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1
Ferguson, C. M., D. M. Barton e B. A. Philip. "Clover root weevil tolerance of clover cultivars". Journal of New Zealand Grasslands 78 (1 gennaio 2016): 197–202. http://dx.doi.org/10.33584/jnzg.2016.78.500.
Testo completoAbstract (sommario):
Clover root weevil arrived in New Zealand about 20 years ago causing major loss of productivity as it progressively spread across the whole country. It is now largely controlled by an introduced parasitic wasp biocontrol agent Microctonus aethiopoides (Irish ecotype). However, management of insect pests should not rely on a single mechanism and clovers resistant or tolerant to this weevil would be a useful augmentation for farmers to have. This investigation reports on the suitability of 22 clover cultivars to attack from the weevil. Results have shown that contrary to popular belief, red clovers are not universally less favourable to the weevil than white clovers and usefully, within both species cultivar differences point to the possibility of resistance to this pest. Keywords: Clover root weevil, Sitona obseletus, clover cultivars
2
Eden, T. M., P. J. Gerard, D. J. Wilson e N. L. Bell. "Effects of invertebrate pests on white and annual clovers in dryland soil". New Zealand Plant Protection 63 (1 agosto 2010): 235–40. http://dx.doi.org/10.30843/nzpp.2010.63.6574.
Testo completoAbstract (sommario):
Two experiments were carried out at Ruakura in soil taken from Whatawhata hill country pasture The relative susceptibility of several annual clovers (Trifolium spp) and perennial white clover (T repens) to slugs (Deroceras reticulatum) clover root weevil (Sitona lepidus) adults native crickets (Nemobius sp) or wheat bugs (Nysius huttoni) was tested by sowing seed of the clovers into separate rows in turf Susceptibility of clovers to clover cyst nematode (Heterodera trifolii) was tested by sowing each clover variety into Whatawhata soil inoculated with the nematode Plant growth was assessed in both experiments 4 weeks after sowing White clover was more susceptible to pests than the annual clovers with slugs and clover root weevil significantly reducing seedling survival and clover cyst nematode significantly reducing plant growth Subterranean clover (T subterraneum) cv Denmark was the least affected by pests showing no significant reduction in survival in the presence of slugs the most damaging pest and no significant decrease in plant root and shoot dry weight when exposed to nematodes
3
Gerard, Crush, e S. Rasmussen. "Formononetin in clovers as a feeding deterrent against clover root weevil". NZGA: Research and Practice Series 12 (1 gennaio 2006): 135–39. http://dx.doi.org/10.33584/rps.12.2006.3027.
Testo completoAbstract (sommario):
The effect of leaf feeding by adult clover root weevils on the isoflavonoid content of red and white clovers was investigated in a glasshouse experiment. Lines of both clovers previously selected for variation in formononetin content were used. A higher percentage of white clover leaves than red clover leaves were damaged by the weevils, and the high formononetin red clover was least readily eaten. The formononetin content of the white clovers did not differ between the selections, was much lower than in the red clovers, and did not change in response to weevil feeding. In both red clover lines, formononetin and biochaninA levels rose in response to weevil feeding, suggesting that both compounds have antifeedant properties against clover root weevil. Because high foliar levels of oestrogenic compounds like formononetin threaten fertility of grazing sheep it is concluded that plant breeding programmes should increase the levels of formononetin and/or biochaninA in clover roots to mitigate the impact of weevil larval feeding on roots and nodules.
4
Gerard, P. J., C. M. Ferguson e S. Van Amsterdam. "Comparison of New Zealand perennial clovers for resilience against common pasture pests". New Zealand Plant Protection 70 (25 luglio 2017): 241–49. http://dx.doi.org/10.30843/nzpp.2017.70.57.
Testo completoAbstract (sommario):
Clovers (Trifolium spp.) are vulnerable to a large number of invertebrate pests so pest resilience amongst 19 leading commercial or near release New Zealand-bred clover cultivars was compared. Laboratory feeding choice tests comparing foliage from the test clovers against Grasslands Kopu II as the standard confirmed that red clovers (T. pratense) were less preferred than white clovers (T. repens) by adult clover root weevil and clover flea. Grey field slug showed no preference between red and white clovers, with the white clover Grassland Prestige performing the best. Porina larvae had lowest weight gains on strawberry clover (T. fragiferum). Subsequent tests using neonate greenheaded leafroller larvae and an artificial diet made with freeze-dried foliage from cultivars in the most and least preferred subgroups indicated antifeedant compounds, rather than leaf morphology, are likely responsible for differences in feeding preferences between red and white clovers.
5
Macfarlane, M. J., P. D. Muir e E. Crofoot. "The role of plantain (Plantago lanceolata) on East Coast dryland: results from three farm case studies". Journal of New Zealand Grasslands 77 (1 gennaio 2015): 103–8. http://dx.doi.org/10.33584/jnzg.2015.77.494.
Testo completoAbstract (sommario):
Three on-farm sites where plantain was sown with legumes and/or perennial ryegrass were monitored for 2 years post-sowing. On two cultivated sites in Hawke's Bay, newly sown plantain/clover pastures produced 20% and 22% more dry matter, respectively, than newly sown ryegrass/clover or established pastures. On an uncultivatable site in coastal Wairarapa, aerially oversowing of plantain and clover resulted in 282% more dry matter than resident pasture on north faces. Plantain pastures had higher clover contents and lambs had faster growth rates and higher dressing-out percentages than lambs finished on traditional ryegrass/clover pastures. Plantain and a mix of annual and perennial clovers offer a promising alternative to ryegrass-based systems in dryland. As with lucerne, plantain and erect annual clovers need to be rotationally grazed to prevent damage to the crown and growing points. The success of these alternative forages in dryland farming systems will depend on farmer willingness to embrace new grazing management techniques. Keywords: forages, plantain, arrowleaf clover, Persian clover, balansa clover, white clover, red clover oversowing, live weight gain.
6
Peprah, Samuel, Enkhjargal Darambazar, Bill Biligetu, Kathy Larson, Alan Iwaasa, Daalkhaijav Damiran, Murillo Ceola Stefano Pereira e Herbert Lardner. "White Prairie Clover (Dalea candida Michx. ex Willd.) and Purple Prairie Clover (Dalea purpurea Vent.) in Binary Mixtures with Grass Species". Sustainable Agriculture Research 11, n. 2 (9 marzo 2022): 30. http://dx.doi.org/10.5539/sar.v11n2p30.
Testo completoAbstract (sommario):
Native forage legumes may have potential for summer/fall grazing in semiarid prairie regions in mixture with grasses. The objective of this study was to evaluate two native clovers in binary mixtures with the introduced grasses when harvested in July and September to simulate late summer or fall stockpile forage. Eight binary clover–grass mixtures were seeded in a split-plot design with 4 replications at Swift Current, Saskatchewan, Canada. Mixtures included (i) AC Antelope white prairie clover (WPC)-Admiral meadow bromegrass (MBG), (ii) WPC-AC Success hybrid bromegrass (HBG), (iii) WPC-Bozoisky Russian wildrye (RWR), (iv) WPC-TomRWR, (v) AC Lamour purple prairie clover (PPC)-AdmiralMBG, (vi) PPC-AC SuccessHBG, (vii) PPC-BozoiskyRWR, and (viii) PPC-TomRWR. Clover establishment differed (p = 0.03) in July where WPC had 77.8% greater proportion in mixture than PPC, although both clovers increased (p < 0.001) in September to similar legume proportions, 663.2 and 876.1 kg/ha, respectively. Clovers with bromegrasses produced 41.9% more forage dry matter yield in summer than clovers with Russian wildryes (p < 0.001), though the latter mixtures had slightly better nutritive value (avg. 7.0% vs. 5.2% crude protein (CP). Clover–MBG exhibited higher (53.6%) in vitro organic matter digestibility (IVOMD) than Clover–HBG (51.2%) (p = 0.04). Purple prairie clover with grass or both clovers in mixture with bromegrasses, produced adequate forage biomass for summer and fall grazing, except clovers with Bozoisky RWR, while clovers with both RWR cultivars had acceptable forage nutritive value for summer in this semiarid prairie region.
7
Ross, S. M., J. R. King, R. C. Izaurralde e J. T. O’Donovan. "The green manure value of seven clover species grown as annual crops on low and high fertility temperate soils". Canadian Journal of Plant Science 89, n. 3 (1 maggio 2009): 465–76. http://dx.doi.org/10.4141/cjps08173.
