Organic chemical priming is an effective strategy in mitigating salt stress to plants.The objective of this study was to determine effects and associated mechanisms of acetic acid regulating plant tolerance to salt st...Organic chemical priming is an effective strategy in mitigating salt stress to plants.The objective of this study was to determine effects and associated mechanisms of acetic acid regulating plant tolerance to salt stress.Perennial ryegrass plants were pre-treated with 20 mM acetic acid and subsequently subjected to salt stress for 28 days.Salt stress caused increased endogenous acetic acid content with up-regulated expression of its key biosynthetic gene LpPDC1.Application of acetic acid effectively alleviated salt caused damage in perennial ryegrass.Acetic acid treatment increased K^(+) content and suppressed Na^(+) accumulation to maintain a higher K^(+)/Na^(+) ratio in leaves exposed to salt stress.Plants O_(2)^(−) treated with acetic acid also had significantly lower levels of and H_(2)O_(2),but higher SOD and CAT activities than those of the control after 21 days of salt stress.Acetic acid treatment also altered the plants endogenous phytohormone content with higher content of jasmonate(including JA,JA-ILe,and cis-OPDA),auxin(IAA),and cytokinins(CK,such as tZ,cZR,and iP),but lower content of abscisic acid(ABA)under salt stress conditions.Furthermore,expression of genes involved in JA,IAA,and CK biosynthesis and signaling pathways were up-regulated,while those involved in ABA were down-regulated by acetic acid treatment under salt stress.The results demonstrate that acetic acid could mitigate salt stress in perennial ryegrass by regulating K^(+) and Na^(+) balance,promoting ROS scavenging,and activating stress-protection hormone synthesis and signaling.展开更多
High temperature is one of the major abiotic stresses limiting growth and development of cool-season grass species,but chitosan could effectively enhance heat tolerance and improve plant growth.The objective of this s...High temperature is one of the major abiotic stresses limiting growth and development of cool-season grass species,but chitosan could effectively enhance heat tolerance and improve plant growth.The objective of this study was to determine the optimal concentration of chitosan that could alleviate heat stress in creeping bentgrass(Agrostis stolonifera)and investigate the effects of exogenous chitosan on photosynthesis and cell membrane stability under heat stress.Under heat stress(38/28°C,day/night),different chitosan concentrations of 0,50,100 and 500 mg·L−1 were applied on the leaves of creeping bentgrass(cv.'Penn-A4').Foliar application of chitosan exhibited the positive effects on plant growth and the optimal concentration was 100 mg·L−1 which significantly improved turf quality,root length,root-shoot ratio as well as shoot and root biomass.Chitosan-treated plants subjected to high temperature stress had a lower decline in photosynthetic rate and photochemical efficiency as well as less increase in electrolyte leakage and malondialdehyde content.The results demonstrate that chitosan-improved heat tolerance as reflected by the superior growth performance of both shoot and root,photosynthesis and cell membrane stability in creeping bentgrass under heat stress.展开更多
Fungal Epichloëendophytes form symbiotic associations with many temperate grasses,such as Lolium and Festuca,giving their host grasses an ecological advantage.The importance of specific Epichloëendophytes in...Fungal Epichloëendophytes form symbiotic associations with many temperate grasses,such as Lolium and Festuca,giving their host grasses an ecological advantage.The importance of specific Epichloëendophytes in providing varying levels of protection against invertebrate pests has been well documented.Similarly,but with fewer studies,the benefits of Epichloëto host grasses in drought events has been shown.Endophyte-infected grasses show an improved persistence against herbivore insect attack as well as resilience under drought.However,there are relatively few studies that investigate the interaction between drought and insect pressure,and yet it is these combined pressures that can prove detrimental for a ryegrass or fescue crop.This review examines the current state of knowledge on the effects of Epichloëon the interactions of insects and drought in temperate grasses.展开更多
Turfgrasses are used extensively throughout the world,and there is a steadfast demand to develop turfgrass varieties with improved abiotic and biotic stress tolerances that will perform well with limited management in...Turfgrasses are used extensively throughout the world,and there is a steadfast demand to develop turfgrass varieties with improved abiotic and biotic stress tolerances that will perform well with limited management inputs.Modern breeding programs incorporate advanced breeding strategies such as DNA sequencing and high-throughput phenotyping with traditional breeding strategies to identify and select germplasm and genes of interest.Molecular biology methods and DNA sequencing technology have rapidly increased in recent years,and,as a result,plant phenotyping is currently a bottleneck in the process of advancing breeding programs.Recent advances in remote sensing technology have offered improved,non-destructive plant phenotyping approaches such as visible light imaging,spectral imaging,infrared thermal imaging,range sensing,and fluorescence imaging.Integrated mobile and time efficient platforms are being developed,coupling remote sensing with robotics and unmanned aerial systems technology for high-throughput plant phenotyping applications across large field spaces.Modern turfgrass breeding programs will continue to research,develop,and implement remote sensing technologies to assess larger numbers of genotypes and identify elite germplasm.All together,these efforts will improve cultivar development efficiency and aid plant breeders in developing improved turfgrass cultivars to meet current and future demands of the turfgrass industry.This review provides an overview of ground-and aerial-based plant phenotyping platforms,with particular emphasis placed on applications to turfgrass breeding practices.Similarly,imaging technologies that have been used in various plant breeding programs are discussed,with indications as to how those technologies could be applicable to turfgrass breeding programs.展开更多
Bermudagrass(Cynodon dactylon)shade tolerance is a trait of immense importance to the turfgrass industry.However,little is known about shade tolerance of turf-type bermudagrass native to China.Additional knowledge of ...Bermudagrass(Cynodon dactylon)shade tolerance is a trait of immense importance to the turfgrass industry.However,little is known about shade tolerance of turf-type bermudagrass native to China.Additional knowledge of the mechanism of shade tolerance in bermudagrass is required to identify specific plant features that promote shade tolerance and assist breeding efforts worldwide.This study examines shade tolerance of two different bermudagrass cultivars,Yangjiang(prostrate form)and Guanzhong(upright form),which were developed in China.Each cultivar was subjected to 0,30.4,61.2,and 90.6%shade levels during growth and assessed for turf quality,turfgrass color intensity,biomass allocation,growth rate,antioxidant enzyme activity,leaf anatomy,and photochemical properties.Results generally demonstrated that turf quality and turf color intensity were lower in Guanzhong compared with Yangjiang on the 90.6%shade testing days.Yangjiang exhibited a less severe reduction of growth rate,leaf thickness,root to shoot ratio,and chlorophyll a to chlorophyll b ratio(Chla/b)under 90.6%shade compared with Guanzhong.Both cultivars exhibited a decrease in photochemical efficiency as determined by reduced qP,ETR,and Fv/Fm values.Photochemical efficiency was impacted less in Yangjian,and superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT)enzymes activities were greater than in Guanzhong when exposed to severe shade.When exposed to 90.6%shade level,Yangjiang had better turf quality than Guanzhong as determined by morphological,anatomical,and physiological features.Breeding efforts focused on these shade tolerance features will lead to improved bermudagrass germplasm and aid turf management in shade environments.展开更多
