Characterization and screening of cotton(Gossypium hirsutum L.)germplasm for leafhopper(Amrasca biguttula biguttula(Ishida))resistance

Background Cotton(Gossypium hirsutum L.)is one of the most significant fibre and cash crops and plays an important role in Indian industrial and agricultural economies.However,over the years quantity and quality have been hampered by the pest leafhopper.Leafhopper alone has been shown to cause yield losses of up to 40%.In this study,screening and evaluation were performed to identify and categorize 100 cotton genotypes along with 5 checks as resistant,moderately resistant,sensitive and highly sensitive to leafhoppers.Results A total of hundred genotypes were evaluated along with five checks for leafhopper resistance.Based on the screening results,a total of 19 genotypes were resistant to leafhoppers,which was on par with the findings of the check KC 3.The contents of total soluble sugar,total soluble protein,and total free amino acids were significantly positively correlated with the mean grade,whereas total phenols content and trichome density were significantly negatively correlated with the susceptibility grade.However,based on screening and biochemical analysis,the genotypes KC 2,JR-23,Samaru-26-T,D 4,TCH 1728,RS 253,and B-61-1862 exhibited high resistance to leafhopper.Conclusion According to the findings of this study,choosing genotypes with high total phenolics content together with high trichome density and low contents of total soluble sugar,total soluble protein,and free amino acids may aid in the development of resistant genotypes.

Screening of drought resistance indices and evaluation of drought resistance in cotton(Gossypium hirsutum L.)

Sixteen cotton cultivars widely planted in China were sowed under five different drought concentrations(0,2.5,5,7.5,and 10%)using PEG6000 to screen the indices of drought resistance identification and explore the drought resistance of different cotton cultivars.Eighteen physiological indices including root,stem,and leaf water contents(RWC,SWC,and LWC),net photosynthetic rate(Pn),the maximum photochemical quantum yield(Fv/Fm),the actual photochemical quantum yield(ΦPSII),non-photochemical quenching coefficient(NPQ),leaf water potential(LWP),osmotic potential(Ψs),leaf relative conductivity(REC),leaf proline content(Pro),leaf and root soluble protein contents(LSPC and RSPC),leaf and root malondialdehyde(MDA)contents(LMDA and RMDA),root superoxide dismutase,peroxidase,and catalase activities(RSOD,RPOD,and RCAT)were measured.Results indicated the 18 physiological indices can be converted into five or six independent comprehensive indices by principal component analysis,and nine typical indices(Fv/Fm,SWC,LWP,Pro,LMDA,RSPC,RMDA,RSOD,and RCAT)screened out by a stepwise regression method could be utilized to evaluate the drought resistance.Moreover,the 16 cotton cultivars were divided into four types:drought sensitive,drought weak sensitive,moderate drought resistant,and drought resistant types.The resistance ability of two selected cotton cultivars(drought resistant cultivar,Dexiamian 1;drought sensitive cultivar,Yuzaomian 9110)with contrasting drought sensitivities were further verified by pot experiment.Results showed that the responses of final cotton biomass,yield,and yield composition to drought were significantly different between the two cultivars.In conclusion,drought resistant cultivar Dexiamian 1 and drought sensitive cultivar Yuzaomian 9110 were screened through hydroponics experiment,which can be used as ideal experimental materials to study the mechanism of different cotton cultivars with contrasting drought sensitivities in response to drought stress.

Differential Expression of Whitebacked Planthopper Resistance in the japonica/indica Doubled Haploid Rice Population under Field Evaluation and Seedbox Screening Test

Whitebacked planthopper (WBPH) -resistance in a japonica / indica doubled haploid (DH) rice population established from a cross between WBPH-resistant japonica Chun]iang 06 and susceptible indica TN1, was comparatively evaluated through a field experiment based on the WBPH immigrant density and standardized seedbox screening test (SSST). All the susceptible DH lines in the field experiment behaved accordingly in SSST. However, 35 of resistant 66 lines (53%) in the field, were categorized to susceptible groups in SSST. Likewise, there were no significant differences in WBPH immigrant densities among 70 DH lines that were highly resistant to susceptible in SSST. The results revealed that SSST could not evaluate properly WBPH resistance in the DH lines. Four QTLs for WBPH-resistance phenotyped by the immigrant density were detected on chromosomes 2, 3, 4, and 11. Of them, the QTL on chromosome 4 was the most effective (LOD 21.8, variance 78%). Five QTLs associated with seedling mortality were mapped on chromosomes 2, 3, 4, 5 and 6. In addition to the QTL (LOD 10.5, variance 68%) on chromosome 4, there was another major QTL (LOD 12.7, variance 71%) located on chromosome 5, which was SSST-specific but might be irrespective of the WBPH resistance traits.