Testo completoAbstract (sommario):
Annual and perennial clover species may differ in green manure value. Seven clover (Trifolium) species were grown as annual crops on low fertility (Breton) and high fertility (Edmonton) soils in Alberta. Four annual clovers [balansa (T. michelianum Savi), berseem (T. alexandrinum L.), crimson (T. incarnatum L.), and Persian (T. resupinatum L.)], three perennial clovers [alsike (T. hybridum L.), red (T. pratense L.), and white Dutch (T. repens L.)] and a non-legume reference crop [fall rye (Secale cereale L.)] were ploughed-down as green manure in autumn, and followed by barley (Hordeum vulgare L.). Annual clovers had greater biomass yields than perennial clovers, and berseem clover had the highest yield. At Breton, mean biomass N content was greater for perennial clovers (2.9 g N kg-1) than annual clovers (1.9 g N kg-1). Clover biomass at Breton yielded an average of 77 kg N ha-1, with N derived from the atmosphere averaging 88% by N difference method and 75% by 15N natural abundance method. At Edmonton, the green manures had few effects on soil nitrate and subsequent barley yields. At Breton, all clover green manures except balansa increased barley yields, and grain yields were greater following perennial clovers than annual clovers in one year. Annual clovers will provide forage biomass and add N in areas where rainfall is adequate, and they may be preferable under zero tillage. However there is no advantage of annual clovers, relative to perennial clovers, in terms of N supply.Key words: Green manure, clover, Trifolium species, nitrogen fixation
8
Howieson, J. G., R. J. Yates, G. W. O'Hara, M. Ryder e D. Real. "The interactions of Rhizobium leguminosarum biovar trifolii in nodulation of annual and perennial Trifolium spp. from diverse centres of origin". Australian Journal of Experimental Agriculture 45, n. 3 (2005): 199. http://dx.doi.org/10.1071/ea03167.
Testo completoAbstract (sommario):
The release of effective inocula for new perennial clovers into cropping zones where subterranean clover is important might compromise N2 fixation by this valuable annual clover if symbiosis between the new inoculants and subterranean clover is not optimal. To assist our understanding of the interactions between clovers and their microsymbionts, rhizobial strains and clovers from South and equatorial Africa, North and South America, and the Euro–Mediterranean regions were tested. Glasshouse-based studies of the cross-inoculation characteristics of 38 strains of Rhizobium leguminosarum bv. trifolii associated with 38 genotypes of annual and perennial Trifolium spp. from these world centres of diversity were undertaken. Less than 7.5% of the perennial clover symbioses were effective whereas 40% of associations were effective for many of the annual clover species of Euro–Mediterranean origin. There was substantial specificity within the African clovers for effective nodulation. Rhizobial strains from the South American perennial T. polymorphum or from the African clovers were unable to nodulate subterranean clover effectively. Also, 7 of the 17 strains from these regions were unable to form nodules with the less promiscuous Mediterranean annual clovers, T. glanduliferum and T. isthmocarpum. Fifty-three of about 400 cross-inoculation treatments examined, which included annual and perennial clovers, were incapable of forming nodules, while only 65 formed effective nodules. There are 2 barriers to effective nodulation: a ‘geographic’ barrier representing the broad centres of clover diversity, across which few host-strain combinations were effective; and, within each region, a significant ‘phenological’ barrier between annual and perennial species. Clovers and their rhizobia from within the Euro–Mediterranean region of diversity were more able to cross the phenological barrier than genotypes from the other regions. It appears that only the relatively promiscuous clovers, whether annual or perennial, have been commercialised to date. The data indicate that, for perennial clovers, it will be a substantial challenge to develop inocula that do not adversely affect N2 fixation by subterranean clover and other annual clovers available commercially, especially if the perennial clovers were originally from Africa or America. Some future strategies for development of inoculants for clovers are proposed.
9
McCurdy, James D., J. Scott McElroy, Michael L. Flessner, Jared A. Hoyle e Ethan T. Parker. "Tolerance of Three Clovers (Trifoliumspp.) to Common Herbicides". Weed Technology 30, n. 2 (giugno 2016): 478–85. http://dx.doi.org/10.1614/wt-d-15-00062.1.
Testo completoAbstract (sommario):
Clover inclusion may increase the sustainability of certain low-maintenance turfgrasses. However, selective weed control within mixed turfgrass–clover swards proves problematic because of clover susceptibility to herbicides. Research was conducted to identify common turf herbicides that are tolerated by threeTrifoliumspecies, including white clover, ball clover, and small hop clover, within low-maintenance turfgrass. Leaf and flower density, as well as plant height, were measured 4 wk after treatment as indicators of clover response to 14 herbicides. The threeTrifoliumspp. were moderately tolerant of bentazon (< 35% decrease in leaf density, height, or flowering). Simazine was well tolerated by white clover (< 5% decrease in all response variables), yet moderate injury to ball clover and small hop clover was observed (> 32% decrease in leaf density and > 27% decrease in flower density). Pronamide was well tolerated by white and ball clovers, with no effect on measured response variables; however, pronamide decreased small hop clover height and flower density (38 and 42%, respectively). Imazethapyr and imazamox were moderately well tolerated by white clover and small hop clover (< 39% decrease by all response variables), yet ball clover may be more susceptible to these herbicides than was anticipated based on previously reported tolerance. The herbicides 2,4-DB, halosulfuron, and metribuzin were well tolerated by white clover, with no effect on measured response variables; however, results suggest ball and small hop clovers were less tolerant. Clopyralid, 2,4-D, glyphosate, imazaquin, metsulfuron-methyl, and nicosulfuron resulted in varying degrees of injury across clover species and response variables, but, in general, these herbicides may not be viable options when attempting to maintain any of the three clover species tested. Further research is needed to quantify long-term effects of herbicide application on sward composition and clover succession.
10
McCurdy, James D., J. Scott McElroy e Michael L. Flessner. "Differential Response of FourTrifoliumSpecies to Common Broadleaf Herbicides: Implications for Mixed Grass-Legume Swards". Weed Technology 27, n. 1 (marzo 2013): 123–28. http://dx.doi.org/10.1614/wt-d-12-00093.1.
Testo completoAbstract (sommario):
Clovers are commonly included as utility plants within mixed grass swards, such as pastures and roadside right-of-ways. As such, they provide supplemental nitrogen, quality forage, and insect habitat. Yet weed control within mixed swards is often hampered by the lack of selective herbicides that are tolerated by clovers. Differential tolerance of legumes to common row-crop and pasture herbicides has previously been reported, yet little information is available that is specific to clover species. Herbicide injury of clover is often inconsistent, hypothetically due to differential species tolerance. Field and greenhouse experiments were conducted with the objective of testing differential tolerance amongst four clover species. Our experiments suggest varying tolerances amongst clover species and common broadleaf herbicides. Only imazaquin control differed due to species; however, treatment by clover interactions were further demonstrated due to variable reductions in clover height. Imazaquin, 2,4-D, 2,4-DB, and triclopyr height reductions differed due to clover species. Differential clover response to herbicide treatment should be an important consideration when managing mixed grass–clover swards and should be accounted for in future research. On a more practical level, our experiments demonstrate a range of herbicides that effectively control clover species, including atrazine, dicamba, clopyralid, 2,4-D, triclopyr, metsulfuron, and trifloxysulfuron. However, results suggest that 2,4-DB, imazethapyr, and bentazon are candidate herbicides for weed control in scenarios in which clover is a desirable crop.
11
Jokinen, Raili. "Effect of liming and N fertilization on growth, macronutrient content and uptake by mixed stands of three clovers and timothy". Agricultural and Food Science 57, n. 4 (1 dicembre 1985): 213–21. http://dx.doi.org/10.23986/afsci.72207.
Testo completoAbstract (sommario):
Mixed stands of clovers and timothy grew well in unlimed (Ca0) acid soil (pH(CaCl2) 4.8). The highest total yield of red clover-timothy was obtained at a low lime level (Ca1 = 12g /pot CaCO3). The yield of red clover alone responded to liming similarly. The reducing effect of N fertilization (2000 mg/pot N as NH4NO3) on the yield of clovers was greatest in the first growing season (cuts 1 to 4) without lime, and in the second growing season (cuts 5 to 7) with lime (Ca1 = 12g /pot, Ca2 = 24g/pot). Liming without N fertilization promoted the growth of timothy only in the two first cuts; N fertilization increased the yield at all lime levels. Liming increased the Ca content of clovers, but there were no differences between lime levels. Mg and K showed a decreasing trend. N fertilization did not affect the nutrient content of clovers. A good quality of clover yield reguired adequate amounts of other fertilizations than N. In timothy, the Ca content increased slightly at all lime levels; the N and K contents increased by N fertilization. The N uptake by red clover was highest at the Ca, level, by white clover and alsike clover at the Ca0 level. The proportion of clover was larger than that of timothy of the uptake of N, P, Ca and Mg. When N was applied, the uptake of K showed an opposite direction.
