This present study identifies endophytic bacteria from Linum usitatissimum with multidimensional plant growth-promoting attributes,positioning them as ecological engineers for sustainable agriculture.Plant growthpromo...This present study identifies endophytic bacteria from Linum usitatissimum with multidimensional plant growth-promoting attributes,positioning them as ecological engineers for sustainable agriculture.Plant growthpromoting bacteria(PGPB)are present in symbiotic associations with plants or rhizosphere.These microbes enhance crop productivity and resilience under different environmental conditions.Endophytes are a type of PGPB that inhabit inside plant tissues and contribute to plant growth by phytohormone production,phosphate solubilisation,zinc solubilisation,siderophore production,ammonia production,nitrogen fixation,stress tolerance,and biocontrol mechanisms.Twelve bacterial strains were isolated from Linum usitatissimum exhibiting plant growth-promoting attributes such as ammonia and indole-3-acetic acid(IAA)production,siderophore synthesis,phosphate solubilisation,and extracellular enzyme synthesis.The isolated endophytes were also assessed for different enzymatic activities such as;cellulase,pectinase,xylanase,amylase,and gelatinase,which contribute to development of a symbiotic relationship and are crucial for the degradation of plant cell wall components The most efficient endophytes identified in the present study were Pseudomonas sp.strain JL-1(ESL1)and Staphylococcus sciuri(ESL2),both of which displayed strong plant growth-promoting potential.ESL1 and ESL2 demonstrated promising plant growth-promoting characteristics and cellulase,pectinase,xylanase,amylase,and gelatinase,activity.ESL2(Staphylococcus sciuri)enhanced nutrient cycling(phosphate solubilisation:196-209μg/ml;siderophores:68-71%)and stress tolerance(IAA:11-12μg/ml),reducing reliance on synthetic inputs.By integrating flax microbiomes into agro-ecosystems,we demonstrate a scalable approach to reconcile crop productivity with soil biodiversity conservation.These results demonstrate the potentiality of these endophytic microbes in sustainable agriculture,environmental management,and microbial biotechnology.Further studies on their metabolic pathways may expand their applications in bioremediation and plant-microbe interactions.展开更多
Flax(Linum usitatissimum L.)is a versatile crop and its seeds are a major source of unsaturated fatty acids.Stearoyl-acyl carrier protein desaturase(SAD)is a dehydrogenase enzyme that plays a key role in oleic acid bi...Flax(Linum usitatissimum L.)is a versatile crop and its seeds are a major source of unsaturated fatty acids.Stearoyl-acyl carrier protein desaturase(SAD)is a dehydrogenase enzyme that plays a key role in oleic acid biosynthesis as well as responses to biotic and abiotic stresses.However,the function of SAD orthologs from L.usitatissimum has not been assessed.Here,we found that two LuSAD genes,LuSAD1 and LuSAD2,are present in the genome of L.usitatissimum cultivar‘Longya 10’.Heterogeneous expression of either LuSAD1 or LuSAD2 in Arabidopsis thaliana resulted in higher contents of total fatty acids and oleic acid in the seeds.Interestingly,ectopic expression of LuSAD2 in A.thaliana caused altered plant architecture.Similarly,the overexpression of either LuSAD1 or LuSAD2 in Brassica napus also resulted in increased contents of total fatty acids and oleic acid in the seeds.Furthermore,we demonstrated that either LuSAD1 or LuSAD2 enhances seedling resistance to cold and drought stresses by improving antioxidant enzyme activity and nonenzymatic antioxidant levels,as well as reducing membrane damage.These findings not only broaden our knowledge of the LuSAD functions in plants,but also offer promising targets for improving the quantity and quality of oil,and the abiotic stress tolerance of oil-producing crops,through molecular manipulation.展开更多