Generation of a series of mutant lines resistant to imidazolinone by screening an EMS-based mutant library in common wheat

The breeding of herbicide-resistant wheat varieties has helped control weeds in wheat fields economically and effectively.Imidazolinone (IMI) herbicides are popular as they have low toxicity in mammals,are effective at small doses,and exhibit broad-spectrum herbicidal action in the field.Therefore,the isolation and genetic and molecular characterization of IMI-resistant wheat mutants will enhance weed management in wheat fields.In the present study,352 IMI-resistant plants were isolated by genetic screening from a mutant pool prepared by EMS-based random mutagenesis.Cloning of the mutated genes from the IMI-resistant plants indicated that ten taals alleles had been isolated,and mutation in one of three Ta ALS homolog genes conferred IMI resistance,and such a mutation is a dominant trait.Further analysis showed that taals-d exhibited the greatest IMI resistance,whereas taals-b exhibited the weakest resistance to IMI among three homologous taals mutants.In terms of IMI resistance,the taals triple mutant was stronger than the taals double mutants,and the taals double mutants were stronger than the single mutants,indicating a dose-dependent effect of the Ta ALS mutation on IMI resistance in wheat.Biochemical analysis indicated that the mutation in Ta ALS increased the tolerance of Ta ALS to inhibition by IMI.Our work details the genetic and molecular characterization of als wheat mutants,provides a foundation for understanding IMI resistance and breeding wheat varieties with herbicide resistance,and indicates that genetic screening using a mutagenized pool is an effective and important means of breeding crops with additional desired agricultural traits.

In vitro Screening of Fusarium Wilt-resistant Germplasm Resources of Red Edible Seed Watermelon( Citrullus lanatus ssp. vulgaris var. megalaspermus Lin et Chao)

[ Objective] This study aimed to establish an appropriate technology system for in vitro screening of Fuzarium wilt-resistant germplasm resources of red edible seed watermelon and obtain variants resistant to fusaric acid, thus providing resistant materials for breeding Fusarium wilt-resistant red edible seed watermel- on. [ Method] Using Zhongxin No. 1 red edible seed watermelon advemitious buds as screening materials and fusaric acid （FA） as a stress agent, in vitro screen- ing of Fusarium wilt-resistant red edible seed watermelon clonal variants and identification of Fusarium wilt-resistance of the germplasm resources of red edible seed watermelon were performed. [ Result] The results showed that the appropriate FA for in vitro screening of Fusarium wilt-resistant red edible seed watermelon vari- ants was 15 mg/L. In vitro screening system for Fusarium wilt-resistant red edible seed watermelon variants was established preliminarily and FA-resistant regenera- ted plants were obtained. Among the 36 germplasm resources of red edible seed watermelon, there were 2 highly resistant materials, 6 moderately resistant materi- als, 11 slightly resistant materials and 17 highly susceptible materials. [ Conclusion] This study confirmed preliminarily that in vitro screening method is effective for obtaining resistant materials of red edible seed watermelon.

Screening of Tomato Resources Resistant to Tomato Gray Mold

This study was conducted to screen tomato resources resistant to gray mold for the first time by in-vitro stem inoculation method.The results showed that Solanum habrochaites T2-07-316 was highly resistant to gray mold,and had the relative stem infection rate and relative stem rot expansion rate of 0 on the 6^(th) day after inoculation.There were also other seven transgenic common tomato materials which showed higher resistance to gray mold,with a relative stem infection rate in the range of 15.00%-38.33% and a relative stem rot expansion rate in the range of 10.22%-23.57%.Among them,T2-07-337 had the best resistance.