12
Norman, Hayley C., David G. Masters, Allan J. Rintoul, Matt G. Wilmot, Vijay Jayasena, Angelo Loi e Clinton K. Revell. "The relative feeding value of a new pasture legume, eastern star clover (Trifolium dasyurum), compared with subterranean clover (Trifolium subterraneum)". Australian Journal of Agricultural Research 56, n. 6 (2005): 637. http://dx.doi.org/10.1071/ar04271.
Testo completoAbstract (sommario):
An accession of eastern star clover (Trifolium dasyurum C. Presl.), a new species to agriculture, has been identified by the National Annual Pasture Legume Improvement Program for commercial release in Australia. This paper reports the findings of an experiment designed to assess the feeding value of eastern star clover compared with a commercial cultivar of subterranean clover (T. subterraneum L. cv. Dalkeith). The hypothesis tested in this experiment is that sheep grazing eastern star clover will have similar growth rates, condition scores, and wool production to sheep grazing subterranean clover. Additionally, it is hypothesised that the sheep grazing the different clover species will have similar health and meat quality. The relative feeding value of the 2 clover species was tested using 14-month-old Merino wethers, grazing 8 by 0.5 ha plots (4 of each species). Stocking rates were such that herbage mass availability would not have limited feed intake. Liveweight, wool growth, and animal health were monitored. After 10 weeks of grazing, 2 animals from each plot were slaughtered for sensory analysis of meat. Although there were generally no differences in liveweight change, condition, or wool growth between sheep grazing eastern star or subterranean clovers, sheep in the subterranean clover plots grew faster during the first month of grazing. There were no differences in meat eating quality (tenderness, juiciness, or flavour), animal health, or vegetable matter contamination of wool. The data suggest that the clovers had the same relative feeding value despite herbage mass from the eastern star clover plots having lower in vitro digestibility, crude protein, and higher fibre than herbage mass from the subterranean clover plots. Given that there was a minimum of 1000 kg/ha of herbage mass in the plots, it is likely that sheep gazing the two clovers were able to maintain the same weight by selecting the high quality components of the pasture. Differences in plant quality are associated with differences in reproductive strategies of the clovers.
13
Sultana, Sharmin, Kevin Foster, Lee Yong Lim, Katherine Hammer e Cornelia Locher. "A Review of the Phytochemistry and Bioactivity of Clover Honeys (Trifolium spp.)". Foods 11, n. 13 (27 giugno 2022): 1901. http://dx.doi.org/10.3390/foods11131901.
Testo completoAbstract (sommario):
This review covers a comprehensive overview of the phytoconstituents and bioactivities reported to date for clover honeys produced from various Trifolium spp. against the backdrop of a more general discussion of the chemistry and bioactivity of these important agricultural species. While research into the phytochemical composition of various honeys and their associated bioactivities is growing, this review demonstrates that the literature to date has seen only a limited number of studies on clover honeys. Surprisingly, there appear to be no comparative data on the concentration of flavonoids in general or isoflavonoids specifically in different clover honeys, although the latter have been identified as a main group of bioactive compounds in red clover plants. Based on the findings of this review, the presence of phytoestrogenic isoflavonoids (e.g., formononetin, biochanin A, genistein, daidzein, glycitein) in clover plants and, by extension, in clover honeys should be further investigated, specifically of clover species outside the three popular perennial clovers (red, white and alsike clovers) to exploit new opportunities of potential benefit to both the pharmaceutical and apiculture industries.
14
MacKinnon Henning, Dianna. "Clover". Psychological Perspectives 64, n. 2 (3 aprile 2021): 276. http://dx.doi.org/10.1080/00332925.2021.1959801.
Testo completo
15
Liu, Qingrui, Changhee Jung, Dongyoon Lee e Devesh Tiwari. "Clover". ACM SIGPLAN Notices 50, n. 5 (22 luglio 2015): 1–10. http://dx.doi.org/10.1145/2808704.2754959.
Testo completo
16
Evers, Gerald W., W. James Grichar, Claude L. Pohler e A. Michael Schubert. "Tolerance of Three Annual Forage Legumes to Selected Postemergence Herbicides". Weed Technology 7, n. 3 (settembre 1993): 735–39. http://dx.doi.org/10.1017/s0890037x00037623.
Testo completoAbstract (sommario):
Field studies were conducted from 1986 through 1989 to evaluate the tolerance of three clover species to selected POST herbicides. 2,4-D at 0.8 and 1.7 kg ha−1injured rose and berseem clovers while the high rate injured subterranean clover. Bentazon and pronamide did not injure rose or subterranean clover; however, pronamide at 3.4 kg ha−1injured berseem clover 18% when rated 72 days after treatment.
17
Gibberd, M. R., e P. S. Cocks. "Effect of waterlogging and soil pH on the micro-distribution of naturalised annual legumes". Australian Journal of Agricultural Research 48, n. 2 (1997): 223. http://dx.doi.org/10.1071/a96074.
Testo completoAbstract (sommario):
Variation in the size and composition of the soil seed bank of 3 naturalised legumes, subterranean clover (Trifolium subterraneum L.), woolly clover (T. tomentosum L.), and cluster clover (T. glomeratum L.), was related to soil characteristics on a transect that ascended from a winter waterlogged area in a wheatbelt pasture. Growth of the 3 species was compared with other species from section Vesicaria (T. resupinatum and T. clusii) in waterlogged and freely drained pots for 34 days. Of the 3 naturalised legumes present in the transect, cluster clover was rare, and woolly and subterranean clovers were separated on the basis of their response to soil pH and the likelihood of winter waterlogging. Subterranean clover was absent from soil with pH > 7·0; these areas were dominated by woolly clover. Areas with pH < 7·0 were dominated by subterranean clover, except where winter waterlogging was likely, in which case they were once again dominated by woolly clover. The waterlogging tolerance of woolly clover, together with that of other species in section Vesicaria, was confirmed in the pot experiment. After 34 days, shoot dry weight of the waterlogged Vesicaria species was an average of 39% greater than the freely drained controls. Root length continued to increase for the duration of the waterlogging treatment with much of the new root growth as laterals. Conversely, shoot and root growth in subterranean and cluster clovers was severely reduced by waterlogging. The patchy distribution of woolly clover in many wheatbelt pastures can be explained by its response to high pH and winter waterlogging compared with subterranean clover.
18
Barbetti, MJ. "Breakdown in resistance of subterranean clovers to clover scorch disease (Kabatiella caulivora)". Australian Journal of Agricultural Research 46, n. 3 (1995): 645. http://dx.doi.org/10.1071/ar9950645.
Testo completoAbstract (sommario):
In spring 1990, in the Australasian Subterranean Clover and Alternative Legume Improvement Program field plots at Denmark, Western Australia, subterranean clover cultivars and crossbred lines normally highly resistant to clover scorch disease caused by Kabatiella caulivora, were severely affected by this disease. Testing the response of subterranean clover varieties to Kabatiella isolates taken from plants from these plots indicates the arrival of a new race of the fungus. The new race differs from all other isolates in overcoming the previously outstanding resistance of cultivars Green Range, Junee, Daliak and Esperance.
19
KÄNKÄNEN, H., C. ERIKSSON e M. RÄKKÖLÄINEN. "Effect of annually repeated undersowing on cereal grain yields". Agricultural and Food Science 10, n. 3 (3 gennaio 2001): 197–208. http://dx.doi.org/10.23986/afsci.5693.
Testo completoAbstract (sommario):
Cover crops can be used to reduce leaching and erosion, introduce variability into crop rotation and fix nitrogen (N) for use by the main crops. In Finland, undersowing is a suitable method for establishing cover crops in cereal cropping. The effect of annual undersowing on cereal grain yield and soil mineral N content in spring was studied at two sites. Red clover (Trifolium pratense L.), white clover (Trifolium repens L.), a mixture of red clover and meadow fescue (Festuca pratensis Huds.), and westerwold ryegrass (Lolium multiflorum Lam. var. westerwoldicum) were undersown in spring cereals in the same plots in six successive seasons, and their effects on cereal yield were estimated. Annual undersowing with clovers increased, and undersowing with westerwold ryegrass decreased cereal grain yields. The grain yield was only slightly lower with a mixture of red clover and meadow fescue than with red clover alone. Westerwold ryegrass did not affect soil mineral N content in spring and the increase attributable to clovers was small. The mixture of red clover and meadow fescue affected similarly to pure red clover. Soil fertility was not notably improved during six years of undersowing according to grain yield two years later.
20
Harrison, Barbara, Todd A. Steinlage, Leslie L. Domier e Cleora J. D'Arcy. "Incidence of Soybean dwarf virus and Identification of Potential Vectors in Illinois". Plant Disease 89, n. 1 (gennaio 2005): 28–32. http://dx.doi.org/10.1094/pd-89-0028.
