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 cont...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.展开更多
In Bacillus thuringenesis(Bt) transgenic cotton, the cotton boll has the lowest insecticidal protein content when compared to the other organs. The present study investigated the effects of amino acid spray applicatio...In Bacillus thuringenesis(Bt) transgenic cotton, the cotton boll has the lowest insecticidal protein content when compared to the other organs. The present study investigated the effects of amino acid spray application at the peak flowering stage on the cotton boll Bt toxin concentration and yield formation. Boll protein synthesis and carbohydrate conversion were also studied to reveal the fundamental mechanism. Three treatments(i.e., CK, the untreated control;LA1, five amino acids;LA2, 21 amino acids) were applied to two Bt cultivars of G. hirsutum(i.e., the hybrid Sikang 3 and the conventional Sikang 1) in the cotton-growing seasons during 2017 and 2018. Amino acid spray application at the peak flowering stage resulted in an increase of 5.2–16.4% in the boll Bt protein concentration and an increase of 5.5–11.3%in the seed cotton yield, but there was no difference between the two amino acid treatments. In addition, amino acid applications led to increases in the amino acid content, soluble protein content, glutamate pyruvate transaminase(GPT)activity, glutamate oxaloacetate transaminase(GOT) activity, glucose content, fructose content and soluble acid invertase(SAI) activity. This study also found that Bt protein content, enhanced boll number and the weight of opened bolls were closely related to carbon and nitrogen metabolism. The Bt protein content had significant linear positive correlations with amino acid and soluble protein contents. Enhanced boll number had significant linear positive correlations with the GPT and GOT activities from 15–25 days after flowering(DAF). The weight of opened bolls from 55–65 DAF had a significant linear positive correlation with the SAI activity. These results indicate that the enhancement of boll protein synthesis and carbohydrate conversion by amino acid application resulted in a simultaneous increase in the boll Bt protein concentration and cotton lint yield.展开更多
[Objective] This study aimed to explore an optimum application amount of nitrogen for cotton cultivation. [Method] In this study, a field experiment was conducted to investigate the effects of nitrogen application amo...[Objective] This study aimed to explore an optimum application amount of nitrogen for cotton cultivation. [Method] In this study, a field experiment was conducted to investigate the effects of nitrogen application amount on the growth characteristics, boll development and lint yield of high quality cotton line FZ-1. [Result] Compared with the nitrogen level of 225 kg/hm2, the lint yield had increased by 28.46% and 18.73%, respectively, with the nitrogen application amount of 300 and 375 kg/hm2. When the nitrogen application amount had increased from 225 to 300 kg/hm2, boll number per plant, boll weight and lint yield had significantly increased. At the nitrogen level of 375 kg/hm2, however, the effects of increasing lint yield were significantly less than that at the nitrogen level of 300 kg/hm2. Compared with the nitrogen levels of 225 and 375, 300 kg/hm2 of nitrogen was the optimum application amount to improve the plant height, daily increment of plant height, number of fruit branches, number ratio of nodes to fruit branches, boll volume and seed cotton weight per boll. [Conclusion] The rational management of nitrogen is the most effective way to promote the growth and development of cotton plants, ensure high yielding ability and minimize the environmental pollution caused by the overuse of nitrogen. This study had provided a sound nitrogen application strategy for the cultivation of this high-quality cotton line in the field plantation.展开更多
