[Objective] The aim of this study was to provide metabolic evidence for the analysis of the ecological and safety assessment of Pi-d2-transgenic rice.[Method] The main agronomic characters of Pi-d2-transgenic rice wer...[Objective] The aim of this study was to provide metabolic evidence for the analysis of the ecological and safety assessment of Pi-d2-transgenic rice.[Method] The main agronomic characters of Pi-d2-transgenic rice were observed in field experiment and the grain chemical characters and amino acid content were measured.[Results] Introduction of foreign gene Pi-d2 resulted in stably hereditable variation in agronomic characteristics in the descents.Most of the transgenic lines grew normally and orderly.Compared with the control(wild type plants),about half of transgenic plants showed an increased or reduced plant height.There was no observable difference between transgenic plants and controls in tiller number,length of panicle,panicles per plant,seed-setting rate and 1 000-grain weight.Total amino acid content in transgenic rice was reduced,while the starch content,GC and GT were not altered in comparison with the control.[Conclusion] Introduction of foreign gene Pi-d2 has remarkable influence on plant height,while little on grain chemical characters.展开更多
The effects of vermicompost on the agronomic characters and yield and quality of flue-cured tobacco were investigated. The results showed that, the field growth periods of various treatments were 117-118 d, 1-2 days l...The effects of vermicompost on the agronomic characters and yield and quality of flue-cured tobacco were investigated. The results showed that, the field growth periods of various treatments were 117-118 d, 1-2 days longer than that of the CK. The numbers of effective leaves of the treatments applied with vermicompost were 0.1-0.3 leaf more than the CK. The highest yield and the highest proportion of high-grade tobacco occurred in treatment 3 as 2 095.5 kg/m^2 and 49%, respectively, which were higher than those in the CK by 6.58 kg and 5.3%. In conclusion, the treatment with the application of vermicompost at 7 500-10 500 kg/hm^2 was the best.展开更多
Fifteen combinations crossed by five JA cytoplasmic male sterile lines (A1, A2, A3, A4, A5) and three restoring lines (R1, R2, R3) were selected to analyze the combining ability and heritability of nine main agron...Fifteen combinations crossed by five JA cytoplasmic male sterile lines (A1, A2, A3, A4, A5) and three restoring lines (R1, R2, R3) were selected to analyze the combining ability and heritability of nine main agronomic characters of Brassica na-pus L. to definite the application potential of these parent materials. The result showed that (i) the general combining ability (GCA) of male parents was R3>R2>R1 and that of female parents was A4>A1>A2>A5>A3; (i ) the special combining ability (SCA) of A2×R3 in plant height, number of branches, number of pods per plant and yield per plant was the best. The yield per plant of A2×R3, A1×R1 and A2×R1 ranked the first three places in the 15 combinations; (i i) the broad heritability of yield per plant was the highest, and that of the height of branches was the lowest. The com-prehensive characters of R3, A2 and A4 were better, which could be used to create new materials; (iv) good offspring were more likely to be chosen from the combina-tion with higher parental GCA, so the GCA and SCA should be considered com-prehensively when choosing parent and determining the optimal combinations.展开更多
[ Objective] This study was to explore the inheritance of BC1 F3 to excellent characteristics of parents( Elymus dahuricus, Hordeum brevisubu/atum), heterosis and fertility restoration. E Methodl The agronomic chara...[ Objective] This study was to explore the inheritance of BC1 F3 to excellent characteristics of parents( Elymus dahuricus, Hordeum brevisubu/atum), heterosis and fertility restoration. E Methodl The agronomic characters such as growth period, growth rate, pollen fertility, fecundity, reproducibility and fresh grass output of Elymus dahudcus, Hordeum brevisubu/atum and BC1 F3 were comparatively studied. E Result l The growth dynamic of the BC1 F3 lined tended to like that of its parent Hordeum brevisubu/atum; although growing periods of various lines were different, they were close to that of Hordeurn brevisubulatum. There were differences in pollen fertility and seed setting, the pollen fertility rate of YF3-93 was higher than recurrent parent Hordeum brevisubulatum, its seed setting rate in open pollination was also higher. Some lines had low pollen fertility rate and seed setting rate, such as the pollen fertility rate of PF3-52. There were significant differences in the output among BC1 F3 lines, e.g. the heterosis (HP) of YF3-64, YF3-74 and YF3-83 were 75.53%, 75.12% and 66.16%, respectively; however, the yields of PF3- 52, PF3-15 and PF3-42 were lower than their parents. ~ Conclusion] This study provided reference for breeding new varieties of forage which is suitable to drought and saline environment.展开更多
[Objectives]To study the optimum sowing density of quinoa in Chengde region.[Methods]Yanli No.2 cultivated by Institute of Millet Crops,Hebei Academy of Agriculture and Forestry Sciences was taken as test material.In ...[Objectives]To study the optimum sowing density of quinoa in Chengde region.[Methods]Yanli No.2 cultivated by Institute of Millet Crops,Hebei Academy of Agriculture and Forestry Sciences was taken as test material.In Chengde region,single-factor density test design was used to study the effects of sowing on agronomic characters and yield of quinoa.[Results]Quinoa had the highest comprehensive yield when row spacing was 30 cm and plant spacing was 25 cm.[Conclusions]The research could provide theoretical basis for quinoa planting in Chengde region.展开更多
[Objectives]The paper was to study the effects of different herbicides on weed control,agronomic characters and grain quality of Coix lacryma-jobi L.[Methods]Six commonly used herbicides were selected for the trial,in...[Objectives]The paper was to study the effects of different herbicides on weed control,agronomic characters and grain quality of Coix lacryma-jobi L.[Methods]Six commonly used herbicides were selected for the trial,including atrazine SC,butachlor SC,monosulfuron WP,MCPA-starane EC,clopyralid AS and tribenuron-methyl WP.[Results](i)Atrazine,butachlor and monosulfuron had no chemical injury to C.lacryma-jobi L.,while clopyralid caused slight chemical injury.(ii)The fresh weight control effects of atrazine,butachlor and monosulfuron on weeds increased first and then decreased.The initial control effect of MCPA-starane and clopyralid reached more than 90%;the control effect of monosulfuron increased gradually in the late stage,reaching 97%at 60 d post spraying,and the overall control effect was optimal.(iii)Compared with manual weeding,herbicides had no significant effect on plant height of C.lacryma-jobi L.However,compared with no weeding,other herbicides except tribenuron-methyl inhibited plant growth to a certain extent.Herbicides had different effects on main stem diameter,tiller number per plant and grain number per plant of C.lacryma-jobi L.(iv)Different herbicides had no significant effect on 100-grain weight,but had significant effect on yield.(v)Compared with manual weeding,atrazine,butachlor and clopyralid decreased the protein content of C.lacryma-jobi L.,and the use of atrazine,butachlor,monosulfuron,MCPA-starane and tribenuron-methyl decreased the fat content of C.lacryma-jobi L.;butachlor and MCPA-starane decreased the glycerol trioleate content of C.lacryma-jobi L.Compared with no weeding,chemical herbicides had no significant effect on the protein content,while atrazine decreased the fat content,and butachlor and MCPA-starane decreased the glycerol trioleate content of C.lacryma-jobi L.[Conclusions]The use of herbicides significantly increases crop yield compared with no weeding,but has an impact on agronomic characters and grain quality.展开更多