Testo completoAbstract (sommario):
Soybean dwarf virus (SbDV), which causes an important disease of soybeans in Japan, is persistently transmitted by aphids and is endemic in forage legumes in the United States. To determine the incidence of SbDV in Illinois, we collected clovers and forage legumes in a total of 49 Illinois counties in 2001 and 2002 and tested them for the presence of SbDV by reversetranscription-polymerase chain reaction. SbDV was detected in 43% of red clover (Trifolium pratense), 10% of white clover (T. repens), and 3% of yellow sweet clover (Melilotus officinalis) plant samples. The dwarfing strain (SbDV-D) was the predominant strain detected in Illinois. In 2000, Aphis glycines, an aphid species that colonizes soybeans, was reported for the first time in North America. To determine whether A. glycines or aphid species found colonizing clover were vectors of SbDV, transmission studies were conducted. Aphids of the species Nearctaphis bakeri reproducibly vectored SbDV among red clovers, and from red clover to soybean. A. glycines did not transmit SbDV; neither did two other clover-infesting aphid species, Acyrthosiphon pisum and Therioaphis trifolii.
21
Gemell, L. G., E. J. Hartley e D. F. Herridge. "Point-of-sale evaluation of preinoculated and custom-inoculated pasture legume seed". Australian Journal of Experimental Agriculture 45, n. 3 (2005): 161. http://dx.doi.org/10.1071/ea03151.
Testo completoAbstract (sommario):
During 1999–2003, 293 samples of preinoculated and custom-inoculated lucerne, subterranean clover, white clover, red clover and miscellaneous species (mainly other clovers) were sourced from commercial outlets and assessed for numbers of rhizobia, seed pellet pH and toxicity, and nodulation in a ‘grow-out’ test. Average rhizobial counts were 8400/seed for preinoculated lucerne, 1380/seed for subterranean clover and <100/seed for white and red clovers and for the miscellaneous species. These counts compared poorly with the average counts of 35 100/seed, 13 800/seed and 10 000/seed for freshly-inoculated lucerne, subterranean clover and white clover, respectively. Thus, overall pass rates of the preinoculated seed were reasonable for lucerne (73%), marginal for subterranean clover (32%) and very low for white clover (3%), red clover (4%) and the miscellaneous species (0%). The ‘grow-out’ tests for nodulation were positively correlated with rhizobial numbers on seed, confirming the use of plate counting of rhizobia to assess quality of pre- and custom-inoculated seed. Many of the seed pellets were toxic to the 2 clover rhizobial strains tested, although the toxicity did not affect numbers of rhizobia on the seed. In light of these results and other data on rhizobial survival on seed, we suggest the current Australian standards for rhizobial numbers on pasture legume seed at the time of sale of 500/seed (very small-seeded legumes with seed numbers >750 000/kg) and 1000/seed (other larger-seeded species, seed numbers <750 000/kg) remain in place. We recommend shelf lives be restricted to 6 months for preinoculated lucerne and the annual medics, to 6 weeks for preinoculated subterranean clover, and to 2 weeks for white clover, red clover and other miscellaneous species. In the long-term, new products and procedures will hopefully enhance the numbers and survival of rhizobia on seed such that the needs of both manufacturers and customers are satisfied.
22
Humphries, A. W., S. S. Robinson, D. Hawkey, D. M. Peck, T. D. Rowe, C. T. de Koning e A. Newman. "Diversity for resistance to a moderately virulent bluegreen aphid (Acyrthosiphon kondoi Shinji) population in Trifolium species". Crop and Pasture Science 67, n. 9 (2016): 1009. http://dx.doi.org/10.1071/cp15102.
Testo completoAbstract (sommario):
The resistance of a diverse range of Trifolium species (clovers) to a highly virulent bluegreen aphid (BGA, Acyrthosiphon kondoi Shinji) population (Urrbrae 2011) collected in South Australia was assessed in greenhouse and field experiments, with the aims of determining the potential impact of this insect pest on biomass and identifying resistant genotypes for future plant-breeding activities. Resistance to BGA was found in populations of clovers that show some level of outcrossing—white clover (T. repens L.), rose clover (T. hirtum All.), crimson clover (T. incarnatum L.) and red clover (T. pratense L.)—and in one entry of the inbreeding subspecies of subterranean clover, T. subterraneum L. subsp. subterraneum (Katzn. and Morley). Resistance was not found in T. s. brachycalycinum (Katzn. and Morley) or T. s. yanninicum (Katzn. and Morley). In a greenhouse experiment, damage from BGA resulted in forage yield penalties of 72–100% when aphids were inoculated at 14 days after sowing and 13−74% when inoculated at 42 days after sowing, showing that in optimum conditions BGA can be a serious pest of clovers. Observations of severe damage caused by BGA in two regenerating field trials in southern New South Wales confirmed that field damage could occur in seasons favourable to aphid growth and reproduction. The severe damage that BGA can cause to clovers, and the sources of resistance we found, suggest that breeding for BGA resistance in clovers is warranted and feasible.
23
Boyle, Paige E., Kelly Kopp, Xin Dai, Bradley Bushman, Paul Johnson e Paul Grossl. "Clover (Trifolium spp.) Inclusion in Kentucky Bluegrass (Poa pratensis) Lawns". HortScience 59, n. 7 (luglio 2024): 1020–26. http://dx.doi.org/10.21273/hortsci17732-24.
Testo completoAbstract (sommario):
Historically, white clover (Trifolium repens) seed was included in turfgrass seed mixtures to provide biodiversity and nitrogen (N) to lawns. White clover dicultures have been studied recently for inclusion in both warm- and cool-season turfgrasses, with the goals of reducing fertilizer applications and providing pollinator forage in lawns; however, other clovers have not been as widely researched in turfgrass. The objectives of this study were to evaluate 1) if white, strawberry (T. fragiferum), crimson (T. incarnatum), and rose (T. hirtum) clovers can persist in dicultures with Kentucky bluegrass (Poa pratensis); 2) if clover inclusion in dicultures impacts broadleaf weed cover; and 3) if low levels of N fertilization impact clover persistence or quality of clover–bluegrass dicultures. Kentucky bluegrass was grown as a monoculture or as a diculture with each of the four clover species. Each mono- or diculture was then treated with a low rate of N fertilizer (48.8 kg⋅ha–1 N) or no N fertilizer to determine quality and percentage of grass, clover, or weed and bare-soil cover. Dicultures contained similar or less weed and bare-soil cover, and maintained similar or greater quality compared with bluegrass monocultures, indicating clover and Kentucky bluegrass dicultures are suitable alternatives to Kentucky bluegrass monoculture lawns, and can potentially lead to reduced fertilizer and pesticide requirements. Fertilizer generally had no effect on cover, likely because of the low rates of N applied.
24
Drew, E. A., N. Charman, R. Dingemanse, E. Hall e R. A. Ballard. "Symbiotic performance of Mediterranean Trifolium spp. with naturalised soil rhizobia". Crop and Pasture Science 62, n. 10 (2011): 903. http://dx.doi.org/10.1071/cp11047.
Testo completoAbstract (sommario):
Naturalised soil rhizobia that nodulate clover occur in high number and are known to vary in their symbiotic performance (SP) with subterranean clover (Trifolium subterraneum L.). However, the extent of suboptimal fixation across a range of other clover species is not well understood. T. subterraneum and nine other annual clover species of Mediterranean origin were evaluated for their SP in combination with the naturalised clover rhizobia in 71 Australian soils and five strains of Rhizobium leguminosarum bv. trifolii that have been used in the inoculants produced for clovers. The most probable number method, using subterranean clover as the trap plant was used to estimate the number of clover rhizobia in the soils. Ninety-two percent of soils tested contained more than 1000 rhizobia/g. An extract of each soil, or strain of rhizobia was used to inoculate plants growing in N-deficient media in the greenhouse. Plants were grown for 4 weeks after inoculation and shoot dry matter determined and expressed as a percentage of the ‘best’ soil rhizobia treatment, to provide a proportional measure of SP for each clover species. SP (mean of clover species) ranged from 96% with the current inoculant strain for annual clovers (WSM1325) down to 48% with former inoculant strain WU95. When inoculated with soils predominantly from mainland Australia, SP (mean of soil treatments) of the different Trifolium spp. was 55% (resupinatum), 53–47% (subterraneum), 50% (nigrescens), 49% (michelianum), 48% (isthmocarpum), 38% (hirtum), 35% (purpureum), 32% (vesiculosum), 25% (spumosum) and 21% (glanduliferum). Within each of the clover species, SP resulting from individual soil treatments ranged from 100% (by definition for the best soil treatment) down to close to zero. Trifolium glanduliferum formed nodules readily with the inoculant strains but nodulation was erratic with the rhizobia in many soils. It is therefore proposed that the naturalised rhizobia in many soils are unlikely to be inoculant strains. This research demonstrates symbiotic efficiency across annual clover species is compromised where diverse populations of clover rhizobia have naturalised in soils.