Arbuscular mycorrhizal(AM)fungi contribute globally to ecosystem services and play an important role in sustainable crop production.However,it is unclear which factors contribute most to their colonization and communi...Arbuscular mycorrhizal(AM)fungi contribute globally to ecosystem services and play an important role in sustainable crop production.However,it is unclear which factors contribute most to their colonization and community structure at different sites,particularly in understudied ecosystems.This study investigated the AM fungal communities associated with switchgrass(Panicum virgatum L.)in the understudied acidic and oligotrophic pine barrens ecosystem using next-generation sequencing.Switchgrass was also sampled from agroecosystems,as well as,from a native prairie for comparison.The pine barrens switchgrass harbored a distinct AM fungal community−Acaulospora and Ambispora were almost exclusively found in the pine barrens sites,and some of these species may represent undescribed taxa.Glomus was the most ubiquitous AM fungal genus recovered from all sites.This study suggests differences in the AM fungal community structure under different soil properties and land uses.This is the first sequence-based report of the AM fungal communities in the pine barrens ecosystem.展开更多
The grass family(Poaceae and Gramineae)is comprised of over 11,500 species classified in 12 subfamilies,52 tribes,90 subtribes,and more than 768 genera,making this family the third most abundant flowering plant in num...The grass family(Poaceae and Gramineae)is comprised of over 11,500 species classified in 12 subfamilies,52 tribes,90 subtribes,and more than 768 genera,making this family the third most abundant flowering plant in number of genera[1].Grass species,besides cereal grasses as food crops,are economically,environmentally,ecologically,recreationally,and aesthetically important in a wide range of applications including,but not limited to,cultivated grasses for turfgrass,forage,pasture,ornamental landscape,biofuel feedstocks,and wild grasses in natural grassland,woodlands,and deserts.The non-food grass species touch everyone’s lives directly and indirectly by serving multiple functions and benefits to humankind and society,such as beautifying landscapes,protecting the environment,enhancing human physical health,improving human recreational activities,providing feed for livestock and wildlife,serving as an alternative source of energy for bioenergy feedstock,and providing a natural habitat for wildlife[2,3,4,5,6].展开更多
Plant growth promoting bacteria(PGPB)directly and indirectly influence the fitness of their host plants.While much of the work on plant growth promoting bacteria is from various plant rhizospheres,less is known about ...Plant growth promoting bacteria(PGPB)directly and indirectly influence the fitness of their host plants.While much of the work on plant growth promoting bacteria is from various plant rhizospheres,less is known about the strains that inhabit the internal spaces of plant tissues.Conversely,Clavicipitalean fungal endophytes of cool season grasses have been intensely investigated for the past few decades.Like plant growth promoting bacteria,the fungal endophytes also promote the health of their hosts.This paper highlights the current knowledge of plant growth promoting bacterial and fungal endophytes of tall fescue(Lolium arundinaceum=Schedonorus arundinaceaus=Festuca arundinacea)which protect the plant from both abiotic and biotic stresses.Much of the work presented indicates just how little is known about the inter-relationships between the multiple endophytic microbial colonizers of turf grasses.展开更多
1-deoxy-D-xylulose-5-phosphate synthase(DXS)catalyzes the first and rate-limiting step of the plastidic 2-C-methyl-D-derythritol-4-phosphate(MEP)pathway which regulates the synthesis of terpenoids,such as gibberellins...1-deoxy-D-xylulose-5-phosphate synthase(DXS)catalyzes the first and rate-limiting step of the plastidic 2-C-methyl-D-derythritol-4-phosphate(MEP)pathway which regulates the synthesis of terpenoids,such as gibberellins,abscisic acid,and chlorophyll.The objective of this study was to determine the functional role of PpDXS1 in plant growth and development in Kentucky bluegrass(Poa pratensis L.).The PpDXS1 gene has a 2139 bp open reading frame that encodes a polypeptide of 712 amino acids with a calculated molecular weight of 76.7 kDa.PpDXS1 gene expression was the highest in leaves.Moreover,the PpDXS1 promoter contained several hormone response elements and gene expression was induced by exogenous treatment with gibberellin,abscisic acid,jasmonate,and pathogen infection.Functional analysis indicated that underexpression of PpDXS1 gene in Poa pratensis decreased plant height and endogenous gibberellin and indole acetic acid production,but promoted abscisic acid accumulation.Furthermore,transcriptome analysis and qRT-PCR results showed that the expression levels of related genes involved in the phytohormone biosynthesis and signal transduction were differentially regulated by PpDXS1 in transgenic Poa pratensis.Overall,these results indicated that PpDXS1 has strong effects on plant height and accumulation of phytohormones,and provided a preliminary understanding of molecular characterization,expression and function of PpDXS1 in Poa pratensis.展开更多
Salinity and drought stress are major abiotic stresses negatively affecting the growth and productivity of alfalfa(Medicago sativa L.).Exploration of genes exhibiting superior tolerance to salinity and drought stress ...Salinity and drought stress are major abiotic stresses negatively affecting the growth and productivity of alfalfa(Medicago sativa L.).Exploration of genes exhibiting superior tolerance to salinity and drought stress in alfalfa will help aid target molecular breeding and developing tolerant forages.In this study,we adopted a high-efficient yeast FOX hunting system for the identification of salinity and drought tolerant genes in alfalfa.Based on the Gateway-compatible vector system,a high-quality expression library was constructed,containing 1.3×10^(7) clones with an average size of 1.44 kb.Through heterologous transformation of mixed library plasmid into salt or drought sensitive yeast mutants,monoclonal resistant strains were screened and tolerant genes were captured.Eighteen salinity-tolerance genes were obtained which were involved in several pathways,containing GRAS and zinc finger transcriptional factors,PP2A interaction module,ERVT vesicle transporter and LETM transmembrane protein.Twelve drought tolerance genes were separated,including ERF and SCL transcriptional factors,CIPK and BSK protein kinases,TGL-type ligase,cPGM and cPDL protease.The mRNA transcription levels of these tolerant genes were inducible or suppressible for response to salt or drought stress conditions following quantitative PCR detection,respectively.Furthermore,heterologous transformation of ERVT and CIPK11 can improve the salt and drought stress tolerance in Arabidopsis,which indicates the conservative function of the screening gene in yeast and Arabidopsis.Obtaining these candidate genes can provide new insights for future research with respect to plant salt and drought tolerance.展开更多
Dichondra(Dichondra repens)is an important ground cover plant and is also used as a herbal medicine in China.Objectives of this study were to evaluate phenotypic and genetic diversities among 33 genotypes by using 18 ...Dichondra(Dichondra repens)is an important ground cover plant and is also used as a herbal medicine in China.Objectives of this study were to evaluate phenotypic and genetic diversities among 33 genotypes by using 18 simple sequence repeat(SSR)markers and to further identify the drought tolerance of these germplasms based on five physiological parameters.Results showed that natural variations in phenotypes including plant height,leaf area,leaf thickness,and petiole length were observed among 33 genotypes under well-watered conditions.All 18 SSR primer pairs were found to be polymorphic and significant genetic variation was found in these genotypes.In addition,there were obvious differences in leaf relative water content(RWC),electrolyte leakage(EL),chlorophyll(Chl)content,photochemical efficiency(Fv/Fm),and performance index on absorption basis(PIABS)among 33 genotypes in response to a prolonged period of drought stress(46 d).Drought tolerance of 33 genotypes was then ranked by using subordinate function value analysis(SFVA)and the most drought-tolerant or-sensitive genotypes were identified as Dr5 or Dr29,respectively.Principal component analysis(PCA)further classified 33 genotypes into group I(drought-tolerant),group II(droughtsensitive),and group III(medium types).Current findings showed that 18 selected SSR primers could be potentially used to analyze genetic diversity and varietal identification in dichondra species.Drought-tolerant wild dichondra resources provide a rich genetic base for breeding of new cultivars.展开更多
