Articles de revues sur le sujet « Alfalfa plant »
Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Alfalfa plant.
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleurs articles de revues pour votre recherche sur le sujet « Alfalfa plant ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les articles de revues sur diverses disciplines et organisez correctement votre bibliographie.
1
Li, Fang, et Yanzhong Li. « Evaluation of pathogenicity, systemic colonisation, and host range of Verticillium alfalfae in a greenhouse ». Crop and Pasture Science 72, no 5 (2021) : 383. http://dx.doi.org/10.1071/cp20449.
Texte intégralRésumé :
Verticillium wilt of alfalfa (Medicago sativa) is a widespread and destructive disease caused by the soil-borne fungal pathogen Verticillium alfalfae (formerly V. albo-atrum before 2011). Owing to an inadequate understanding of the pathogenicity, systemic colonisation, and host range of V. alfalfae, it has been challenging to develop an effective control measure against this disease. In the present study, seven inoculation methods, including seed inoculation, leaf spraying (LS), fungal plugs placed on leaves (FP), stem injection (SI), root dipping (RD), root injuring and dipping (RI), and watering conidia suspension into soil (WI) were used to analyse the pathogenicity and systemic colonisation of V. alfalfae on alfalfa. The typical verticillium wilt symptoms including V-shaped necrosis of leaves and leaf wilting were observed in alfalfa plants with all inoculation methods. The shortest incubation period (9 days) was observed with stem injection and the longest (40 days) with root dipping. Alfalfa plants inoculated by stem injection showed the highest disease incidence (91%), disease index (65%), and percentage of infected plants (80%), which resulted in the highest shoot biomass loss rate (34%). However, the plants inoculated by fungal plugs showed the lowest disease index (4%), percentage of infected plants (10%), and root biomass loss rate (2%). Further, the stem injection method was used to assess the host range of V. alfalfae on seven non-alfalfa plant species including erect milkvetch, sainfoin, common vetch, sunflower, potato, cotton, and bluish dogbane. The artificial inoculation of V. alfalfae by stem injection successfully infected these plants, with disease incidence ranged from 13 to 100% and disease index ranged from 10 to 69. This indicates that host range of V. alfalfae is not only alfalfa, but also other plant species.
2
Bhattarai, Surendra, Dilip Biswas, Yong-Bi Fu et Bill Biligetu. « Morphological, Physiological, and Genetic Responses to Salt Stress in Alfalfa : A Review ». Agronomy 10, no 4 (17 avril 2020) : 577. http://dx.doi.org/10.3390/agronomy10040577.
Texte intégralRésumé :
Alfalfa (Medicago sativa L.) is an important legume forage crop. However, its genetic improvement for salt tolerance is challenging, as alfalfa’s response to salt stress is genetically and physiologically complex. A review was made to update the knowledge of morphological, physiological, biochemical, and genetic responses of alfalfa plants to salt stress, and to discuss the potential of applying modern plant technologies to enhance alfalfa salt-resistant breeding, including genomic selection, RNA-Seq analysis, and cutting-edge Synchrotron beamlines. It is clear that alfalfa salt tolerance can be better characterized, genes conditioning salt tolerance be identified, and new marker-based tools be developed to accelerate alfalfa breeding for salt tolerance.
3
Manglitz, G. R., et Michael Rethwisch. « Alfalfa Weevil and Plant Bug Control in Alfalfa, 1984 ». Insecticide and Acaricide Tests 10, no 1 (1 janvier 1985) : 181. http://dx.doi.org/10.1093/iat/10.1.181.
Texte intégralRésumé :
Abstract This test was conducted at the University of Nebraska Field Laboratory, Mead, NE in a fourth-year stand of ‘Vernal’ alfalfa. Plots were 9 X 15 ft, arranged in a randomized complete block design replicated 4 times. A single application of 10 insecticides, at various rates, was made on 26 May ’84. Insecticides were applied with a CO2, activated pressure sprayer calibrated to deliver 12.5 gal/acre at 20 psi and equipped with a 5.5-ft boom. Each plot was sampled twice, 6 and 12 days posttreatment, by taking 5 sweeps per plot with a 15-inch diam insect net.
4
Xu, Shan, Michael J. Christensen, Rebecca Creamer et Yan Zhong Li. « Identification, Characterization, Pathogenicity, and Distribution of Verticillium alfalfae in Alfalfa Plants in China ». Plant Disease 103, no 7 (juillet 2019) : 1565–76. http://dx.doi.org/10.1094/pdis-07-18-1272-re.
Texte intégralRésumé :
Verticillium wilt caused by Verticillium alfalfae results in severe production losses in alfalfa crops and is a Class A quarantined disease in China. During 2015 to 2017, 365 alfalfa fields from 21 locations in six provinces were surveyed, and 45 fields from three closely located sites in Gansu, China were found to have alfalfa plants with symptoms typical of Verticillium wilt, with disease incidence of 12.6 to 53.6%. Isolates were identified to species using morphological characteristics and a maximum likelihood phylogeny of the concatenated partial sequences of actin, elongation factor, glyceraldehyde-3-phosphate dehydrogenase, and tryptophan synthase gene regions of Verticillium isolates. Isolation incidence was 93.9% from roots, 71.7% from stems, 66.1% from petioles, and 32.2% from leaves of field-infected plants, indicative of systemic disease and sporadic distribution of this pathogen. In greenhouse tests, the pathogen infected seedlings and colonized vascular tissues when inoculated on seeds, on root tips, in soil, or in injured, but not uninjured, aerial tissues, causing systemic symptoms like those in the field and significant losses. Pathogenicity testing also revealed that five locally grown perennial legumes (stylo, milkvetch, sainfoin, white clover, and red clover) could host V. alfalfae, with a high virulence to milkvetch, sainfoin, and stylo. This study confirmed that V. alfalfae has become established in some regions of Gansu, China and that is a risk to the alfalfa industry in China.
5
Juan, N. A., C. C. Sheaffer et D. K. Barnes. « Root and crown characteristics of alfalfas varying in fall dormancy ». Canadian Journal of Plant Science 74, no 1 (1 janvier 1994) : 125–27. http://dx.doi.org/10.4141/cjps94-022.
Texte intégralRésumé :
We compared root and crown characteristics of five alfalfa (Medicago sativa L.) entries which differed in fall dormancy. Alfalfas were subjected to bud or mid-bloom harvests. The most consistent entry effect occurred for root and crown dry weight and root total nonstructural carbohydrate (TNC) concentrations. Root TNC concentration was highest and root and crown weight were greatest for the nondormant and least in the most dormant entries. Entries did not consistently differ in crown bud numbers, shoot number, or shoot origin. In October, the number of elongated crown buds were greater for a non-fall dormant alfalfa Nitro than for the most fall dormant alfalfa. Key words: Alfalfa, root and crown morphology, fall dormancy, root carbohydrates
6
Hendrickson, John R., Mark A. Liebig et John D. Berdahl. « Responses of Medicago sativa and M. falcata type alfalfas to different defoliation times and grass competition ». Canadian Journal of Plant Science 88, no 1 (1 janvier 2008) : 61–69. http://dx.doi.org/10.4141/cjps06012.
Texte intégralRésumé :
Incorporating alfalfa into rangelands can enhance the quantity and quality of forage production. We evaluated the impact of clipping timing and selective clipping on two M. falcata (Anik and Yellowhead) and one M. sativa type alfalfas (Vernal) near Mandan, North Dakota, USA. Cultivars were space-planted into an existing mixed grass prairie and clipped at the mid-bud, flower or flower and subsequent vegetative stages. In each clipping treatment, half of the plots had only the alfalfa clipped and half had both the alfalfa and the associated native vegetation clipped. Plots without alfalfa were also included to evaluate the impact of alfalfa on grass and forb biomass. Including Yellowhead increased total productivity by 38 to 185% without lowering the productivity of the grass or forb biomass components. Plots with Yellowhead produced 17 to 26% more total biomass than the next highest entry every year. In 2003 and 2005, alfalfa biomass was increased 1.5 to 2.7 times by clipping only alfalfa in the flower and regrowth stages compared with a mid-bud clipping of only alfalfa. Vernal and Yellowhead generally produced more total biomass when clipping was deferred to the flower stage, but clipping Anik in the mid-bud stage produced as much or more total biomass than did the later clipping treatments. Selective clipping of the alfalfa did not have a consistent impact on yield. Yellowhead appeared to be a good choice for incorporating into rangelands. Producers with Yellowhead or Vernal should consider delaying defoliation until flowering to maximize productivity. Key words: Grazing-type alfalfa, hay-type alfalfa, defoliation timing, biomass productivity
7
Li, Shuo, Zhongnan Nie, Juan Sun, Xianglin Li et Guofeng Yang. « The Physiological Role of Abscisic Acid in Regulating Root System Architecture of Alfalfa in Its Adaptation to Water Deficit ». Agronomy 12, no 8 (10 août 2022) : 1882. http://dx.doi.org/10.3390/agronomy12081882.
