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Tesi sul tema "Ryegrass"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 8 febbraio 2022

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1

Kopec, David M., Jeffrey J. Gilbert e David M. Jensen. "Ryegrass Germplasm Overseeding Trials". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001. http://hdl.handle.net/10150/216377.

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A field test was conducted to evaluate the turf performance of improved hybrid ryegrass (sometimes called intermediate ryegrass) Lolium hybridum versus that of perennial ryegrass germplasm (Lolium perenne) for winter overseeding purposes. "Gulf" annual ryegrass was also evaluated for comparison purposes. On all evaluation dates, the treatment effect was significant for all visual response variables measured (quality, color, texture, density, etc.). The mixture of LHRT hybrid ryegrass/Poa trivialis established quicker than other treatments during the first month (November). Perennial ryegrass entries provided the darkest color turf. Among hybrid ryegrasses, Pick A-97 was slightly darker in turf color when compared to LHRT. LHRT alone was darker in color than when mixed with Poa trivialis. In terms of overall turf quality, Pick A-97 and LHRT hybrid ryegrasses were essentially equal in performance. The spring decline was greater among hybrid ryegrasses than that of perennial ryegrass. Both hybrid ryegrasses (A-97 and LHRT) were superior to annual ryegrasses in all aspects of turf performance. By mid-June of 1999, Pick A-97 had more bermudagrass present (52%) than LHRT (28%). LHRT had more straw-colored (dead transition grass) than A-97 as well. By early July, A-97 and LHRT had 72% and 62% bermudagrass, respectively, and essentially the same amount of overseed present (20-23%). LHRT had 15% plot straw at this time, while A-97 had 8%. Among perennial ryegrasses, Sunshine had the slowest transition (42%), followed by Jiffie (50%) and Future 2500 (71%) by early July. The addition of Poa trivialis to LHRT hybrid ryegrass increased overall quality of the LHRT alone, but slowed transition slightly, most likely due to increased canopy densities achieved by the addition of Poa trivialis. This test demonstrated that the hybrid ryegrass germplasm tested here provided adequate fairway turf performance, and that transition among and between Lolium germplasm is variable, and genetically dependant.

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2

Dhaliwal, Amandeep Kaur Van Santen Edzard. "Recurrent phenotypic selection for increased winter productivity in annual ryegrass (Lolium multiflorum Lam.)". Auburn, Ala., 2009. http://hdl.handle.net/10415/1797.

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3

Kopec, D. M., C. F. Mancino, A. Terrey e S. Gomperts. "Ryegrass Overseed Trials for 1986-1987". College of Agriculture, University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/215830.

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Ryegrass cultivars, experimental accessions, blends and composite mixtures were tested for overall adaptation to overseeded turfgrass management practices under desert conditions. Entries were significantly different from each other for color and overall turfgrass quality. Gennplasm for overseeding differs for tolerance to close mowing under desert conditions. In most cases, the better adapted entries had superior scores in two years of testing.

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4

Kopec, D. M., C. F. Mancino, M. J. Petty e L. Salo. "Ryegrass Turf Trials for 1987-1988". College of Agriculture, University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/215849.

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5

Kopec, David M., Jeff J. Gilbert, Steve Nolan e Mohammed Pessarakli. "Perennial Ryegrass Transition Using Selected Herbicides". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2009. http://hdl.handle.net/10150/216646.

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Thirteen herbicide treatments were applied on May 8, 2006, on a golf course fairway to assess transition and turf quality effects. Initial injury to perennial ryegrass was most extreme for Tranxit GTA when applied at 1.0 oz/prod/acre and Katana applied at 2.0 oz/prod/acre. Katana resulted in the total elimination of ryegrass and resulted in a fully necrotic canopy (straw cover) within two weeks after application to July 19, 2006 (72 Days after treatment). The development and persistence of necrotic leaf tissue of perennial ryegrass (straw) had the greatest impact on decreasing overall turfgrass quality ratings. No treatment went through the summer without some loss of quality at some point, including the untreated control. Certainty had little or no effect on transition when applied once at the rate of 1.25 oz/prod/acre. Surflan was not effective in ryegrass transition. The tank mix of Transit and nicosulfuron applied at the rate of 0.25 oz/prod./A each, produced an enhanced transition with nominal quality. In similar fashion, Monument applied at 0.35 oz./A produced an enhanced transition with nominal quality. A rates used in this test, other treatments had either too slow of a transition or had poor and extended low quality turf scores from rapid development of dead ryegrass (straw) and subsequent slow bermudagrass re-establishment. The UTC turf maintained a high percentage of living green ryegrass into the summer and 20% live ryegrass on August 8, 2006 which is roughly six weeks before the next overseeding.