The genealogical relationship and agronomic characters of 13 peanut varieties,breeded by Hezhou Academy of Agricultural Sciences,which had been authorized were analyzed.The results showed that 20 direct parents were i...The genealogical relationship and agronomic characters of 13 peanut varieties,breeded by Hezhou Academy of Agricultural Sciences,which had been authorized were analyzed.The results showed that 20 direct parents were involved in 13 varieties,80%of which came from Guangxi and Guangdong Province.Shanyou 523 and Yueyou 193 were used for more times;The genealogical analysis of these certified varieties can be traced back to 30 ancestral parents,the proportion of which contained consanguinity of Fu Peanut and Shitouqi were 84.62%.This demonstrated that genetic basis was rather narrow and it was quite difficult to make a great breakthrough in breeding.Plant height,total number of branches and oil content changed very little,100-pod weight and pod yield increased,whereas there was a downward trend in shelling percentage.Therefore,it is quite necessary to further broaden the germplasm basis of parents,enrich breeding methods,and continue to strengthen disease-resistant breeding and specific peanut breeding.展开更多
[Objective] The aim was to investigate the effects of DPC chemical controlling technique on agronomic traits, yield and quality of machine-harvested cotton in the Yellow River Valley of China, and clarify the reasonab...[Objective] The aim was to investigate the effects of DPC chemical controlling technique on agronomic traits, yield and quality of machine-harvested cotton in the Yellow River Valley of China, and clarify the reasonable control period and the application amount of DPC. [Method] The new machine-harvested cotton variety Hengmian HD008 was used as the test material, and 3 different DPC treatments were set. [Result] DPC significantly reduced plant height and branch length, reduced branch angle and leaf area, so the rational control can effectively shape the ideal plant type of machine-harvested cotton. DPC had significant effects on yield and yield components, and the proper amount of DPC could increase the number of bolls during hot days, the number bolls in autumn and the total number of bolls. It increased the boll weight and seed index, but decreased lint percentage decreased, and proper amount of DPC could increase the yield. DPC significantly increased the specific breaking strength of fibers, and proper control could improve the uniformity of fibers, but other indexes had no significant influence. [Conclusion] According to the requirements of machine harvest to the agronomic traits of cotton and the growth characteristics of cotton plant, chemical control could begin after floral bud emergence in cotton about every 10 d, and the spraying amount can be controlled according to the growth amount of the main stem. The daily growth amount of plant height should be controlled at 1.5-1.8 cm, and the plant height should be within 75-90 cm.展开更多
The suitable plant density was favorable for sorghum yield increase. In order to clarify the suitable plant density of dwarf-stem, early-maturing sorghum variety 'Jiza141 ', in the open field condition,150 000, 200 ...The suitable plant density was favorable for sorghum yield increase. In order to clarify the suitable plant density of dwarf-stem, early-maturing sorghum variety 'Jiza141 ', in the open field condition,150 000, 200 000, 250 000, 300 000 and 350 000 plants/hm^2 tests were set to study the effect of different densities on yield and yield traits. The results showed that with the increase of planting density, LAI increased, chlorophyll content decreased, plant length had no significant difference, era length and era diameter tended to decrease, while biomass increased with the increase of density. The 1000-grain weight and single panicle weight had the maximum effects on yield, and both of them showed a significantly positive correlation with the yield. In Jiamusi growing areas, the optimal plant density of sorghum 'Jiza141' was 200 000 plants/hm^2, and the yield could reach 9 183.00 kg/hm^2. The study provides a theo- retical basis and technical support for the 'Jiza141' variety in the Jiamusi ecological region.展开更多
A field experiment was conducted at the experimental farm of Hamelmalo Agricultural College during summer 2017,to evaluate the agronomic,physiological,and biochemical performance of the collected Eritrean germplasm of...A field experiment was conducted at the experimental farm of Hamelmalo Agricultural College during summer 2017,to evaluate the agronomic,physiological,and biochemical performance of the collected Eritrean germplasm of pearl millet.A total of 16 accessions were tested,out of which 2 were improved varieties included as a check.The experiment was laid out in 4 x 4 Simple Lattice Design with Randomized Block using 4 replications with a gross plot size of 3.0 m x 1.2 m,row to row spacing of 75 cm and plant to plant spacing of 30 cm.The data collected were Agronomic parameters(growth,development,yield,and yield contributing characters);Physiological parameters(Relative water content and Water Use Efficiency);and Biochemical parameters(crude fat,crude fiber,protein content,TSS,and ash content).The data were analyzed using GENSTAT software and correlation analysis was worked to see the positive and negative contribution of agronomic,physiological,and biochemical attributes.The results of the study showed that Bariyay908 and Kona being statistically at par with Bariyay 910,Hagaz,Zibedi,Shleti,Delkata,Tokroray,and Kunama produced significantly higher grain yield.However,among these Baryay908 because of its superior agronomic characteristics,lower incidence of downy mildew,relatively higher water use efficiency and higher crude protein content were found to be comparatively superior to the check improved varieties Kona and Hagaz.Grain yield has shown a positive and significant correlation with harvest index,number of seeds per panicle,panicle length,leaf area and water use efficiency.These promising accessions need to be further tested for future breeding programs to develop varieties higher in productivity and resistant to downy mildew under semi-arid conditions of Eritrea.展开更多
F1 heterosis of agronomic characters and chemical components of 8 fluecured tobacco varieties and 6 self-bred high-potassium new lines was studied. The results showed that 4-5 weeks after transplanting was the main ch...F1 heterosis of agronomic characters and chemical components of 8 fluecured tobacco varieties and 6 self-bred high-potassium new lines was studied. The results showed that 4-5 weeks after transplanting was the main changing period of agronomic traits. Compared with the comparative heterosis, among the proportions of combinations showing positive comparative heterosis at the significant level, the heterosis proportions of plant height (97.92%), internode length (100%) and stem girth (58.33%) were larger, these of total nitrogen (83.33%), protein (79.17%), nicotine (79.17%) and potassium (95.83%) in upper leaves were larger, these of total sugar (64.58%), total nitrogen (68.75%), protein (72.92%) and nicotine (64.58%) in middle leaves were larger, and in lower leaves, except that the proportion of chlorine was smaller (12.50%), the proportions of other chemical components all exceeded 40%. Compared with average heterosis, among the proportions of combinations showing positive comparative heterosis at the significant level, the heterosis proportions of plant height (54.17%), leaf width (43.75%), stem girth (43.75%) and internode length (72.92%) were larger, these of total sugar (47.92%) and reducing sugar (54.17%) in upper leaves were larger, these of all the chemical components in middle leaves exceeded 30%, and these of all the chemical components in lower leaves were in the range of 27.08%-41.67%. Compared with heterobeltiosis, among the proportions of combinations showing positive comparative heterosis at the significant level, that of the internode length (60.42%) was larger, these of chemical components in upper leaves were in the range of 8.33%-29.17%, these of chemical components in middle leaves were in the range of 20.83%-39.58%, and these of chemical components in lower leaves were in the range of 16.67%-35.42%. It was indicated that rational effective control of water and fertilizer in this sensitive period could significantly enhance heterosis.展开更多