Objective:The aim of this study was to evaluate the anlilungal activity of the major fraction of fatty acids methyl esters(FAMEs)isolated from Linum usitatissimum L.seeds oil collected from Bechar department(Algeria)....Objective:The aim of this study was to evaluate the anlilungal activity of the major fraction of fatty acids methyl esters(FAMEs)isolated from Linum usitatissimum L.seeds oil collected from Bechar department(Algeria).Methods:The assessment ol antifungal activity was carried out in terms of percentage of radial growth on solid medium potatoes dextrose agar PDA)and biomass growth inhibition on liquid medium(potatoes dextrose broth PDB)against two fungi.Results:The FAMEs was found to be effective in inhibiting the radial mycelial growth of Aspergillus fluctis more than Aspergillus ochraceus on all tested concentrations.The highest antifungal index was found to be(54.19%]compared to Aspergillus ochraeeus(40.48%).The results of the antifungal activity of the FAMEs inhibition of bioniass on liquid medium gave no discounted results,but this does not exclude the antifungal activity.Conclusions:We can assume that the observed antifungal potency may be due to the abundance of linoleic andα-linolenic acids in linseed oil which appears to be promising to treat fungal infections,storage fungi and food spoilage in food industry field.展开更多
Green macroalgae Chaetomorpha aerea and C. linum are taxonomically confused. In this paper, we tried morphological and molecular analyses to separate these two species. C. aerea and C. linum can be distinguished from ...Green macroalgae Chaetomorpha aerea and C. linum are taxonomically confused. In this paper, we tried morphological and molecular analyses to separate these two species. C. aerea and C. linum can be distinguished from morphological characteritics, such as frond dimension, cells size and shape, their mean length/width ratios（LWR）, and cell walls constriction. Thalli of C. aerea attenuate basipetally, with diameter 270–500 μm at upper portion, 160–360 μm at middle portion, 100–160 μm at basal portion. For the upper part, the length of cells is less than their diameter. Cell walls usually constrict at the dissepiments, which are pellucid or colorless and give the filament beaded appearance. In contrast, thalli of C. linum often have a constant diameter of 90–300 μm within the same individual, cell walls usually do not constrict and cells are cylindrical or barrel shaped. The LWR is larger than that of C. aerea. Results show that the pairwise distance between two species is 3.6%–3.7% for 18 S r RNA gene and 53.5%–54.3% for ITS region. In phylogeny, they distribute at distant clades, which confirms a genetic divergence at molecular level. In addition, morphological data indicates that filament diameter of C. linum samples is highly variable, ranging from 90 μm to 300 μm. Then these two species can be considered as separate species.展开更多
Oilseed flax(Linum usitatissimum L.)is one of the most important oil crops in alpine regions of North and Northwest China,which is an annual herb and belongs to Linaceae family and Linum genus.According to the applica...Oilseed flax(Linum usitatissimum L.)is one of the most important oil crops in alpine regions of North and Northwest China,which is an annual herb and belongs to Linaceae family and Linum genus.According to the application,Linum is often divided into three types,production oil,extraction fiber and both for production oil and extraction fiber.Oilseed flax is native to Near East and Mediterranean coasts.It is widely distributed throughout the world,with the largest cultivated area in Asia and Europe,followed by the Americas.Canada is the largest area for planting oilseed flax and China is second.In China.展开更多
Seeds of flax or linseed(Linum usitatissimum L.)are important nutraceutical foods with antioxidant,anti-inflammatory,estrogenic,laxative,and antibacterial properties.Flaxseed oil and seeds are the richest vegetarian s...Seeds of flax or linseed(Linum usitatissimum L.)are important nutraceutical foods with antioxidant,anti-inflammatory,estrogenic,laxative,and antibacterial properties.Flaxseed oil and seeds are the richest vegetarian source of omega-3 fatty acids.Consumption of flaxseeds helps in prevention and control of cardiovascular disease,neurodegenerative disorders,obesity,diabetes mellitus,polycystic ovary syndrome,gout,liver and kidney dysfunction,oxidative stress-related diseases,post-menopausal symptoms,osteoporosis,irritable bowel syndrome,dry eye disease,cystic fibrosis,diarrhea,and cancer,particularly of the mammary and prostate gland cancer.Of late,flaxseed is gaining more importance not only because of its industrial values but also due to its nutraceutical and pharmaceutical properties.The literature review was performed using PubMed,Scopus,PubMed Central,Google Scholar,and Web of Science from 1995 onwards.Data was also obtained from websites/books/book chapters.展开更多