Field Screening of Lesotho and South African Wheat Cultivars for Russian Wheat Aphid Resistance

Russian wheat aphid (Diuraphis noxia) is an international wheat pest and was first recorded in South Africa in 1978 in the Bethlehem area in the Eastern Free State. Le-sotho lies adjacent to one of the largest wheat producing areas in South Africa, the Eastern Free State, where winter wheat and facultative types are cultivated under dry land conditions. Wheat (Triticum aestivum L.) is an important crop adapted to all agro-ecological zones of Lesotho. Russian wheat aphid may have a significant impact on wheat yield. No monitoring or pest control is being done in Lesotho and at this stage there is very little information on the Russian wheat aphid resistance of wheat culti-vars cultivated in Lesotho. In view of this it is important to monitor the distribution of Russian wheat aphid biotypes in Lesotho and determine the level of Russian wheat aphid resistance in local Lesotho wheat cultivars. Two local Lesotho wheat cultivars, Bolane and Makalaote were screened together with South African cultivars Elands, Matlabas, Senqu, PAN3379, PAN3118 and SST387, in the glasshouse against all four known biotypes that occur in South Africa. All these cultivars were also planted in 5 m plots in the field at two localities Leribe and Roma in the lowlands of Lesotho. These cultivars were screened in the field for Russian wheat aphid resistance. The predomi-nant Russian wheat aphid biotypes in these areas were also determined. The Lesotho cultivar, Bolane had resistance against RWASA2 in the glasshouse, while Makalaote did not have any Russian wheat aphid resistance in either the glasshouse or field screenings. To contribute to food security an increasing wheat yield potential is a high priority. Russian wheat aphid has been included in the list of important international cereal pests. Russian wheat aphid adapts to changing environments and taking their ecology, distribution, virulence patterns, and variability into account is important in minimizing the gap between actual and attainable yields. Current management prac-tices for winter wheat in South Africa include the use of resistant cultivars, which is the most economical management strategy for Russian wheat aphid. Introducing Russian wheat aphid resistant cultivars in Lesotho will improve overall yield and as a result food security. This will also result in lower Russian wheat aphid pest pressure in the adjacent wheat production areas in the Eastern Free State, South Africa.

Cassava Anthracnose Disease and Varietal Screening for Resistance in Akwa Ibom State of Nigeria

Cassava （Manihot esculenta Crantz） production in Akwa Ibom State is limited by cassava anthracnose disease （CAD） which causes enormous losses in planting materials. Survey of the disease was conducted in the wet and dry seasons in six major cassava-growing areas （Essien Udim, Ikono, Itu, Nsit Atai, Oruk Anam and Uyo） of the State to determine the incidence and severity of the disease. Ten commonly grown cassava varieties were then screened in the greenhouse by inoculating each variety with the spore suspension of virulent isolate of the cassava anthracnose pathogen. Disease severity was assessed using size of lesions on the inoculated plants and defoliation caused by the infection. Results of the survey showed that Nsit Atai is a high infection area for CAD. It recorded the highest disease incidence and severity in both the wet season （36.59% and 3.52） and dry season （9.26% and 2.20）, respectively. The mean disease incidence （24.10%） and severity （3.23） for the six study areas were higher in the wet season indicating the importance of this season in the occurrence of CAD. Results of the screening test showed that TMS 98/30572 was resistant to the disease. The small lesion size （5.00 mm） observed in this variety would ensure less stem disruption and timely delivery of resources to the actively growing points. The low defoliation （5,65%） observed in the same variety would enhance the photosynthetic capacity of the plant. Therefore, TMS 98/30572 may be recommended to cassava farmers in Akwa Ibom State.

Screening and evaluation for soybean resistance to Phakopsora pachyrhyzi in Glycine soja

Soybean rust caused by Phakopsora pachyrhizy is an important disease of soybean, and yield losses are very common in humid growing regions. Most commercial cultivars are susceptible and the disease is usually managed with fungicides. Resistance breeding is the most effective in controlling the disease. In this study, detached - leaf assay and greenhouse inoculation were used to screen 200 Glycine soja accessions for resistance to Phakopsora pachyrhizi in China. Most of the accessions were susceptible, and W8214 was the only accession that demonstrated RB resistance to Phakopsora pachyrhizy. The further repeated tests confirmed the resistance in W8214.