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6

Pinkerton, E. H. "Mechanisms involved in ryegrass leaf development". Thesis, Queen's University Belfast, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411834.

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7

Cook, Casey Lee. "Seeding rate and seed size as management techniques for ryegrass (Lolium Multiflorum, Lam) in winter wheat". Texas A&M University, 2002. http://hdl.handle.net/1969.1/2284.

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Higher seeding rates and larger seed sizes could enhance the competitiveness of wheat with ryegrass. Growth room and field research evaluated the effects of wheat seeding rates and seed size in competition with Italian ryegrass. Winter wheat seeds cultivar “Ogallala” were divided into three seed sizes: small seed passed through a sieve with 2.08mm round holes, large seed which did not pass through a sieve with 3.18mm round holes, and bulk seed directly from a commercial seed bag. These wheat seed and seed of the Italian ryegrass cultivar AGulf@ were planted in plastic pots containing fritted clay. A replacement series design with 12 plants per pot compared the relative growth in pure culture and competitiveness in mixtures of the two species. The planting proportions of each wheat seed group and ryegrass were 100% and 0%, 50% and 50%, and 0% and 100%, respectively. Wheat seed size did not affect the growth of the wheat plants in pure culture. Wheat seed size did not affect competitiveness with ryegrass. There were no differences related to seed size among the pure or mixed cultures of wheat. The failure of increased wheat seed size to affect competition with ryegrass may be the result of the relative seed size difference between the two species. Even the small wheat seed in this study were almost 9-fold greater inweight than the ryegrass seed. Field experiments conducted for two years from fall 2002 through spring 2004 at the Texas A&M University Agronomy Farm measured wheat yields at the same three wheat seed sizes, two wheat densities of 250 plants m-2 and 400 plants m-2, and three ryegrass densities of 0, 100 and 200 plants m-2. Small, bulk, and large wheat seed produced similar yields in both years: one season favorable (2003) for growth and the other (2004) unfavorable. Thus, seed size in the field under favorable or unfavorable conditions or in the growth room experiment did not affect the competitiveness of wheat in the presence of ryegrass. Increasing the wheat plant population from 250 to 400 plants m-2 in the field also failed to enhance the competitiveness of wheat in either year.

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8

Coll, R. J. "Estimation of genetic difference as a measure of relatedness and as an indication of essential derivation in Lolium perenne". Thesis, Queen's University Belfast, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368762.

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9

Heap, Ian Michael. "Resistance to herbicides in annual ryegrass (Lolium Rigidum)". Adelaide, 1988. http://hdl.handle.net/2440/18842.

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10

Huang, Ji-Wei. "Wear tolerance in perennial ryegrass (Lolium perenne L.)". Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389474.

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11

Kopec, David M., Jeffrey J. Gilbert e Darren E. Kerr. "Response of Perennial Ryegrass to R.P.-EXP31130Aand R.P.-EXP31598A". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001. http://hdl.handle.net/10150/216360.

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EXP31130A and EXP31598A were applied as repeat applications on June 5 and July 23, 1997 to perennial ryegrass maintained at 3.0 inches. Application rates were 0.18 and 0.36 lbs. AI/A (31130A) and 7.0 and 14.0 fl. oz/prod/A (31598A). Each treatment was applied with and without Sequestrene 338 iron chelate, at the rate of 0.1 oz/m². Untreated and iron-only controls were included in the test. Ryegrass was generally unaffected by either compound, under the conditions of this test. Inclusion of iron (in the tank mix) was more beneficial for EXP31598A, than for EXP31130A. Untreated controls generally had lower performance scores, than did turf which received either herbicide compound. Treatment effects for overall turfgrass quality were significant only on three of ten evaluation dates, and on one of ten evaluation dates for turfgrass color. In general both compounds appear safe to use on high cut perennial ryegrass turf under summer conditions in a desert environment.

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12

James, Nicola Lewis. "The management and utilisation of white clover/perennial ryegrass and perennial ryegrass swards in relation to milk production and behaviour of dairy cattle". Thesis, Bangor University, 1992. https://research.bangor.ac.uk/portal/en/theses/the-management-and-utilisation-of-white-cloverperennial-ryegrass-and-perennial-ryegrass-swards-in-relation-to-milk-production-and-behaviour-of-dairy-cattle(1a1a64ab-31af-40f0-9dcc-fd88c15e8795).html.