To assess the performance and the variability of 49 flax varieties based on agronomic parameters using cluster analysis, a field experiment was conducted in 2011/2012 and 2012/2013 winter seasons at the farm of the Na...To assess the performance and the variability of 49 flax varieties based on agronomic parameters using cluster analysis, a field experiment was conducted in 2011/2012 and 2012/2013 winter seasons at the farm of the National Research Center at Nubria district, Albehira Governorate, Egypt. The results revealed high significant difference among all flax varieties in all the studied characters. Letwania-9 and Evelen cultivars surpassed all other varieties in seed and oil yields/fed. On the other hand, D variety gave the lowest value of seed yield/fed and F variety gave the lowest values of oil% and oil yield/fed. While, G Variety surpassed all other varieties in straw yield/fed. Blanka variety recorded the lowest values of straw yield/fed and biological yield/fed, while, Posna variety gave the lowest values of technical stem length (cm). In cluster analysis, all the studied characters were used to construct a distance matrix using the Euclidian coefficient, and generate dendrogram showing dissimilarity among all the varieties. Distance coefficient was ranged from 1.2 between Piltstar and Litwania-1 varieties and 10.8 between Posna and G varieties, which reveal the genetic diversity among varieties. The varieties can be divided into 4 groups based on cluster analysis.展开更多
为明确砜吡草唑在亚麻田应用的可行性,采用土壤喷雾法,于2023年分别通过室内生物试验(剂量设置为15、30、45、60、75 g a.i./hm^(2))和田间试验(剂量设置为15、45、75 g a.i./hm^(2))测定砜吡草唑对亚麻的安全性和对亚麻田杂草的防控效...为明确砜吡草唑在亚麻田应用的可行性,采用土壤喷雾法,于2023年分别通过室内生物试验(剂量设置为15、30、45、60、75 g a.i./hm^(2))和田间试验(剂量设置为15、45、75 g a.i./hm^(2))测定砜吡草唑对亚麻的安全性和对亚麻田杂草的防控效果。室内生物试验结果表明,砜吡草唑不会影响亚麻出苗,且对幼苗无明显药害;砜吡草唑对稗的毒力较高,GR_(50)、GR_(90)分别为20.51、83.52 g a.i./hm^(2),对反枝苋的GR_(50)、GR_(90)分别为27.05、243.37 g a.i./hm^(2);对亚麻生长抑制10%的量(GR 10)为132.96 g a.i./hm^(2);砜吡草唑对稗、反枝苋的选择性指数分别为1.59、0.55,表明该药剂在防控稗时的安全性比反枝苋高,但对亚麻幼苗存在一定的药害风险。田间试验结果显示,砜吡草唑用量为15~75 g a.i./hm^(2)时,对伊犁、哈尔滨2地亚麻苗无药害;用量为75 g a.i./hm^(2)、药后30 d,对伊犁亚麻田杂草的鲜重防效为85.60%,极显著高于对照药剂精异丙甲草胺(P<0.01);对哈尔滨亚麻田杂草的鲜重防效为76.82%,与对照药剂精异丙甲草胺相当。综合来看,由于实验室环境的局限性,不能完全模拟田间环境,导致室内试验结果与田间试验结果出现偏差,但是田间试验结果良好。因此,如果在田间生产中无其他药可用而不得不使用砜吡草唑时,应遵循用药规范,谨慎使用。展开更多
The extreme climate of the Canadian Prairies poses a major chal enge to improve yield. Although it is possible to breed for yield per se, focusing on yield-related traits could be advantageous because of their simpler...The extreme climate of the Canadian Prairies poses a major chal enge to improve yield. Although it is possible to breed for yield per se, focusing on yield-related traits could be advantageous because of their simpler genetic architecture. The Canadian flax core col ection of 390 accessions was genotyped with 464 simple sequence repeat markers, and phenotypic data for nine agronomic traits including yield, bol s per area, 1,000 seed weight, seeds per bol , start of flowering, end of flowering, plant height, plant branching, and lodging col ected from up to eight environments was used for association mapping. Based on a mixed model （principal component analysis （PCA） t kinship matrix （K））, 12 significant marker-trait associations for six agronomic traits were identi-fied. Most of the associations were stable across environments as revealed by multivariate analyses. Statistical simulation for five markers associated with 1000 seed weight indicated that the favorable al eles have additive effects. None of the modern cultivars carried the five favorable al eles and the maximum number of four observed in any accessions was mostly in＆amp;nbsp;breeding lines. Our results confirmed the complex genetic architecture of yield-related traits and the inherent difficulties associated with their identification while il ustrating the potential for improvement through marker-assisted selection.展开更多