Soybean is an important legume food crop,and its seeds are rich in nutrients,providing humans and animals with edible oil and protein feed.However,soybean is sensitive to water requirements,and drought is an important...Soybean is an important legume food crop,and its seeds are rich in nutrients,providing humans and animals with edible oil and protein feed.However,soybean is sensitive to water requirements,and drought is an important factor limiting soybean yield and quality.This study used Heinong 84(drought resistant variety)and Hefeng 46(intermediate variety)as tested varieties planted in chernozem,albic,and black soils.The effects of drought stress on the activities of key enzymes in carbon metabolism and photosynthetic characteristics of soybean were studied during the flowering stage,most sensitive to water.(1)The activities of SS-1,6PGDH,and G6PDH enzymes in soybean leaves first increased and then decreased under drought stress.The enzyme activity was the highest under moderate drought stress and weakest in the blank group.(2)Drought stress increased Phi2,PhiNO,and Fm in soybean leaves and reached the highest value under severe drought;with the increase in drought stress,PhiNPQ and Fv/Fm of soybean leaves gradually decreased,reaching the lowest under severe drought.(3)With the increase in drought stress,F0 and Fs of soybean leaves showed a single peak curve,and the maximum was at moderate drought.(4)Correlation analysis showed that F0 was greatly affected by varieties and soil types;Fs,F0,and Fm soil varieties had a great influence,and chlorophyll fluorescence parameters were affected differently under drought stress with different drought degrees.(5)Drought stress changed the agronomic traits and yield of soybean.With the increase of drought degree,plant height,node number of main stem,effective pod number,100-seed weight and total yield decreased continuously.(6)Drought stress affected the dry matter accumulation of soybean.With the increase of drought degree,the dry matter accumulation gradually decreased.Among them,the leaf was most seriously affected by drought,and SD decreased by about 55%compared with CK.Under the condition of black soil,the dry matter accumulation of soybean was least affected by drought.展开更多
With 10 elite soybean varieties from Huang-Huai-Hai Valleys as materials,25 hybridization combinations were compounded based on NC II,and the heterosis and combining ability for the major agronomic characters in summe...With 10 elite soybean varieties from Huang-Huai-Hai Valleys as materials,25 hybridization combinations were compounded based on NC II,and the heterosis and combining ability for the major agronomic characters in summer soybean was studied.The results showed that heterosis of agronomic traits of soybean was ubiquity,and the average heterosis of all characters showed positive advantages.The advantage of seed weight per plant,number of seeds per plant and number of pods per plant were the highest,at 35.58%,34.23%and 31.47%,respectively,and thus made a great contribution to yield heterosis.The general combining ability of Hedou 19,Handou 6,Shanning 14 and Williams 82 was relatively higher in seed weight per plant,number of seeds per plant and number of pods per plant,and they are quality parents for designing strong hybridization combinations.There were significant differences in special combining ability(SCA)among parents for the same trait in different combinations.Some showed positive effect,and others showed negative effects.We should select the best combination according to breeding objective in selecting and matching special elite combinations.展开更多
To elucidate the genetic relationship of the soybean varieties registered in Henan province, we analyzed the pedigrees, the major agronomic traits, and the eco- nomic traits of 74 soybean varieties registered in Henan...To elucidate the genetic relationship of the soybean varieties registered in Henan province, we analyzed the pedigrees, the major agronomic traits, and the eco- nomic traits of 74 soybean varieties registered in Henan province from 1985 to 2012, with reference to experience and technologies beneficial to breeding. The resuits indicated that these varieties originated from 113 parents, and positive correla- tion between the yield and the number of original parents was significant. In the major agronomic traits, the growth stage was about 106 days with relatively small variation, while the final height varied largely among these varieties. Among the fac- tore affecting the final yield, the pod number per plant exhibited an increasing trend, while the variation of 100-grain weight was relatively small. More than 50% of the 113 original parents came from Henan Province and its neighbor provinces, and the genetic relationship among the registered varieties was too close. The rational criteria of yield components of soybean varieties in Henan Province should be as fol- lows: the pod number per plant was about 48. 6, with 100-grain weight ranging from 17.55 g to 21.80 g.展开更多
The transplanting period, density, the number of left leaves and fertilizer amounts of HQ No.1 were explored in Hengyang. The results showed that with transplanting periods of March 5-March 15, and planting space of 1...The transplanting period, density, the number of left leaves and fertilizer amounts of HQ No.1 were explored in Hengyang. The results showed that with transplanting periods of March 5-March 15, and planting space of 120 cmx(50-60) cm, agronomic and economic characters of tobaccos showed insignificant differences. Specifically, plant height was growing upon the number of left leaf and fertilizer amount; tobacco yield and output value kept increasing upon fertilizer, and both reached maximums with pure N at 195 kg/hm^2, showing significant differences with the treatment of pure N at 135 kg/hm^2; the number of left leaf had the least effects on agronomic and economic characters of tobaccos. The research indicated that highly-qualified HQ No.1 can be produced, given that tobaccos are transplanted during March 10-March 15, planting density of 15 000-16 500 seedlings/hm^2, the number of left leaves of 22-24 leaves per seedling, and pure N of 150-165 kg/hm^2 in Hengyang.展开更多
[Objective] This study was conducted to provide theoretic support for improving yield and quality of flue-cured tobacco by applying microbial organic fertilizers. [Method] A field plot experiment was conducted to stud...[Objective] This study was conducted to provide theoretic support for improving yield and quality of flue-cured tobacco by applying microbial organic fertilizers. [Method] A field plot experiment was conducted to study the effects of the Engran series of microbial organic fertilizers on growth and development, diseases and pests and economic traits of flue-cured tobacco. [Result] The result showed that the treatment of conventional fertilization + Engran microbial agent could promote the growth and dry matter accumulation of flue-cured tobacco during the growth period in the field, enhance the disease resistance of tobacco, and improve yield and output value of flue-cured tobacco and income of tobacco growers. Compared with T1,the proportion of high-grade tobacco, the proportion of mid-high grade tobacco,yield, output value and average price increased by 4.4%, 3.8%, 5.48%, 11.51% and5.73% respectively. [Conclusion] The treatment of conventional fertilization + Engran microbial agent showed outstanding performance, is optimum for field production,and could be applied to Flue-cured tobacco.展开更多