Texte intégralRésumé :
Alfalfa (Medicago sativa L.) is a perennial leguminous plant, with a strong tap root system that plays an important role in alfalfa’s adaptation to drought stress. However, a better understanding of root functional traits and how these root traits are related to whole plant responses in order to improve pasture productivity under water deficit. Two greenhouse experiments were conducted: Experiment 1 used three alfalfa cultivars and four levels of soil water content treatments to investigate herbage productivity, growth point density, residual shoot weight, and root weight. Experiment 2 assessed relationships among root-sourced abscisic acid (ABA), root system architecture and plant biomass in response to water deficit. The results demonstrated that root system was used as a useful tool to improve tolerant and adaptation when alfalfa copied with lower levels of soil water content. On average, maintaining 60–65% soil water-holding capacity alfalfa had the highest herbage accumulation (6.7 g DM pot-1), growing point density (46.5 pot-1), and residual shoot biomass (1.8 g DM pot-1). At the level of water stress, Medicago sativa L. cv Zhaodong (ZD) and cv Aohan (AH) tended to exhibit a herringbone branching pattern with less root tips, root forks, altitude, and magnitude than cv Golden empress (GE). Principal component analysis and structural equation modeling revealed that root-sourced ABA positively regulated the altitude and magnitude of root system architecture, root tips and root forks, and was closely associated with plant root biomass and herbage biomass. It was concluded that these findings can contribute to developing optimum irrigation strategies and help alfalfa breeders in the development of new cultivars with improved drought tolerance based on root system architecture, plant hormone, and plant growth.
8
Wang, Yajie, Yingde Li, Zhen Tian et Tingyu Duan. « Arbuscular Mycorrhizal Fungus Alters Alfalfa (Medicago sativa) Defense Enzyme Activities and Volatile Organic Compound Contents in Response to Pea Aphid (Acyrthosiphon pisum) Infestation ». Journal of Fungi 8, no 12 (16 décembre 2022) : 1308. http://dx.doi.org/10.3390/jof8121308.
Texte intégralRésumé :
Pea aphid (Acyrthosiphon pisum) infestation leads to withering, reduced yield, and lower quality of the host plant. Arbuscular mycorrhizal (AM) fungi have been found to enhance their host plants’ nutrient uptake, growth, and resistance to biotic stresses, including pathogen infection and insect pest infestation. Therefore, we evaluated the effects of AM fungus Rhizophagus intraradices on alfalfa defense responses to pea aphid infestation. Aphid infestation did not affect the colonization of AM fungus. The inoculation of AM fungus, on average, enhanced alfalfa catalase and the contents of salicylic acid and trypsin inhibitor by 101, 9.05, and 7.89% compared with non-mycorrhizal alfalfa, respectively. In addition, polyphenol oxidase activities significantly increased by six-fold after aphid infestation in mycorrhizal alfalfa. Moreover, the fungus significantly (p < 0.05) improved alfalfa shoot N content, net photosynthetic and transpiration rates, and shoot dry weight in aphid infected treatment. The aphid infestation changed the total volatile organic compounds (VOCs) in alfalfa, while AM fungus enhanced the contents of methyl salicylate (MeSA). The co-expression network analysis of differentially expressed genes (DEGs) and differentially expressed VOCs analysis showed that three DEGs, namely MS.gene23894, MS.gene003889, and MS.gene012415, positively correlated with MeSA both in aphid and AM fungus groups. In conclusion, AM fungus increased alfalfa’s growth, defense enzyme activities, hormones, and VOCs content and up-regulated VOC-related genes to enhance the alfalfa’s resistance following aphid infestation.
9
Soroka, Juliana J., et Dorothy C. Murrell. « THE EFFECTS OF ALFALFA PLANT BUG (HEMIPTERA : MIRIDAE) FEEDING LATE IN THE SEASON ON ALFALFA SEED YIELD IN NORTHERN SASKATCHEWAN ». Canadian Entomologist 125, no 5 (octobre 1993) : 815–24. http://dx.doi.org/10.4039/ent125815-5.
Texte intégralRésumé :
AbstractA 4-year field cage study was conducted to determine what effects feeding of alfalfa plant bug, Adelphocoris lineolatus (Goeze), late in the season had on alfalfa seed yields. When zero, one, two, or four alfalfa plant bugs were placed in sleeve cages containing stems of alfalfa at the green pod stage of growth, there was a significant decrease in the number of pods per cage and per raceme, the number of healthy seeds, and the weight of seeds with two or four bugs per cage. Increasing the duration of infestation resulted in significant increases in the number of damaged seeds per cage. An insecticide field trial was conducted in north central Saskatchewan in 1988 to determine what effects the occurrence of plant bugs had on seed yields of alfalfa. Alfalfa plant bug, lygus bug (Lygus spp.), pea aphid [Acyrthosiphon pisum (Harris)], and beneficial arthropod populations were monitored from 23 June to 1 September 1988. Seed yields were significantly greater in plots that were treated with trichlorfon in June and in June and August than in plots that were treated in August alone. The implications of a large alfalfa plant bug population late in the season to alfalfa seed production in the area are discussed.
10
Monteiro, Mariza, Beatriz Appezzato-da-Glória, Maria José Valarini, Carlos Alberto de Oliveira et Maria Lucia Carneiro Vieira. « Plant regeneration from proroplasts of alfalfa (Medicago sativa) via somatic embryogenesis ». Scientia Agricola 60, no 4 (décembre 2003) : 683–89. http://dx.doi.org/10.1590/s0103-90162003000400012.
Texte intégralRésumé :
Alfalfa is one of the most frequently studied species from the production of tissue culture-derived embryos point of view. In this study, five alfalfa cultivars were analyzed with reference to their ability to regenerate plants from protoplast cultures via somatic embryogenesis. Plant regeneration from leaf-derived protoplasts isolated from the cultivar Rangelander was achieved using a protocol defined for alfalfa cell suspension-derived embryogenesis. Because of its high efficiency, this procedure is recommended for protoplast electroporation-mediated genetic transformation of alfalfa.
11
Rumbaugh, M. D., et B. M. Pendery. « Stability of forage yield of alfalfa clones grown with five associate species ». Canadian Journal of Plant Science 71, no 2 (1 avril 1991) : 453–59. http://dx.doi.org/10.4141/cjps91-062.
Texte intégralRésumé :
Single species spaced-plant clonal nurseries are useful in the first stage of selection to develop forage crop cultivars for semiarid and arid environment pastures. The objectives of this study were (1) to quantify the degree of stability of forage yield of individual alfalfa (Medicago sativa L.) clones when grown with five associate species and (2) to examine the relationships of alfalfa and the associate species in the determination of total plot forage yield in a spaced-plant nursery with a stand density comparable to that of natural plant communities on semiarid rangelands. One hundred plants of NC-83-1 alfalfa were vegetatively propagated and grown in a replicated spaced-plant selection nursery in association with Fairway crested wheatgrass (Agropyron cristatum [L.] Gaertner s. lat.), Oahe intermediate wheatgrass (Thinopyrum intermedium [Host] Barkworth & D. R. Dewey), RS-2 hybrid wheatgrass (Elytrigia repens [L.] Nevski × Pseudoroegneria spicata [Pursh]Löve), Vinall Russian wildrye (Psathyrostachys juncea [Fisch.] Nevski), and NC-83-1 alfalfa. Plants were spaced 0.5-m apart on a rectangular grid in which eight plants of an associated species surrounded each alfalfa plant. Forage yield per plant was measured in four harvests each year during the 2nd and 3rd years following establishment. Alfalfa was the most competitive associated species. Rhizomatous grasses were more competitive to alfalfa than were bunchgrasses. Some clones were phenotypically more stable than others. The degree of stability was inversely, but weakly, associated with the amount of alfalfa forage produced. Alfalfa plant yield was negatively related to yield of the associate species. This compensatory effect tended to stabilize total plot forage yield. Simultaneous selection of range forage species may best be accomplished in nurseries in which a grass and a legume are interplanted at a density and in a pattern that simulates the competitive relations occurring in semiarid environments. Key words: Competition, grass, Medicago, plant breeding, pasture, range
12
Yang, Bo, Yao Zhao et Zhenfei Guo. « Research Progress and Prospect of Alfalfa Resistance to Pathogens and Pests ». Plants 11, no 15 (1 août 2022) : 2008. http://dx.doi.org/10.3390/plants11152008.
