Boll Retention Research Articles

Architecture of stem and branch affects yield formation in short season cotton

The cotton direct seeding after wheat (rape) harvested is under trial and would be the future direction at the Yangtze River Valley region of China. The objective of this study was to quantify the effects of branch and stem architecture on cotton yield and identify the optimal cotton architecture to compensate the yield loss due to the reduction of individual production capacity under high planting density in the direst seeding after wheat harvested cropping system. The characteristics of the stem and branch architecture and the relationships between architecture of the stem and branch with yield formation were studied on eight short season cotton cultivars during 2015 and 2016 cotton growth seasons. Based on the two years results, three cultivars with different architectures of stem and branch were selected to investigate the effect of mepiquat chloride (MC) application on the architecture of the stem and branch, boll retention, and the yield in 2017. Significant differences were observed on plant height, all fruiting nodes to branches ratio (NBR) in the cotton plant, and the curvature of the fruiting branch (CFB) among the studied cultivars. There were three types of stem and fruiting branch structures: Zhong425 with stable and suitable plant height and NBR (about 90 cm and 2.5, respectively), high CFB (more than 10.0), and high boll retention speed and seed cotton yield; Siyang 822 with excessive plant height and NBR, low CFB, and low boll retention speed and seed cotton yield; and other studied cultivars with unstable structure of stem and branch, boll retention speed, and seed cotton yield across years. And MC application could promote the appropriate plant height and NBR and high CFB and thus resulted in high boll retention speed and the yield. The results suggested that the suitable plant height and NBR (about 90 cm and 2.5 respectively), and high CFB (more than 10.0), which was related to both genotype and cultural practice, could promote the higher boll retention speed and seed cotton yield.

Comparisons of Cotton Boll Injury Caused by Four Species of Boll-Feeding Insects (Hemiptera: Pentatomidae and Miridae)

Field experiments with individually caged cotton bolls were conducted in 2013 and 2014 to characterize boll injury from a species complex of boll-feeding insects represented by the verde plant bug, Creontiades signatus (Distant) (Hemiptera: Miridae); redbanded stink bug, Piezodorus guildinii (Westwood); brown stink bug, Euschistus servus (Say); and green stink bug, Chinavia hilaris (Say) (Hemiptera: Pentatomidae). Field-collected adult bugs were used individually to infest single cotton bolls of several ages (0-7 days post-anthesis) previously maintained free of insect injury. Individual cotton bolls were infested at mid-bloom for seven days with one bug per boll for each species, and an uninfested control was included. Species and boll age varied across years, allowing selective within-year comparisons. Response to feeding resulted in reduced boll retention, increased boll injury in the form of reduced lint, and increased frequency of boll rot. Results showed that verde plant bugs readily fed on comparatively less mature bolls and feeding decreased boll retention. In contrast, stink bugs fed on larger bolls and caused significant injury. Variation in boll retention, boll injury, cotton boll rot, and yield were associated primarily with species differences and secondarily with boll age from 0 to 7 days old. Boll injury was apparent across species and subsequent yield reduction attributed to insect feeding was detected for all species, except the redbanded stink bug.

Square formation, boll retention, yield and quality parameters of Bt and non-Bt cotton in relation to plant density and NPK levels

Square formation, boll retention, yield and quality parameters of Bt and non-Bt cotton in relation to plant density and NPK levels

Plant Density Influences Reproductive Growth, Lint Yield and Boll Spatial Distribution of Cotton