The symbiotic relationship between Lolium perenne and Epichloëfestucae var.lolii,a fungal endophyte that lives asymptomatically in its above-ground parts,benefits both the host and fungus.In an outdoor container ...The symbiotic relationship between Lolium perenne and Epichloëfestucae var.lolii,a fungal endophyte that lives asymptomatically in its above-ground parts,benefits both the host and fungus.In an outdoor container experiment,the effects of three distinct endophyte haplotypes(AR1,AR37 and CT)on natural infestations of a root aphid,Aploneura lentisci and a mealybug Phenococcus graminicola were compared with an endophyte-free(Nil)control.Populations of these insects were suppressed in a genetically identical set of plants treated with insecticide.Over 18 months,foliar and root growth,tiller numbers and plant mortality were compared between the different endophyte treatments and between insecticide-treated and untreated plants.Hyphal densities were recorded once during the trial.Untreated plants infected with AR37 had the lowest populations of A.lentisci and P.graminicola,and the highest root and foliar growth compared with other treatments.Growth parameters of untreated plants infected with CT often exceeded that of AR1 and Nil due to low infestations of P.graminicola and lower populations of A.lentisci.Growth of Nil,AR1 and CT plants were higher in insecticide-treated than in corresponding untreated plants but was unaffected in AR37.Untreated Nil and AR1 plants had a lower survival than AR37 and CT plants.Cumulative root outgrowth for treated AR37 plants was significantly lower than for treated AR1 on three sampling occasions.These Epichloëhaplotypes are primarily mutualists,although there are circumstances when they may be disadvantageous to their host.Opposing outcomes likely originate in the ecosystems in which associations evolved.展开更多
Shade caused by trees or buildings can affect the quality and growth of turfgrasses.Thus,breeding for shade tolerance is an essential component of most turfgrass improvement programs.The objective of this study was to...Shade caused by trees or buildings can affect the quality and growth of turfgrasses.Thus,breeding for shade tolerance is an essential component of most turfgrass improvement programs.The objective of this study was to evaluate the performance of seashore paspalum(Paspalum vaginatum Sw.)breeding lines under shade in multi-environment trials.Germplasm sources were 20 lines from the University of Georgia seashore paspalum breeding program and two checks,the cultivars'SeaDwarf'and'SeaStar'.Field trials were conducted from 2016 to 2019 under shade structures designed to reduce ambient sunlight at three locations:Citra(FL),Tifton(GA),and Raleigh(NC).The response variables evaluated were percent living ground cover(%GC),dark green color index(DGCI),canopy height(CH)and turfgrass quality(TQ).Data were analyzed by mixed model approaches using ASReml-R,and the t-statistics were used to group the entries.Significant genetic variances were observed in the single-location-repeated-measures analysis for CH and DGCI at Citra and Tifton,%GC at Citra,and TQ at Raleigh.Spearman correlations of the predicted values for entries between locations ranged from low to moderate,with the exception of between Citra and Tifton(0.76)for CH.There were a few breeding lines with superior performance to the entry average for all traits for which the entry variance was significant.In conclusion,genetic variability was observed for all traits and superior seashore paspalum breeding lines for multiple traits were identified under shade.展开更多
γ-Aminobutyric acid(GABA)is known for its positive effects on improving plant stress tolerance,while the association of its role in regulating nutritional availability and GABA priming-enhanced heat tolerance is not ...γ-Aminobutyric acid(GABA)is known for its positive effects on improving plant stress tolerance,while the association of its role in regulating nutritional availability and GABA priming-enhanced heat tolerance is not well documented.The objective of this study was to determine whether GABA priming may improve heat tolerance in cool-season grass species involving regulation of plant nutrition for macronutrients and micronutrient elements.Plants of creeping bentgrass(Agrostis stolonifera)(cv.'Penncross')in each pot were treated with 10 mL of water(control)or 0.5 mM GABA(GABA priming)by foliar spray and then subjected to heat stress(35/30°C,day/night)or optimal growth temperature(control)(21/19°C,day/night)(non-stress control)for 30 d in growth chambers.GABA-primed plants had significantly higher endogenous GABA content associated with improved heat tolerance compared to non-treated plants,as reflected by higher leaf cell membrane stability,relative water content,osmotic adjustment,chlorophyll content,photochemical efficiency,and net photosynthetic rate.Plants pretreated with GABA exhibited significantly higher content of nitrogen(N),phosphorus(P),calcium(Ca),sodium(Na),and copper(Cu)but lower content of boron(B)and manganese(Mn)in leaves than non-treated plants under heat stress.The enhanced accumulation of N,P,Ca,Na,and Cu and restricted B and Mn accumulation by GABA priming indicate that GABA could modulate mineral nutrient availability in plants,contributing to improved heat tolerance for creeping bentgrass.展开更多
Plants naturally carry microbes on seeds and within seeds that may facilitate development and early survival of seedlings.Some crops have lost seed-vectored microbes in the process of domestication or during seed stor...Plants naturally carry microbes on seeds and within seeds that may facilitate development and early survival of seedlings.Some crops have lost seed-vectored microbes in the process of domestication or during seed storage and seed treatment.Biostimulant microbes from wild plants were used by pre-modern cultures to re-acquire beneficial seed microbes.Today some companies have developed or are developing the use of microbes obtained from soils or plant sources to stimulate plant development and growth.Many of these biostimulant microbes are endophytic in plants.Biostimulant products also include humic substances,which appear to function as signal molecules in plants,triggering increased internalization of soil microbes into root cells and tissues.In addition,protein coatings on seeds fuel the growth of seed surface-vectored microbes,increasing microbial activity around and within roots.In this article,we provide evidence of the endophytic nature of many biostimulant microbes,and suggest that many of the beneficial effects of microbial biostimulants stem from their action as endophytes or as participants or stimulants of rhizophagy cycle activity.展开更多
Leaf senescence is accelerated by prolonged exposure to high temperatures in cool-season plants and is characterized by loss of chlorophyll and adjustment in amino acid metabolism.The objectives of this study included...Leaf senescence is accelerated by prolonged exposure to high temperatures in cool-season plants and is characterized by loss of chlorophyll and adjustment in amino acid metabolism.The objectives of this study included ascertaining how glutamate may affect the tolerance of cool-season grass species to heat stress in relation to leaf senescence through the regulation of leaf chlorophyll(Chl)and amino acid metabolism.Creeping bentgrass(Agrostis stolonifera L.)plants were maintained for 35d under optimal growth temperature(22/18℃,day/night,non-stress control)or heat stress(35/30℃,day/night)in growth chambers,and glutamate(60 mM)or water(untreated control)was applied weekly as a foliar treatment.Under heat stress,turf quality(TQ),photochemical efficiency(Fv/Fm),and Chl content were significantly higher in plants treated with glutamate at 14-35 d,7-28 d,and 7-35 d,respectively,compared to untreated controls.Glutamate application significantly reduced the activities of chlorophyll-degrading peroxidase and chlorophyllase,two Chl-degrading enzymes,at 14,21,and 35 d of heat stress,whereas activity of the rate-limiting Chl synthesis enzyme,porphobilinogen deaminase,was not significantly affected.Glutamate treatment significantly increased the endogenous content of serine,threonine,lysine,aspartate,glutamate,and GABA under heat stress,while methionine,asparagine,isoleucine,and histidine were significantly up-regulated exclusively under heat stress.These findings suggest that glutamate could serve as a repressor for heat-accelerated leaf senescence by suppressing Chl degradation and activating amino acid metabolism involved in energy production,antioxidant defense,and nitrogen balance.展开更多