Cotton growth and development are determined and influenced by cultivars, meteorological conditions, and management practices. The objective of this study was to quantify the optimum of temperature-light meteorologica...Cotton growth and development are determined and influenced by cultivars, meteorological conditions, and management practices. The objective of this study was to quantify the optimum of temperature-light meteorological factors for seedcotton biomass per boll with respect to boll positions. Field experiments were conducted using two cultivars of Kemian 1 and Sumian 15 with three planting dates of 25 April (mean daily temperature (MDT) was 28.0 and 25.4°C in 2010 and 2011, respectively), 25 May (MDT was 22.5 and 21.2°C in 2010 and 2011, respectively), and 10 Jun (MDT was 18.7 and 17.9°C in 2010 and 2011, respectively), and under three shading levels (crop relative light rates (CRLR) were 100, 80, and 60%) during 2010 and 2011 cotton boll development period (from anthesis to boll open stages). The main meteorological factors (temperature and light) affected seedcotton biomass per boll differently among different boll positions and cultivars. Mean daily radiation (MDR) affected seedcotton biomass per boll at all boll positions, except fruiting branch 2 (FB2) fruting node 1 (FN1). However, its influence was less than temperature factors, especially growing degree-days (GDD). Optimum mean daily maximum temperature (MDTmax) for seedcotton biomass per boll at FB11FN3 was 29.9-32.4°C, and the optimum MDR at aforementioned position was 15.8-17.5 MJ m-2. Definitely, these results can contribute to future cultural practices such as rational cultivars choice and distribution, simplifying field managements and mechanization to acquire more efficient and economical cotton management.展开更多
Sowing cotton directly after harvesting wheat in the Yangtze River Valley of China requires early mature of cotton without yield reduction.Boll-setting period synchronisation and more yield bolls distributed at the up...Sowing cotton directly after harvesting wheat in the Yangtze River Valley of China requires early mature of cotton without yield reduction.Boll-setting period synchronisation and more yield bolls distributed at the upper and middle canopy layers are also required for harvesting.The objective of this study is to quantify the individual and interaction effects of plant density and plant growth regulator mepiquat chloride(MC)on temporal and spatial distributions of yield bolls,as well as yield and yield components.During the 2013–2016 cotton growing seasons,the experiments were conducted on a shortseason cotton cultivar CRRI50 at Yangzhou University,China.Various combinations of plant density(12.0,13.5 and 15.0 plants m^(–2))and MC dose(180,270 and 360 g ha^(–1))were applied on cotton plants.The combination of 13.5 plants m^(–2)and 270 g ha^(–1)MC resulted in the greatest boll number per unit area,the highest daily boll setting number and more than 90%of bolls positioned within 45–80 cm above the ground.In conclusion,appropriate MC dose in combination of high plant density could synchronize boll-setting period and retain more bolls at the upper and middle canopy layers without yield reduction in the system of direct-seeded cotton after wheat harvest,and thus overcome the labor-intensive problem in current transplanting cropping system.展开更多
Cotton yield per unit ground area has stagnated for a dozen years in Hubei Province, China, although a series of new high- yielding varieties have been commercialized. A multi-location investigation was carried out in...Cotton yield per unit ground area has stagnated for a dozen years in Hubei Province, China, although a series of new high- yielding varieties have been commercialized. A multi-location investigation was carried out in 2008 and 2009 in 13 counties to determine if increased planting population density (PPD) would break the stagnant yield. The results showed that significant differences among the fields existed in theoretical yield, PPD, and bolls per square meter (BPM). The lowest yield of 1 641.1 kg ha-I was resulted from the lowest PPD of 1.7 plants m-2 and the lowest BPM of 71.8 bolls m-2, while the highest yield of 2 779.7 kg ha-~ was resulted from the highest PPD of 2.5 plants m-2, and the highest BPM of 129.4 bolls m-z. Plant mapping revealed that boll retention rate (BRR) was maintained over 30 or 40% for the first 17-18 fruiting branches (FBs) and decreased dramatically thereafter, rotten boll rate (RBR) decreased, but open boll rate (OBR) rose first and dropped later with rising FB from the bottom to the top. But BRR, RBR, and OBR were all dropped with the fruiting positions (FPs) extending outwards. The optimum range of plant density would be 2-3 plants m-2 and the proper individual plant structure would be 16-19 FBs with 5-7 FPs for cotton production in Hubei Province.展开更多