Aims Floral traits in animal-pollinated plants are proposed to be selected by the behavior of pollinators,which create differential fitness.However,fitness estimation is not trivial and there is no agreed or universal...Aims Floral traits in animal-pollinated plants are proposed to be selected by the behavior of pollinators,which create differential fitness.However,fitness estimation is not trivial and there is no agreed or universal measure of fitness.in plants,fitness can be measured in various ways,including the number of fruits or seeds,probability of survival,or growth rate.Methods Because each fitness measure can be associated with different pol-linator behavior,estimating pollinator-mediated selection on floral traits can differ among various fitness measures.We used the annual Mediterranean plant,Linum pubescens,as a model to assess the relative role of various fitness measures in estimating pollinator-mediated selection on floral traits.We compared four maternal fit-ness measures and estimated their relative advantage in assessing natural selection on floral traits of L.pubescens.To identify whether each trait is under pollinator-mediated selection,we used media-tional analysis.Important Findings We found that each floral trait was under natural selection assessed by a different fitness measure.The color combination of floral tube throat and stamen color was under selection when using seed mass as a fitness measure,and floral diameter was under positive direc-tional selection when the number of seeds or number of fruits was used as a fitness measure.Selection on floral color was not mediated by pollinators’visitation rates,while flower diameter showed par-tial pollinator-mediated selection.We conclude that using several fitness measures gives an insight into the mechanisms underlying phenotypic selection on a floral trait,and facilitates the understand-ing of pollinator-mediated selection.展开更多
文摘This present study identifies endophytic bacteria from Linum usitatissimum with multidimensional plant growth-promoting attributes,positioning them as ecological engineers for sustainable agriculture.Plant growthpromoting bacteria(PGPB)are present in symbiotic associations with plants or rhizosphere.These microbes enhance crop productivity and resilience under different environmental conditions.Endophytes are a type of PGPB that inhabit inside plant tissues and contribute to plant growth by phytohormone production,phosphate solubilisation,zinc solubilisation,siderophore production,ammonia production,nitrogen fixation,stress tolerance,and biocontrol mechanisms.Twelve bacterial strains were isolated from Linum usitatissimum exhibiting plant growth-promoting attributes such as ammonia and indole-3-acetic acid(IAA)production,siderophore synthesis,phosphate solubilisation,and extracellular enzyme synthesis.The isolated endophytes were also assessed for different enzymatic activities such as;cellulase,pectinase,xylanase,amylase,and gelatinase,which contribute to development of a symbiotic relationship and are crucial for the degradation of plant cell wall components The most efficient endophytes identified in the present study were Pseudomonas sp.strain JL-1(ESL1)and Staphylococcus sciuri(ESL2),both of which displayed strong plant growth-promoting potential.ESL1 and ESL2 demonstrated promising plant growth-promoting characteristics and cellulase,pectinase,xylanase,amylase,and gelatinase,activity.ESL2(Staphylococcus sciuri)enhanced nutrient cycling(phosphate solubilisation:196-209μg/ml;siderophores:68-71%)and stress tolerance(IAA:11-12μg/ml),reducing reliance on synthetic inputs.By integrating flax microbiomes into agro-ecosystems,we demonstrate a scalable approach to reconcile crop productivity with soil biodiversity conservation.These results demonstrate the potentiality of these endophytic microbes in sustainable agriculture,environmental management,and microbial biotechnology.Further studies on their metabolic pathways may expand their applications in bioremediation and plant-microbe interactions.