Bermudagrass[Cynodon dactylon var.dactylon(L.)Pers.]is a major warm-season turf and forage grass worldwide.Seed yield is an important trait targeted for improvement in bermudagrass breeding programs because of the inc...Bermudagrass[Cynodon dactylon var.dactylon(L.)Pers.]is a major warm-season turf and forage grass worldwide.Seed yield is an important trait targeted for improvement in bermudagrass breeding programs because of the increased interest in seed-propagated cultivars.Understanding the nature of genetic variation for seed yield and its components in bermudagrass would aid the development of seed-propagated cultivars.The objective of this study was to estimate the genetic variation and narrow-sense heritability for seed yield and its two major components,inflorescences prolificacy and seed set percentage in bermudagrass.Twenty-five half-sib families and their respective clonal parents were evaluated at two Oklahoma locations,Perkins and Stillwater(Oklahoma,USA),over two years.Half-sib families were different for seed yield,inflorescences prolificacy and seed set percentage,indicating the expression of additive genes in controlling these traits.Family×location effects were observed for seed set percentage and seed yield.All three traits showed family×year interaction effects.There was a significant family×location×year interaction in inflorescences prolificacy and seed set percentage.Narrow-sense heritability estimates for seed yield was 0.18 based on variance component analysis among half-sib families and ranged from 0.26 to 0.68 based on parent-offspring regressions,indicating genetic complexity of seed yield.Heritability estimates were moderate(0.30−0.55)for inflorescences prolificacy and moderate to relatively high(0.41−0.78)for seed set percentage.The results indicate that sufficient magnitudes of additive genetic variation for seed set percentage and inflorescence prolificacy permit positive response to selection and conventional progeny-based genotypic evaluation is necessary for seed yield improvement.Citation:Tan C,Wu Y,Taliaferro CM,Bell GE,Martin DL,et al.2022.Heritability estimates for seed yield and its components in Cynodon dactylon var.展开更多
Coastal saline soils are increasing year by year caused by climate change and human activities.Most of the coastal saline soils are idle due to their high salinity level and few crops can grow normally.Salinity tolera...Coastal saline soils are increasing year by year caused by climate change and human activities.Most of the coastal saline soils are idle due to their high salinity level and few crops can grow normally.Salinity tolerant legumes are naturally tolerant to salt,which can ecologically cover the coastal saline soil,enhance soil fertility by symbiotic nitrogen fixation and increase the smallholder farmers’benefits in terms of forage,green manure,food or medicine.However,few reports are available for the systematic evaluation of salinity tolerant legumes.This review summarizes and evaluates currently available salinity tolerant legume species that could potentially be used and discusses their potential for integration into smallholder mixed coastal systems of the Asia-Pacific region.Fourty four salinity tolerant legumes were summarized,six of them showed a high level of salinity tolerance,17 of them showed a moderate level of salinity tolerance and 21 of them showed potential salinity tolerance but need to be further studied.Many gaps such as combined tolerance evaluation,nitrogen fixation efficiency,animal feeding experiments and salinity tolerant rhizobia screening/inoculants exist.Case studies demonstrate legumes could be used to reclaim coastal saline soils,but commitment and support from government and public services are necessary to address both seed system and extension needs,through the provision of adequate incentives,policies and development efforts.展开更多
Switchgrass(Panicum virgatum L.)is a native and prominent perennial grass species used for feedstocks.High-throughput phenotyping of biomass component traits is desirable for switchgrass improvement and production.The...Switchgrass(Panicum virgatum L.)is a native and prominent perennial grass species used for feedstocks.High-throughput phenotyping of biomass component traits is desirable for switchgrass improvement and production.The objective of this study was to establish correlations between the manually measured traits and image-extracted measurements in switchgrass grown in a controlled environment.Red-green-blue(RGB)images from side-and top-views were automatically collected from the plants varying in growth stages for assessing their relationships with manually measured traits.Plant height,tiller number,crown diameter,and shoot dry weight were all significantly correlated with RGB image-based measurements including side-view height(SHT),side convex hull(SCH),side projected area(SPA),top convex hull(TCH),and top projected area(TPA).For a particular plant trait,a good prediction was observed based on an image-based measurement,including plant height and SHT(R2=0.992),tiller number and SPA(R2=0.86),crown diameter and SCH(R2=0.72),and shoot dry weight and SPA(R2=0.88).Plant height was also well predicted by SCH(R2=0.94)and SPA(R2=0.88).Overall,SHT,SCH,and SPA extracted from RGB images well predicted plant height,tiller number and shoot dry weight.The results demonstrated that the image-based parameters could be leveraged in quantifying the growth and development of switchgrass.展开更多
Shade tolerance is a highly desirable trait when breeding new bermudagrass(Cynodon spp.)lines,but current screening methods can take many years to complete.There is a clear need for large-scale turfgrass breeding prog...Shade tolerance is a highly desirable trait when breeding new bermudagrass(Cynodon spp.)lines,but current screening methods can take many years to complete.There is a clear need for large-scale turfgrass breeding programs to reliably,accurately,and quickly predict shade tolerance in their germplasm.The objectives of this research were to:(i)build custom chambers to reproducibly estimate photosynthetic characteristics from turfgrass canopies at different light intensities and(ii)determine which photosynthetic characteristics are indicative of past shade performance.A custom-built chamber was constructed to determine average photosynthetic characteristics for the whole plant by studying the turfgrass canopy at natural leaf angles for light interception.Shade tolerant(11-T-56)and shade sensitive(Tifway)bermudagrass cultivars were used to examine the effectiveness of the chamber within an array of photosynthetic characteristics when the grasses were grown in full-sun and 73%shade environments.Light compensation point,chlorophyll content,quantum yield,dark respiration rate,and maximum quantum yield of photosystem II were evaluated in this trial.Based on the results of this study,the authors recommend that light compensation point or maximum quantum yield be further evaluated as an accurate indicator of shade tolerance when performed in the field on spring days with grasses grown in full sun or 73%shade environments.Lower Rd rates and ambient temperatures on spring days appear to minimize unexplained variance in the data,which would allow researchers to better detect genotypic differences during this season.展开更多
基金supported by the Natural Science Foundation of Jiangsu Province(Grant No.BK20180546)by the discipline construction fund project of Gansu Agricultural University(Grant No.GAU-XKJS-2018-002)by National Natural Science Foundation of China(Grant No.31760701).