25
Evans, P. M., S. Walton, P. A. Riffkin e G. A. Kearney. "Effect of plant density on the winter production of annual clovers grown in monocultures". Australian Journal of Experimental Agriculture 42, n. 2 (2002): 135. http://dx.doi.org/10.1071/ea01003.
Testo completoAbstract (sommario):
The small-seeded annual clovers, balansa and Persian, are often assumed to be poor winter producers. Their small seed size, of about 1 mg or less, and poor regeneration, possibly due to inappropriate grazing management in many instances, contributes to this perception. To test the hypothesis that early growth of these clovers is determined by the weight of germinating seed, as it is in subterranean clover, an experiment with 2 cultivars of subterranean clover, Leura and Trikkala, 2 cultivars of balansa clover, Paradana and Bolta, and 1 of Persian clover, Nitro Plus, was established in the field at Hamilton, western Victoria, at 6 sowing densities. The winter production at 2 additional sites, Lake Bolac and Streatham, in their third and second and third seasons, respectively, was also examined. Plant density varied from 30 to 37000 plants/m2 across sites and species. With equal weight of germinating seed per unit area at sowing, balansa and Persian clovers produced more herbage in winter than did the 2 subterranean clover cultivars Leura and Trikkala (P<0.05). Even though there was high correlation between seed weight and seedling weight across all species shortly after emergence (r2 = 0.99), by harvest time no differences in plant weight existed between any treatments growing at the same plant density. From this we conclude the following: (i) for the same weight of germinable seed per unit area, balansa and Persian clovers produced more dry weight per hectare than subterranean clover, because they had higher plant densities; (ii) there were no differences in dry matter production per hectare between species growing at similar plant densities by harvest time at the end of winter; (iii) it appeared that in winter the small-seeded species exhibited a higher relative growth rate than the 2 subterranean clovers.
26
Black, A. D., D. J. Moot e R. J. Lucas. "Seasonal growth and development of Caucasian and white clovers under irrigated and dryland conditions". NZGA: Research and Practice Series 11 (1 gennaio 2003): 81–89. http://dx.doi.org/10.33584/rps.11.2003.2992.
Testo completoAbstract (sommario):
Dry matter (DM) production of sown monocultures of Caucasian and white clovers was compared under irrigated and dryland (non-irrigated) conditions in their third year. Caucasian clover produced 11.9 t DM/ ha when irrigated and 9.4 t DM/ha under dryland conditions, and both treatments exceeded white clover by ~2.5 t DM/ha. This increase in yield reflected ~23 kg DM/ha/day higher production rates in spring and summer. During this period, production rates of irrigated treatments increased by 11 kg DM/ ha/day/oC for Caucasian compared with 8 kg DM/ha/ day/oC for white clover as mean daily air temperature increased from 8-16 oC. In late summer/autumn, production rates of Caucasian clover decreased more than white clover when air temperature dropped from 16-9 oC. Growth (photosynthesis) and development (leaf appearance) characteristics of each species were also examined. Leaf photosynthesis was ~6 ƒÊmol CO2/m2/ s higher for Caucasian than for white clover irrespective of measured air temperatures (7-28 oC) and soil moisture from 1.00-0.39 of water holding capacity (WHC, 512 mm to 1.5 m depth). Both clovers had similar ranges of optimum temperature (21-25 oC) and soil moisture (1.00-0.86 of WHC) for photosynthesis. These results could explain the observed higher production rates for Caucasian clover in spring and summer, under both irrigated and dryland conditions. Lower production rates of Caucasian clover in autumn may be attributed to a similar phyllochron (126 oCd), but higher base temperature (5 oC) than for white clover (1 oC), and hence a slower recovery to canopy closure post grazing. This study shows that Caucasian clover has potential to increase spring and summer legume production, in combination or as the sole legume species in both irrigated and dryland grass/clover pastures in lowland temperate environments of New Zealand. Key words: irrigation, photosynthesis, phyllochron, seasonal production, Trifolium ambiguum M. Bieb, T. repens
27
Potter, Daniel A., Carl T. Redmond, Timothy D. McNamara e Gregg C. Munshaw. "Dwarf White Clover Supports Pollinators, Augments Nitrogen in Clover–Turfgrass Lawns, and Suppresses Root-Feeding Grubs in Monoculture but Not in Mixed Swards". Sustainability 13, n. 21 (26 ottobre 2021): 11801. http://dx.doi.org/10.3390/su132111801.
Testo completoAbstract (sommario):
The runoff or leaching of nitrogen fertilizers from monoculture turfgrass lawns contri-butes to water pollution, and such lawns are susceptible to insect pests and provide few resources for pollinators. One approach to creating more sustainable lawns is to incorporate white clover (Trifolium repens L.), a nitrogen-fixing legume, into grass seed mixtures or existing turfgrass swards. “Dutch” white clover (DWC), a ubiquitous landrace, forms non-uniform clumps when intermixed with turfgrasses, thus it is often considered to be a lawn weed. Recently, several dwarf varieties of white clover have been selected for their small leaf size and low growth habit, allowing them to tolerate low mowing heights and blend better with grasses. To date, there have been no studies published on the entomological aspects of dwarf clover in pure stands or intermixed with turfgrass. We established field plots with combinations of DWC, two cultivars of dwarf clover, and tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.) in monoculture or mixed swards, and compared the invertebrate communities therein. Predatory arthropods and earthworm numbers were similar in all plot types. The clover monocultures were resistant to white grubs, but the grub densities in the clover–tall fescue dicultures were similar to those found in the pure tall fescue swards. Dwarf clovers and DWC were similarly attractive to bees and supported similar bee assemblages. The tall fescue foliar N content was elevated 17–27% in the dicultures with clovers.
28
Hill, MJ. "Sward growth of monocultures and binary mixtures of phalaris, lucerne, white clover and subterranean clover under two defoliation regimes". Australian Journal of Experimental Agriculture 31, n. 1 (1991): 51. http://dx.doi.org/10.1071/ea9910051.
Testo completoAbstract (sommario):
Sirosa phalaris, WL5 15 lucerne, Haifa white clover and Seaton Park subterranean clover were grown in monocultures and binary mixtures on a cracking clay soil and cut at 4- and 8-week intervals over 3 growing seasons at Scone, New South Wales (32�S.). The plots were given supplementary irrigation between mid April and November to prevent water deficits. The deep-rooted perennials dominated mixtures under infrequent cutting, with cumulative dry matter yields for the growing season reaching 11 t/ha for lucerne-based mixtures. Frequent defoliation increased the contribution of the clovers in mixtures, and mixtures and monocultures containing clovers were more productive than other plots in winter, 1986. Frequent defoliation reduced the vigour and density of lucerne, resulting in balanced mixtures with phalaris and subterranean clover in the third year. Only lucerne plots contributed large amounts of dry matter yield (up to 4 t/ha) between December and April. Regeneration of subterranean clover from seedlings, and white clover from seedlings or stolons, was better in clover-only plots than in mixtures with phalaris. The growth of mixtures in response to mean daily air temperature in spring could be divided into 2 distinct patterns, with growth peaking at about 15�C for determinate (annual or dormant) mixtures, and at about 18�C for lucerne mixtures and pure white clover. In autumn, growth patterns were determined by the method of regeneration (i.e. by seedings or dormant crowns).
29
Black, A. D., e J. L. Moir. "Dry matter and sheep production of four dryland tall fescue-clover pastures 4-6 years after establishment". Journal of New Zealand Grasslands 77 (1 gennaio 2015): 117–22. http://dx.doi.org/10.33584/jnzg.2015.77.492.