The growth, development and consumption of successive three generations of cotton bollworm, Helicoverpa armigera (Htibner), fed on cotton bolls grown under elevated CO2 (double-ambient vs. ambient) in open-top cha...The growth, development and consumption of successive three generations of cotton bollworm, Helicoverpa armigera (Htibner), fed on cotton bolls grown under elevated CO2 (double-ambient vs. ambient) in open-top chambers were examined. Significant decreases in protein, total amino acid, water and nitrogen content and increases in free fatty acid were observed in cotton bolls. Changes in quality of cotton bolls affected the growth, development and food utilization of H. armigera. Significantly longer larval development duration in three successive generations and lower pupal weight of the second and third generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower fecundity was also found in successive three generations of H. armigera fed on cotton bolls grown under elevated CO2. The consumption per larva occurred significant increase in successive three generations and frass per larva were also significantly increased during the second and third generations under elevated CO2. Significantly lower relative growth rate, efficiency of conversion of ingested food and significant higher relative consumption rate in successive three generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower potential female fecundity, larval numbers and population consumption were found in the second and third generations of cotton bollworm fed on cotton bolls grown under elevated CO2. The integrative effect of higher larval mortality rate and lower adult fecundity resulted in significant decreases in potential population consumption in the latter two generations. The results show that elevated CO2 adversely affects cotton bolls quality, which indicates the potential population dynamics and potential population consumption of cotton bollworm will alleviate the harm to the plants in the future rising CO2 atmosphere.展开更多
To optimize the spatial distribution of cotton bolls and to increase the yield,the relationship between yield components and boll spatial distribution was investigated among different Bt(Bacillus thuringensis)cotton v...To optimize the spatial distribution of cotton bolls and to increase the yield,the relationship between yield components and boll spatial distribution was investigated among different Bt(Bacillus thuringensis)cotton varieties.A five-year field experiment was conducted to reveal the reasons for the differences in lint yield and fiber quality across three Bt cotton varieties with different yield formations from 2013 to 2017.The lint yield of Jiman 169(the average yield from 2013-2017 was 42.2 g/plant)was the highest,i.e.,16.3 and 36.9%higher than Lumianyan 21(L21)and Daizimian 99B(99B),respectively.And the differences in boll weight among the three cultivars were similar to the lint yield,while the others yield components were not.So the increase in lint yield was mainly attributed to the enlargement in boll weight.However,the change in fiber quality was inconsistent with the lint yield,and the quality of L21 was significantly better than that of Jimian 169(J169)and 99B,which was caused by the diversity of boll spatial distribution.Compared with 99B,the loose-type J169 had the highest number of large bolls in inner positions;the tight-type L21 had a few large bolls and the highest number of lower and middle bolls.And approximately 80.72%of the lint yield was concentrated on the inner nodes in Jiman 169,compared with 77.44%of L21 and 66.73%of 99B during the five-year experiment.Although lint yield was significantly affected by the interannual changes,the lint yield of J169 was the highest and the most stable,as well as its yield components.These observations demonstrated the increase in lint yield was due to the increase in boll weight,and the large bolls and high fiber quality were attributed to the optimal distribution of bolls within the canopies.展开更多
Plant growth regulators(PGRs)are frequently used to adjust cotton growth and development.The objectives of this study were to determine how PGRs affect plant morphology,light distribution and the spatial distribution ...Plant growth regulators(PGRs)are frequently used to adjust cotton growth and development.The objectives of this study were to determine how PGRs affect plant morphology,light distribution and the spatial distribution of leaves and bolls within the cotton canopy.The field experiments were carried out at Shihezi(Xinjiang Uyghur Autonomous Region,China)in 2014 and 2015.The experiment included two PGR treatments:(i)flumetralin(active ingredient(a.i),N-N-ethy)-2,6-dinitro-4-aniline and(i)mepiquat chloride(ai,1-dimethyl-piperidiniuchloride)plus flumetralin.No PGR(manual topping)was applied in the control treatment.The chemically-topped plants were taller and had more main stem internodes than the manually-topped plants.Furthermore,the