Evaluation and screening for resistance of some varieties(lines)to major diseases and insect pests of rice

During 1984-1988,2,231 varieties(lines)from International Rice Testing Program(IRTP)were evaluated and screened for resistance to riceblast(Bl),bacterial blight(BB),sheath blight

Evaluation of maize inbred lines currently used in Chinese breeding programs for resistance to six foliar diseases

Foliar diseases are common in most maize-producing regions and have caused serious yield reduction in China. To evaluate genetic resistance of parental lines actively used in maize breeding programs to major foliar diseases, 152 maize inbred lines were tested against northern corn leaf blight(NCLB), southern corn leaf blight(SCLB), Curvularia leaf spot(CLS),gray leaf spot(GLS), common rust, and southern rust from 2003 to 2005. A small number of lines exhibited highly resistant reactions to common rust and southern rust, but none were highly resistant to NCLB, SCLB, CLS, and GLS. Although 53.3%, 40.8%, and 80.7% of lines were resistant to NCLB, SCLB, and common rust, the resistance in most lines was moderate.Resistance to CLS, GLS, and southern rust was rare in this collection of maize lines. Five lines,313, Chang 7-2, Qi 319, Qi 318, and Shen 137, were resistant to five diseases tested. Lines belonging to heterotic subgroup PB exhibited better resistance to the foliar diseases than lines from other heterotic subgroups, such as BSSS, PA, Lancaster, LRC, and PA. The results will be of benefit to breeders for selecting lines in disease resistance breeding programs.

Screening of Prolific Micromonospora carbonacea in Antibiotics Production by Sodium Nitrite Mutagenesis

[Objective] The purpose of the study is to breed Micromonospora car- bonacea highly producing antibiotics and then to improve the antibiotic production. [Method] Sodium Nitrite mutagenesis, combined with rifampicin resistance screening, was used in mutation breeding of M. carbonacea highly producing antibiotics from the strain of M. carbonacea JXNU-I. [Result] The overproducing strain JXNU-1-16- Y65 was screened with the production of antibiotics 266.05% more than that of the original strain. [Conclusion] The effectiveness of sodium nitrite mutation in breeding microorganisms highly producing antibiotic was proved, and the study may lay the foundation on further development and application of the antibiotic from M. car- bonacea JXNU-1.

Experimental study on performance of flow & desulfurisation of a gas-liquid screen scrubber for wet flue gas desulfurization

In the paper, the gas-liquid two-phase flow performance and desulfurisation performance of the gas-liquid screen scrubber were experimentally studied when limestone was used as absorbent. Experiments were carried out at varying the flue gas velocity and slurry flux in concurrent and countercurrent tower respectively. The experimental results showed that the flow resistance of absorber increased rapidly with an increase of the flue gas velocity whether in concurrent or in countereurrent tower, and the up trend of the flow resistance in the cotmtercurrent tower was higher than those in the concurrent one. The influence of the flue gas velocity on the flow resistance of absorber was more than those of the slurry flux density. Whether in the concurrent tower or in the cotmtercurrent one, increasing the flue gas velocity or the slurry flux density would enhance the desulphurization efficiency. The influence of the slurry flux density on the desulfurisation efficiency was greater than those of the flue gas velocity.

The Phenomenon of High Hardness Values on the S-Phase Layer of Austenitic Stainless Steel via Screen Plasma Nitriding Process

The purpose of this study is to improve the surface properties of austenitic stainless steel using the double-folded electrode screen plasma nitriding (SPN) process. In general, the S-phase is well-known for its excellent properties such as improved hardness and wear resistance along with sustained corrosion resistance. The concentrated nitrogen via SPN process was injected to form S-phase with time at 713 K. This study was carried out under the conditions of 44 at% of nitrogen injection, which was higher than 25 at% known as the condition of no precipitation of S-phase formed by the SPN process, and 20 K higher than the maximum temperature without precipitation phase. The hardness analysis of stainless steel sample treated by the SPN process at 713 K showed a much higher value than the typical nitriding hardness at a depth of lower nitrogen than the maximum nitrogen concentration. The SPN 20 hr treated specimen showed the average value of 2339 HV while 40 hr showed the average value of 2215 HV. The result is attributed to the concentrated nitrogen formed in the SPN process reacting with the alloying elements contained in the base material to form fine precipitates, thus producing a synergy effect of the extreme hardening effect;that is, the movement of precipitates and dislocations due to the GP-zone (Guinier-Preston zone).