Texte intégralRésumé :
Alfalfa is one of the most important legume forages in the world and contributes greatly to the improvement of ecosystems, nutrition, and food security. Diseases caused by pathogens and pests severely restrict the production of alfalfa. Breeding resistant varieties is the most economical and effective strategy for the control of alfalfa diseases and pests, and the key to breeding resistant varieties is to identify important resistance genes. Plant innate immunity is the theoretical basis for identifying resistant genes and breeding resistant varieties. In recent years, the framework of plant immunity theory has been gradually formed and improved, and considerable progress has been made in the identification of alfalfa resistance genes and the revelation of the related mechanisms. In this review, we summarize the basic theory of plant immunity and identify alfalfa resistance genes to different pathogens and insects and resistance mechanisms. The current situation, problems, and future prospects of alfalfa resistance research are also discussed. Breeding resistant cultivars with effective resistance genes, together with other novel plant protection technologies, will greatly improve alfalfa production.
13
Qiong, Wu, Wang Yu hui, Zhang Xiao hong, Li En hui et Yang Shen jiao. « Analysis of Crop Growth Rhythm in Alfalfa - Wheat Intercropping ». Scholars Journal of Agriculture and Veterinary Sciences 9, no 3 (18 mars 2022) : 35–42. http://dx.doi.org/10.36347/sjavs.2022.v09i03.002.
Texte intégralRésumé :
Logistic equation was used to fit the plant height growth of wheat and alfalfa in different intercropping treatments, and the effects of intercropping on the plant height growth of wheat and alfalfa were analyzed according to the results of fitting curve model parameters. The results showed that the plant height growth of wheat and alfalfa under different intercropping patterns was in line with "S" curve. According to the turning point of the growth curve, the plant height growth can be divided into three stages: gradual growth stage, linear growth stage and slow growth stage. In late March, wheat and alfalfa began to enter linear growth phase, which lasted about one month and one and a half months, respectively. The linear growth of wheat and alfalfa in all treatments accounted for more than 50% of the total growth in growth period. Intercropping alfalfa extended the linear growth period of wheat, but reduced the growth rate and amount of wheat in the linear growth period. While intercropping with wheat shortened the linear growth period of alfalfa, but accelerated its growth rate.
14
Lyons, Tana, Dan Undersander, Randy Welch et Derek Donnelly. « Estimating Alfalfa Yield from Plant Height ». Crop, Forage & ; Turfgrass Management 2, no 1 (14 juillet 2016) : 1–3. http://dx.doi.org/10.2134/cftm2015.0203.
Texte intégral
15
Glagoleva, L. E., K. K. Polyansky, N. P. Zatsepilina et I. P. Nesterenko. « Processed cheese using alfalfa plant complex ». Cheesemaking and buttermaking 55, no 4 (2021) : 40–41. http://dx.doi.org/10.31515/2073-4018-2021-4-40-41.
Texte intégral
16
Moyer, J. R., R. W. Richards et G. B. Schaalje. « Effect of plant density and herbicide application on alfalfa seed and weed yields ». Canadian Journal of Plant Science 71, no 2 (1 avril 1991) : 481–89. http://dx.doi.org/10.4141/cjps91-065.
Texte intégralRésumé :
Alfalfa was seeded in row spacings of 36, 72 and 108 cm and at broadcast seeding rates of 0.33, 1.0 and 3.0 kg ha−1 on irrigated land at Tilley (1983) and Lethbridge (1984), Alberta to determine the effect of plant density on weed growth and alfalfa seed yield. During the seed-producing years at each location, herbicide treatments were overlaid on seeding treatments in a split-block arrangement to assess the joint effect of herbicides and plant density on alfalfa seed yield. Hexazinone was the main herbicide used for weed control. Alfalfa seed and weeds were harvested for 5 yr following alfalfa establishment. Alfalfa seed yields tended to be maximum with 36-cm row spacings or the 3.0 kg ha−1 broadcast seeding rate, and were similar in row-seeded and broadcast-seeded alfalfa. Dry matter yields of weeds decreased as row spacings decreased or the broadcast seeding rate increased. Hexazinone controlled quackgrass, sow thistle, flixweed and kochia. In the experiment at Tilley with perennial weed infestations, mean alfalfa seed yields from 1984 to 1985 were 20% larger when herbicides were used than in the untreated check. Alfalfa plant densities slightly larger than currently recommended usually produced the largest seed yields and smallest weed infestations. Key words: Medicago sativa, quackgrass, kochia, sow thistle, flixweed, hexazinone
17
Small, Ernest. « Adaptations to herbivory in alfalfa (Medicago sativa) ». Canadian Journal of Botany 74, no 6 (1 juin 1996) : 807–22. http://dx.doi.org/10.1139/b96-102.
Texte intégralRésumé :
Alfalfa (Medicago sativa L.) possesses numerous adaptations to herbivores. As with other wild plants, general chemical defences (notably medicagenic acid in alfalfa) and general anti-insect structures (notably trichomes) provide some protection against a wide spectrum of polyphagous insects. Several morphological adaptations protect alfalfa against specialized insect feeders, especially those that consume the seeds. Alfalfa has been disruptively selected by man to possess morphological adaptations and tolerance for two contrasting classes of herbivory: continuous grazing by livestock and intermittent harvesting for hay. Domestication of alfalfa has lowered the effectiveness of several natural adaptations against insects. Occasionally, however, artificial selection for resistance against certain insect species has, often unintentionally, resulted in selection for structural features discouraging these insects. Preadaptations of wild alfalfa for the horse facilitated this plant's domestication as a specialized horse feed, despite the fact that horses are poorly adapted in the wild to such a nutritious forage. Under conditions of domestication, however, alfalfa appears to offer horses several invaluable dietary advantages, and is much more suited to the horse than to man's other grazing herbivores. Anti-herbivorous hemolytic saponins are present in high concentrations in certain alfalfa lineages and cultivars. Horses in southern Europe and Asia have been fed low-saponin alfalfa for millenia, whereas high-saponin alfalfa has been utilized in northern Europe and much of the New World only since about the 16th century. While these compounds are poisonous for most herbivores, they could be beneficial for the horse. A very high degree of herbivorous coadaptation exists between alfalfa and its specialized pollinator, the alfalfa leafcutter bee (Megachile rotundata), and there is evidence that this relationship has coevolved. As the world's most efficient protein crop, alfalfa is preeminently adapted to mankind's future need for increased direct consumption of plant proteins. Keywords: adaptation, alfalfa, fodder, forage, herbivory, Medicago sativa.
18
Mirab-balou, Majid, et Mohammad Khanjani. « Harmful Hemiptera of Lygus Genus (Miridae, Hemiptera) On Alfalfa (Medicago Sativa L.) In Hamedan Province (Western Iran) ». Journal of Plant Protection Research 48, no 3 (1 septembre 2008) : 313–22. http://dx.doi.org/10.2478/v10045-008-0040-7.
Texte intégralRésumé :
Harmful Hemiptera ofLygus Genus(Miridae, Hemiptera) On Alfalfa (Medicago SativaL.) In Hamedan Province (Western Iran)The research on the occurrence of herbivorous heteroptera ofLygusgenus on alfalfa (Medicago sativaL.) was carried out over 2005-2006 in the Hamedan province (Western Iran). The analysis of the faunistic material collected from Hemiptera showed the occurrence of 4 species where dominant Heteroptera were represented by:Lygus rugulipennisPoppius,L. pratensisL.,L. gemellatusH.-S. andL. punctatusZ. The maximum abundance of these species coincided with full flowering alfalfa. AmongLygusspecies,L. rugulipennisP. was the most highly abundant in alfalfa's the main species in these fields.
19
I., Prihantoro,, Anandia, A., Aryanto, A. T., Setiana, M. A. et Karti, P. D. M. H. « THE ADAPTATION LEVEL OF ALFALFA (MEDICAGO SATIVA L.) THAT IRRADIATED WITH GAMMA RAYS ON A FIELD SCALE ». Pastura 9, no 1 (24 septembre 2019) : 1. http://dx.doi.org/10.24843/pastura.2019.v09.i01.p01.