PGRs significantly reduced the length of fruiting branches in the upper canopy,resulting in a more compact canopy.The maximum leaf area index was signifcantly greater in the chemically-topped treatments than that in the control.In particular,the PGRs increased leaf area index by 25%in the upper canopy.The leaf area duration was also longer in the chemically-topped treatments than in the control.Compared with the control,the chemically-topped treatments increased canopy diffuse non-interceptance by 35.75%in the upper canopy layer,while reducing the fraction of intercepted photosynthetically active radiation by 14.45%in the upper canopy layer.Light transmittance in the upper and middle canopy layers was greater in the chemically-topped treatments than in the control,which increased boll numbers in both the upper canopy and the middle canopy.However,the chemically-topped treatments resulted in less light-leakage through the lower canopy layer during the late growth stages,which had a tendency to increase boll numbers in the whole canopy.In summary,the PGRs optimized canopy shape,light distribution and the spatial distribution of bolls and leaves.展开更多
Samples of pheromone lures used in boll weevil, Anthonomus grandis (Boheman), eradication programs are routinely analyzed by Gas Chromatography (GC) to ensure lures are adequately dosed with grandlure, the synthet...Samples of pheromone lures used in boll weevil, Anthonomus grandis (Boheman), eradication programs are routinely analyzed by Gas Chromatography (GC) to ensure lures are adequately dosed with grandlure, the synthetic aggregation phero- mone produced by male weevils. However, preparation of GC samples is tedious, time consuming, and requires a moderate level of experience. We examined the use of a commercially-available electronic nose (e-nose) for rapidly assessing the grandlure contents of lures. The e-nose was trained to recognize headspace collections of grandlure emitted from new lures and after lures were aged under field conditions for 4 d, 7 d, 10 d, and 14 d. Based on cross-validation of the training set, the e-nose was 82% accurate in discriminating among the different age classes of lures. Upon sampling headspace collections of pheromone from a different set of field-aged lures, the e-nose was 〈50% accurate in discriminating 4 d, 7 d, and 10 d aged lures from the other age classes of lures. However, the e-nose identified new and 14 d aged lure samples with 100% accuracy. In light of these findings, e-nose technology shows considerable promise as an alternative approach for rapidly assessing the initial grandlure contents of lures used in boll weevil eradication programs.展开更多
Bt cotton hybrids require large supply of metabolites to support their greater boll load and commonly suffer from premature leaf senescence. A field experiment was conducted to study the nutritional status of Bt cotto...Bt cotton hybrids require large supply of metabolites to support their greater boll load and commonly suffer from premature leaf senescence. A field experiment was conducted to study the nutritional status of Bt cotton leaves during boll development stage and to evaluate the most profitable source of foliar fertilizers. Treatments included basal application of 0 and 60 kg·K2O·ha-1 as muriate of potash (MOP) in main plots and foliar spray treatments viz: 4 & 6 sprays of 2% potassium nitrate (Multi-K, 13-00-45), 4 & 6 sprays of NPK Blend (Polyfed, 19-19-19), 4 sprays of MOP, 4 sprays of MOP + urea (to supply same amount of N & K as in potassium nitrate) and unsprayed control in sub plots. The results revealed that only N and K contents of premature senesced leaves were below the sufficiency range for cotton sufficient levels of P, Fe, Mn, Zn and Cu were observed. Though the concentrations of N and K in both the petiole and leaf blade initially improved with foliar spray, N content declined below the unsprayed control at later stages. Basal application of MOP increased seed cotton yield by 19%. Four foliar sprays of KNO3, NPK, MOP and MOP + urea recorded yield increase in seed cotton yield of 22.8%, 22.4%, 18.5% and 24.5%, respectively over unsprayed control. Six sprays of KNO3 and NPK had no yield advantage over four sprays and rather proved economically less viable.展开更多
基金supported by the National Natural Science Foundation of China(31901462 and 31671613)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(22KJA210005)+1 种基金the China Scholarship Council(202308320440)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX22_3508)。
文摘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.