文摘Organic chemical priming is an effective strategy in mitigating salt stress to plants.The objective of this study was to determine effects and associated mechanisms of acetic acid regulating plant tolerance to salt stress.Perennial ryegrass plants were pre-treated with 20 mM acetic acid and subsequently subjected to salt stress for 28 days.Salt stress caused increased endogenous acetic acid content with up-regulated expression of its key biosynthetic gene LpPDC1.Application of acetic acid effectively alleviated salt caused damage in perennial ryegrass.Acetic acid treatment increased K^(+) content and suppressed Na^(+) accumulation to maintain a higher K^(+)/Na^(+) ratio in leaves exposed to salt stress.Plants O_(2)^(−) treated with acetic acid also had significantly lower levels of and H_(2)O_(2),but higher SOD and CAT activities than those of the control after 21 days of salt stress.Acetic acid treatment also altered the plants endogenous phytohormone content with higher content of jasmonate(including JA,JA-ILe,and cis-OPDA),auxin(IAA),and cytokinins(CK,such as tZ,cZR,and iP),but lower content of abscisic acid(ABA)under salt stress conditions.Furthermore,expression of genes involved in JA,IAA,and CK biosynthesis and signaling pathways were up-regulated,while those involved in ABA were down-regulated by acetic acid treatment under salt stress.The results demonstrate that acetic acid could mitigate salt stress in perennial ryegrass by regulating K^(+) and Na^(+) balance,promoting ROS scavenging,and activating stress-protection hormone synthesis and signaling.
基金supported by the Chongqing Key Laboratory of Germplasm Innovation and Utilization of Native Plants(XTZW2021-KF04)Innovation and Promotion of Forestry Science and Technology of Jiangsu Province(LYKJ[2021]29).
文摘High temperature is one of the major abiotic stresses limiting growth and development of cool-season grass species,but chitosan could effectively enhance heat tolerance and improve plant growth.The objective of this study was to determine the optimal concentration of chitosan that could alleviate heat stress in creeping bentgrass(Agrostis stolonifera)and investigate the effects of exogenous chitosan on photosynthesis and cell membrane stability under heat stress.Under heat stress(38/28°C,day/night),different chitosan concentrations of 0,50,100 and 500 mg·L−1 were applied on the leaves of creeping bentgrass(cv.'Penn-A4').Foliar application of chitosan exhibited the positive effects on plant growth and the optimal concentration was 100 mg·L−1 which significantly improved turf quality,root length,root-shoot ratio as well as shoot and root biomass.Chitosan-treated plants subjected to high temperature stress had a lower decline in photosynthetic rate and photochemical efficiency as well as less increase in electrolyte leakage and malondialdehyde content.The results demonstrate that chitosan-improved heat tolerance as reflected by the superior growth performance of both shoot and root,photosynthesis and cell membrane stability in creeping bentgrass under heat stress.
文摘Fungal Epichloëendophytes form symbiotic associations with many temperate grasses,such as Lolium and Festuca,giving their host grasses an ecological advantage.The importance of specific Epichloëendophytes in providing varying levels of protection against invertebrate pests has been well documented.Similarly,but with fewer studies,the benefits of Epichloëto host grasses in drought events has been shown.Endophyte-infected grasses show an improved persistence against herbivore insect attack as well as resilience under drought.However,there are relatively few studies that investigate the interaction between drought and insect pressure,and yet it is these combined pressures that can prove detrimental for a ryegrass or fescue crop.This review examines the current state of knowledge on the effects of Epichloëon the interactions of insects and drought in temperate grasses.
基金the Rutgers Center for Turfgrass Science and the USDA–NIFA Specialty Crop Research Initiative(grant number:2019-51181-30472)for partial funding of this effort.
文摘Turfgrasses are used extensively throughout the world,and there is a steadfast demand to develop turfgrass varieties with improved abiotic and biotic stress tolerances that will perform well with limited management inputs.Modern breeding programs incorporate advanced breeding strategies such as DNA sequencing and high-throughput phenotyping with traditional breeding strategies to identify and select germplasm and genes of interest.Molecular biology methods and DNA sequencing technology have rapidly increased in recent years,and,as a result,plant phenotyping is currently a bottleneck in the process of advancing breeding programs.Recent advances in remote sensing technology have offered improved,non-destructive plant phenotyping approaches such as visible light imaging,spectral imaging,infrared thermal imaging,range sensing,and fluorescence imaging.Integrated mobile and time efficient platforms are being developed,coupling remote sensing with robotics and unmanned aerial systems technology for high-throughput plant phenotyping applications across large field spaces.Modern turfgrass breeding programs will continue to research,develop,and implement remote sensing technologies to assess larger numbers of genotypes and identify elite germplasm.All together,these efforts will improve cultivar development efficiency and aid plant breeders in developing improved turfgrass cultivars to meet current and future demands of the turfgrass industry.This review provides an overview of ground-and aerial-based plant phenotyping platforms,with particular emphasis placed on applications to turfgrass breeding practices.Similarly,imaging technologies that have been used in various plant breeding programs are discussed,with indications as to how those technologies could be applicable to turfgrass breeding programs.
基金supported by the National Natural Science Foundation of China(No.3197177232001407).
文摘Bermudagrass(Cynodon dactylon)shade tolerance is a trait of immense importance to the turfgrass industry.However,little is known about shade tolerance of turf-type bermudagrass native to China.Additional knowledge of the mechanism of shade tolerance in bermudagrass is required to identify specific plant features that promote shade tolerance and assist breeding efforts worldwide.This study examines shade tolerance of two different bermudagrass cultivars,Yangjiang(prostrate form)and Guanzhong(upright form),which were developed in China.Each cultivar was subjected to 0,30.4,61.2,and 90.6%shade levels during growth and assessed for turf quality,turfgrass color intensity,biomass allocation,growth rate,antioxidant enzyme activity,leaf anatomy,and photochemical properties.Results generally demonstrated that turf quality and turf color intensity were lower in Guanzhong compared with Yangjiang on the 90.6%shade testing days.Yangjiang exhibited a less severe reduction of growth rate,leaf thickness,root to shoot ratio,and chlorophyll a to chlorophyll b ratio(Chla/b)under 90.6%shade compared with Guanzhong.Both cultivars exhibited a decrease in photochemical efficiency as determined by reduced qP,ETR,and Fv/Fm values.Photochemical efficiency was impacted less in Yangjian,and superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT)enzymes activities were greater than in Guanzhong when exposed to severe shade.When exposed to 90.6%shade level,Yangjiang had better turf quality than Guanzhong as determined by morphological,anatomical,and physiological features.Breeding efforts focused on these shade tolerance features will lead to improved bermudagrass germplasm and aid turf management in shade environments.