Texte intégralRésumé :
Alfalfa (Medicago sativa L.) a high nutritious and palatability legume for ruminant. Constrain of alfalfa availability in Indonesia are due to the plant adaptability in tropical environment. Aim of the study was to measure the adaptation level of alfalfa that irradiated with gamma rays on a field scale. The study consisted of four types of plant sources, mutation plants with different gamma ray levels (0Gy, 200Gy, 300Gy and 400Gy). Plant tillers was analyzed with a complete randomized design with 3 replications, 20 plants per replication. Growth capability, leaf color, flowering time and pest attack level were analyzed descriptively. The results showed that alfalfa irradiated with 300 Gy significantly (p<0.05) produced highest tillers. Irradiated 300 Gy plant gave better result on growth capability, flowering capability, and number of not attack plant from pests. The higher level of gamma ray irradiation showed the changed in leaf color levels from dark green to light green.
Keywords: alfalfa (Medicago sativa L.), mutation, gamma ray irradiation, field scale
20
Zhang, Zhiqiang, Qi Chen, Yao Tan, Shuang Shuang, Rui Dai, Xiaohong Jiang et Buhe Temuer. « Combined Transcriptome and Metabolome Analysis of Alfalfa Response to Thrips Infection ». Genes 12, no 12 (10 décembre 2021) : 1967. http://dx.doi.org/10.3390/genes12121967.
Texte intégralRésumé :
Thrips (Thysanoptera: Thripidae) is a major insect pest for alfalfa which can result in decreased plant nutrients, low yields, and even plant death. To identify the differentially expressed genes and metabolites in response to thrips in alfalfa, a combination of metabolomics and transcriptomics was employed using alfalfa (Caoyuan No. 2) with and without thrips infestation. The results showed that the flavonoid biosynthesis and isoflavonoid biosynthesis pathways were the most significantly enriched pathways in response to thrips infection, as shown by the combined transcriptome and metabolome analysis. The transcriptome results showed that SA and JA signal transduction and PAPM-triggered immunity and the MAPK signaling pathway–plant pathways played a crucial role in thrips-induced plant resistance in alfalfa. In addition, we found that thrips infestation could also induce numerous changes in plant primary metabolism, such as carbohydrate and amino acid metabolism as compared to the control. Overall, our results described here should improve fundamental knowledge of molecular responses to herbivore-inducible plant defenses and contribute to the design of strategies against thrips in alfalfa.
21
Bernier, Steve P., Laura Silo-Suh, Donald E. Woods, Dennis E. Ohman et Pamela A. Sokol. « Comparative Analysis of Plant and Animal Models for Characterization of Burkholderia cepacia Virulence ». Infection and Immunity 71, no 9 (septembre 2003) : 5306–13. http://dx.doi.org/10.1128/iai.71.9.5306-5313.2003.
Texte intégralRésumé :
ABSTRACT A simple alfalfa model was developed as an alternative infection model for virulence studies of the Burkholderia cepacia complex. Symptoms of disease were observed in wounded alfalfa seedlings within 7 days following inoculation of 101 to 105 CFU of most strains of the B. cepacia complex. Strains from seven genomovars of the B. cepacia complex were tested for virulence in the alfalfa model, and the degree of virulence was generally similar in strains belonging to the same genomovar. Strains of Burkholderia multivorans and some strains of Burkholderia stabilis did not cause symptoms of disease in alfalfa seedlings. Representative strains were also tested for virulence using the rat agar bead model. Most of the strains tested were able to establish chronic lung infections; B. stabilis strains were the exception. Most of the strains that were virulent in the alfalfa infection model were also virulent in the lung infection model. The B. cepacia genomovar III mutants K56pvdA::tp and K56-H15 were significantly less virulent in the alfalfa infection model than their parent strain. Therefore, this alfalfa infection model may be a useful tool for assessing virulence of strains of the B. cepacia complex and identifying new virulence-associated genes.
22
Beghdadi, Abdellatif, Claude Richard et Daniel Dostaler. « L'Aphanomyces euteiches des luzernières du Québec : isolement, morphologie et variabilité de la croissance et du pouvoir pathogène ». Canadian Journal of Botany 70, no 9 (1 septembre 1992) : 1903–11. http://dx.doi.org/10.1139/b92-236.
Texte intégralRésumé :
Sixteen strains of Aphanomyces euteiches were obtained from alfalfa seedlings by a baiting technique. They were found in the soil of 10 out of the 12 alfalfa fields sampled. In spite of some morphological variabililty, these strains were not taxonomically distinguishable from one another. They had different cultural characteristics (minimal, maximal, and optimal growth temperatures). Their pathogenicity was tested on alfalfa, garden pea, green bean, and garden beet. The green bean was lightly affected and a wide spectrum of pathogenicity was observed on alfalfa. Four pathogenicity groups were distinguished: (i) 13% of the strains were nonvirulent to the four hosts, (ii) 25% were specific to alfalfa, (iii) 25% were more virulent to alfalfa than to garden pea, and (iv) 37% were slightly pathogenic to both alfalfa and garden beet. The last group was characterized by a reduced mycelial growth at temperatures above 24 °C and the symptoms noticed on garden beet were similar to those caused by Aphanomyces cochlioides. Key words: Aphanomyces euteiches, alfalfa, garden beet, garden pea, green bean, pathogenicity.
23
Zhang, Lili, et Yanzhong Li. « Occurrence and Nutrition Indicators of Alfalfa with Leptosphaerulina in Chifeng, Inner Mongolia ». Agriculture 12, no 9 (14 septembre 2022) : 1465. http://dx.doi.org/10.3390/agriculture12091465.
Texte intégralRésumé :
Alfalfa Leptosphaerulina leaf spot is a common disease of alfalfa, while its effect on alfalfa quality has not been reported. The present study aimed to investigate the alfalfa Leptosphaerulina leaf spot in Chifeng City, Inner Mongolia, China and determine the quality of alfalfa plants and leaves with different scales. The incidence and disease index of nine alfalfa cultivars ranged from 12.1% to 59.8% and 10.0 to 51.0, respectively. The incidence of the Optimus cultivar and the disease index of the WL168 cultivar were significantly higher than those of the other cultivars. Therefore, different scales (0–4) of the alfalfa WL168 plant and leaves were used to determine their nutritional levels. Compared with healthy plants and leaves, the severity of alfalfa leaf spot on a scale of 4 decreased by 3.7% to 29.4% or 1.7% to 40.7%, respectively, in 18 nutrients; and increased by 12.0% to 14.5% or 17.8% to 26.9% in the Rumen protein (RUP), acid detergent fiber (ADF) and neutral detergent fiber (NDF), respectively. In addition, the crude protein (CP) content of alfalfa plants or leaves based on a severity scale of 4 decreased by 16.7% and 6.2%, respectively. Correlation analysis revealed a strong negative correlation between 18 nutritional contents and disease severity, except for NDF, ADF and RUP. Conclusively, alfalfa Leptosphaerulina leaf spot strongly influences the plant and the leaves’ nutrient content in the plant.
24
Ding, Ke Qiang. « Phytoremediation of Benzo[a]Pyrene-Contaminated Soil by Alfalfa (Medicago sativa L.) ». Advanced Materials Research 518-523 (mai 2012) : 5559–64. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.5559.
Texte intégralRésumé :
The roles of alfalfa(Lolium multiflorum L ) on remediation of B[a]P contaminated soil，the growth of alfalfa were studied in a pot experiment. The results showed that B[a]P content in soil decreased with culture time during 75d culture period. Alfalfa promotes this decrease. 75 days pot experiment showed that the concentration of B[a]P in soil grown alfalfa was significantly lower than that without plant grown ( P < 0. 05) .Under 1 ,10 and 100mg kg-1 B[a]P treatments, B[a]P biodegradability amounted to 69.5%, 75.2% and 79.1% respectively. While that of soil without plant growth were 47.4%，60.2% and 61.8%, respectively. The activity of soil urease are increasing in soil with plant grown and were obviously higher than those plant growing in uncontaminated soil(p < 0.05), which improved soil degradation ability of soil microbial and plants. There is also inhibition of high contamination on enzyme. Alfalfa makes little contribution to the removal of soil B[a]P. Though soil itself can biodegrade B[a]P, alfalfa could improve bioremediation role of B[a]P contaminated soil. Therefore, increasing alfalfa biomass, enhancing the activity of soil enzymes, creating a good environment condition can enhance the plants ability to remediate B[a]P contaminated soil.
25
Ells, James E., et Ann E. McSay. « Allelopathic Effects of Alfalfa Plant Residues on Emergence and Growth of Cucumber Seedlings ». HortScience 26, no 4 (avril 1991) : 368–70. http://dx.doi.org/10.21273/hortsci.26.4.368.