The number of cotton plants grown per unit of ground area has gained attention due to the high prices of inputs and lower production. Cotton yield per unit of area in Henan province has been stagnant in the last few years. The objectives of this study were to investigate cotton growth, yield, boll spatial distribution and biomass accumulation using different plant densities at cultivation and to find out the optimal plant density. A 2-year field experiment was conducted in a randomized complete block design under six plant densities (D1, 15,000; D2, 33,000; D3, 51,000; D4, 69,000; D5, 87,000 and D6, 105,000 ha−1). Cotton grown at lower plant density produced taller plants and high number of leaves per plant while greater number of branches, fruiting nodes and high number of bolls per unit of ground area were produced under high plant density. Boll retention rate decreased as plant population increased and at nodes 1–8 the rate decreased slowly and then increased dramatically. The highest seed cotton yield (4546 kg ha−1) and lint yield (1682 kg ha−1) was produced by D5. The seed cotton and lint yield produced by D5 were 51–55%, 40–37%, 22–26%, 11–15%, 12–15%, 28–30%, 21–24%, 15–20%, 7–13% and 13–17% higher than D1, D2, D3, D4 and D6 during both years of experimentation, respectively. The increase in seed yield was due to higher biomass accumulation in reproductive organs under D5 plant density. The highest average (110.4 VA kg ha−1 d−1) and maximum (126 VM kg ha−1 d−1) rate of reproductive organs biomass was also accumulated by D5 as compared to other plant densities. The results suggest that D5 is the optimal plant density for high reproductive biomass accumulation and high yield for the area of Henan province.

Additive and interactive effects of pollination and biological pest control on crop yield

Abstract Insect pollination and biological pest control simultaneously influence crop yield, but are often investigated individually. This can lead to under‐ or over‐estimation of the importance of individual services when they interact to affect yield. Recent, limited evidence from field studies showed contrasting results with both additive and non‐additive positive and negative effects. To disentangle the mechanisms underlying these responses, we conducted a greenhouse experiment and a field study. We tested the potential and realized contribution of insect pollination to cotton boll retention and yield under various pest pressures and biocontrol levels. We found both additive and interactive effects of insect pollination and biocontrol within a single crop system depending on the level of pest pressure. In the greenhouse experiment, pollination did not contribute to cotton boll retention and final yield at low pest pressure. At high pest abundances, boll retention and final yield were higher when pollinators were present. In the field study, pollination was sufficient to alter the negative effect of pests on boll retention. Thus, interactive effect between the two ecosystem services on boll retention was present at high pest pressure in the greenhouse and at natural levels of pest pressure in the field, but not at lower pest abundances in controlled conditions. Although cotton plants partly compensated for bolls shedding by increasing their weight in the greenhouse experiment, this effect was not detected in the field study, likely due to higher environmental variation. Similarly, interactive effect of pollination and biocontrol on the final yield was present only in the greenhouse study. Synthesis and applications. We conclude that the contrasting findings of additive versus non‐additive effects between ecosystem services may be due to the levels of services and disservices tested and environmental variation. Further, this study shows that even when an ecosystem service does not appear to limit crop yield, it can make a substantial contribution to yield and act as insurance when the other service is reduced. For achieving food and fibre security, it is essential that future studies test interactive effects between these ecosystem services in different systems and environmental conditions.

Non–2,4-D–resistant cotton response to glyphosate plus 2,4-D choline tank contamination

AbstractField trials were conducted near Lubbock, TX, in 2013, 2014, and 2015 to evaluate non–2,4-D–resistant cotton response to low rates of glyphosate plus 2,4-D choline. Cotton was treated with five rates of glyphosate plus 2,4-D choline (0.0183, 0.183, 1.83, 18.3, and 183 g ae ha−1) at two application timings (nine leaf and first bloom). These rates correspond to contamination rates of 0.0008%, 0.008%, 0.08%, 0.8%, and 8%, respectively. Visual cotton injury, boll retention, lint yield, and fiber properties were recorded. When averaged over contamination rates, visual injury after applications made to nine-leaf cotton was greater than for first-bloom cotton in three of 3 yr and yield loss was greater when applications were made to nine-leaf cotton when compared with first-bloom cotton in two of 3 yr. Averaged over application timing, lint yield in 2013, 2014, and 2015 after glyphosate plus 2,4-D choline contamination rates of 0.0008% and 0.008% were not different than that of the nontreated control, whereas contamination rates of 0.08%, 0.8%, and 8% decreased yield by 3% to 20%, 45% to 58%, and 80% to 96%, respectively. Contamination rates of 0.0008%, 0.008%, 0.08%, and 0.8% rarely affected fiber quality; however, a contamination rate of 8% frequently decreased micronaire, fiber length, fiber length uniformity, and fiber strength. This decrease in fiber quality also resulted in a reduction in cotton loan value and potential financial return. Although decreases in fiber quality parameters were not observed with the 0.8% contamination rate, significant reductions in financial return occurred due to yield loss caused by injury from glyphosate plus 2,4-D choline.