基金supported by the National Science Foundation(grant number DEB 1452971)Rutgers Alberts Research Awards in Biodiversity,Rutgers Center for Turfgrass Science and the New Jersey Agricultural Experiment Station to N.Zhangthe National Military Family Association,and the Garden Club of America。
文摘Arbuscular mycorrhizal(AM)fungi contribute globally to ecosystem services and play an important role in sustainable crop production.However,it is unclear which factors contribute most to their colonization and community structure at different sites,particularly in understudied ecosystems.This study investigated the AM fungal communities associated with switchgrass(Panicum virgatum L.)in the understudied acidic and oligotrophic pine barrens ecosystem using next-generation sequencing.Switchgrass was also sampled from agroecosystems,as well as,from a native prairie for comparison.The pine barrens switchgrass harbored a distinct AM fungal community−Acaulospora and Ambispora were almost exclusively found in the pine barrens sites,and some of these species may represent undescribed taxa.Glomus was the most ubiquitous AM fungal genus recovered from all sites.This study suggests differences in the AM fungal community structure under different soil properties and land uses.This is the first sequence-based report of the AM fungal communities in the pine barrens ecosystem.
文摘The grass family(Poaceae and Gramineae)is comprised of over 11,500 species classified in 12 subfamilies,52 tribes,90 subtribes,and more than 768 genera,making this family the third most abundant flowering plant in number of genera[1].Grass species,besides cereal grasses as food crops,are economically,environmentally,ecologically,recreationally,and aesthetically important in a wide range of applications including,but not limited to,cultivated grasses for turfgrass,forage,pasture,ornamental landscape,biofuel feedstocks,and wild grasses in natural grassland,woodlands,and deserts.The non-food grass species touch everyone’s lives directly and indirectly by serving multiple functions and benefits to humankind and society,such as beautifying landscapes,protecting the environment,enhancing human physical health,improving human recreational activities,providing feed for livestock and wildlife,serving as an alternative source of energy for bioenergy feedstock,and providing a natural habitat for wildlife[2,3,4,5,6].
基金This work was made possible through a Connecticut State Colleges and University Grant-AAUP Research Grant and a USDA-NIFA Education and Learning Initiative(Grant No.2017-67032-26013)。
文摘Plant growth promoting bacteria(PGPB)directly and indirectly influence the fitness of their host plants.While much of the work on plant growth promoting bacteria is from various plant rhizospheres,less is known about the strains that inhabit the internal spaces of plant tissues.Conversely,Clavicipitalean fungal endophytes of cool season grasses have been intensely investigated for the past few decades.Like plant growth promoting bacteria,the fungal endophytes also promote the health of their hosts.This paper highlights the current knowledge of plant growth promoting bacterial and fungal endophytes of tall fescue(Lolium arundinaceum=Schedonorus arundinaceaus=Festuca arundinacea)which protect the plant from both abiotic and biotic stresses.Much of the work presented indicates just how little is known about the inter-relationships between the multiple endophytic microbial colonizers of turf grasses.
基金supported by the National Natural Science Foundation of China(No.31302016).
文摘1-deoxy-D-xylulose-5-phosphate synthase(DXS)catalyzes the first and rate-limiting step of the plastidic 2-C-methyl-D-derythritol-4-phosphate(MEP)pathway which regulates the synthesis of terpenoids,such as gibberellins,abscisic acid,and chlorophyll.The objective of this study was to determine the functional role of PpDXS1 in plant growth and development in Kentucky bluegrass(Poa pratensis L.).The PpDXS1 gene has a 2139 bp open reading frame that encodes a polypeptide of 712 amino acids with a calculated molecular weight of 76.7 kDa.PpDXS1 gene expression was the highest in leaves.Moreover,the PpDXS1 promoter contained several hormone response elements and gene expression was induced by exogenous treatment with gibberellin,abscisic acid,jasmonate,and pathogen infection.Functional analysis indicated that underexpression of PpDXS1 gene in Poa pratensis decreased plant height and endogenous gibberellin and indole acetic acid production,but promoted abscisic acid accumulation.Furthermore,transcriptome analysis and qRT-PCR results showed that the expression levels of related genes involved in the phytohormone biosynthesis and signal transduction were differentially regulated by PpDXS1 in transgenic Poa pratensis.Overall,these results indicated that PpDXS1 has strong effects on plant height and accumulation of phytohormones,and provided a preliminary understanding of molecular characterization,expression and function of PpDXS1 in Poa pratensis.
基金supported by the program of National Natural Science Foundation of China(NSFC,32071876,31672193)Open-end Funds of State Key Laboratory of Grassland Agro-ecosystems(SKGAE),Lanzhou University,China.
文摘Salinity and drought stress are major abiotic stresses negatively affecting the growth and productivity of alfalfa(Medicago sativa L.).Exploration of genes exhibiting superior tolerance to salinity and drought stress in alfalfa will help aid target molecular breeding and developing tolerant forages.In this study,we adopted a high-efficient yeast FOX hunting system for the identification of salinity and drought tolerant genes in alfalfa.Based on the Gateway-compatible vector system,a high-quality expression library was constructed,containing 1.3×10^(7) clones with an average size of 1.44 kb.Through heterologous transformation of mixed library plasmid into salt or drought sensitive yeast mutants,monoclonal resistant strains were screened and tolerant genes were captured.Eighteen salinity-tolerance genes were obtained which were involved in several pathways,containing GRAS and zinc finger transcriptional factors,PP2A interaction module,ERVT vesicle transporter and LETM transmembrane protein.Twelve drought tolerance genes were separated,including ERF and SCL transcriptional factors,CIPK and BSK protein kinases,TGL-type ligase,cPGM and cPDL protease.The mRNA transcription levels of these tolerant genes were inducible or suppressible for response to salt or drought stress conditions following quantitative PCR detection,respectively.Furthermore,heterologous transformation of ERVT and CIPK11 can improve the salt and drought stress tolerance in Arabidopsis,which indicates the conservative function of the screening gene in yeast and Arabidopsis.Obtaining these candidate genes can provide new insights for future research with respect to plant salt and drought tolerance.