Texte intégralRésumé :
Growth chamber tests demonstrated that alfalfa (Medicago sativa L.) residue is toxic to cucumber (Cucumis sativus L.) seed germination and seedling growth. Ground alfalfa roots at 0.5% (w/w, dry weight) inhibited germination when added to the growing medium. Alfalfa roots at 0.5% were also toxic to pregerminated cucumber seed. However, cucumber seedlings grew normally if this same medium was watered and incubated for >1 day before planting. Alfalfa particle size in media influenced cucumber performance, with the intermediate size (1 to 2 mm) being lethal to cucumbers.
26
Gao, Yakun, Yinli Bi, Shaopeng Ma, Yanxu Zhang, Yun Guo, Yang Zhou, Shihao Xu et Peter Christie. « Yields of Buckwheat and Alfalfa in an Intercropping System Inoculated with Dark Septate Endophytes in a Coal Mining Subsidence Dryland Area ». Agronomy 12, no 11 (16 novembre 2022) : 2860. http://dx.doi.org/10.3390/agronomy12112860.
Texte intégralRésumé :
Coal mining subsidence areas in north Shaanxi province in north China are commonly low-fertility drylands, and intercropping is a popular method locally of maximizing crop yields. Inoculation with dark septate endophytes (DSE) can increase the yields of conventional crops grown in monoculture, but the effects of DSE on the growth and yield of intercropped plants are unknown. Here, a field experiment was conducted in a coal mining subsidence area on the loess plateau in 2020 and 2021. The two crops were buckwheat and alfalfa, with four treatments for each crop: sole cropping control, sole cropping with DSE inoculation, intercropping control, and intercropping with DSE inoculation. The yields, land equivalent ratios, DSE colonization rates, and yield components of buckwheat and alfalfa were compared in the different treatments. Stepwise regression and path analysis was conducted to identify the factors that determined crop yields. Yields of intercropped buckwheat and alfalfa with DSE inoculation increased in two consecutive years compared with sole cropping control, with yields increasing in 2020 by 117 and 86%, respectively. In 2021, the yield of buckwheat in intercropping with DSE inoculation did not increase significantly, but the yield of alfalfa increased by 120% compared with the sole cropping control. Buckwheat-alfalfa intercropping has the advantage of increasing the yield. DSE inoculation significantly increased the yield of buckwheat-alfalfa intercropping in 2020, but there was no yield advantage in 2021. The yield components of buckwheat and alfalfa showed inconsistent differences among experimental treatments. Stepwise regression and path analysis shows that the DSE colonization rate played an important role in the yield, which was an increased in buckwheat and alfalfa in 2020 and 2021. DSE affected the buckwheat yield indirectly by increasing the grain weight per plant, plant phosphorus uptake, and plant nitrogen content. DSE indirectly affected alfalfa yields by increasing plant nitrogen uptake and plant height. DSE may therefore have some potential to increase yields in buckwheat-alfalfa intercropping systems in coal mining subsidence areas.
27
Berg, B. P., W. Majak, T. A. McAllister, J. W. Hall, D. McCartney, B. E. Coulman, B. P. Goplen, S. N. Acharya, R. M. Tait et K. J. Cheng. « Bloat in cattle grazing alfalfa cultivars selected for a low initial rate of digestion : A review ». Canadian Journal of Plant Science 80, no 3 (1 juillet 2000) : 493–502. http://dx.doi.org/10.4141/p99-051.
Texte intégralRésumé :
The occurrence of frothy bloat limits the practice of alfalfa grazing in spite of the availability of strains bred specifically for pasture. Bloat is a chronic condition, endemic to cattle. Prophylactics and management techniques are available to reduce its incidence but they are expensive, difficult to administer, conflict with traditional grazing management regimens and do not eliminate bloat in all circumstances. A program to breed and evaluate a bloat-reduced strain of alfalfa was initiated in 1980 to overcome some of these limitations. A review of the results of grazing and feeding trials using alfalfas with low initial rates of digestion (LIRD) shows that this new strain reduces the incidence and severity of frothy bloat on pasture. Their effectiveness in controlling bloat was related to feeding or grazing management practices, the maturity of the plants and the season of use. Graziers may reduce the risk of occasional livestock losses from bloat by using LIRD cultivars, like AC Grazeland, or managing species/cultivar mixtures in ways that reduce the initial rate of digestion. Other bloat preventive strategies, including co-seeding with bloat-free legumes and using bloat-controlling prophylactics in combination with a LIRD alfalfa, are being investigated. Key words: Bloat, alfalfa, lucerne, legume, low initial rates of digestion, cattle, grazing
28
Schaber, B. D., W. A. Charnetski et T. Entz. « Early and Late-Season Insecticide Applications in Seed Alfalfa : Impact on Pest Species and Yield2 ». Journal of Entomological Science 25, no 4 (1 octobre 1990) : 548–58. http://dx.doi.org/10.18474/0749-8004-25.4.548.
Texte intégralRésumé :
Alfalfa is grown for seed on approximately 9,500 ha in Alberta, Canada. Pest insects, such as Lygus spp. and the alfalfa plant bug, Adelphocoris lineolatus (Goeze), (Heteroptera: Miridae) can reduce seed yield if they are not controlled. However, little is known of the damage caused by these pest insects during late seed formation and development. Field studies were conducted during 1983 and 1986 to determine the effect of early- and late-season applications of the insecticides trichlorfon and phosmet alone and combined on Lygus spp., alfalfa plant bug and seed yield of alfalfa. Effects were dependent on the time of application, year, and insect species. Lygus spp. densities for late-season trichlorfon treatments were significantly (P < 0.05) lower than the control. Trichlorfon and phosmet had no effect on densities of alfalfa plant bugs in 1983, but some late-season trichlorfon treatments did reduce plant bug densities in 1986. Seed yields in plots receiving late-season trichlorfon were generally greater than in the control in both years.
29
Sisi, Davod Efhami, Alinaghi Karimi, Kambiz Pourtahmasi, Hamid Reza Taghiyari et Farhad Asadi. « The Effects of Agroforestry practices on vessel properties in Populus Nigra var. Betulifolia ». IAWA Journal 31, no 4 (2010) : 481–87. http://dx.doi.org/10.1163/22941932-90000037.
Texte intégralRésumé :
The effects of intercropping with alfalfa and initial tree spacing on vessel diameter and frequency in Populus nigra var. betulifolia are reported, on the basis of a study of fifteen trees. Material was harvested from anagroforestry trial near Karaj city, Iran. Treatments included four initial spacings between poplar trees intercropped with alfalfa as a nitrogenfixing plant, as well as one control treatment without alfalfa. Intercropping with alfalfa as well as increasing initial spacing had a positive effect on growth rate which in turn affected the diameter and frequency of the vessels. Intercropping with alfalfa resulted in increased vessel diameter and frequency; while wider initial spacing decreased the vessel frequency (VF), and to some extent the vessel lumen area percentage (VLA%), but increased vessel lumen diameter (VLD).
30
STAVARACHE, Mihai, Costel SAMUIL, Constantin I. POPOVICI, Doina TARCĂU et Vasile VÂNTU. « The Productivity and Quality of Alfalfa (Medicago sativa L.) in Romanian Forest Steppe ». Notulae Botanicae Horti Agrobotanici Cluj-Napoca 43, no 1 (19 juin 2015) : 179–85. http://dx.doi.org/10.15835/nbha4319939.
Texte intégralRésumé :
Alternative use of alfalfa, for various purposes, including the production of biofuels or food supplement for human alimentation, is a study topic still in its early stages of research. Studying and understanding the biology of alfalfa and the factors with a major influence on it are very important activities. The productivity and quality of alfalfa are two indicators that help determine, in addition to economic value, the way in which alfalfa can be used. Evolution of alfalfa yield and quality depends on many factors, such as the growth stage of alfalfa plants at harvesting. It was observed over three years of vegetation the influence of alfalfa plant growth stage at harvest on plant height, leaves/stems ratio, production of leaves, stems and whole plant (DM - dry matter) per hectare and on quality indicators (CP - crude protein, NDF - neutral detergent fiber and ADF - acid detergent fiber). The results showed that, with the advancement of phenological phases, from early bud stage to complete flowering, the total biomass output raised from 2.79 Mg·ha-1 to 4.60 Mg·ha-1, the neutral detergent fiber raised from 48.4-50.6% to 62.0-67.7%, while crude protein content decreased from 21.2-24.0% to 13.3-16.5%. The parameter values were correlated with alfalfa growth stage during the harvesting (significant at the 0.05 and 0.01 probability levels).