基金supported by the National Natural Science Foundation of China (31901462 and 31671613)the Natural Science Foundation of Jiangsu Province,China (BK20191439)+1 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX22_3508)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China (PAPD)。
文摘In Bacillus thuringenesis(Bt) transgenic cotton, the cotton boll has the lowest insecticidal protein content when compared to the other organs. The present study investigated the effects of amino acid spray application at the peak flowering stage on the cotton boll Bt toxin concentration and yield formation. Boll protein synthesis and carbohydrate conversion were also studied to reveal the fundamental mechanism. Three treatments(i.e., CK, the untreated control;LA1, five amino acids;LA2, 21 amino acids) were applied to two Bt cultivars of G. hirsutum(i.e., the hybrid Sikang 3 and the conventional Sikang 1) in the cotton-growing seasons during 2017 and 2018. Amino acid spray application at the peak flowering stage resulted in an increase of 5.2–16.4% in the boll Bt protein concentration and an increase of 5.5–11.3%in the seed cotton yield, but there was no difference between the two amino acid treatments. In addition, amino acid applications led to increases in the amino acid content, soluble protein content, glutamate pyruvate transaminase(GPT)activity, glutamate oxaloacetate transaminase(GOT) activity, glucose content, fructose content and soluble acid invertase(SAI) activity. This study also found that Bt protein content, enhanced boll number and the weight of opened bolls were closely related to carbon and nitrogen metabolism. The Bt protein content had significant linear positive correlations with amino acid and soluble protein contents. Enhanced boll number had significant linear positive correlations with the GPT and GOT activities from 15–25 days after flowering(DAF). The weight of opened bolls from 55–65 DAF had a significant linear positive correlation with the SAI activity. These results indicate that the enhancement of boll protein synthesis and carbohydrate conversion by amino acid application resulted in a simultaneous increase in the boll Bt protein concentration and cotton lint yield.
基金Supported by Natural Science Foundation of China(NSFC No.30771272,31171483)the Priority Academic Development Program of Jiangsu Higher Education Institutions+1 种基金Jiangsu Innovation Project for Agriculture Science and Technology(cx(11)2054)Jiangsu Agriculture Science and Technology Support Program(SBE2010307)~~
文摘[Objective] This study aimed to explore an optimum application amount of nitrogen for cotton cultivation. [Method] In this study, a field experiment was conducted to investigate the effects of nitrogen application amount on the growth characteristics, boll development and lint yield of high quality cotton line FZ-1. [Result] Compared with the nitrogen level of 225 kg/hm2, the lint yield had increased by 28.46% and 18.73%, respectively, with the nitrogen application amount of 300 and 375 kg/hm2. When the nitrogen application amount had increased from 225 to 300 kg/hm2, boll number per plant, boll weight and lint yield had significantly increased. At the nitrogen level of 375 kg/hm2, however, the effects of increasing lint yield were significantly less than that at the nitrogen level of 300 kg/hm2. Compared with the nitrogen levels of 225 and 375, 300 kg/hm2 of nitrogen was the optimum application amount to improve the plant height, daily increment of plant height, number of fruit branches, number ratio of nodes to fruit branches, boll volume and seed cotton weight per boll. [Conclusion] The rational management of nitrogen is the most effective way to promote the growth and development of cotton plants, ensure high yielding ability and minimize the environmental pollution caused by the overuse of nitrogen. This study had provided a sound nitrogen application strategy for the cultivation of this high-quality cotton line in the field plantation.