Quick screening and easy detection method of NDM-gene in clinical isolates:A need of the time

The emerging trend of multidrug resistance is becoming a major threat to community acquired and nosocomial infections,worldwide[1].The carbapenems are used as last-source drugs because of increasing resistance against beta-lactam groups of antibiotics due to its excessive use to treat wide range of infections[2].The

Influence of Seedling Age on the Susceptibility of Tomato Plants to <i>Ralstonia solanacearum</i>during Protray Screening and at Transplanting

The study was undertaken to assess whether seedling age played any role in governing the vulnerability of tomato to the bacterial wilt pathogen, Ralstonia solanacearum, based on the preliminary observations that the extent of mortality during seedling-stage screening was relatively less in older seedlings. Employing the virulent strain ‘NH-Av01’ isolated from tomato, 2-, 3-, 4- or 5-week-old seedlings of susceptible ‘Arka Vikas’ raised in organic cocopeat in 98 cavity protrays were inoculated with the pathogen through root-injury inoculation approach. Disease symptoms appeared earlier and with more severity in 2-week-old seedlings followed by 3-, 4- and 5-week-old saplings recording 74%, 68%, 63% and 49% mortality, respectively, after four weeks of inoculation suggesting that older the seedlings, less the susceptibility to the pathogen. The growth characteristics of seedlings (shoot height, shoot and root weights) showed a significant increase with seedling age (0.21, 0.54, 1.14 and 2.09 g gross weight/seedling at 2, 3, 4 and 5 weeks, respectively) indicating healthier saplings with delay in inoculation time. In subsequent trials, seedlings of 3, 4, 5 or 6 weeks were transplanted to field-sick soil in protrays or in pots with monitoring for 1 - 4 months which indicated a significant reduction in disease incidence and severity with increase in seedling age. The observations suggested that seedling age should be considered as a major factor influencing the susceptibility of tomato seedlings to R. solanacearum with the chances of variations in the extent of disease incidence or inconsistent results during seedling-stage screening and the possibility of escapes with older seedlings. Two-week seedlings formed the best when the aim is to induce maximum disease incidence, while transplanting at 5 - 6 weeks stage appeared the best when the objective is minimal disease incidence or formulating disease management strategies.

Possibility of a Straightening Flow-Meter by Using Woven Screen

In this paper, the possibility of the flow rate measurement for a circular pipe flow by using a wo-ven screen with the property of straightening un-uniform flows is discussed. The resistance coefficient and the flow rate coefficient are estimated from the pressure difference caused by the woven screen under the experiment ranges of the wire Reynolds number, Red = 2.2 × 102-1.8 × 103, and of the open area ratio, β = 0.28-0.65. As a result, the resistance coefficient decreases and the flow rate coefficient increases as the wire Reynolds number Red or the open area ratio β increases. In addition, both coefficients are not affected by the difference between uniform and turbulent pipe flows approaching the woven screen. Therefore, the possibility of a flow-meter having the property to straighten the un-uniform flow is expected.