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The literature concerning the nutritional content of white clover as a grazed herbage or conserved crop offered to dairy cattle and aspects of frothy bloat are reviewed. In the first nine week change-over design experiment the effect on milk production and behaviour of spring calving dairy cows grazing white clover/grass swards at contrasting sward heights were examined. Grazing the clover/perennial ryegrass sward to a height of 4 cm increased clover content, but reduced milk production. The 8 cm sward increased milk yields by 15.8%. This was accompanied by an increase in fat and protein yields. Grazing time and biting rate were increased on the 4 cm sward. Cows offered choice between sward types produced intermediate milk production values. A second change-over design experiment conducted over 12 weeks examined milk production and behaviour of spring calving dairy cows in early lactation grazing perennial ryegrass or White clover/perennial ryegrass swards alone or offered a choice between the two sward types or grazed on clover/perennial ryegrass during the day and perennial ryegrass at night. The inclusion of clover in the diet of the dairy cows significantly increased milk production, but reduced fat content. Protein content, fat and protein yields were increased. Cows offered a choice or mixed day and night grazing regime produced similar results, which were intermediate between the clover/ryegrass and perennial ryegrass treatments. Grazing time was increased on clover/perennial ryegrass swards. This experiment also 1 demonstrated the ability of cows to adjust their grazing time to maximise herbage intake. The third experiment compared the value in relation to milk production of three different buffer forages fed to spring calving dairy cows in late lactation grazing either clover/ryegrass or ryegrass swards. The forages were ryegrass and ryegrass/clover silages and ryegrass hay. Milk yield and composition were not affected by forage type, but intakes were higher for grass silage for cows grazing clover/ryegrass swards and visa versa. Hay OM intake was low. The final experiment conducted over the first 15 weeks of the grazing season studied the effect of energy:protein concentration of strawmix supplements on the productivity of spring calving dairy cows grazing a high white clover sward. Milk yields were increased by the provision of a strawmix supplement. The energy:protein ratio had a significant effect on milk composition except fat content. The high energy:high protein supplement tended to precipitate ruminal tympany (bloat), while the low energy:high protein supplement tended to reduce ruminal tympany on this clover based sward. These experiments have given some insight into the use of clover and stimulated questions which require further investigation to enable the farmer to safely incorporate clover into dairy farming systems.

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13

Carpenter, Alexandra Cathryn. "Wheat interactions with Italian ryegrass; forage production and quality in pure and mixed stands of wheat, oats, and ryegrass; and halosulfuron interaction with soils". Texas A&M University, 2003. http://hdl.handle.net/1969.1/5956.

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A growth room experiment compared seedling growth after nine weeks of two wheat genotypes in pure cultures and mixtures with Italian ryegrass at a low phosphorus (P) level and the P level recommended by soil testing. At the recommended P level in both pure and mixed culture, Mit, a semi-dwarf genotype, had a greater height, leaf area, tiller number, and dry weight of leaves, stems and roots than did Kharkof, a landrace. These results reflected the visual selection criteria for seedling vigor and tillering used in the initial development of the semi-dwarf cultivars. Field experiments compared total dry matter, calories, and percent crude protein and acid detergent fiber of oats, wheat, and ryegrass in pure culture and mixtures at four locations in central Texas at first clipping, second clipping, and unclipped. Although, forage yield was lower for the first clipping than the second clipping or the unclipped treatment, the first clipping had the best forage quality. There was a strong environmental influence on yield and quality. The best forage was pure wheat at College Station, pure ryegrass at Marlin, the wheat-ryegrass mixture at Temple, and pure oats at Thrall. Since Temple had the greatest yield of any site, the wheat-ryegrass mixture demonstrated the highest yield potential. The soil adsorption characteristics of halosulfuron was examined using six soils. Soil adsorption of halosulfuron appeared to be a function of organic matter. Low Kf,ads values indicated that a relatively high plant availability of halosulfuron could be available for plant uptake. Sorghum produced in soils with a low organic matter content may experience injury because of the high plant availability.

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14

Zuk, Alan James. "Factors affecting establishment of seeded zoysiagrass in perennial ryegrass turf /". Search for this dissertation online, 2005. http://wwwlib.umi.com/cr/ksu/main.

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15

Liu, Jianyang. "Morphological and genetic variation within perennial ryegrass (Lolium perenne l.)". Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1127245394.