基金supported by the National Natural Science Foundation of China (31471444,31401327)the Special Fund for Agro-scientific Research in the Public Interest of China (Impact of Climate Change on Agriculture Production,201203096)the Jiangsu Overseas Research and Training Program for University Prominent Young and Middle-aged Teachers and President,China (2016)
文摘Cotton growth and development are determined and influenced by cultivars, meteorological conditions, and management practices. The objective of this study was to quantify the optimum of temperature-light meteorological factors for seedcotton biomass per boll with respect to boll positions. Field experiments were conducted using two cultivars of Kemian 1 and Sumian 15 with three planting dates of 25 April (mean daily temperature (MDT) was 28.0 and 25.4°C in 2010 and 2011, respectively), 25 May (MDT was 22.5 and 21.2°C in 2010 and 2011, respectively), and 10 Jun (MDT was 18.7 and 17.9°C in 2010 and 2011, respectively), and under three shading levels (crop relative light rates (CRLR) were 100, 80, and 60%) during 2010 and 2011 cotton boll development period (from anthesis to boll open stages). The main meteorological factors (temperature and light) affected seedcotton biomass per boll differently among different boll positions and cultivars. Mean daily radiation (MDR) affected seedcotton biomass per boll at all boll positions, except fruiting branch 2 (FB2) fruting node 1 (FN1). However, its influence was less than temperature factors, especially growing degree-days (GDD). Optimum mean daily maximum temperature (MDTmax) for seedcotton biomass per boll at FB11FN3 was 29.9-32.4°C, and the optimum MDR at aforementioned position was 15.8-17.5 MJ m-2. Definitely, these results can contribute to future cultural practices such as rational cultivars choice and distribution, simplifying field managements and mechanization to acquire more efficient and economical cotton management.
基金supported by the National Key Research and Development Program of China(2018YFD1000900)the Natural Science Foundation of Jiangsu Higher Education Institution,China(18KJB210013 and 17KJA210003)the Natural Science Foundation of Jiangsu Province,China(BK20191439)。
文摘Sowing cotton directly after harvesting wheat in the Yangtze River Valley of China requires early mature of cotton without yield reduction.Boll-setting period synchronisation and more yield bolls distributed at the upper and middle canopy layers are also required for harvesting.The objective of this study is to quantify the individual and interaction effects of plant density and plant growth regulator mepiquat chloride(MC)on temporal and spatial distributions of yield bolls,as well as yield and yield components.During the 2013–2016 cotton growing seasons,the experiments were conducted on a shortseason cotton cultivar CRRI50 at Yangzhou University,China.Various combinations of plant density(12.0,13.5 and 15.0 plants m^(–2))and MC dose(180,270 and 360 g ha^(–1))were applied on cotton plants.The combination of 13.5 plants m^(–2)and 270 g ha^(–1)MC resulted in the greatest boll number per unit area,the highest daily boll setting number and more than 90%of bolls positioned within 45–80 cm above the ground.In conclusion,appropriate MC dose in combination of high plant density could synchronize boll-setting period and retain more bolls at the upper and middle canopy layers without yield reduction in the system of direct-seeded cotton after wheat harvest,and thus overcome the labor-intensive problem in current transplanting cropping system.
基金funded by the Professional (Agriculture) Researching Project for Public Benefit of Ministry of Agriculture,China (3-5)High-Yielding Promotion Project of Ministry of Agriculture,Chinathe National Industrial System Program of Modern Agriculture,China
文摘Cotton yield per unit ground area has stagnated for a dozen years in Hubei Province, China, although a series of new high- yielding varieties have been commercialized. A multi-location investigation was carried out in 2008 and 2009 in 13 counties to determine if increased planting population density (PPD) would break the stagnant yield. The results showed that significant differences among the fields existed in theoretical yield, PPD, and bolls per square meter (BPM). The lowest yield of 1 641.1 kg ha-I was resulted from the lowest PPD of 1.7 plants m-2 and the lowest BPM of 71.8 bolls m-2, while the highest yield of 2 779.7 kg ha-~ was resulted from the highest PPD of 2.5 plants m-2, and the highest BPM of 129.4 bolls m-z. Plant mapping revealed that boll retention rate (BRR) was maintained over 30 or 40% for the first 17-18 fruiting branches (FBs) and decreased dramatically thereafter, rotten boll rate (RBR) decreased, but open boll rate (OBR) rose first and dropped later with rising FB from the bottom to the top. But BRR, RBR, and OBR were all dropped with the fruiting positions (FPs) extending outwards. The optimum range of plant density would be 2-3 plants m-2 and the proper individual plant structure would be 16-19 FBs with 5-7 FPs for cotton production in Hubei Province.