Foliar and seed application of plant growth regulators affects cotton yield by altering leaf physiology and floral bud carbohydrate accumulation

The development of cotton (Gossypium hirsutum L.) floral bud prior to flowering is fundamental for yield formation since it is the initial step in the fruiting cycle. However, little information is available on the early reproductive stage of cotton subjected to plant growth regulators (PGRs). A 2-year experiment was conducted to investigate the effects of gibberellic acid (GA3), N6-benzyladenine (6-BA) and N, N-dimethyl piperidinium chloride (DPC) with two application methods [(A) seed soaking and (B) foliar spraying at squaring stage] on cotton floral bud development, yield and yield components compared with the control (water application). The results showed that seedcotton yield increased by 6.3%–7.5% and 12.1%–13.3% respectively in GA3 and 6-BA seed soaking treatments, and by 7.7%–8.5% and 8.2%–11.0% after foliar application compared to control due to increased boll numbers, which were associated with higher floral bud numbers. However, there was no response to yield for DPC treatment. Additionally, GA3 and 6-BA significantly increased photosynthesis rate (Pn) accordingly affecting the subtending leaf carbohydrate content and translocation, resulting in higher sucrose and starch contents in floral buds, which substantially enhanced dry matter of floral buds and reduced abscission rate. Those responses in floral buds are conductive to favorable boll development, which was evidenced by higher boll retention and boll opening rate for GA3 and 6-BA application relative to control. Specially, 6-BA showed equal effects to GA3 on yield and yield components with application method B, whereas induced a greater promotion than GA3 with application method A in the following aspects: (1) square numbers, boll numbers and seedcotton yield increased more obviously under 6-BA than GA3; (2) the increases in boll retention and boll opening rate were larger under 6-BA than GA3; (3) 6-BA induced higher carbohydrate content in floral buds than GA3.

Identification of stable QTLs for fiber quality and plant structure in Upland cotton (G. hirsutum L.) under drought stress

Cotton is an economically important commodity for nearly fifty industries including the textile sector which is largely based on cotton fiber. Identification of markers linked to loci for fiber traits under drought stress may be particularly beneficial because such loci could provide the genetic adaptability needed to produce good fiber under water limitation. In the present study, 177 simple sequence repeat (SSR) markers were used to detect significant quantitative trait loci (QTLs) linked to 11 fiber quality and plant structure traits in a panel of 99 Upland cotton (Gossypium hirsutum L.) genotypes using GLM and MLM analysis. The fiber quality traits, including fiber length (FL), fiber fineness (FF), fiber strength (FS), fiber elasticity (FE), fiber uniformity (FU), spinning conversion index (SCI), earliness (EAR), 1st position boll retention (1st PBR), 2nd position boll retention (2nd PBR), total boll number (TBN) and plant height (PH), were tested under both well-watered and water-limited irrigations in two locations. At both locations, GLM identified a total of 74 and 70 QTLs under well-watered and water limited conditions, respectively, at p ≤ 0.005. MLM detected seven and 23 QTLs under well-watered and water-limited conditions, respectively. Of the identified QTLs, some QTLs were detected in both locations: three for well-watered and two for water-stress conditions. Moreover, a total of 19 QTLs were stable under both watering-regimes. The QTLs identified herein could be useful in the development of cotton cultivars that have adaptability to drought conditions worldwide.

Information about the Effect of Climatic Factors and Soil Moisture Status on Cotton Production using Different Statistical Relations

Understanding the impacts of climatic factors on cotton production may help physiologists to determine the control mechanisms of boll retention in cotton. However, weather affects crop growth interactively, sometimes resulting in unexpected responses to prevailing conditions. Field trials, using cotton G. barbadense were carried out, to investigate the relationships between climatic factors, soil moisture status, and flower and boll production. The climatic factors considered were, i.e., daily data of maximum air temperature (°C), minimum air temperatures (°C), maximum-minimum temperature (diurnal temperature range or temperature magnitude) (°C), sunshine duration (hd-1), maximum humidity (%), minimum humidity (%) and wind speed (ms-1). It could be generally concluded that minimum humidity (water stress) and sunshine duration, were the most significant climatic factors affecting cotton flower and boll production and retention in Egyptian. Temperature appeared to be less important in the reproduction growth stage of cotton in Egypt than minimum humidity and sunshine duration. The soil moisture status showed low and insignificant correlation to flower and boll production. The positive correlation between minimum humidity value along with the negative correlation between each ofhigh maximum air temperature(temperature equalled or exceeded 37.5°C) and sunshine duration with flower and boll formation, indicate that high value of minimum humidity, short period of sunshine duration and low value of temperature would enhance flower and boll formation.