Testo completoAbstract (sommario):
Effects of tall fescue cultivar ('Advance' and 'Flecha') and clover species (white and subterranean (sub) clovers) combinations on pasture dry matter (DM) and sheep production were assessed in years four (2011/12), five (2012/13) and six (2013/14) after establishment in dryland, Canterbury. 'Advance' pastures yielded less total herbage than 'Flecha' pastures (13.9 cf. 16.5 t DM/ha) but more fescue (8.6 cf. 5.9 t DM/ha) and 2.1 t DM/ha clover in year four, 13.5 t DM/ha total herbage with more fescue (8.0 cf. 4.1 t DM/ha) and 1.9 t DM/ha clover in year five, and 11.7 t DM/ha total herbage, 5.4 t DM/ha fescue and 0.8 t DM/ha clover in year six. Sub clover pastures yielded more total, fescue and clover herbage (16.9, 8.8 and 3.2 t DM/ha) than white clover pastures (13.5, 5.7 and 1.0 t DM/ha) in year four, more fescue in year five (7.2 cf. 4.9 t DM/ha), and more clover in year six (1.2 cf. 0.3 t DM/ha). Sheep liveweight gain was greater for sub than white clover pastures in year four (939 cf. 431 kg/ha) and five (697 cf. 481 kg/ha) and 689 kg/ha in year six. Therefore, sub clover and 'Advance' were generally more productive than white clover and 'Flecha', but both fescues showed similar persistence after 6 years. Keywords: cultivar, Festuca arundinacea, grass-clover mixtures, liveweight gain, Trifolium subterraneum, Trifolium repens
30
Macfarlane, M. J., E. W. Crofoot e P. D. Muir. "Effects of closing date on seeding and hardseededness of balansa, gland, Persian and arrowleaf clovers on East Coast dryland". Journal of New Zealand Grasslands 77 (1 gennaio 2015): 219–26. http://dx.doi.org/10.33584/jnzg.2015.77.461.
Testo completoAbstract (sommario):
Four annual clovers (Arrowleaf (Trifolium versiculosum), balansa (T. michelianum), Persian (T. resupinatum) and gland (T. glanduliferum)) were sown on five East Coast dryland farms and one moist Taranaki site. Hardseededness was measured at all sites and seed production and hardseededness was measured at three sites following different closing dates. There were no differences in seed size for any species between sites or closing dates. High levels of seed (500-700 kg/ha) were set by balansa and arrowleaf clovers after an early closing date (early September). Flowering and seed production decreased with later closings. Gland clover was the earliest to flower and with Persian clover was very susceptible to early grazing. Gland clover produced virtually no seed as flowers had already been grazed prior to the first closing. Arrowleaf clover produced very high levels (>92%) of hard seed and Persian very low levels (
31
Tyller, R., V. Tyller e I. Macháčková. "Red clover Bonus". Czech Journal of Genetics and Plant Breeding 44, No. 3 (4 novembre 2008): 123–24. http://dx.doi.org/10.17221/52/2008-cjgpb.
Testo completo
32
Tyller, R., V. Tyller e I. Macháčková. "Red clover Garant". Czech Journal of Genetics and Plant Breeding 44, No. 3 (4 novembre 2008): 125–26. http://dx.doi.org/10.17221/53/2008-cjgpb.
Testo completo
33
Lichvárová, M. "Red Clover Magura". Czech Journal of Genetics and Plant Breeding 38, No. 3-4 (1 agosto 2012): 143–44. http://dx.doi.org/10.17221/6254-cjgpb.
Testo completo
34
Witte, John. "The Clover". Iowa Review 46, n. 1 (marzo 2016): 156. http://dx.doi.org/10.17077/0021-065x.7710.
Testo completo
35
Lee, Monica. "Creating clover". Human Resource Development International 1, n. 3 (ottobre 1998): 259–62. http://dx.doi.org/10.1080/13678869800000034.
Testo completo
36
BAUMANN, LESLIE S. "Red Clover". Skin & Allergy News 36, n. 4 (aprile 2005): 14. http://dx.doi.org/10.1016/s0037-6337(05)70088-7.
Testo completo
37
Koehler-Cole, Katja, James R. Brandle, Charles A. Francis, Charles A. Shapiro, Erin E. Blankenship e P. Stephen Baenziger. "Clover green manure productivity and weed suppression in an organic grain rotation". Renewable Agriculture and Food Systems 32, n. 5 (5 dicembre 2016): 474–83. http://dx.doi.org/10.1017/s1742170516000430.
Testo completoAbstract (sommario):
AbstractGreen manure crops must produce high biomass to supply biological N, increase organic matter and control weeds. The objectives of our study were to assess above-ground biomass productivity and weed suppression of clover (Trifolium spp.) green manures in an organic soybean [Glycine max (L.) Merr.]-winter wheat (Triticum aestivum L.)-corn (Zea mays L.) rotation in eastern Nebraska in three cycles (2011–12, 2012–13, 2013–14). Treatments were green manure species [red clover (T. pratense L.) and white clover (T. repens L.)] undersown into winter wheat in March and green manure mowing regime (one late summer mowing or no mowing). We measured wheat productivity and grain protein at wheat harvest, and clover and weed above-ground biomass as dry matter (DM) at wheat harvest, 35 days after wheat harvest, in October and in April before clover termination. Winter wheat grain yields and grain protein were not affected by undersown clovers. DM was higher for red than for white clover at most sampling times. Red clover produced between 0.4 and 5.5 Mg ha−1 in the fall and 0.4–5.2 Mg ha−1 in the spring. White clover produced between 0.1 and 2.5 Mg ha−1 in the fall and 0.2–3.1 Mg ha−1 in the spring. Weed DM was lower under red clover than under white clover at most sampling times. In the spring, weed DM ranged from 0.0 to 0.6 Mg ha−1 under red clover and from 0.0 to 3.1 Mg ha−1 under white clover. Mowing did not consistently affect clover or weed DM. For organic growers in eastern Nebraska, red clover undersown into winter wheat can be a productive green manure with good weed suppression potential.
38
Zhao, Xueying, Zhi Tian, Lintao Cheng, Jia Jiang, Yujiao Liu, Lizhi Liu, Chunxu You et al. "Comparative Study on the Morpho-Physiological Responses of White Clover Cultivars with Different Leaf Types to Water Deficiency". Agronomy 13, n. 7 (14 luglio 2023): 1859. http://dx.doi.org/10.3390/agronomy13071859.
Testo completoAbstract (sommario):
White clover (Trifolium repens L.) is one of the legume herbages with high feed quality, but it is sensitive to water deficiency. The objectives of this study were to compare morpho-physiological responses to drought stress and post-drought recovery in four-leafed white clover cultivars. Under well-watered conditions, drought stress (3 d, 6 d, 9 d and 12 d), and rehydration, the relative water content (RWC), membrane lipid permeability, osmoregulatory substances, photosynthetic characteristics and stomatal features of Chinese native Longping No.1 (LP, small-leafed) and three introduced cultivars, namely Pudi (PD, small-leafed), Rivendel (RD, medium-leafed) and Koala (KL, large-leafed), were evaluated. Results showed that small-leafed white clover maintained higher RWC and better membrane stability and osmotic regulation with increased drought intensities, compared to the medium-leafed and large-leafed cultivars. Following rewatering, small-leafed white clover recovered more rapidly with all of the parameters than the other cultivars. The increase of drought stress intensity led to the decline of net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Cs). However, the decreased range of Pn, Tr and Cs in the small-leafed white clover was significantly smaller than that in the medium-leafed and large-leafed white clovers. Meanwhile, the small-leafed white clover showed a smaller size and higher density of stoma either under normal or drought conditions than the intermediate- and large-leafed cultivars. Taken together, the results indicated that the adaptability of small-leafed white clover to drought stresses and post-drought recovery was better than that of medium-leafed and large-leafed white clovers. The study will provide better insights into the mechanism of drought response and recovery potential in different white clover cultivars.
39
ANNICCHIARICO, P., e E. PIANO. "Response of white clover genotypes to intergenotypic and interspecific interference". Journal of Agricultural Science 128, n. 4 (giugno 1997): 431–37. http://dx.doi.org/10.1017/s0021859697004334.
Testo completoAbstract (sommario):
Six white clover genotypes that were easily distinguishable from each other on the basis of leaf lamina marks and morphology were grown at Lodi, Italy, during 1990 and 1991 in dense swards, under field conditions and a mowing regime, as (i) pure stands, (ii) a complex mixture of all genotypes, (iii) binary mixtures of each genotype with each of two ryegrass varieties, and (iv) complex mixtures of all clover genotypes in binary association with each grass variety. The grass components were of known, different vigour. The study assessed both intergenotypic and interspecific interference and related dry matter yield responses to morpho-physiological traits of the clovers, and also determined whether a high level of morpho-physiological heterogeneity conferred a yield advantage on clover populations.Greater heterogeneity (i.e. a complex mixture of clover genotypes) did not produce higher clover yields either in the presence or absence of interspecific interference from grass; thus, the use of blends of varieties or the development of varieties with a fairly high degree of heterogeneity was not recommended for short-term meadows in environments with relatively low spatial and temporal variability. Interactions for yield occurred between clover genotypes and the presence or absence of intergenotypic interference (P<0·001), and between clover genotypes and the presence or absence of interspecific interference from the grass variety characterized by greater vigour and aggressiveness (P<0·01). The variance of the former interaction tended to be consistently larger than that of the latter interaction, indicating that competitive effects were greater between clovers than between the clover and grass components. A lower Spring [ratio ] Summer yield ratio and taller canopy tended to confer a competitive advantage under intergenotypic interference. Relatively better performance under interspecific interference was related to higher stolon density, suggesting that selection for this trait may increase the general ecological compatibility of large-leaved white clover types grown with vigorous grass companions.
