiment entitled “Influence of plant density vis-à-vis architecture on Bt cotton (Gossypium hirsutum L.) yield and quality parameters” was carried out on sandy loam soil at College farm, College of Agriculture, PJTSAU, Rajendranagar, Hyderabad during 2021-22. The experiment was laid out in split plot design with three replications. Results revealed that plant densities, plants sown under planting density of 90 x 20 cm (55,555 plants ha-1) recorded highest growth contributing characters such as plant height, dry matter production, first fruiting node length, internode length and height node ratio. Planting density of 90 x 30 cm (37,037 plants ha-1) has recorded significantly higher number of sympodial branches and no of nodes per plant during 2021 and 2022 and pooled mean. Length of fruiting branches from node 5 to 15, length of fruiting branches from node 15 to terminal, length of all fruiting branches, distance from main stem to first boll position from node 5 to 15, distance from main stem to first boll position from node 15 to terminal, distance from main stem to first boll position of all fruiting branches, internode diameter, days to initiation of sympodial branches, days to square initiation, days to 50% flowering, days to boll formation, days to boll bursting stage were found to be highest in plants spaced at 90 x 60 cm (18,518 plants ha-1) during two years of study and pooled mean. Interaction was found to be significant on drymatter production at 120 DAS and found highest in treatment combination of semi open plant type (Sadanand) and 90 x 20 cm (55,555 plants ha-1) during 2021 and 2022 and pooled mean. Number of monopodial branches and days to initiation of monopodial branches were showed non-significant results.

The Effect of New Nano-Released 1,1-Dimethyl-Piperidinium Chloride (DPC) Drip Application on Cotton Agronomic Traits

The use of 1,1-dimethyl-piperidinium chloride (DPC) in Xinjiang is one of the necessary measures for regulating cotton populations and optimizing canopy structure. However, mechanical spraying involves operation and energy consumption, which can alternatively be achieved via drip application. In the present study, to investigate the effect of drip application, two types of hydrophobic nano-released DPCs were used to regulate plant type at different dosages. DPC dripingation reduced plant height by more than 10 cm and plant width by more than 4 cm, and the effect improved with increasing concentration and times. The main effect of height control was at the 6th–10th nodes of the main stem, and the effect of width control was observed at the 1st and 2nd nodes of the fruit branch. The SPAD value was higher than that in the control group during the initial stages. An irregular downward trend was observed in the subsequent stages. The proline content was higher than that of the control and increased with higher concentrations of DPC. There was no significant difference in the soil DPC content at the different sites. The DPC content decreased by more than 30% at the seventh day after dripping, and the content was 2–4 μg·g−1 in each treatment. At 15 days after application, the soil DPC was lower than 1 μg·g−1 in all treatments. The number of harvested plants was more than 150,000 plants·hm−2, and the number of bolls per plant increased at least by one, compared with the control. The final yield of seed cotton increased by at least 300 kg·hm−2, with a maximum increase of 1672.01 kg·hm−2. Considering the different types of DPCs, nano-released types worked better than the conventional type in terms of plant height, plant width, degradation in soil and boll formation. Nano-released DPC can play an even better role than conventional DPC in chemical regulation with drip irrigation.