Response of cotton genotypes to water and heat stress: from field to genes

Cotton is a crop of tropical and subtropical regions but the seed cotton yield is highly influenced by abiotic stresses like drought and heat. Response of cotton genome to abiotic stresses is highly complex and involve many genes. A comprehensive study, involving cotton genotypes developed through conventional and synthetic tetraploid method, was designed to (i) study the introgression of heat and water stress tolerance by using wild relatives (ii) evaluate genetic markers for marker assisted selection against water and heat stress. Two separate experiments for water and heat stress tolerance with a common control were established. Treatments in each experiment include a control and a stress treatment. Heat stress was applied by sowing crop two month earlier than the control treatment, whereas water stress was imposed by withholding alternate irrigation. Analyses of variance depicted highly significant (P ≤ 0.01) effect of genotypes and both stresses on boll retention, boll weight and seed cotton yield. Interaction of genotypes with stress in both experiments was also highly significant (P ≤ 0.01). Genotypes derived from interspecific crosses performed consistently in stress conditions compared to control which prove it a reliable method to introgress stress related genes from wild parents. Four genes reported for water stress tolerance and five genes reported for heat stress tolerance were evaluated by field results for efficient marker assisted selection (MAS). Results verified drought stress genes but heat stress genes could not explain genetic variability caused by heat stress. It is concluded from the results that separate genes may be responsible for heat stress tolerance for vegetative and reproductive stages, therefore, selection criteria should include both the traits.

Effects of Plant Density on Boll Retention and Yield of Cotton in the Mid-South

The number of cotton (Gossypium hirsutum L.) plants being grown per unit of land area has gained attention due to the technology fees associated with seed containing value added traits. We investigated boll retention, yield, and yield components of cotton grown with reduced stands of 20% to 40% from the uniform planting pattern of four seeds per 30.5 cm of row. Five field experiments were conducted from 2012-2014 using eight treatments arranged in a randomized complete design with six replications. Yield and yield component data were collected. The plant one-row skip one-row treatment resulted in significant yield losses across all five experiments compared to the uniform planting pattern. Treatments with 20% stand reductions did not result in lower total yields; however, each plant in these treatments had to produce two additional bolls to maintain yield. Treatments which had at least 61 cm skips, 40% stand reduction, resulted in lower yields. Treatments had minor affects on boll weight, and lint percentage. The uniform planting pattern produced 67% of its yield from position one bolls compared to about 50% for treatments with reduced stands. Reduced stand treatments produced about 20% of their yield on monopodial branches compared to 10% for the uniform treatment. With modern precision planting equipments, opportunities exist to reduce seed rate and maintain yield; however, many production risk factors must also be considered before a reduced seeding rate is adopted.

Effects of Chilling Temperatures on Photosynthesis

Environmental stress is an inescapable reality for most plants growing in natural settings. Conditions of sub- or supraoptimal temperatures, water deficit, water logging, salinity, and pollution can have dramatic effects on plant growth and development, and in agricultural settings, yield. In cotton, yield is a product of the number of mature bolls produced in a given area and the amount of cotton produced by each boll. Though cotton is among the most stress-tolerant crop plants, suboptimal environmental conditions limit the yields and quality of fiber and seed. The most significant effects of abiotic stress related to yield are on fertilization, boll retention, and boll filling. Maintenance of photoassimilate supply during fruit development is critical in achieving high yields in cotton. Because photosynthesis is the driving force behind plant productivity, although not the only factor that determines yield, plants have developed numerous mechanisms that serve to protect the photosynthetic apparatus during stressful conditions. Cotton is produced across a wide range of environments and management conditions, from hot and humid subtropical to semiarid environments. Although production is limited by varying environmental conditions across these environments, it is clear that the physiological resilience to abiotic stress is considerable. We present a review of our understanding of low-temperature limitations to photosynthesis and the impact on productivity. Additionally, we use the High Plains region of Texas as a case study to highlight potential key developmental aspects of low-temperature stress on yield.