40
Kemp, D. R., D. L. Michalk e M. Goodacre. "Productivity of pasture legumes and chicory in central New South Wales". Australian Journal of Experimental Agriculture 42, n. 1 (2002): 15. http://dx.doi.org/10.1071/ea98171.
Testo completoAbstract (sommario):
Seven experiments were established across a range of environments (latitude 33°S) in central New South Wales to evaluate 52 legume cultivars and lines against currently recommended cultivars. Plots were grazed by either sheep or cattle after each harvest. Criteria for inclusion were that lines were either commercially available or in the process of being registered. Three experiments also included chicory. Sites had from 600 to 900 mm annual rainfall and were at altitudes of 440–1000 m. The 4-year program included the dry summer of 1990–91. White clover and subterranean clover were the most productive species over time. Among subterranean clovers, the subspecies subterraneum cultivars were more productive than the yanninicum or brachycalycinum subspecies. Other species such as balansa, Persian, strawberry, red and crimson clovers, lotus major and murex medic were more variable in production. These legumes often grew well in the establishment year, but failed to persist. Lucerne was in general, not as productive as white or subterranean clover. Caucasian clover and yellow serradella should be evaluated further as conclusive judgements could not be formed. Chicory was often the most productive species in the experiments, especially over the warmer 6 months of the year. It persisted under a 6-week harvest regime and during the drought year. The newer subterranean clover cultivars, Leura, Goulburn and Denmark all exceeded the production from the previously recommended cultivars, Woogenellup and Karridale, even though no major disease was evident in the later group. The lines 89820D and 89841E were sufficiently productive to warrant further evaluation and possible development as cultivars. In contrast, while Huia, Tahora, Bonadino and Tamar were often as productive as the recommended white clover cultivar Haifa, they were not consistently better. Where summer rainfall occurs and the annual rainfall exceeds 650 mm, the greater potential yield of white clover compared with subterranean clover justifies its use. However, no white clover cultivars survived the summer drought in 1990–91 as intact plants. Further work is needed to develop more drought-tolerant cultivars.
41
Fraser, J., e H. T. Kunelius. "Influence of seeding time on the yield of white clover/orchardgrass mixtures in Atlantic Canada". Journal of Agricultural Science 120, n. 2 (aprile 1993): 197–203. http://dx.doi.org/10.1017/s0021859600074232.
Testo completoAbstract (sommario):
SUMMARYThe influence of four seeding times on herbage dry matter (DM) yields and clover content of white clover (Trifolium repens L.)/orchardgrass (Dactylis glomerata L.) mixtures was evaluated at Truro, Nova Scotia and Charlottetown, Prince Edward Island from 1985 to 1988. Sacramento, Sonja and Milkanova white clover/orchardgrass mixtures were assessed under simulated grazing (four or five harvests per year) over two production years at each location.Delaying seeding from May to August reduced total herbage DM yields significantly in the first production year, from 8·1 to 3·3 t/ha in Truro and from 11·0 to 7·2 t/ha in Charlottetown. Late seeding significantly reduced clover content in the herbage of the first two harvests in the first production year but, by the mid to late-season harvests, white clover content had increased to levels similar to those of the May seeding. Estimated white clover DM yields were highest in June, and dropped in the second production year at both locations. Sonja and Milkanova white clovers consistently outyielded Sacramento in herbage DM yields and clover content in both locations irrespective of seeding dates.
42
Norton, M. R., e G. R. Johnstone. "Occurrence of alfalfa mosaic, clover yellow vein, subterranean clover red leaf, and white clover mosaic viruses in white clover throughout Australia". Australian Journal of Agricultural Research 49, n. 4 (1998): 723. http://dx.doi.org/10.1071/a97114.
Testo completoAbstract (sommario):
The levels of infection with 4 viruses in young white clover (Trifolium repens L.) plots sown in 1991 or 1992 were monitored at a total of 17 sites across the 6 States of Australia. Tests were undertaken for alfalfa mosaic (AMV), clover yellow vein (ClYVV), subterranean clover red leaf (SCRLV) (syn. soybean dwarf), and white clover mosaic (WClMV) viruses on field samples of 17 different cultivars, plus a local naturalised ecotype at each location, twice yearly over 3 years. The tests were undertaken using double antibody sandwich enzyme-linked immunosorbent assay (DASELISA). AMV and WClMV were the most common and widespread viruses. They infected plants atmany sites soon after establishment and then rapidly increased to high levels, occasionally exceeding 90% of plants. In contrast, at some sites, no infection with these viruses was detected. Analysis of the infection data at 4 sites, where significant spread of AMV occurred, indicated that the epidemics developed like compound interest models. Tests for SCRLV were done only in 1994 when moderate levels of infection were found at most southern, winter-rainfall dominant sites. The occurrence o fClYVV was sporadic and infection levels were always low.
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Norman, Hayley C., Philip S. Cocks e Nick W. Galwey. "Annual clovers (Trifolium spp.) have different reproductive strategies to achieve persistence in Mediterranean-type climates". Australian Journal of Agricultural Research 56, n. 1 (2005): 33. http://dx.doi.org/10.1071/ar03236.
Testo completoAbstract (sommario):
The aim of this work was to determine whether different species of annual clover (Trifolium spp.), obtained from the same environment, have different reproductive strategies (combinations of reproductive traits) to achieve ecological success. A better understanding of the traits that improve persistence should allow agronomists to narrow the selection criteria for new clover cultivars for ley-farming systems in southern Australia. Seeds of 18 annual clover species were obtained from 3 Australian and 6 Mediterranean sites and were subsequently grown in a common garden in Western Australia. Reproductive traits, including time of flowering, weight per seed, fecundity, pollen to ovule ratio, and pattern of seed softening, were observed. Accessions of different clover species from the same site of collection had different reproductive strategies. Across a range of collection sites, accessions of the same species demonstrated the same broad reproductive strategy; however, some traits, e.g. the timing of flowering, varied within species across collection sites. Principal component analysis suggested that there are 3 broad reproductive strategies demonstrated by these clover species. At one extreme were the relatively large-seeded clovers (T. subterraneum, T. clypeatum, and T. stellatum). The associated cost of these large seeds is reduced fecundity. The large-seeded clovers do not have high long-term hardseededness (the predominant form of seed dormancy in clovers). The relatively small-seeded clovers were all characterised by high fecundity. Many of the small-seeded clovers have high levels of long-term hardseededness, which allow the risk of failure to be spread across seasons (T. spumosum, T. hirtum, T. lappaceum, T. angustifolium, and T. tomentosum). Some of the small-seeded clovers (T. glomeratum, T. nigrescens, T. campestre, T. cernuum, and T. suffocatum) are generalists, producing as many seeds as possible in each season, with very little hardseededness. There are several possible explanations for the apparent success of such different reproductive strategies among clover accessions of different species at the same site. A plant may achieve the same goal by trading one reproductive trait for another. For example, it may either produce many small seeds to spread the risk of failure or produce fewer large seeds with an inherent competitive advantage. Alternatively, temporal and spatial variation may favour clovers with a number of different reproductive strategies. It is likely that a mixture of species with different reproductive strategies will maximise production and persistence of legume-based pastures in ley-farming systems.
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Belgrave, B. "Factors influencing farmer acceptance and uptake of new white clover cultivars". NZGA: Research and Practice Series 6 (1 gennaio 1996): 51–54. http://dx.doi.org/10.33584/rps.6.1995.3377.
Testo completoAbstract (sommario):
White clover is important to New Zealand pastoral farming yet uptake of new agronomically superior cultivars by farmers is slower than expected. Three main areas which explain why this is occurring are: 1. The need to demonstrate economic benefits due to superior agronomic performance of new cultivars to overcome barriers such as price and farmers satisfaction with existing products. 2. Farmers are influenced by advice of seed retailers/extension personnel, their knowledge of white clover cultivars, local research, and their economic situation. 3. White clover seed quantity and quality has been adversely affected by poor weather conditions at flowering and harvest over the last 3 or 4 years. Seed availability is also being affected by the cultivar change regulations and the changing land use patterns of Canterbury. The problem is magnified by the increasing number of white clovers being grown on a decreasing land base. For greater uptake and use of new white clovers, strategies that deal with all three areas are required. Keywords: buying decision, economic benefit, farmer use, seed availability, white clover
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KUUSELA, E. "Annual and seasonal changes in mineral contents (Ca, Mg, P, K and Na) of grazed clover-grass mixtures in organic farming". Agricultural and Food Science 15, n. 1 (4 dicembre 2008): 23. http://dx.doi.org/10.2137/145960606777245551.