Pot experiments were conducted to study the effects of different organic fertilizers made from distiller's grains on the physiological characteristics and growth of flue-cured tobacco. The results showed that the agr...Pot experiments were conducted to study the effects of different organic fertilizers made from distiller's grains on the physiological characteristics and growth of flue-cured tobacco. The results showed that the agronomic traits and biomass of flue-cured tobacco in the three treatments were higher than that of the control group,and the mixed application of different organic fertilizers made from distiller's grains and compound fertilizer could promote the growth and development of flue-cured tobacco significantly.展开更多
In order to explore the optimal phosphorus application rate of tobacco in Yongzhou area and provide scientific basis for the rational application of phosphorus fertilizer in tobacco production,field plot experiments w...In order to explore the optimal phosphorus application rate of tobacco in Yongzhou area and provide scientific basis for the rational application of phosphorus fertilizer in tobacco production,field plot experiments with 4 phosphorus application rates were conducted to study the effects of different phosphorus application rate on the growth period,agronomic characters and economic characters of tobacco.The results showed that when the nitrogen fertilizer,phosphorus fertilizer and potassium fertilizer was 135,135 and 418.5 kg/hm2,respectively,namely the ratio of 1∶1∶3.1,the field growth period was the shortest,only 107 d;the agronomic characters and physical indexes showed good results in their performance;the ratio of superior tobacco leaves,average price and output value were 49.36%、26.04 yuan/kg and 56064.12 yuan/hm2 respectively,significantly higher than that of other treatments.Therefore,the suitable phosphorus application in Yongzhou tobacco area was 135 kg/hm2.In conclusion,rational phosphorus application rate was conducive to accelerating the growth and development of tobacco plant and early harvest;it could also effectively increase the output value and yield of tobacco leaves and was more conducive to the formation of high-quality tobacco leaves.展开更多
[Objective] This study aimed to characterize 124 flue-cured tobacco germplasm resources, and to provide reference for making the best use of the existing flue-cured tobacco germplasm resources. [Method] A total of 124...[Objective] This study aimed to characterize 124 flue-cured tobacco germplasm resources, and to provide reference for making the best use of the existing flue-cured tobacco germplasm resources. [Method] A total of 124 flue-cured tobacco germplasm resources were studied via field experiment and statistic analysis to investigate characteristics of their growth period, morphologic characters, main agronomic traits, and economic characters. [Result] There were significant differences among the 124 flue-cured tobacco germplasm resources in growth period, morphologic characters, main agronomic traits, and economic characters. The coefficients of variation (CV) varied in a range of 7.9%-22.5%. Among them, CV of bud stage was higher, and that of corolla length was lower. Many germplasm resources were attacked seriously by black shank disease at the end of field experiment, including those with disease index higher than 90, like Kutsaga 110, TI706, Ky 151, KM10, Longshe, Chaoxian Kangchi, Kutsaga 51E, Yongding No.1, and those with disease index among 75-90 such as Liaoyan No. 8, Lingnong No.2, Shandong Duoye, 581, Cunjingyan, KRK26, and Special 400. The tobacco root knot nematode invasion was light in some germplasm or never happened in other germplasm resources. TMV happened sporadically. CV 87, Yunyan 99, Yunyan 85, K326, Yunyan 87, Zhubuo No.1, T64 and T66 produced higher yield, production value, proportion of good leaves and sold at a higher price. Finally, we screened out the germpalsm resources with good comprehensive economic values and high disease resistance such as CV 87, Yunyan 99, Yunyan 85, K326, Yunyan 87, Zhubuo No.1, T64, T66, Honghuadajinyan, G-28, Taiyan No. 8, 77089-12, Yunyan 97, K346, V2, K149, NC567, NC297, Yunyan 201, Yunyan 203, KRK22. [Conclusion] This study provides reference for making better use of tobacco germplasm resources, and breeding new varieties.展开更多
[Objective]The paper was to study the effects of plant extract mixture on growth and development,photosynthetic indexes and disease control of flue-cured tobacco.[Method]Using field test method,a total of five treatme...[Objective]The paper was to study the effects of plant extract mixture on growth and development,photosynthetic indexes and disease control of flue-cured tobacco.[Method]Using field test method,a total of five treatments were designed in the test,including T1(control,conven-tional pesticide control),T2(conventional pesticide control+spraying plant extract mixture at 15 and 30 d post transplanting),T3(conventional pesticide control+spraying plant extract mixture at 15,30 and 45 d post transplanting),T4(conventional pesticide control+spraying plant extract mixture at 15,30,45 and 60 d post transplanting),and T5(conventional pesticide control+spraying plant extract mixture at 15,30,45,60 and 75 d post transplanting).In addition,flue-cured tobacco in treatments T2-T5 were sprayed with antiviral agent once at 30 d post transplanting,and sprayed with quality promoting agent at 30 and 75 d post transplanting,respectively.[Result]The agronomic traits and photosynthetic indexes of all treatments were improved by spraying plant extract mixture,and those in T5 treatment were the best.Spraying plant extract mixture had significant control effect on brown spot;the disease index in T5 treatment was the lowest,and the control effect was the best.The results showed that spraying plant extract mixture promoted the growth and development of flue-cured tobacco,reduced the disease index of brown spot,and improved the quality of tobacco leaves.[Conclusion]Spraying plant extract mixture has positive effect on growth and development and disease control of flue-cured tobacco.展开更多
基金Supported by Program for New Century Excellent Talents in University of Ministry of Education of China(NCET-04-0907)Program for Young Scholars in Breeding from Sichuan Provincial Department of Finance(2009QNJJ-D18)~~
文摘[Objective] The aim of this study was to provide metabolic evidence for the analysis of the ecological and safety assessment of Pi-d2-transgenic rice.[Method] The main agronomic characters of Pi-d2-transgenic rice were observed in field experiment and the grain chemical characters and amino acid content were measured.[Results] Introduction of foreign gene Pi-d2 resulted in stably hereditable variation in agronomic characteristics in the descents.Most of the transgenic lines grew normally and orderly.Compared with the control(wild type plants),about half of transgenic plants showed an increased or reduced plant height.There was no observable difference between transgenic plants and controls in tiller number,length of panicle,panicles per plant,seed-setting rate and 1 000-grain weight.Total amino acid content in transgenic rice was reduced,while the starch content,GC and GT were not altered in comparison with the control.[Conclusion] Introduction of foreign gene Pi-d2 has remarkable influence on plant height,while little on grain chemical characters.