文摘Dichondra(Dichondra repens)is an important ground cover plant and is also used as a herbal medicine in China.Objectives of this study were to evaluate phenotypic and genetic diversities among 33 genotypes by using 18 simple sequence repeat(SSR)markers and to further identify the drought tolerance of these germplasms based on five physiological parameters.Results showed that natural variations in phenotypes including plant height,leaf area,leaf thickness,and petiole length were observed among 33 genotypes under well-watered conditions.All 18 SSR primer pairs were found to be polymorphic and significant genetic variation was found in these genotypes.In addition,there were obvious differences in leaf relative water content(RWC),electrolyte leakage(EL),chlorophyll(Chl)content,photochemical efficiency(Fv/Fm),and performance index on absorption basis(PIABS)among 33 genotypes in response to a prolonged period of drought stress(46 d).Drought tolerance of 33 genotypes was then ranked by using subordinate function value analysis(SFVA)and the most drought-tolerant or-sensitive genotypes were identified as Dr5 or Dr29,respectively.Principal component analysis(PCA)further classified 33 genotypes into group I(drought-tolerant),group II(droughtsensitive),and group III(medium types).Current findings showed that 18 selected SSR primers could be potentially used to analyze genetic diversity and varietal identification in dichondra species.Drought-tolerant wild dichondra resources provide a rich genetic base for breeding of new cultivars.
文摘The symbiotic relationship between Lolium perenne and Epichloëfestucae var.lolii,a fungal endophyte that lives asymptomatically in its above-ground parts,benefits both the host and fungus.In an outdoor container experiment,the effects of three distinct endophyte haplotypes(AR1,AR37 and CT)on natural infestations of a root aphid,Aploneura lentisci and a mealybug Phenococcus graminicola were compared with an endophyte-free(Nil)control.Populations of these insects were suppressed in a genetically identical set of plants treated with insecticide.Over 18 months,foliar and root growth,tiller numbers and plant mortality were compared between the different endophyte treatments and between insecticide-treated and untreated plants.Hyphal densities were recorded once during the trial.Untreated plants infected with AR37 had the lowest populations of A.lentisci and P.graminicola,and the highest root and foliar growth compared with other treatments.Growth parameters of untreated plants infected with CT often exceeded that of AR1 and Nil due to low infestations of P.graminicola and lower populations of A.lentisci.Growth of Nil,AR1 and CT plants were higher in insecticide-treated than in corresponding untreated plants but was unaffected in AR37.Untreated Nil and AR1 plants had a lower survival than AR37 and CT plants.Cumulative root outgrowth for treated AR37 plants was significantly lower than for treated AR1 on three sampling occasions.These Epichloëhaplotypes are primarily mutualists,although there are circumstances when they may be disadvantageous to their host.Opposing outcomes likely originate in the ecosystems in which associations evolved.
基金Funding for this project was provided by a Specialty Crop Research Initiative grant[2015-51181-24291]from the USDA National Institute for Food and Agriculture。
文摘Shade caused by trees or buildings can affect the quality and growth of turfgrasses.Thus,breeding for shade tolerance is an essential component of most turfgrass improvement programs.The objective of this study was to evaluate the performance of seashore paspalum(Paspalum vaginatum Sw.)breeding lines under shade in multi-environment trials.Germplasm sources were 20 lines from the University of Georgia seashore paspalum breeding program and two checks,the cultivars'SeaDwarf'and'SeaStar'.Field trials were conducted from 2016 to 2019 under shade structures designed to reduce ambient sunlight at three locations:Citra(FL),Tifton(GA),and Raleigh(NC).The response variables evaluated were percent living ground cover(%GC),dark green color index(DGCI),canopy height(CH)and turfgrass quality(TQ).Data were analyzed by mixed model approaches using ASReml-R,and the t-statistics were used to group the entries.Significant genetic variances were observed in the single-location-repeated-measures analysis for CH and DGCI at Citra and Tifton,%GC at Citra,and TQ at Raleigh.Spearman correlations of the predicted values for entries between locations ranged from low to moderate,with the exception of between Citra and Tifton(0.76)for CH.There were a few breeding lines with superior performance to the entry average for all traits for which the entry variance was significant.In conclusion,genetic variability was observed for all traits and superior seashore paspalum breeding lines for multiple traits were identified under shade.
文摘γ-Aminobutyric acid(GABA)is known for its positive effects on improving plant stress tolerance,while the association of its role in regulating nutritional availability and GABA priming-enhanced heat tolerance is not well documented.The objective of this study was to determine whether GABA priming may improve heat tolerance in cool-season grass species involving regulation of plant nutrition for macronutrients and micronutrient elements.Plants of creeping bentgrass(Agrostis stolonifera)(cv.'Penncross')in each pot were treated with 10 mL of water(control)or 0.5 mM GABA(GABA priming)by foliar spray and then subjected to heat stress(35/30°C,day/night)or optimal growth temperature(control)(21/19°C,day/night)(non-stress control)for 30 d in growth chambers.GABA-primed plants had significantly higher endogenous GABA content associated with improved heat tolerance compared to non-treated plants,as reflected by higher leaf cell membrane stability,relative water content,osmotic adjustment,chlorophyll content,photochemical efficiency,and net photosynthetic rate.Plants pretreated with GABA exhibited significantly higher content of nitrogen(N),phosphorus(P),calcium(Ca),sodium(Na),and copper(Cu)but lower content of boron(B)and manganese(Mn)in leaves than non-treated plants under heat stress.The enhanced accumulation of N,P,Ca,Na,and Cu and restricted B and Mn accumulation by GABA priming indicate that GABA could modulate mineral nutrient availability in plants,contributing to improved heat tolerance for creeping bentgrass.
基金support was provided from USDA-NIFA Multistate Project W4147the New Jersey Agricultural Experiment Station,and from a Cooperative Ecosystems Studies Unit CESU G16AC00433 grant between Rutgers University and the U.S.Geological Survey for control of invasive Phragmites australis,and Rey Juan Carlos University,grant DRIADES-2020/00006/009.
文摘Plants naturally carry microbes on seeds and within seeds that may facilitate development and early survival of seedlings.Some crops have lost seed-vectored microbes in the process of domestication or during seed storage and seed treatment.Biostimulant microbes from wild plants were used by pre-modern cultures to re-acquire beneficial seed microbes.Today some companies have developed or are developing the use of microbes obtained from soils or plant sources to stimulate plant development and growth.Many of these biostimulant microbes are endophytic in plants.Biostimulant products also include humic substances,which appear to function as signal molecules in plants,triggering increased internalization of soil microbes into root cells and tissues.In addition,protein coatings on seeds fuel the growth of seed surface-vectored microbes,increasing microbial activity around and within roots.In this article,we provide evidence of the endophytic nature of many biostimulant microbes,and suggest that many of the beneficial effects of microbial biostimulants stem from their action as endophytes or as participants or stimulants of rhizophagy cycle activity.