31
Mao, Kai, Zhu Yu, Shuai Huang, Musen Wang et David B. Hannaway. « Effect of Storage Period on the Fermentation Profile and Bacterial Community of Silage Prepared with Alfalfa, Whole-Plant Corn and Their Mixture ». Fermentation 8, no 10 (26 septembre 2022) : 486. http://dx.doi.org/10.3390/fermentation8100486.
Texte intégralRésumé :
This study aimed to investigate the impact of storage time on the bacterial community and fermentation profile of silage prepared with alfalfa, whole-plant corn, and their mixture. Fresh alfalfa and whole-plant corn were chopped and combined in fresh weight ratios of 1:0 (alfalfa, control), 0.8:0.2 (M1), 0.6:0.4 (M2), and 0:1 (corn). Three silos of each treatment were analyzed after 30, 60, and 90 d of storage. With storage time, pH, acetic acid, propionic acid, butyric acid, and ammonia nitrogen levels increased in alfalfa silage (p < 0.01), whereas lactic acid level decreased (p < 0.01). Compared to alfalfa silage, M1, M2, and corn silages were better fermented and more stable during storage. The dominant bacteria in M1, M2, and corn silages shifted significantly from L. plantarum, L. buchneri, and L. brevis to L. acetotolerans and L. buchneri during 30 to 60–90 d of storage, and storage time decreased the bacterial diversity of these silages. In conclusion, storage time significantly decreased the fermentation quality of alfalfa silage and remarkably optimized the bacterial community structure of well-fermented M1, M2, and corn silages. Alfalfa should be ensiled with at least 20% whole-plant corn to improve silage fermentation quality and storage stability.
32
Shalan Augu, Razzaq, et H. H. Al-Saffar. « Survey of Coleopteran Insects on Alfalfa Plant ». International Journal of Current Microbiology and Applied Sciences 5, no 3 (10 mars 2016) : 792–801. http://dx.doi.org/10.20546/ijcmas.2016.503.092.
Texte intégral
33
Brummer, E. C., et J. H. Bouton. « Plant Traits Associated with Grazing‐Tolerant Alfalfa ». Agronomy Journal 83, no 6 (novembre 1991) : 996–1000. http://dx.doi.org/10.2134/agronj1991.00021962008300060014x.
Texte intégral
34
Chung, Ill‐Min, et Darrell A. Miller. « Effect of Alfalfa Plant and Soil Extracts on Germination and Growth of Alfalfa ». Agronomy Journal 87, no 4 (juillet 1995) : 762–67. http://dx.doi.org/10.2134/agronj1995.00021962008700040025x.
Texte intégral
35
SMALL, ERNEST. « INSECT PESTS AND THE EVOLUTION OF DEFENSIVE GLANDULAR TRICHOMES IN ALFALFA ». Canadian Journal of Plant Science 65, no 3 (1 juillet 1985) : 589–96. http://dx.doi.org/10.4141/cjps85-081.
Texte intégralRésumé :
Glandular trichomes can defend (Medicago species from herbivores in a variety of insect orders. Wild alfalfas with high concentrations of glandular trichomes occur in a restricted portion of the geographical range of the species (Medicago saliva L. sensu lato), especially in the Caucasus, Ukraine, and adjacent areas of the USSR. These observations suggest that this adaptation was developed to defend the alfalfa against insect pests with similar geographical distribution. That M. sativa plants with pods covered with glandular hairs tend to have larger, if fewer, seeds than plants with pods lacking the hairs also suggests an adaptation against herbivores. Because the glandular trichomes occur primarily on the ovaries and pods, the pests likely feed on seeds. After considering the biology and geography of the major Soviet insect pests of cultivated alfalfa, it was concluded that the most likely insects responsible for the localized evolution of pod glandularity are species of Tychius (Coleoptera: Curculionidae).Key words: Alfalfa, Medicago sativa L., seed chalcid, Brachophagus, Tychius, glandular trichomes, pest resistance (immunity)
36
Abbasi, Mohammad Reza. « Resistance to the alfalfa weevil in the Iranian collection of Medicago sativa ». Tropical Grasslands-Forrajes Tropicales 8, no 3 (30 septembre 2020) : 263–79. http://dx.doi.org/10.17138/tgft(8)263-279.
Texte intégralRésumé :
The Iranian collection of Medicago sativa (alfalfa, 502 accessions) was evaluated under field conditions to identify variation in resistance to the alfalfa weevil (Hypera postica Gyllenhal) between accessions over 4 years. Twenty-one accessions were identified as resistant (score 3) to semi-resistant (score 5) based on K-means cluster analysis. These materials were grouped into 10 groups by means of Duncan's Multiple Range Test. Susceptibility to alfalfa weevil was significantly correlated with some of the agro-morphological traits such as plant height (r = 0.314, P<0.01), regrowth rate (r = 0.435, P<0.01) and fall dormancy score (r = 0.284, P<0.01). In general, the resistant germplasm originated from elevated regions at high latitudes, where a co-evolution between the plant and the pest may have taken place. Multiple regression analysis showed a positive linear relationship between susceptibility to the alfalfa weevil and traits such as growth habit, plant height, length and width of the central leaflet and regrowth rate. The resulting bi-plot based on factor analysis ranked accessions for susceptibility to the pest. The identified germplasm should prove useful in alfalfa breeding programs to develop accessions resistant to the alfalfa weevil.
37
Nameth, Stephen G. P., Landon H. Rhodes et Magally Luque-Williams. « A Survey of Viruses Infecting Alfalfa in Ohio ». Plant Health Progress 2, no 1 (janvier 2001) : 16. http://dx.doi.org/10.1094/php-2001-0605-01-hn.
Texte intégralRésumé :
This report describes a survey of the alfalfa-growing areas in Ohio in an effort to identify the viruses present in alfalfa and their frequency. Results indicate that approximately 75% of the alfalfa samples tested were infected with either AMV and/or RCVMV. This is the first report of these viruses in Ohio alfalfa. Accepted for publication 25 May 2001. Published 5 June 2001.
38
Kassimi, Abderrahmane, et Lahcen El Watik. « Comparison of Insecticide Effect of Plant Extracts on Aphids of Watermelon and Green Alfalfa ». Sustainable Agriculture Research 1, no 2 (29 juillet 2012) : 301. http://dx.doi.org/10.5539/sar.v1n2p301.
Texte intégralRésumé :
<p>The watermelon and the green alfalfa are important crops in Morocco. The ripe fruit of the watermelon has a high nutritional value, rich in vitamin and mineral salts and used for medicinal purposes (kidneys and cleaning of the urinary tract). The alfalfa green is principally cultivated for livestock feed.</p> <p>A common problem in the production of watermelon and the alfalfa is the infestation by aphids. They transmit viruses of the tile to the plants. They are more likely to be a problem in the time costs. The study presents the effects of products Thyme, Oregano, Neem and their mixture on the aphids of watermelon in comparison with their effects on aphids of alfalfa green.</p> <p>The tests were conducted of the months from May to September on the aphids on the fields of watermelon and alfalfa green. It determines the percentage of deaths of aphids in function of the dose 1% and 5% for these products and the time 3, 5 and 7 hours after treatment. A comparison between the results obtained showed that the extract of Thyme is more active in watermelon and the Oregano is in alfalfa.</p>
39
Tao, Menghuan, Yao Zhao, Tianxue Hu, Quan Zhang, Hui Feng, Yiwen Lu, Zhenfei Guo et Bo Yang. « Screening of Alfalfa Varieties Resistant to Phytophthora cactorum and Related Resistance Mechanism ». Plants 12, no 4 (5 février 2023) : 702. http://dx.doi.org/10.3390/plants12040702.
Texte intégralRésumé :
Alfalfa is one of the most important legume forages in the world. Root rot caused by soil-borne pathogens severely restricts the production of alfalfa. The knowledge of the interaction between alfalfa and root rot-pathogens is still lacking in China. Phytophthora cactorum was isolated from symptomatic seedlings of an alfalfa field in Nanjing with high levels of damping-off. We observed the different infection stages of P. cactorum on alfalfa, and found that the purified P. cactorum strain was aggressive in causing alfalfa seed and root rot. The infecting hyphae penetrated the epidermal cells and wrapped around the alfalfa roots within 48 h. By evaluating the resistance of 37 alfalfa cultivars from different countries to P. cactorum, we found Weston is a resistant variety, while Longdong is a susceptible variety. We further compared the activities of various enzymes in the plant antioxidant enzyme system between Weston and Longdong during P. cactorum infection, as well as gene expression associated with plant hormone biosynthesis and response pathways. The results showed that the disease-resistant variety Weston has stronger antioxidant enzyme activity and high levels of SA-responsive PR genes, when compared to the susceptible variety Longdong. These findings highlighted the process of interaction between P. cactorum and alfalfa, as well as the mechanism of alfalfa resistance to P. cactorum, which provides an important foundation for breeding resistant alfalfa varieties, as well as managing Phytophthora-caused alfalfa root rot.