基金supported by the National Science and Technology Innovation 2030 of China(2022ZD04010)the National Key Research and Development Program of China(2022YFD1200400)+2 种基金the Key Research and Development Program of Shaanxi Province,China(2022NY-158)the Ph D Start-up Fund of Northwest A&F University,China(Z1090121052)a grant from the Yang Ling Seed Industry Innovation Center,China(K3031122024).
文摘Flax(Linum usitatissimum L.)is a versatile crop and its seeds are a major source of unsaturated fatty acids.Stearoyl-acyl carrier protein desaturase(SAD)is a dehydrogenase enzyme that plays a key role in oleic acid biosynthesis as well as responses to biotic and abiotic stresses.However,the function of SAD orthologs from L.usitatissimum has not been assessed.Here,we found that two LuSAD genes,LuSAD1 and LuSAD2,are present in the genome of L.usitatissimum cultivar‘Longya 10’.Heterogeneous expression of either LuSAD1 or LuSAD2 in Arabidopsis thaliana resulted in higher contents of total fatty acids and oleic acid in the seeds.Interestingly,ectopic expression of LuSAD2 in A.thaliana caused altered plant architecture.Similarly,the overexpression of either LuSAD1 or LuSAD2 in Brassica napus also resulted in increased contents of total fatty acids and oleic acid in the seeds.Furthermore,we demonstrated that either LuSAD1 or LuSAD2 enhances seedling resistance to cold and drought stresses by improving antioxidant enzyme activity and nonenzymatic antioxidant levels,as well as reducing membrane damage.These findings not only broaden our knowledge of the LuSAD functions in plants,but also offer promising targets for improving the quantity and quality of oil,and the abiotic stress tolerance of oil-producing crops,through molecular manipulation.
基金Supported from the Algerian Ministry of the higher education and scientific research,PRU project approved in 2011/2013 under the code F03820100015
文摘Objective:The aim of this study was to evaluate the anlilungal activity of the major fraction of fatty acids methyl esters(FAMEs)isolated from Linum usitatissimum L.seeds oil collected from Bechar department(Algeria).Methods:The assessment ol antifungal activity was carried out in terms of percentage of radial growth on solid medium potatoes dextrose agar PDA)and biomass growth inhibition on liquid medium(potatoes dextrose broth PDB)against two fungi.Results:The FAMEs was found to be effective in inhibiting the radial mycelial growth of Aspergillus fluctis more than Aspergillus ochraceus on all tested concentrations.The highest antifungal index was found to be(54.19%]compared to Aspergillus ochraeeus(40.48%).The results of the antifungal activity of the FAMEs inhibition of bioniass on liquid medium gave no discounted results,but this does not exclude the antifungal activity.Conclusions:We can assume that the observed antifungal potency may be due to the abundance of linoleic andα-linolenic acids in linseed oil which appears to be promising to treat fungal infections,storage fungi and food spoilage in food industry field.
基金The National Key Technology R&D Program of China under contract No.2012BAC07B05the National Natural Science Foundation of China under contract Nos 31400186,31270257 and 31093440+1 种基金the Science and Technology Plan Project of Guangdong Province under contract No.2012A020200007the Science and Technology Plan Project of Shantou City,China under contract No.2012–171
文摘Green macroalgae Chaetomorpha aerea and C. linum are taxonomically confused. In this paper, we tried morphological and molecular analyses to separate these two species. C. aerea and C. linum can be distinguished from morphological characteritics, such as frond dimension, cells size and shape, their mean length/width ratios（LWR）, and cell walls constriction. Thalli of C. aerea attenuate basipetally, with diameter 270–500 μm at upper portion, 160–360 μm at middle portion, 100–160 μm at basal portion. For the upper part, the length of cells is less than their diameter. Cell walls usually constrict at the dissepiments, which are pellucid or colorless and give the filament beaded appearance. In contrast, thalli of C. linum often have a constant diameter of 90–300 μm within the same individual, cell walls usually do not constrict and cells are cylindrical or barrel shaped. The LWR is larger than that of C. aerea. Results show that the pairwise distance between two species is 3.6%–3.7% for 18 S r RNA gene and 53.5%–54.3% for ITS region. In phylogeny, they distribute at distant clades, which confirms a genetic divergence at molecular level. In addition, morphological data indicates that filament diameter of C. linum samples is highly variable, ranging from 90 μm to 300 μm. Then these two species can be considered as separate species.