Genotypic Differences for Crossed Boll Retention in Cotton

Genotypic Differences for Crossed Boll Retention in Cotton

Heat-tolerance in Cotton Is Correlated with Induced Overexpression of Heat-Shock Factors, Heat-Shock Proteins, and General Stress Response Genes

Breeding for heat tolerance is complicated by the polygenic nature of the trait and genetic engineering awaits delineation of the molecular mechanisms. To understand heat-tolerance mechanisms in cotton (Gossypum hirsutum L.), the world’s most important natural fiber crop, this study compared expression of selected heat-stress response genes between heat-tolerant (VH260 and MNH456) and heat-sensitive (ST213 and ST4288) cotton genotypes. Cotton orthologs of selected Arabidopsis heat-stress response genes included two heat-stress transcription factors, three heat-shock proteins, and the general stress response genes: ascorbate peroxidase and the calcium-dependent stress responder, ANNAT8. The seedlings and flowering plants of each genotype were exposed to heat (38°C) for 1 to 3 hours or days, respectively, followed by RNA isolation from the seedlings and ovaries of flowering plants for gene expression analysis by real-time quantitative polymerase chain reactions. All genes, except the heat-shock protein GHSP26, were found to be induced exclusively in the heat-tolerant lines. The genotype VH260, which reportedly is tolerant to extreme heat (45°C), was found to display much higher induction of these genes than MNH456, the heat-tolerance level of which has not been thoroughly studied. Further, VH260 showed high gene induction in both seedlings and ovaries, whereas MNH456 showed lower induction levels. Strong heat tolerance in VH260 most likely is based on early induction of multiple mechanisms coordinately functioning to defend the plants against membrane damage, protein denaturation, and oxidative stress, in addition to rapid sensing of heat stress to signal the defense processes at the flowering stage towards minimizing yield losses and increasing boll retention during heat stress.

English

Cotton is major contributor in fiber and edible oil production of Pakistan. However, its growth and development is severely hampered by boron (B) deficiency in semi-arid regions of the country. This experiment was conducted to determine the influence of soil applied B (0.5, 1.0, 1.5, 2.0 and 2.5 kg B ha -1 ) on the performance of cotton genotypes FH-113, MNH-786 and CIM-496. Boron application significantly improved the boll retention, cotton seed yield, ginning out turn and net economic returns of cotton genotypes. In this regard, soil application at 1.5 kg B ha -1 was the most effective. Amongst the tested genotypes, FH-113 performed better than others. In conclusion, soil application of B at 1.5 kg ha -1 was the most cost effective in improving the yield and yield contributing traits of cotton and fetching the maximum net economic returns. © 2016 Friends Science Publishers

Effect of different defoliants and their rate and time of application on American cotton cultivars under semi-arid conditions of north-western India

Field studies were conducted to determine the effect of different defoliants i. e. Dropp ultra® and Ethrel (ethefon), their rates and time of application (140 and 150 DAS) to influence earliness and yield in three cotton cultivars. MRC 7361 BGII (3171.8 kg/ha) and MRC 7017 BGII (3083.3 kg/ha) gave significantly higher yield as compared to F 1861 (2454.9 kg/ha) due to better boll retention, boll weight and sympods. Dropp ultra® @ 200 ml/ha recorded significantly highest yield (3111.6 kg/ha) followed by Ethrel @ 2000 ppm (2948.3 kg/ha) and control (2878.9 kg/ha), while statistically least yield (2674.5 kg/ha) was observed with Dropp ultra® @ 225 ml/ha. Defoliants applied at 150 days after sowing (DAS) resulted in significantly higher yield (3017.7 kg/ha) as compared to early application at 140 DAS (2789.0 kg/ha) owing to significantly improved boll retention and better boll weight. Data indicated that Dropp ultra® @ 200 ml/ha had potential to promote crop earliness, better boll retention by keeping vegetative and reproductive growth in harmony to enhance seed cotton yield.