基金Supported by the Major Project of China Tobacco Corporation in 2014(110201402003)~~
文摘The effects of vermicompost on the agronomic characters and yield and quality of flue-cured tobacco were investigated. The results showed that, the field growth periods of various treatments were 117-118 d, 1-2 days longer than that of the CK. The numbers of effective leaves of the treatments applied with vermicompost were 0.1-0.3 leaf more than the CK. The highest yield and the highest proportion of high-grade tobacco occurred in treatment 3 as 2 095.5 kg/m^2 and 49%, respectively, which were higher than those in the CK by 6.58 kg and 5.3%. In conclusion, the treatment with the application of vermicompost at 7 500-10 500 kg/hm^2 was the best.
基金Supported by the National High Technology Research and Development Program of China(863 Program,2011AA10A104)Special Funds of the Modern Agricultural Industry Technology System(CAES-13)+5 种基金National Science and Technology Support Program(2010BAD01B08,2011BAD35B04)Sichuan Breeding Key Project(2011NZ0098-5)Financial Genetic Engineering Program of Sichuan Province(2011JYGC04013)Special Funds for Sichuan Agricultural Innovation Team ConstructionOutstanding Youth AcademicTechnical Leader Training Program of Sichuan Province(2010JQ0054)~~
文摘Fifteen combinations crossed by five JA cytoplasmic male sterile lines (A1, A2, A3, A4, A5) and three restoring lines (R1, R2, R3) were selected to analyze the combining ability and heritability of nine main agronomic characters of Brassica na-pus L. to definite the application potential of these parent materials. The result showed that (i) the general combining ability (GCA) of male parents was R3>R2>R1 and that of female parents was A4>A1>A2>A5>A3; (i ) the special combining ability (SCA) of A2×R3 in plant height, number of branches, number of pods per plant and yield per plant was the best. The yield per plant of A2×R3, A1×R1 and A2×R1 ranked the first three places in the 15 combinations; (i i) the broad heritability of yield per plant was the highest, and that of the height of branches was the lowest. The com-prehensive characters of R3, A2 and A4 were better, which could be used to create new materials; (iv) good offspring were more likely to be chosen from the combina-tion with higher parental GCA, so the GCA and SCA should be considered com-prehensively when choosing parent and determining the optimal combinations.
文摘[ Objective] This study was to explore the inheritance of BC1 F3 to excellent characteristics of parents( Elymus dahuricus, Hordeum brevisubu/atum), heterosis and fertility restoration. E Methodl The agronomic characters such as growth period, growth rate, pollen fertility, fecundity, reproducibility and fresh grass output of Elymus dahudcus, Hordeum brevisubu/atum and BC1 F3 were comparatively studied. E Result l The growth dynamic of the BC1 F3 lined tended to like that of its parent Hordeum brevisubu/atum; although growing periods of various lines were different, they were close to that of Hordeurn brevisubulatum. There were differences in pollen fertility and seed setting, the pollen fertility rate of YF3-93 was higher than recurrent parent Hordeum brevisubulatum, its seed setting rate in open pollination was also higher. Some lines had low pollen fertility rate and seed setting rate, such as the pollen fertility rate of PF3-52. There were significant differences in the output among BC1 F3 lines, e.g. the heterosis (HP) of YF3-64, YF3-74 and YF3-83 were 75.53%, 75.12% and 66.16%, respectively; however, the yields of PF3- 52, PF3-15 and PF3-42 were lower than their parents. ~ Conclusion] This study provided reference for breeding new varieties of forage which is suitable to drought and saline environment.
基金Supported by Key R&D Projects in Hebei Province(19227527D)Science and Technology Innovation Team Project of Hebei Coarse Grain and Soybean Seed Industry。
文摘[Objectives]To study the optimum sowing density of quinoa in Chengde region.[Methods]Yanli No.2 cultivated by Institute of Millet Crops,Hebei Academy of Agriculture and Forestry Sciences was taken as test material.In Chengde region,single-factor density test design was used to study the effects of sowing on agronomic characters and yield of quinoa.[Results]Quinoa had the highest comprehensive yield when row spacing was 30 cm and plant spacing was 25 cm.[Conclusions]The research could provide theoretical basis for quinoa planting in Chengde region.