Reversal of Tetracycline Resistance by Cepharanthine,Cinchonidine,Ellagic Acid and Propyl Gallate in a Multi-drug Resistant Escherichia coli

Bacterial resistance to antibiotics is an increasing threat to global healthcare systems.We therefore sought compounds with potential to reverse antibiotic resistance in a clinically relevant multi-drug resistant isolate of Escherichia coli(NCTC 13400).200 natural compounds with a history of either safe oral use in man,or as a component of a traditional herb or medicine,were screened.Four compounds;ellagic acid,propyl gallate,cinchonidine and cepharanthine,lowered the minimum inhibi-tory concentrations(MICs)of tetracycline,chloramphenicol and tobramycin by up to fourfold,and when combined up to eightfold.These compounds had no impact on the MICs of ampicillin,erythromycin or trimethoprim.Mechanistic studies revealed that while cepharanthine potently suppressed efflux of the marker Nile red from bacterial cells,the other hit com-pounds slowed cellular accumulation of this marker,and/or slowed bacterial growth in the absence of antibiotic.Although cepharanthine showed some toxicity in a cultured HEK-293 mammalian cell-line model,the other hit compounds exhibited no toxicity at concentrations where they are active against E.coli NCTC 13400.The results suggest that phytochemicals with capacity to reverse antibiotic resistance may be more common in traditional medicines than previously appreciated,and may offer useful scaffolds for the development of antibiotic-sensitising drugs.

杨叶枯病病原菌生物学特性、防治药剂筛选及杨树抗病性评价

为防治杨树叶枯病,利用单因素试验,对中荷64杨(P.×euramericana cv.‘N3016’)上分离获得的链格孢菌(Alternaria alternata)进行了生物学特性及室内防治药剂筛选研究,并开展了不同品种杨树抗叶枯病综合评价。结果表明:链格孢菌菌丝生长的适宜培养基为马铃薯蔗糖琼脂培养基,适宜碳源为玉米粉,适宜氮源为酵母提取物,适宜培养温度范围为25~30℃,适宜pH为8,光照条件对菌丝生长影响不大,致死温度为52℃。采用生长速率法进行室内防治药剂筛选,结果显示,选用的5种生物制剂防治效果优于2种化学药剂,各药剂抑制作用排序从大到小依次为哈茨木霉(3亿菌落/g)、枯草芽孢杆菌(100亿芽孢/g)、质量分数为10%的多抗霉素、质量分数为3%的中生菌素、质量分数为2%的宁南霉素、质量分数为50%的多菌灵、质量分数为75%的百菌清,将哈茨木霉(3亿菌落/g)和枯草芽孢杆菌(100亿芽孢/g)作为防治链格孢菌的适宜药剂。选用7个黑杨派品种杨树,利用模糊数学隶属度函数法,开展了杨树抗叶枯病综合评价,确定中荷64杨为高感品种,中辽1号杨和欧美杨177为中感品种,渤丰1号杨、渤丰3号杨、辽育3号杨和欧美杨111为高抗品种。

基于大数据挖掘下多重耐药菌风险评估的研究价值

目的 基于大数据构建多重耐药菌感染的风险预测模型,并对其应用价值进行评估。方法 收集2018年1月至2022年12月于新疆医科大学第五附属医院诊治的405例患者,根据是否发生多重耐药菌(multidrug-resistant organisms,MDRO)感染分为非MDRO组(n=324)和MDRO组(n=81),比较并分析各指标与MDRO发生风险的相关性。构建大数据风险预测模型,分析各指标重要性,验证其准确性。结果 MDRO组合并糖尿病、原发肺部感染的患者比例,机械通气、广谱抗菌药物使用时间及降钙素原水平显著高于非MDRO组,而血红蛋白、白蛋白水平显著低于非MDRO组(均P <0.05);相关性分析显示,合并糖尿病、原发肺部感染等因素与MDRO风险的相关性较高,且合并糖尿病与原发肺部感染及联合使用抗生素等指标间相关性较高;大数据模型示抗生素使用时间、吞咽功能障碍等因素重要性较高,而血红蛋白及白蛋白重要性较低;大数据模型预测MDRO发生风险的AUC显著高于Logistic回归模型(Z=2.415,P=0.016),两种预测模型的训练集预测准确率差异无统计学意义(P>0.05);但测试集大数据模型预测准确率、敏感度及特异度均显著高于Logistic回归模型(χ^(2)=9.062,5.385,4.267;均P<0.05)。结论 合并糖尿病、原发肺部感染及联合使用抗生素等因素与MDRO发生风险具有一定相关性,基于MDRO危险因素指标的大数据模型对MDRO发生风险具有较高预测价值。