基金Project supported by the National Basic Research Program(973)of China(No.2006CB102002)the Pilot Project of Knowledge Innovation Program of Chinese Academy of Sciences(No.KSCX2-YW-N-006)National Natural Science Foundation of China(No.30571253,30621003)
文摘The growth, development and consumption of successive three generations of cotton bollworm, Helicoverpa armigera (Htibner), fed on cotton bolls grown under elevated CO2 (double-ambient vs. ambient) in open-top chambers were examined. Significant decreases in protein, total amino acid, water and nitrogen content and increases in free fatty acid were observed in cotton bolls. Changes in quality of cotton bolls affected the growth, development and food utilization of H. armigera. Significantly longer larval development duration in three successive generations and lower pupal weight of the second and third generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower fecundity was also found in successive three generations of H. armigera fed on cotton bolls grown under elevated CO2. The consumption per larva occurred significant increase in successive three generations and frass per larva were also significantly increased during the second and third generations under elevated CO2. Significantly lower relative growth rate, efficiency of conversion of ingested food and significant higher relative consumption rate in successive three generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower potential female fecundity, larval numbers and population consumption were found in the second and third generations of cotton bollworm fed on cotton bolls grown under elevated CO2. The integrative effect of higher larval mortality rate and lower adult fecundity resulted in significant decreases in potential population consumption in the latter two generations. The results show that elevated CO2 adversely affects cotton bolls quality, which indicates the potential population dynamics and potential population consumption of cotton bollworm will alleviate the harm to the plants in the future rising CO2 atmosphere.
基金supported by the National Natural Science Foundation of China (31601253)the Modern Agroindustry Technology Research System, China (SDAIT-03)the Natural Science Foundation of Shandong Province, China (ZR2016CQ20)
文摘To optimize the spatial distribution of cotton bolls and to increase the yield,the relationship between yield components and boll spatial distribution was investigated among different Bt(Bacillus thuringensis)cotton varieties.A five-year field experiment was conducted to reveal the reasons for the differences in lint yield and fiber quality across three Bt cotton varieties with different yield formations from 2013 to 2017.The lint yield of Jiman 169(the average yield from 2013-2017 was 42.2 g/plant)was the highest,i.e.,16.3 and 36.9%higher than Lumianyan 21(L21)and Daizimian 99B(99B),respectively.And the differences in boll weight among the three cultivars were similar to the lint yield,while the others yield components were not.So the increase in lint yield was mainly attributed to the enlargement in boll weight.However,the change in fiber quality was inconsistent with the lint yield,and the quality of L21 was significantly better than that of Jimian 169(J169)and 99B,which was caused by the diversity of boll spatial distribution.Compared with 99B,the loose-type J169 had the highest number of large bolls in inner positions;the tight-type L21 had a few large bolls and the highest number of lower and middle bolls.And approximately 80.72%of the lint yield was concentrated on the inner nodes in Jiman 169,compared with 77.44%of L21 and 66.73%of 99B during the five-year experiment.Although lint yield was significantly affected by the interannual changes,the lint yield of J169 was the highest and the most stable,as well as its yield components.These observations demonstrated the increase in lint yield was due to the increase in boll weight,and the large bolls and high fiber quality were attributed to the optimal distribution of bolls within the canopies.
基金This study was financially supported by the 948 Program from Ministry of Agriculture of China(2016-X25)the National Key Technology R&D Program of China(2014BAD09B03)The authors are grateful to Dr.William J.Gale(Shihezi University,China)for his helpful revision of the paper especially in English language.