基金Key Technology R&D Program of Guizhou Province(QKHZC[2021]247)QKHZC[2018]2310。
文摘[Objectives]The paper was to study the effects of different herbicides on weed control,agronomic characters and grain quality of Coix lacryma-jobi L.[Methods]Six commonly used herbicides were selected for the trial,including atrazine SC,butachlor SC,monosulfuron WP,MCPA-starane EC,clopyralid AS and tribenuron-methyl WP.[Results](i)Atrazine,butachlor and monosulfuron had no chemical injury to C.lacryma-jobi L.,while clopyralid caused slight chemical injury.(ii)The fresh weight control effects of atrazine,butachlor and monosulfuron on weeds increased first and then decreased.The initial control effect of MCPA-starane and clopyralid reached more than 90%;the control effect of monosulfuron increased gradually in the late stage,reaching 97%at 60 d post spraying,and the overall control effect was optimal.(iii)Compared with manual weeding,herbicides had no significant effect on plant height of C.lacryma-jobi L.However,compared with no weeding,other herbicides except tribenuron-methyl inhibited plant growth to a certain extent.Herbicides had different effects on main stem diameter,tiller number per plant and grain number per plant of C.lacryma-jobi L.(iv)Different herbicides had no significant effect on 100-grain weight,but had significant effect on yield.(v)Compared with manual weeding,atrazine,butachlor and clopyralid decreased the protein content of C.lacryma-jobi L.,and the use of atrazine,butachlor,monosulfuron,MCPA-starane and tribenuron-methyl decreased the fat content of C.lacryma-jobi L.;butachlor and MCPA-starane decreased the glycerol trioleate content of C.lacryma-jobi L.Compared with no weeding,chemical herbicides had no significant effect on the protein content,while atrazine decreased the fat content,and butachlor and MCPA-starane decreased the glycerol trioleate content of C.lacryma-jobi L.[Conclusions]The use of herbicides significantly increases crop yield compared with no weeding,but has an impact on agronomic characters and grain quality.
文摘The genealogical relationship and agronomic characters of 13 peanut varieties,breeded by Hezhou Academy of Agricultural Sciences,which had been authorized were analyzed.The results showed that 20 direct parents were involved in 13 varieties,80%of which came from Guangxi and Guangdong Province.Shanyou 523 and Yueyou 193 were used for more times;The genealogical analysis of these certified varieties can be traced back to 30 ancestral parents,the proportion of which contained consanguinity of Fu Peanut and Shitouqi were 84.62%.This demonstrated that genetic basis was rather narrow and it was quite difficult to make a great breakthrough in breeding.Plant height,total number of branches and oil content changed very little,100-pod weight and pod yield increased,whereas there was a downward trend in shelling percentage.Therefore,it is quite necessary to further broaden the germplasm basis of parents,enrich breeding methods,and continue to strengthen disease-resistant breeding and specific peanut breeding.
基金Supported by the Fundamental Research Funds of the Heibei Academy of Agriculture and Forestry Sciences(A2015040201)the Cotton Industry Technology System of Hebei Province+1 种基金the Key Research and Development Planning Program of Hebei Province(16226303D)the Financial Program of Hebei Province(F17C10005)~~
文摘[Objective] The aim was to investigate the effects of DPC chemical controlling technique on agronomic traits, yield and quality of machine-harvested cotton in the Yellow River Valley of China, and clarify the reasonable control period and the application amount of DPC. [Method] The new machine-harvested cotton variety Hengmian HD008 was used as the test material, and 3 different DPC treatments were set. [Result] DPC significantly reduced plant height and branch length, reduced branch angle and leaf area, so the rational control can effectively shape the ideal plant type of machine-harvested cotton. DPC had significant effects on yield and yield components, and the proper amount of DPC could increase the number of bolls during hot days, the number bolls in autumn and the total number of bolls. It increased the boll weight and seed index, but decreased lint percentage decreased, and proper amount of DPC could increase the yield. DPC significantly increased the specific breaking strength of fibers, and proper control could improve the uniformity of fibers, but other indexes had no significant influence. [Conclusion] According to the requirements of machine harvest to the agronomic traits of cotton and the growth characteristics of cotton plant, chemical control could begin after floral bud emergence in cotton about every 10 d, and the spraying amount can be controlled according to the growth amount of the main stem. The daily growth amount of plant height should be controlled at 1.5-1.8 cm, and the plant height should be within 75-90 cm.
基金Supported by Seed Innovation Foundation of Heilongjiang Province Agricultural S&T Innovation Engineering(2013-03-02)~~
文摘The suitable plant density was favorable for sorghum yield increase. In order to clarify the suitable plant density of dwarf-stem, early-maturing sorghum variety 'Jiza141 ', in the open field condition,150 000, 200 000, 250 000, 300 000 and 350 000 plants/hm^2 tests were set to study the effect of different densities on yield and yield traits. The results showed that with the increase of planting density, LAI increased, chlorophyll content decreased, plant length had no significant difference, era length and era diameter tended to decrease, while biomass increased with the increase of density. The 1000-grain weight and single panicle weight had the maximum effects on yield, and both of them showed a significantly positive correlation with the yield. In Jiamusi growing areas, the optimal plant density of sorghum 'Jiza141' was 200 000 plants/hm^2, and the yield could reach 9 183.00 kg/hm^2. The study provides a theo- retical basis and technical support for the 'Jiza141' variety in the Jiamusi ecological region.
文摘A field experiment was conducted at the experimental farm of Hamelmalo Agricultural College during summer 2017,to evaluate the agronomic,physiological,and biochemical performance of the collected Eritrean germplasm of pearl millet.A total of 16 accessions were tested,out of which 2 were improved varieties included as a check.The experiment was laid out in 4 x 4 Simple Lattice Design with Randomized Block using 4 replications with a gross plot size of 3.0 m x 1.2 m,row to row spacing of 75 cm and plant to plant spacing of 30 cm.The data collected were Agronomic parameters(growth,development,yield,and yield contributing characters);Physiological parameters(Relative water content and Water Use Efficiency);and Biochemical parameters(crude fat,crude fiber,protein content,TSS,and ash content).The data were analyzed using GENSTAT software and correlation analysis was worked to see the positive and negative contribution of agronomic,physiological,and biochemical attributes.The results of the study showed that Bariyay908 and Kona being statistically at par with Bariyay 910,Hagaz,Zibedi,Shleti,Delkata,Tokroray,and Kunama produced significantly higher grain yield.However,among these Baryay908 because of its superior agronomic characteristics,lower incidence of downy mildew,relatively higher water use efficiency and higher crude protein content were found to be comparatively superior to the check improved varieties Kona and Hagaz.Grain yield has shown a positive and significant correlation with harvest index,number of seeds per panicle,panicle length,leaf area and water use efficiency.These promising accessions need to be further tested for future breeding programs to develop varieties higher in productivity and resistant to downy mildew under semi-arid conditions of Eritrea.