文摘Leaf senescence is accelerated by prolonged exposure to high temperatures in cool-season plants and is characterized by loss of chlorophyll and adjustment in amino acid metabolism.The objectives of this study included ascertaining how glutamate may affect the tolerance of cool-season grass species to heat stress in relation to leaf senescence through the regulation of leaf chlorophyll(Chl)and amino acid metabolism.Creeping bentgrass(Agrostis stolonifera L.)plants were maintained for 35d under optimal growth temperature(22/18℃,day/night,non-stress control)or heat stress(35/30℃,day/night)in growth chambers,and glutamate(60 mM)or water(untreated control)was applied weekly as a foliar treatment.Under heat stress,turf quality(TQ),photochemical efficiency(Fv/Fm),and Chl content were significantly higher in plants treated with glutamate at 14-35 d,7-28 d,and 7-35 d,respectively,compared to untreated controls.Glutamate application significantly reduced the activities of chlorophyll-degrading peroxidase and chlorophyllase,two Chl-degrading enzymes,at 14,21,and 35 d of heat stress,whereas activity of the rate-limiting Chl synthesis enzyme,porphobilinogen deaminase,was not significantly affected.Glutamate treatment significantly increased the endogenous content of serine,threonine,lysine,aspartate,glutamate,and GABA under heat stress,while methionine,asparagine,isoleucine,and histidine were significantly up-regulated exclusively under heat stress.These findings suggest that glutamate could serve as a repressor for heat-accelerated leaf senescence by suppressing Chl degradation and activating amino acid metabolism involved in energy production,antioxidant defense,and nitrogen balance.
基金supported,in part,by the United State Department of Agriculture Specialty Crop Research Initiative award 2010-51181-21064,the Oklahoma Agricultural Experiment Station,and the United States Golf Association.
文摘Bermudagrass[Cynodon dactylon var.dactylon(L.)Pers.]is a major warm-season turf and forage grass worldwide.Seed yield is an important trait targeted for improvement in bermudagrass breeding programs because of the increased interest in seed-propagated cultivars.Understanding the nature of genetic variation for seed yield and its components in bermudagrass would aid the development of seed-propagated cultivars.The objective of this study was to estimate the genetic variation and narrow-sense heritability for seed yield and its two major components,inflorescences prolificacy and seed set percentage in bermudagrass.Twenty-five half-sib families and their respective clonal parents were evaluated at two Oklahoma locations,Perkins and Stillwater(Oklahoma,USA),over two years.Half-sib families were different for seed yield,inflorescences prolificacy and seed set percentage,indicating the expression of additive genes in controlling these traits.Family×location effects were observed for seed set percentage and seed yield.All three traits showed family×year interaction effects.There was a significant family×location×year interaction in inflorescences prolificacy and seed set percentage.Narrow-sense heritability estimates for seed yield was 0.18 based on variance component analysis among half-sib families and ranged from 0.26 to 0.68 based on parent-offspring regressions,indicating genetic complexity of seed yield.Heritability estimates were moderate(0.30−0.55)for inflorescences prolificacy and moderate to relatively high(0.41−0.78)for seed set percentage.The results indicate that sufficient magnitudes of additive genetic variation for seed set percentage and inflorescence prolificacy permit positive response to selection and conventional progeny-based genotypic evaluation is necessary for seed yield improvement.Citation:Tan C,Wu Y,Taliaferro CM,Bell GE,Martin DL,et al.2022.Heritability estimates for seed yield and its components in Cynodon dactylon var.
基金funded by the National Science and Technology Basic Resources Investigation Project(2017FY100600)Feeds and Forages flagship of the CGIAR Research Program on Livestock,the Key Research and Development Program of Hainan(321RC646)China Agriculture Research System of MOF and MARA(CARS-22)。
文摘Coastal saline soils are increasing year by year caused by climate change and human activities.Most of the coastal saline soils are idle due to their high salinity level and few crops can grow normally.Salinity tolerant legumes are naturally tolerant to salt,which can ecologically cover the coastal saline soil,enhance soil fertility by symbiotic nitrogen fixation and increase the smallholder farmers’benefits in terms of forage,green manure,food or medicine.However,few reports are available for the systematic evaluation of salinity tolerant legumes.This review summarizes and evaluates currently available salinity tolerant legume species that could potentially be used and discusses their potential for integration into smallholder mixed coastal systems of the Asia-Pacific region.Fourty four salinity tolerant legumes were summarized,six of them showed a high level of salinity tolerance,17 of them showed a moderate level of salinity tolerance and 21 of them showed potential salinity tolerance but need to be further studied.Many gaps such as combined tolerance evaluation,nitrogen fixation efficiency,animal feeding experiments and salinity tolerant rhizobia screening/inoculants exist.Case studies demonstrate legumes could be used to reclaim coastal saline soils,but commitment and support from government and public services are necessary to address both seed system and extension needs,through the provision of adequate incentives,policies and development efforts.
文摘Switchgrass(Panicum virgatum L.)is a native and prominent perennial grass species used for feedstocks.High-throughput phenotyping of biomass component traits is desirable for switchgrass improvement and production.The objective of this study was to establish correlations between the manually measured traits and image-extracted measurements in switchgrass grown in a controlled environment.Red-green-blue(RGB)images from side-and top-views were automatically collected from the plants varying in growth stages for assessing their relationships with manually measured traits.Plant height,tiller number,crown diameter,and shoot dry weight were all significantly correlated with RGB image-based measurements including side-view height(SHT),side convex hull(SCH),side projected area(SPA),top convex hull(TCH),and top projected area(TPA).For a particular plant trait,a good prediction was observed based on an image-based measurement,including plant height and SHT(R2=0.992),tiller number and SPA(R2=0.86),crown diameter and SCH(R2=0.72),and shoot dry weight and SPA(R2=0.88).Plant height was also well predicted by SCH(R2=0.94)and SPA(R2=0.88).Overall,SHT,SCH,and SPA extracted from RGB images well predicted plant height,tiller number and shoot dry weight.The results demonstrated that the image-based parameters could be leveraged in quantifying the growth and development of switchgrass.
基金funded in part by the University of Georgia College of Agriculture&Environmental Sciences,and by the National Institute of Food and Agriculture,U.S.Department of Agriculture,under award number 2010-51181-21064.
文摘Shade tolerance is a highly desirable trait when breeding new bermudagrass(Cynodon spp.)lines,but current screening methods can take many years to complete.There is a clear need for large-scale turfgrass breeding programs to reliably,accurately,and quickly predict shade tolerance in their germplasm.The objectives of this research were to:(i)build custom chambers to reproducibly estimate photosynthetic characteristics from turfgrass canopies at different light intensities and(ii)determine which photosynthetic characteristics are indicative of past shade performance.A custom-built chamber was constructed to determine average photosynthetic characteristics for the whole plant by studying the turfgrass canopy at natural leaf angles for light interception.Shade tolerant(11-T-56)and shade sensitive(Tifway)bermudagrass cultivars were used to examine the effectiveness of the chamber within an array of photosynthetic characteristics when the grasses were grown in full-sun and 73%shade environments.Light compensation point,chlorophyll content,quantum yield,dark respiration rate,and maximum quantum yield of photosystem II were evaluated in this trial.Based on the results of this study,the authors recommend that light compensation point or maximum quantum yield be further evaluated as an accurate indicator of shade tolerance when performed in the field on spring days with grasses grown in full sun or 73%shade environments.Lower Rd rates and ambient temperatures on spring days appear to minimize unexplained variance in the data,which would allow researchers to better detect genotypic differences during this season.