40
Kang, Sang-Mo, Muhammad-Aaqil Khan, Muhammad Hamayun, Lee-Rang Kim, Eun-Hae Kwon, Yo-Sep Kang, Ki-Yong Kim, Jae-Jeong Park et In-Jung Lee. « Phosphate-Solubilizing Enterobacter ludwigii AFFR02 and Bacillus megaterium Mj1212 Rescues Alfalfa’s Growth under Post-Drought Stress ». Agriculture 11, no 6 (24 mai 2021) : 485. http://dx.doi.org/10.3390/agriculture11060485.
Texte intégralRésumé :
Drought stress is a prevalent environmental stress that adversely affects agricultural industries worldwide. In this study, bacterial isolates, AFFR02 and Mj1212, showed tolerance to polyethylene glycol-induced (PEG) drought stress (approximately 15%) and possess strong phosphate-solubilizing capacity. Moreover, we investigated the plant growth attributes, chlorophyll content, and ion uptake in alfalfa plants (Medicago sativa L) inoculated with isolates AFFR02 and Mj1212 under drought stress. We observed that drought stress drastically affects alfalfa’s growth attributes: shoot length: SL (24.88%), root length: RL (29.62%), shoot fresh weight: SFW (49.62%), root fresh weight: RFW (45.09%), stalk diameter: SD (52.84%), and chlorophyll content: CC (19.2%). However, in bacterial-inoculated alfalfa plants, the growth attributes significantly recovered were SL (12.42%), RL (21.30%), SFW (50.74%), RFW (46.42%), SD (76.72%), and CC (17.98%). In drought-stressed alfalfa plants, we observed a significant decrease in the relative water content (7.45%), whereas there was an increase in electrical conductivity (68.87%) and abscisic acid contents (164.42%). Antioxidant analysis showed a significant increase in total phenolic content (46.08%), DPPH-scavenging activity (39.66%), total flavonoid (13.68%), and superoxide dismutase (28.51%) in alfalfa treated with drought stress and bacterial isolates AFFR02 and Mj1212 simultaneously. Moreover, an increase in inductively coupled plasma (ICP) analysis of potassium (17.98%), phosphorous (11.14%), calcium (3.07%), and magnesium (6.71%) was recorded for bacteria-inoculated alfalfa plants under drought stress. In conclusion, bacterial isolates AFFR02 and Mj1212 enhance alfalfa growth under drought stress. Therefore, the isolates could be used as potential candidates in smart-climate agricultural practices in drought-stricken areas worldwide.
41
She, Dong Li, Ming An Shao, Luis Carlos Timm et Klaus Reichardt. « Temporal changes of an alfalfa succession and related soil physical properties on the Loess Plateau, China ». Pesquisa Agropecuária Brasileira 44, no 2 (février 2009) : 189–96. http://dx.doi.org/10.1590/s0100-204x2009000200011.
Texte intégralRésumé :
The objective of this work was to investigate the relationship between changes in the plant community and changes in soil physical properties and water availability, during a succession from alfalfa (Medicago sativa L.) to natural vegetation on the Loess Plateau, China. Data from a succession sere spanning 32 years were collated, and vegetative indexes were compared to changes related to soil bulk density and soil water storage. The alfalfa yield increased for approximately 7 years, then it declined and the alfalfa was replaced by a natural community dominated by Stipa bungeana that began to thrive about 10 years after alfalfa seeding. Soil bulk density increased over time, but the deterioration of the alfalfa was mainly ascribed to a severe reduction in soil water storage, which was lowest around the time when degradation commenced. The results indicated that water consumption by alfalfa could be reduced by reducing plant density. The analysis of the data also suggested that soil water recharge could be facilitated by rotating the alfalfa with other crops, natural vegetation, or bare soil.
42
Zhang, Mingzhu, Chao Peng, Wentao Sun, Rui Dong et Jun Hao. « Effects of Variety, Plant Location, and Season on the Phyllosphere Bacterial Community Structure of Alfalfa (Medicago sativa L.) ». Microorganisms 10, no 10 (13 octobre 2022) : 2023. http://dx.doi.org/10.3390/microorganisms10102023.
Texte intégralRésumé :
Plant phyllosphere bacteria are vital for plant health and productivity and are affected by both abiotic and biotic factors. In this study, we surveyed the structure of the phyllosphere bacterial community associated with alfalfa. For two varieties of alfalfa, forty-eight samples of phyllosphere communities were collected at two locations over four seasons in 2020. Proteobacteria and actinobacteria were associated with the dominating phylum in the bacterial communities of the alfalfa phyllosphere. Sphingomonas was the most abundant genus-level bacteria, followed by Methylobacterium, Burkholderia-Caballeronia-Paraburkholderia, and Pseudomonas. Sampling time had a greater affect than site and variety on alfalfa surface microorganisms. The variation in phyllosphere bacterial community assembly was mostly explained by the season–site interaction (43%), season–variety interaction (35%), and season (28%). Variety, site–variety interaction, and season–site–variety interactions did not have a meaningful effect on phyllosphere bacterial diversity and community structure. The bacterial community in the phyllosphere of alfalfa showed seasonal changes over time. The environmental factors that contributed most to the phyllosphere bacterial community of alfalfa were temperature and sunshine duration, which were significantly positively correlated with most of the dominant bacterial genera in the alfalfa phyllosphere.
43
Bagavathiannan, Muthukumar V., Robert H. Gulden et Rene C. Van Acker. « The Ability of Alfalfa (Medicago sativa) to Establish in a Seminatural Habitat under Different Seed Dispersal Times and Disturbance ». Weed Science 59, no 3 (septembre 2011) : 314–20. http://dx.doi.org/10.1614/ws-d-10-00144.1.
Texte intégralRésumé :
Alfalfa is an important forage crop in North America, and it can also be found as a roadside weed in alfalfa-growing regions. Weediness and invasiveness are greatly facilitated by establishment ability, yet little is known about the ability of alfalfa to establish in competitive environments such as roadsides. The primary objective of this study was to estimate the degree of alfalfa establishment without managed cultivation under different seed-dispersal times and disturbance regimes. The study had a split-plot design with two main plots (spring and fall seed dispersal) and five subplots (mowing, soil disturbance, herbicide spray, seedbed, and undisturbed control). The study examined establishment, growth attributes, and reproductive output of alfalfa in response to these treatments. Alfalfa establishment in the undisturbed grass swards ranged between 0.5 and 9.7% (out of the total number of seeds dispersed) across the dispersal times. The density of alfalfa in fall-seeded plots was about 82% lower than in spring-seeded plots. Soil disturbance reduced the density of alfalfa to < 50% of the initial density. Generally, low plant densities were compensated over time by increased numbers of shoots and reproductive units (racemes and pods) per plant. Herbicide application (2,4-D + dicamba) effectively controlled all emerged alfalfa plants, but in some cases, seedling recruitment was observed in the years following herbicide application. Although mowing did not kill alfalfa plants, mowed plants did not produce mature seeds, and as such, mowing may be useful in restricting the reproductive success and population growth of alfalfa. Overall, it is evident that alfalfa is capable of establishing in competitive environments (such as roadside habitats) and rapidly recovering from moderate disturbances. The results of this study have implications for managing roadside alfalfa and for designing novel trait-confinement protocols for alfalfa.
44
Fischer, Albert J., Jean H. Dawson et Arnold P. Appleby. « Interference of Annual Weeds in Seedling Alfalfa (Medicago sativa) ». Weed Science 36, no 5 (septembre 1988) : 583–88. http://dx.doi.org/10.1017/s0043174500075445.