基金Supported by Key Project of China Tobacco Corporation in 2014(110201402003)~~
文摘F1 heterosis of agronomic characters and chemical components of 8 fluecured tobacco varieties and 6 self-bred high-potassium new lines was studied. The results showed that 4-5 weeks after transplanting was the main changing period of agronomic traits. Compared with the comparative heterosis, among the proportions of combinations showing positive comparative heterosis at the significant level, the heterosis proportions of plant height (97.92%), internode length (100%) and stem girth (58.33%) were larger, these of total nitrogen (83.33%), protein (79.17%), nicotine (79.17%) and potassium (95.83%) in upper leaves were larger, these of total sugar (64.58%), total nitrogen (68.75%), protein (72.92%) and nicotine (64.58%) in middle leaves were larger, and in lower leaves, except that the proportion of chlorine was smaller (12.50%), the proportions of other chemical components all exceeded 40%. Compared with average heterosis, among the proportions of combinations showing positive comparative heterosis at the significant level, the heterosis proportions of plant height (54.17%), leaf width (43.75%), stem girth (43.75%) and internode length (72.92%) were larger, these of total sugar (47.92%) and reducing sugar (54.17%) in upper leaves were larger, these of all the chemical components in middle leaves exceeded 30%, and these of all the chemical components in lower leaves were in the range of 27.08%-41.67%. Compared with heterobeltiosis, among the proportions of combinations showing positive comparative heterosis at the significant level, that of the internode length (60.42%) was larger, these of chemical components in upper leaves were in the range of 8.33%-29.17%, these of chemical components in middle leaves were in the range of 20.83%-39.58%, and these of chemical components in lower leaves were in the range of 16.67%-35.42%. It was indicated that rational effective control of water and fertilizer in this sensitive period could significantly enhance heterosis.
基金funded by the National Key R&D Program of China,Grant No.2018YFD1000903And funded by Natural Science Foundation of Heilongjiang Province of China,Grant No.LH2021C023.
文摘Soybean is an important legume food crop,and its seeds are rich in nutrients,providing humans and animals with edible oil and protein feed.However,soybean is sensitive to water requirements,and drought is an important factor limiting soybean yield and quality.This study used Heinong 84(drought resistant variety)and Hefeng 46(intermediate variety)as tested varieties planted in chernozem,albic,and black soils.The effects of drought stress on the activities of key enzymes in carbon metabolism and photosynthetic characteristics of soybean were studied during the flowering stage,most sensitive to water.(1)The activities of SS-1,6PGDH,and G6PDH enzymes in soybean leaves first increased and then decreased under drought stress.The enzyme activity was the highest under moderate drought stress and weakest in the blank group.(2)Drought stress increased Phi2,PhiNO,and Fm in soybean leaves and reached the highest value under severe drought;with the increase in drought stress,PhiNPQ and Fv/Fm of soybean leaves gradually decreased,reaching the lowest under severe drought.(3)With the increase in drought stress,F0 and Fs of soybean leaves showed a single peak curve,and the maximum was at moderate drought.(4)Correlation analysis showed that F0 was greatly affected by varieties and soil types;Fs,F0,and Fm soil varieties had a great influence,and chlorophyll fluorescence parameters were affected differently under drought stress with different drought degrees.(5)Drought stress changed the agronomic traits and yield of soybean.With the increase of drought degree,plant height,node number of main stem,effective pod number,100-seed weight and total yield decreased continuously.(6)Drought stress affected the dry matter accumulation of soybean.With the increase of drought degree,the dry matter accumulation gradually decreased.Among them,the leaf was most seriously affected by drought,and SD decreased by about 55%compared with CK.Under the condition of black soil,the dry matter accumulation of soybean was least affected by drought.
基金Supported by the Earmarked Fund for CARS(CARS-04)Key R&D Plan of Jining CityYouth Fund of Jining Academy of Agricultural Sciences.
文摘With 10 elite soybean varieties from Huang-Huai-Hai Valleys as materials,25 hybridization combinations were compounded based on NC II,and the heterosis and combining ability for the major agronomic characters in summer soybean was studied.The results showed that heterosis of agronomic traits of soybean was ubiquity,and the average heterosis of all characters showed positive advantages.The advantage of seed weight per plant,number of seeds per plant and number of pods per plant were the highest,at 35.58%,34.23%and 31.47%,respectively,and thus made a great contribution to yield heterosis.The general combining ability of Hedou 19,Handou 6,Shanning 14 and Williams 82 was relatively higher in seed weight per plant,number of seeds per plant and number of pods per plant,and they are quality parents for designing strong hybridization combinations.There were significant differences in special combining ability(SCA)among parents for the same trait in different combinations.Some showed positive effect,and others showed negative effects.We should select the best combination according to breeding objective in selecting and matching special elite combinations.
基金Supported by National Soybean Industrial Technology Support Program(nycytx-004)National Scientific and Technological Innovation ProgramIndigenuous Innovative Program of Henan Academy of Agricultural Science~~
文摘To elucidate the genetic relationship of the soybean varieties registered in Henan province, we analyzed the pedigrees, the major agronomic traits, and the eco- nomic traits of 74 soybean varieties registered in Henan province from 1985 to 2012, with reference to experience and technologies beneficial to breeding. The resuits indicated that these varieties originated from 113 parents, and positive correla- tion between the yield and the number of original parents was significant. In the major agronomic traits, the growth stage was about 106 days with relatively small variation, while the final height varied largely among these varieties. Among the fac- tore affecting the final yield, the pod number per plant exhibited an increasing trend, while the variation of 100-grain weight was relatively small. More than 50% of the 113 original parents came from Henan Province and its neighbor provinces, and the genetic relationship among the registered varieties was too close. The rational criteria of yield components of soybean varieties in Henan Province should be as fol- lows: the pod number per plant was about 48. 6, with 100-grain weight ranging from 17.55 g to 21.80 g.