English

Gossypium hirsutum flowers are easily emasculated by splitting the staminal column with the fingernail and removing the corolla and androecium. However, any damage to the ovary is considered detrimental to successful boll formation and damaged flowers are typically discarded.  This study evaluated boll retention after different emasculation treatments. Removal of the membrane surrounding the ovary reduces boll retention compared to self-pollinated flowers, and showed a similar response across 18 genotypes.  Damage to the ovary wall reduced boll retention compared to emasculate flowers without ovary damage. Damaged flowers could be cross-pollinated to produce additional bolls as compared to discarding the flowers.   Key words:  Breeding, emasculation, Gossypium hirsutum, hybridization

The effects of high-temperature stress on the germination of pollen grains of upland cotton during square development

The reproductive stage of flowering plants is sensitive to high-temperature stresses. High temperature is a major factor influencing pollen grain viability in upland cotton (Gossypium hirsutum). The objective of this study was to identify the relationship between cotton pollen germination percentage and temperature by assaying the pollen germination of four upland cotton cultivars in vitro at different temperatures during the blooming period. The results showed that in vitro pollen germination percentage was related to the culture temperature of pollen germination and the temperature of the square development process. High temperature affected pollen development and germination, and high-temperature tolerance differed among the cotton cultivars. The pollen germination percentage decreased rapidly with changes in the culture temperature from 30 to 39 °C. A culture temperature of 35 °C might be a critical temperature for the pollen viability transition and could be used to screen cotton cultivars that have pollen grains with high-temperature resistance. Before the high-temperature stage, cultivars with rates of decrease in the percentage of pollen germination of less than 41 % at 35 °C relative to the rates at 30 °C might be considered as high-temperature tolerance cultivars, and cultivars with rates of decrease in the percentage of pollen germination greater than 41 % might be considered as susceptible cultivars. The high-temperature stress for pollen grain germination in vitro was greater than 30 °C, and the high-temperature stress for square development might be greater than 33 °C. Boll retention was significant; it was positively correlated with the pollen germination percentage and negatively correlated with temperature during the high-temperature stage. This study provided a method for rapidly screening cultivars (lines) with high-temperature tolerance pollen in upland cotton breeding.

Statistical Relation Nature between Climatic Variables and Soil Moisture during the Production of Cotton (Gossypium barbadense)

The information on impact of climatic factors on cotton production is not generally available, or at least not available or at least not available in the required form. Understanding this impact may help physiologists determine a possible control of the flowering mechanism in cotton plant. Field trials, in two successive seasons using cotton G. barbadense were carried out, to investigate the relationships between climatic factors, soil moisture status, and flower and boll production. The climatic factors considered were daily maximum air temperature, minimum air temperatures, maximum-minimum temperature (diurnal temperature range), sunshine duration, maximum relative humidity, minimum relative humidity, and wind speed. Minimum relative humidity and sunshine duration were the most significant climatic factors affecting flower and boll retention and production. Temperature appeared to be less important in the reproduction growth stage of cotton in Egypt than minimum relative humidity and sunshine duration. The soil moisture status showed low and insignificant correlation to flower and boll production [1].

Statistical Study: Nature Relationship between Climatic Variables Prevailing Prior to Flowering or Subsequent to Boll Setting and Cotton Production

This study investigates the statistical relationship between climatic variables and aspects of cotton production (G. barbadense), and the effects of climatic factors prevailing prior to flowering or subsequent to boll setting on flower and boll production and retention in cotton. The effects of specific climatic factors during both pre- and post-anthesis periods on boll production and retention are mostly unknown. Thus, an understanding of these relationships may help physiologists to determine control mechanisms of production in cotton plants. Evaporation, sunshine duration, relative humidity, surface soil temperature at 1800 h, and maximum air temperature, are the important climatic factors that significantly affect flower and boll production. The least important variables were found to be surface soil temperature at 0600 h and minimum temperature. There was a negative correlation between flower and boll production and either evaporation or sunshine duration, while that correlation with minimum relative humidity was positive. Higher minimum relative humidity, short period of sunshine duration, and low temperatures enhanced flower and boll formation.