Texte intégralRésumé :
Barnyardgrass [Echinochloa crus-galli(L.) Beauv. #4ECHCG] and pigweeds (mixture ofAmaranthus retroflexusL. # AMARE andA. powelliiS. Wats. # AMAPO) seeded separately with alfalfa (Medicago sativaL.) in mid-August suppressed alfalfa severely before frost killed them in October and November. Some alfalfa was killed, and yield of alfalfa forage was reduced in each of three harvests the following year. These weeds did not harm alfalfa seeded in mid-September. Downy brome (Bromus tectorumL. # BROTE) and tumble mustard (Sisymbrium altissimumL. # SSYAL) suppressed alfalfa seeded in August and September. They reduced alfalfa stands and reduced yield of alfalfa forage in each of three harvests the following year. Alfalfa seeded August 27 and allowed to compete with a mixture of these species for various periods was injured most by weeds that emerged with the alfalfa and remained uncontrolled until forage harvest in May. These weeds did not reduce alfalfa yields if removed by 36 days after alfalfa emergence. Thereafter, yield decreased as the period of weed interference increased. Interference was most damaging in early spring, when growth of winter annual weeds was rapid and vigorous. Weeds seeded 65 or more days after alfalfa emergence did not reduce alfalfa yields but sometimes produced enough biomass to reduce the quality of the first-cutting alfalfa hay.
45
Ma, Lin, Yongchao Zhang, Hongyu Wen, Wenhui Liu, Yu Zhou et Xuemin Wang. « Silencing of MsD14 Resulted in Enhanced Forage Biomass through Increasing Shoot Branching in Alfalfa (Medicago sativa L.) ». Plants 11, no 7 (30 mars 2022) : 939. http://dx.doi.org/10.3390/plants11070939.
Texte intégralRésumé :
Branching is one of the key determinants of plant architecture that dramatically affects crop yield. As alfalfa is the most important forage crop, understanding the genetic basis of branching in this plant can facilitate breeding for a high biomass yield. In this study, we characterized the strigolactone receptor gene MsD14 in alfalfa and demonstrated that MsD14 was predominantly expressed in flowers, roots, and seedpods. Furthermore, we found that MsD14 expression could significantly respond to strigolactone in alfalfa seedlings, and its protein was located in the nucleus, cytoplasm, and cytomembrane. Most importantly, transformation assays demonstrated that silencing of MsD14 in alfalfa resulted in increased shoot branching and forage biomass. Significantly, MsD14 could physically interact with AtMAX2 and MsMAX2 in the presence of strigolactone, suggesting a similarity between MsD14 and AtD14. Together, our results revealed the conserved D14-MAX2 module in alfalfa branching regulation and provided candidate genes for alfalfa high-yield molecular breeding.
46
Spandl, Eric, James J. Kells et Oran B. Hesterman. « Weed Invasion in Established Alfalfa (Medicago sativa) Seeded with Perennial Forage Grasses ». Weed Technology 11, no 3 (septembre 1997) : 556–60. http://dx.doi.org/10.1017/s0890037x00045413.
Texte intégralRésumé :
Component yields and forage quality were evaluated in established stands of alfalfa seeded alone and in binary mixtures with smooth bromegrass, orchardgrass, or timothy. Forage yields and quality were determined at three annual harvests in the third and fourth years after seeding. Weed yields in alfalfa seeded alone were significantly greater than those in the alfalfa–orchardgrass mixture. Average weed content was 24, 17, 2, and 15% for the alfalfa seeded alone, alfalfa–bromegrass, alfalfa–orchardgrass, and alfalfa–timothy, respectively. Seeding alfalfa with orchardgrass increased first harvest and annual forage yields while reducing alfalfa yield. Yields of orchardgrass often exceeded those of bromegrass or timothy. In the first harvest each year, crude protein was reduced and acid detergent fiber and neutral detergent fiber increased by including orchardgrass. Neutral detergent fiber was greater in alfalfa–orchardgrass than in the alfalfa seeded alone at most harvests. There were no consistent differences among the alfalfa seeded alone and the other mixtures in yield or quality.
47
Grabber, John H., Damon L. Smith, William R. Osterholz et Mark J. Renz. « Establishment and First Year Yield of Interseeded Alfalfa as Influenced by Corn Plant Density and Treatment with Prohexadione, Fungicide and Insecticide ». Agronomy 11, no 11 (19 novembre 2021) : 2343. http://dx.doi.org/10.3390/agronomy11112343.
Texte intégralRésumé :
Interseeding alfalfa (Medicago sativa L.) into a silage corn (Zea mays L.) companion crop can increase the yield and profitability of forage production and reduce the risk of nutrient and soil loss from cropland, but unreliable establishment of alfalfa hampers the adoption of this practice on dairy farms. This study evaluated plant survival, foliar health, and dry matter yields of two alfalfa varieties when established in corn sown at populations ranging from about 47,500 to 100,000 plants per ha−1 and when treated with prohexadione (PHD), PHD followed by fungicide and insecticide (PHD-FI), or not treated with agrichemicals. The plant density of alfalfa during establishment was adversely impacted by above average precipitation and high corn populations, but substantially improved by PHD-FI treatment, which limited alfalfa etiolation, disease, and defoliation. First-cut dry-matter yields of interseeded alfalfa after corn were maximized at a stand density of approximately 200 plants m−2 or 850 stems m−2 and total first year yield exceeded conventionally spring-seeded alfalfa by 59 to 75%. Overall, our results indicated that PHD-FI treatment promoted good establishment and subsequent forage production of interseeded alfalfa. Applications of PHD-FI must, however, be fine-tuned, and additional management practices must be developed to ensure both good yields of corn silage and reliable establishment of interseeded alfalfa, especially during wet growing conditions.
48
Acharya, S. N., et H. Steppuhn. « Bridgeview alfalfa ». Canadian Journal of Plant Science 92, no 1 (janvier 2012) : 203–6. http://dx.doi.org/10.4141/cjps2011-114.
Texte intégralRésumé :
Acharya, S. N. and Steppuhn, H. 2012. Bridgeview alfalfa. Can. J. Plant Sci. 92: 203–206. Bridgeview salt tolerant alfalfa (Medicago sativa L.) was developed by the Agriculture and Agri-Food Canada Research Centre, Lethbridge, Alberta in cooperation with the salt laboratory at Semiarid Prairie Agricultural Research Centre, Swift Current, Saskatchewan. This synthetic cultivar, tested as SC-A101 in the Western Forage Testing System (WFTest), was developed for improved seedling vigor and high forage yield under saline conditions. This cultivar yielded about 1% better than Beaver check in the WFTest over 36 location years. The pedigree of this cultivar consists of saline tolerant selections from Apica, AC Blue J, Barrier, Beaver, Heinrichs, Rangelander and Roamer alfalfa. This cultivar produced higher dry matter yield than Beaver in the third year of a test conducted in a naturally saline seep area in Vauxhall, AB. SC-A101 was found to perform significantly higher emergence, survival and biomass production than Rangelander alfalfa in an indoor test at salt levels higher than 16 dS m−8. Bridgeview was registered by CFIA on 2011 May 16 (Reg. No. 7018) and was licensed to SeCan for seed multiplication and distribution. This cultivar is well suited for hay production in western Canada.
49
Wood, Karl V., Kelly J. Stringham, David L. Smith, Jeffrey J. Volenec, Kerry L. Hendershot, Kimberly A. Jackson, Patrick J. Rich, Wen-Ju Yang et David Rhodes. « Betaines of Alfalfa ». Plant Physiology 96, no 3 (1 juillet 1991) : 892–97. http://dx.doi.org/10.1104/pp.96.3.892.
Texte intégral
50
Huo, Wei Jie, Huai Dong Zhou, Ling Hua Liu et Jia Peng Wu. « Performance of Soil-Plant Systems in Agricultural Pollutants Removal in Surface Runoff ». Advanced Materials Research 518-523 (mai 2012) : 2640–48. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.2640.
Texte intégralRésumé :
Simulated runoff was conducted on self-designed soil bins to compare the effectiveness of 6m treating systems consisting of contrast system(bear soil),soil-tall fescue system and soil-alfalfa system in reducing SS, NO3--N,NH4+-N,TDP and PP. The concentration reductions were greater in soil-plant system compared with contrast. Vegetation type (Tall fescue and alfalfa) had somewhat affection on contaminant removal. The mean concentration reductions of SS, NO3--N,NH4+-N,TDP and PP reached 86.61%,25.83%,52.03%,26.53%and 76.59% under tall fescue, which were slightly higher than Alfalfa. However, the load reductions of alfalfa neared to that of tall fescue due to more water detained, which made Alfalfa show the same potential in runoff clarification as tall fescue. The removal efficiency of NO3--N and NH4+-N decreased significantly with increasing concentration, while the changes of SS ,PP and TDP were much smaller, which meant the conditions of vegetation and soil in this study were not enough to deal with NO3--N and NH4+-N increasing, and the ground roughness could bear SS and PP increasing. Most SS and PP were trapped in first 2m and it was ineffective to increase the runoff distance beyond 4m for removal. The reduction of resolved compound occurred uniformly along the runoff and it related with runoff extension distance linearly.