文摘The transplanting period, density, the number of left leaves and fertilizer amounts of HQ No.1 were explored in Hengyang. The results showed that with transplanting periods of March 5-March 15, and planting space of 120 cmx(50-60) cm, agronomic and economic characters of tobaccos showed insignificant differences. Specifically, plant height was growing upon the number of left leaf and fertilizer amount; tobacco yield and output value kept increasing upon fertilizer, and both reached maximums with pure N at 195 kg/hm^2, showing significant differences with the treatment of pure N at 135 kg/hm^2; the number of left leaf had the least effects on agronomic and economic characters of tobaccos. The research indicated that highly-qualified HQ No.1 can be produced, given that tobaccos are transplanted during March 10-March 15, planting density of 15 000-16 500 seedlings/hm^2, the number of left leaves of 22-24 leaves per seedling, and pure N of 150-165 kg/hm^2 in Hengyang.
基金Supported by the Science and Technology Project of China Tobacco Corporation(2003YJ007)~~
文摘[Objective] This study was conducted to provide theoretic support for improving yield and quality of flue-cured tobacco by applying microbial organic fertilizers. [Method] A field plot experiment was conducted to study the effects of the Engran series of microbial organic fertilizers on growth and development, diseases and pests and economic traits of flue-cured tobacco. [Result] The result showed that the treatment of conventional fertilization + Engran microbial agent could promote the growth and dry matter accumulation of flue-cured tobacco during the growth period in the field, enhance the disease resistance of tobacco, and improve yield and output value of flue-cured tobacco and income of tobacco growers. Compared with T1,the proportion of high-grade tobacco, the proportion of mid-high grade tobacco,yield, output value and average price increased by 4.4%, 3.8%, 5.48%, 11.51% and5.73% respectively. [Conclusion] The treatment of conventional fertilization + Engran microbial agent showed outstanding performance, is optimum for field production,and could be applied to Flue-cured tobacco.
基金Supported by the Project of Luzhou Company of Sichuan Provincial Tobacco Company"Comprehensive Application of Distillers'Grains on Tobacco"
文摘Pot experiments were conducted to study the effects of different organic fertilizers made from distiller's grains on the physiological characteristics and growth of flue-cured tobacco. The results showed that the agronomic traits and biomass of flue-cured tobacco in the three treatments were higher than that of the control group,and the mixed application of different organic fertilizers made from distiller's grains and compound fertilizer could promote the growth and development of flue-cured tobacco significantly.
文摘In order to explore the optimal phosphorus application rate of tobacco in Yongzhou area and provide scientific basis for the rational application of phosphorus fertilizer in tobacco production,field plot experiments with 4 phosphorus application rates were conducted to study the effects of different phosphorus application rate on the growth period,agronomic characters and economic characters of tobacco.The results showed that when the nitrogen fertilizer,phosphorus fertilizer and potassium fertilizer was 135,135 and 418.5 kg/hm2,respectively,namely the ratio of 1∶1∶3.1,the field growth period was the shortest,only 107 d;the agronomic characters and physical indexes showed good results in their performance;the ratio of superior tobacco leaves,average price and output value were 49.36%、26.04 yuan/kg and 56064.12 yuan/hm2 respectively,significantly higher than that of other treatments.Therefore,the suitable phosphorus application in Yongzhou tobacco area was 135 kg/hm2.In conclusion,rational phosphorus application rate was conducive to accelerating the growth and development of tobacco plant and early harvest;it could also effectively increase the output value and yield of tobacco leaves and was more conducive to the formation of high-quality tobacco leaves.
基金Supported by a grant from Yunnan Tobacco Company of China Tobacco Corporation(2010YN02)~~
文摘[Objective] This study aimed to characterize 124 flue-cured tobacco germplasm resources, and to provide reference for making the best use of the existing flue-cured tobacco germplasm resources. [Method] A total of 124 flue-cured tobacco germplasm resources were studied via field experiment and statistic analysis to investigate characteristics of their growth period, morphologic characters, main agronomic traits, and economic characters. [Result] There were significant differences among the 124 flue-cured tobacco germplasm resources in growth period, morphologic characters, main agronomic traits, and economic characters. The coefficients of variation (CV) varied in a range of 7.9%-22.5%. Among them, CV of bud stage was higher, and that of corolla length was lower. Many germplasm resources were attacked seriously by black shank disease at the end of field experiment, including those with disease index higher than 90, like Kutsaga 110, TI706, Ky 151, KM10, Longshe, Chaoxian Kangchi, Kutsaga 51E, Yongding No.1, and those with disease index among 75-90 such as Liaoyan No. 8, Lingnong No.2, Shandong Duoye, 581, Cunjingyan, KRK26, and Special 400. The tobacco root knot nematode invasion was light in some germplasm or never happened in other germplasm resources. TMV happened sporadically. CV 87, Yunyan 99, Yunyan 85, K326, Yunyan 87, Zhubuo No.1, T64 and T66 produced higher yield, production value, proportion of good leaves and sold at a higher price. Finally, we screened out the germpalsm resources with good comprehensive economic values and high disease resistance such as CV 87, Yunyan 99, Yunyan 85, K326, Yunyan 87, Zhubuo No.1, T64, T66, Honghuadajinyan, G-28, Taiyan No. 8, 77089-12, Yunyan 97, K346, V2, K149, NC567, NC297, Yunyan 201, Yunyan 203, KRK22. [Conclusion] This study provides reference for making better use of tobacco germplasm resources, and breeding new varieties.
文摘[Objective]The paper was to study the effects of plant extract mixture on growth and development,photosynthetic indexes and disease control of flue-cured tobacco.[Method]Using field test method,a total of five treatments were designed in the test,including T1(control,conven-tional pesticide control),T2(conventional pesticide control+spraying plant extract mixture at 15 and 30 d post transplanting),T3(conventional pesticide control+spraying plant extract mixture at 15,30 and 45 d post transplanting),T4(conventional pesticide control+spraying plant extract mixture at 15,30,45 and 60 d post transplanting),and T5(conventional pesticide control+spraying plant extract mixture at 15,30,45,60 and 75 d post transplanting).In addition,flue-cured tobacco in treatments T2-T5 were sprayed with antiviral agent once at 30 d post transplanting,and sprayed with quality promoting agent at 30 and 75 d post transplanting,respectively.[Result]The agronomic traits and photosynthetic indexes of all treatments were improved by spraying plant extract mixture,and those in T5 treatment were the best.Spraying plant extract mixture had significant control effect on brown spot;the disease index in T5 treatment was the lowest,and the control effect was the best.The results showed that spraying plant extract mixture promoted the growth and development of flue-cured tobacco,reduced the disease index of brown spot,and improved the quality of tobacco leaves.[Conclusion]Spraying plant extract mixture has positive effect on growth and development and disease control of flue-cured tobacco.