文摘Plant growth regulators(PGRs)are frequently used to adjust cotton growth and development.The objectives of this study were to determine how PGRs affect plant morphology,light distribution and the spatial distribution of leaves and bolls within the cotton canopy.The field experiments were carried out at Shihezi(Xinjiang Uyghur Autonomous Region,China)in 2014 and 2015.The experiment included two PGR treatments:(i)flumetralin(active ingredient(a.i),N-N-ethy)-2,6-dinitro-4-aniline and(i)mepiquat chloride(ai,1-dimethyl-piperidiniuchloride)plus flumetralin.No PGR(manual topping)was applied in the control treatment.The chemically-topped plants were taller and had more main stem internodes than the manually-topped plants.Furthermore,the PGRs significantly reduced the length of fruiting branches in the upper canopy,resulting in a more compact canopy.The maximum leaf area index was signifcantly greater in the chemically-topped treatments than that in the control.In particular,the PGRs increased leaf area index by 25%in the upper canopy.The leaf area duration was also longer in the chemically-topped treatments than in the control.Compared with the control,the chemically-topped treatments increased canopy diffuse non-interceptance by 35.75%in the upper canopy layer,while reducing the fraction of intercepted photosynthetically active radiation by 14.45%in the upper canopy layer.Light transmittance in the upper and middle canopy layers was greater in the chemically-topped treatments than in the control,which increased boll numbers in both the upper canopy and the middle canopy.However,the chemically-topped treatments resulted in less light-leakage through the lower canopy layer during the late growth stages,which had a tendency to increase boll numbers in the whole canopy.In summary,the PGRs optimized canopy shape,light distribution and the spatial distribution of bolls and leaves.
文摘Samples of pheromone lures used in boll weevil, Anthonomus grandis (Boheman), eradication programs are routinely analyzed by Gas Chromatography (GC) to ensure lures are adequately dosed with grandlure, the synthetic aggregation phero- mone produced by male weevils. However, preparation of GC samples is tedious, time consuming, and requires a moderate level of experience. We examined the use of a commercially-available electronic nose (e-nose) for rapidly assessing the grandlure contents of lures. The e-nose was trained to recognize headspace collections of grandlure emitted from new lures and after lures were aged under field conditions for 4 d, 7 d, 10 d, and 14 d. Based on cross-validation of the training set, the e-nose was 82% accurate in discriminating among the different age classes of lures. Upon sampling headspace collections of pheromone from a different set of field-aged lures, the e-nose was 〈50% accurate in discriminating 4 d, 7 d, and 10 d aged lures from the other age classes of lures. However, the e-nose identified new and 14 d aged lure samples with 100% accuracy. In light of these findings, e-nose technology shows considerable promise as an alternative approach for rapidly assessing the initial grandlure contents of lures used in boll weevil eradication programs.
文摘Bt cotton hybrids require large supply of metabolites to support their greater boll load and commonly suffer from premature leaf senescence. A field experiment was conducted to study the nutritional status of Bt cotton leaves during boll development stage and to evaluate the most profitable source of foliar fertilizers. Treatments included basal application of 0 and 60 kg·K2O·ha-1 as muriate of potash (MOP) in main plots and foliar spray treatments viz: 4 & 6 sprays of 2% potassium nitrate (Multi-K, 13-00-45), 4 & 6 sprays of NPK Blend (Polyfed, 19-19-19), 4 sprays of MOP, 4 sprays of MOP + urea (to supply same amount of N & K as in potassium nitrate) and unsprayed control in sub plots. The results revealed that only N and K contents of premature senesced leaves were below the sufficiency range for cotton sufficient levels of P, Fe, Mn, Zn and Cu were observed. Though the concentrations of N and K in both the petiole and leaf blade initially improved with foliar spray, N content declined below the unsprayed control at later stages. Basal application of MOP increased seed cotton yield by 19%. Four foliar sprays of KNO3, NPK, MOP and MOP + urea recorded yield increase in seed cotton yield of 22.8%, 22.4%, 18.5% and 24.5%, respectively over unsprayed control. Six sprays of KNO3 and NPK had no yield advantage over four sprays and rather proved economically less viable.