基金financial support provided by the National Natural Science Programs of China(31360315,31760363)the China Agriculture Research System of Construct Special(CARS-14-1-16)the Fuxi Outstanding Talent Cultivation Plan of Gansu Agricultural University(Gaufx-02J05)。
文摘Oilseed flax(Linum usitatissimum L.)is one of the most important oil crops in alpine regions of North and Northwest China,which is an annual herb and belongs to Linaceae family and Linum genus.According to the application,Linum is often divided into three types,production oil,extraction fiber and both for production oil and extraction fiber.Oilseed flax is native to Near East and Mediterranean coasts.It is widely distributed throughout the world,with the largest cultivated area in Asia and Europe,followed by the Americas.Canada is the largest area for planting oilseed flax and China is second.In China.
文摘Seeds of flax or linseed(Linum usitatissimum L.)are important nutraceutical foods with antioxidant,anti-inflammatory,estrogenic,laxative,and antibacterial properties.Flaxseed oil and seeds are the richest vegetarian source of omega-3 fatty acids.Consumption of flaxseeds helps in prevention and control of cardiovascular disease,neurodegenerative disorders,obesity,diabetes mellitus,polycystic ovary syndrome,gout,liver and kidney dysfunction,oxidative stress-related diseases,post-menopausal symptoms,osteoporosis,irritable bowel syndrome,dry eye disease,cystic fibrosis,diarrhea,and cancer,particularly of the mammary and prostate gland cancer.Of late,flaxseed is gaining more importance not only because of its industrial values but also due to its nutraceutical and pharmaceutical properties.The literature review was performed using PubMed,Scopus,PubMed Central,Google Scholar,and Web of Science from 1995 onwards.Data was also obtained from websites/books/book chapters.
文摘To assess the performance and the variability of 49 flax varieties based on agronomic parameters using cluster analysis, a field experiment was conducted in 2011/2012 and 2012/2013 winter seasons at the farm of the National Research Center at Nubria district, Albehira Governorate, Egypt. The results revealed high significant difference among all flax varieties in all the studied characters. Letwania-9 and Evelen cultivars surpassed all other varieties in seed and oil yields/fed. On the other hand, D variety gave the lowest value of seed yield/fed and F variety gave the lowest values of oil% and oil yield/fed. While, G Variety surpassed all other varieties in straw yield/fed. Blanka variety recorded the lowest values of straw yield/fed and biological yield/fed, while, Posna variety gave the lowest values of technical stem length (cm). In cluster analysis, all the studied characters were used to construct a distance matrix using the Euclidian coefficient, and generate dendrogram showing dissimilarity among all the varieties. Distance coefficient was ranged from 1.2 between Piltstar and Litwania-1 varieties and 10.8 between Posna and G varieties, which reveal the genetic diversity among varieties. The varieties can be divided into 4 groups based on cluster analysis.