Testo completoAbstract (sommario):
A grazed field experiment was established in 1995 to evaluate alsike clover (Trifoliun hybridum L.), red clover (Trifolium pratense L.) and white clover (Trifolium repens L.) in clover-grass mixtures under organic farming practices. In this study the effect of seed mixture (alsike clover, red clover, white clover, white and alsike clover or grass mixture), year (1997, 1998) and grazing period (5 per grazing season) on the herbage calcium (Ca), magnesium (Mg), potassium (K) phosphorous (P) and sodium (Na) contents was assessed and the relationships between botanical proportions and herbage mineral contents were studied. Herbage Ca and Na contents varied between the seed mixtures, Ca, Mg, P and Na contents between the years and all measured minerals, except Na, between the grazing periods. The white clover mixture resulted in higher Ca and Na contents. The contents of Ca and Mg were positively related with the proportions of clovers and weeds and were higher in 1997. The contents of P and K were higher in the rainy summer of 1998. The seed mixtures resulted in similar mean K/(Ca + Mg) equivalent ratios, but the Ca/P ratio was higher for the white clover mixture. Mineral rations varied between and within grazing seasons. Under organic practices the supply of minerals in the pasture herbage varied temporally and according to the botanical contents and was unable to meet fully the requirements of dairy cows. Additional mineral feeding is recommended for organic farming systems to balance the dietary mineral contents for grazing cows.;
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Jones, Chris, Warren Williams, Kerry Hancock, Nick Ellison, Alicia Scott, Vern Collette, Zulfi Jahufer et al. "Pastoral Genomics - a foray into the clover genome". NZGA: Research and Practice Series 12 (1 gennaio 2006): 21–23. http://dx.doi.org/10.33584/rps.12.2006.3035.
Testo completoAbstract (sommario):
Pastoral Genomics is engaged in applying molecular mapping and functional genomics to characterise and manipulate key phenotypic traits associated with improved productivity in the commercially important forage crop white clover (Trifolium repens L.). We report on the development of a framework linkage map for white clover and the application of this map to the identification of quantitative trait loci (QTL) associated with vegetative and seed yield traits. Homologues of genes responsible for the traits of interest have been identified and cloned in order to identify 'perfect markers' for marker assisted breeding and to develop a cisgenic® clover cultivar. We introduce western clover (T. occidentale), a diploid perennial clover species closely related to white clover, as a stoloniferous clover model to dissect low heritability traits initially intractable in white clover. We have identified extensive genetic variation in this species, which previously has been reported to be remarkably uniform. We have developed a framework map for T. occidentale and demonstrated conservation of marker order and spacing with white clover. An ethyl methane sulfonate (EMS) mutant population has been used to isolate three distinct groups of condensed tannin (CT) mutants. We have also investigated our model's transformation potential, achieving frequencies 2-3 fold higher than for white clover and suggest that this model is potentially useful for genomic analysis of white clover and other clonal species
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Cohen, D. C. "Degradability of crude protein from clover herbages used in irrigated dairy production systems in northern Victoria". Australian Journal of Agricultural Research 52, n. 3 (2001): 415. http://dx.doi.org/10.1071/ar00033.
Testo completoAbstract (sommario):
An in sacco (nylon bag) technique was used to estimate the degradability of dry matter (DM) and crude protein, and to estimate the effective rumen degradability of protein (ERDP), for 3 irrigated clover herbages. Pasture characteristics (nutritive values and leaf: stem ratios) were also described, and relationships to ERDP established. The nutritive value characteristics and degradabilities of white clover (Trifolium repens L.), Persian clover (Trifolium resupinatum L.), and subterranean clover (Trifolium subterraneum L.) were also compared for various regrowth periods (of 3, 4, 6, and 12 weeks). Nutritive value characteristics of clover herbages varied from 9.9 to 11.9 MJ/kg DM for metabolisable energy, 153 to 304 g/kg DM for crude protein, and 209 to 377 g/kg DM for neutral detergent fibre. The leaf: stem ratio correlated well with the crude protein content of the clovers, with herbages consisting of more leaf generally having superior crude protein content (R2 = 0.64, P < 0.001). The effective rumen degradability of protein for clover herbages ranged from 60 g/kg DM for mature (12 week regrowth) subterranean clover to 195 g/kg DM for vegetative (3 weeks regrowth) Persian clover. For clover herbages with a 3-week regrowth period, after initial cutting to 5 cm, and at ruminal outflow rates of 0.08/h, the effective rumen degradability of protein varied from 136 to 195 g/kg DM. A positive relationship between crude protein and ERDP (R2 = 0.82) suggested that ERDP could be estimated for clover herbages that have been previously assessed for crude protein content, obviating the need for in sacco studies. Calculated degradabilities were lower for all clovers when higher ruminal outflow rates were assumed. Using the metabolisable protein system, metabolisable protein supply and metabolisable protein in excess of animal requirements were calculated. Ruminal losses of nitrogen were also estimated for cows consuming white clover of varying regrowth periods in both early and late lactation. It was concluded that metabolisable protein supply is unlikely to limit production in these examples. At regrowth periods of 3 weeks, metabolisable protein contributions from microbial and dietary sources were similar, and twice that required by the animal. Ruminal losses of nitrogen were substantial and amounted to 66—23% of nitrogen intake. In the experiments reported here, if all of the energy required to excrete excess protein (as urea) could instead be used for the production of milk, cows may have produced 0.5mp;mdash;2.0 kg more milk per day. Such losses could potentially be reduced if the protein content and/or degradabilities of clover herbages were reduced, and/or energy rich supplements were offered.
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Lattimore, MAE, HG Beecher e KL O'Callaghan. "Establishment and early growth after rice of subterranean clover (Trifolium subterraneum), Persian clover (T. resupinatum), balansa clover (T. michelianum), and white clover (T. repens)". Australian Journal of Experimental Agriculture 34, n. 4 (1994): 459. http://dx.doi.org/10.1071/ea9940459.
Testo completoAbstract (sommario):
Four temperate clovers were grown on a typical rice-growing soil in the Murrumbidgee Valley, New South Wales, to assess their establishment and early growth potential. Subterranean clover (Trifolium subterraneum var. yanninicum) cv. Trikkala, Persian clover (T. resupinatum) cv. Maral, balansa clover (T. michelianum var. balansae) cv. Paradana, and white clover (T. repens) cv. Haifa were sown immediately following a rice crop in autumn of 3 consecutive years. Seven sowing methods were compared, including combinations of surface or drill sowing with land preparation techniques commonly used in rice-farming systems. All cultivars established successfully. Trikkala had the best establishment on the basis of per cent seed sown in year 2, and equal best in years 1 and 3, although Paradana and Maral had higher plant densities at the sowing rates used. Paradana and Maral produced the highest dry matter yields and Haifa the lowest (P<0.05) in the growing period to mid-spring. Sowing method strongly influenced (P<0.05) both establishment and yield of clover. Sowing into a dense rice canopy before harvest severely restricted clover performance, while harvesting rice before sowing greatly improved (P<0.05) clover establishment and dry matter production. Establishment from surface sowing was generally more successful than from drill sowing, although yields with both methods were mostly satisfactory. Establishment and yields were highest after burning stubble, but this effect was variable and not always significant. Sowing after cultivation was not successful, especially in the 2 wetter years, due to poor seedbed preparation and waterlogging.
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Care, D. A., J. R. Crush, S. Hardwick, S. N. Nichols e L. Ouyang. "Interaction between clover root weevil and clover root type". New Zealand Plant Protection 53 (1 agosto 2000): 420–24. http://dx.doi.org/10.30843/nzpp.2000.53.3657.
Testo completoAbstract (sommario):
A slant board experiment investigated the effect of four white clover (Trifolium repens L) root types on tolerance of root feeding by larvae of clover root weevil (Sitona lepidus Gyllenhål) Root damage was determined by image analysis and larval weight gains were measured Differences in root type did not have a major impact on initial damage by clover root weevil However different root types were affected differently by the clover root weevil A clover genotype with long fine roots had more functional root length after larval feeding than genotypes with different root types
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Gildersleeve, Rhonda R., G. R. Smith, Indre J. Pemberton e C. L. Gilbert. "Screening Rose Clover and Subterranean Clover Germplasm for Isoflavones". Crop Science 31, n. 5 (settembre 1991): 1374–76. http://dx.doi.org/10.2135/cropsci1991.0011183x003100050062x.
Testo completo