文摘为明确砜吡草唑在亚麻田应用的可行性,采用土壤喷雾法,于2023年分别通过室内生物试验(剂量设置为15、30、45、60、75 g a.i./hm^(2))和田间试验(剂量设置为15、45、75 g a.i./hm^(2))测定砜吡草唑对亚麻的安全性和对亚麻田杂草的防控效果。室内生物试验结果表明,砜吡草唑不会影响亚麻出苗,且对幼苗无明显药害;砜吡草唑对稗的毒力较高,GR_(50)、GR_(90)分别为20.51、83.52 g a.i./hm^(2),对反枝苋的GR_(50)、GR_(90)分别为27.05、243.37 g a.i./hm^(2);对亚麻生长抑制10%的量(GR 10)为132.96 g a.i./hm^(2);砜吡草唑对稗、反枝苋的选择性指数分别为1.59、0.55,表明该药剂在防控稗时的安全性比反枝苋高,但对亚麻幼苗存在一定的药害风险。田间试验结果显示,砜吡草唑用量为15~75 g a.i./hm^(2)时,对伊犁、哈尔滨2地亚麻苗无药害;用量为75 g a.i./hm^(2)、药后30 d,对伊犁亚麻田杂草的鲜重防效为85.60%,极显著高于对照药剂精异丙甲草胺(P<0.01);对哈尔滨亚麻田杂草的鲜重防效为76.82%,与对照药剂精异丙甲草胺相当。综合来看,由于实验室环境的局限性,不能完全模拟田间环境,导致室内试验结果与田间试验结果出现偏差,但是田间试验结果良好。因此,如果在田间生产中无其他药可用而不得不使用砜吡草唑时,应遵循用药规范,谨慎使用。
基金conducted as part of the Total Utilization Flax Genomics (TUFGEN) project funded by Genome Canadaco-funded by the Government of Manitoba,the Flax Council of Canada,the Saskatchewan Flax Development Commission,Agricultural Development Fund and the Manitoba Flax Growers AssociationProject management and support by Genome Prairie are also gratefully acknowledged
文摘The extreme climate of the Canadian Prairies poses a major chal enge to improve yield. Although it is possible to breed for yield per se, focusing on yield-related traits could be advantageous because of their simpler genetic architecture. The Canadian flax core col ection of 390 accessions was genotyped with 464 simple sequence repeat markers, and phenotypic data for nine agronomic traits including yield, bol s per area, 1,000 seed weight, seeds per bol , start of flowering, end of flowering, plant height, plant branching, and lodging col ected from up to eight environments was used for association mapping. Based on a mixed model （principal component analysis （PCA） t kinship matrix （K））, 12 significant marker-trait associations for six agronomic traits were identi-fied. Most of the associations were stable across environments as revealed by multivariate analyses. Statistical simulation for five markers associated with 1000 seed weight indicated that the favorable al eles have additive effects. None of the modern cultivars carried the five favorable al eles and the maximum number of four observed in any accessions was mostly in＆amp;nbsp;breeding lines. Our results confirmed the complex genetic architecture of yield-related traits and the inherent difficulties associated with their identification while il ustrating the potential for improvement through marker-assisted selection.
文摘Aims Floral traits in animal-pollinated plants are proposed to be selected by the behavior of pollinators,which create differential fitness.However,fitness estimation is not trivial and there is no agreed or universal measure of fitness.in plants,fitness can be measured in various ways,including the number of fruits or seeds,probability of survival,or growth rate.Methods Because each fitness measure can be associated with different pol-linator behavior,estimating pollinator-mediated selection on floral traits can differ among various fitness measures.We used the annual Mediterranean plant,Linum pubescens,as a model to assess the relative role of various fitness measures in estimating pollinator-mediated selection on floral traits.We compared four maternal fit-ness measures and estimated their relative advantage in assessing natural selection on floral traits of L.pubescens.To identify whether each trait is under pollinator-mediated selection,we used media-tional analysis.Important Findings We found that each floral trait was under natural selection assessed by a different fitness measure.The color combination of floral tube throat and stamen color was under selection when using seed mass as a fitness measure,and floral diameter was under positive direc-tional selection when the number of seeds or number of fruits was used as a fitness measure.Selection on floral color was not mediated by pollinators’visitation rates,while flower diameter showed par-tial pollinator-mediated selection.We conclude that using several fitness measures gives an insight into the mechanisms underlying phenotypic selection on a floral trait,and facilitates the understand-ing of pollinator-mediated selection.