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Thesis (Ph. D.)--Ohio State University, 2005.
Title from first page of PDF file. Document formatted into pages; contains xiii, 123 p.; also includes graphics (some col.). Includes bibliographical references (p. 99-107). Available online via OhioLINK's ETD Center

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16

Zhang, Chunzhen. "Identification and characterization of cold-responsive genes in perennial ryegrass". [Ames, Iowa : Iowa State University], 2009.

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17

Manzanares, Chloé. "Genetics of self-incompatibility in perennial ryegrass (Lolium perenne L.)". Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4280/.

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Self-incompatibility (SI) prevents pollination by “self” pollen and promotes outbreeding. SI is a widespread mechanism among angiosperms. Grass SI is known to be controlled by two loci, S and Z, mapped in linkage group 1 and 2 respectively but the mechanism remains elusive. SI in perennial ryegrass (Lolium perenne L.) is studied at the gene level for the S-locus. Using a fine-mapping approach, followed by the sequencing of the genomic S-locus region and the transcripts from pollen and stigma, the project identified four stigma S-candidate genes and potentially six pollen S-candidate genes. Moreover, using closely linked markers, the allelic diversity in a breeding population was assessed for both S and Z. This assay demonstrated that allelic diversity is maintained in a half-sib family recurrent selection programme and that even if the SI genes are unknown, it is possible to predict their genotypes. Finally, self-compatibility has been reported in many grasses. Using self-compatible perennial ryegrass populations, two additional loci, F and T, have been investigated, by a mapping approach as well as observation of self-pollination under the microscope. For both loci, a distortion segregation was observed on linkage group 3 (F) and 5 (T) and initial marker recombination maps were created.

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18

Liu, Jianyang. "Morpholotical and genetic variation within perennial ryegrass (lylium perenne l.)". The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1127245394.

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19

Zysko, Agnieszka. "Bacterial responses to changes in phosphorus supply in Ryegrass Rhizosphere". Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.518478.

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20

Barrett, S. K. "Growth regulators in Lolium perenne grown for seed". Thesis, University of Nottingham, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378463.

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21

Kavanagh, S. E. "Low temperature growth and frost tolerance of winter rye (Secale cereale L.) and perennial ryegrass (Lolium perenne L.)". Thesis, University of Newcastle Upon Tyne, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278781.

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22

Xu, Xiangming. "The genetic assessment of inbred lines and their hybrids in Lolium perenne L". Thesis, Aberystwyth University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283766.

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23

El, Hassani T. A. "Growth studies in Lolium multiflorum in a Mediterranean environment". Thesis, University of Reading, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370833.

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24

Mittlesteadt, Tyler Lee. "Evaluation of novel techniques to establish and transition overseeded grasses on bermudagrass sports turf". Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/32596.

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Most professional turf in Virginia is comprised of bermudagrass (Cynodon dactylon L.) or (Cynodon dactylon x C. transvaalensis Burtt Davy) as a monoculture in summer and overseeded with perennial ryegrass (Lolium perenne L.) (PR) in winter, during bermudagrass dormancy. Two transitions are required in an overseeding program, fall establishment of PR and spring control of PR. During each transition, turf quality suffers as one grass dies or enters dormancy while another grass is promoted to fill voided areas. Field studies at various locations in Virginia were conducted to investigate methods of improving spring and fall transition. Bermudagrass green cover in August was influenced by duration of PR competition variably between three bermudagrass cultivars. For example, â Midironâ , â Patriotâ , and â Rivieraâ bermudagrass required 218, 139, and 327 cumulative growing degree days at base 18.3 C (GDD) to reach 95% cover. Bermudagrass biomass was also positively correlated with increasing duration of noncompetitive GDD. Total nonstructural carbohydrates were not correlated to duration of PR competition. Novel application methods were invented and tested at Virginia Tech. Drip, sponge, and strip application methods were used to create patterns of PR control using selective herbicides. Controlling a portion of PR with these methods maintained acceptable turfgrass quality throughout the spring transition and improved bermudagrass cover 12 to 20%, speeding transition by 20 or more days. Efforts to improve PR establishment in dense bermudagrass suggest chemicals that injure existing bermudagrass can improve PR establishment, but cause unacceptable turf discoloration. Mechanical methods to disrupt the bermudagrass canopy had less effect on PR establishment than chemical treatments.
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25

Aronsson, Helena. "Nitrogen turnover and leaching in cropping systems with ryegrass catch crops /". Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/a214.pdf.

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26

Kopec, David M., D. P. Jensen, Steven B. Liddell, Jeffrey J. Gilbert e K. B. Marcum. "Evaluation of Proxy and Primo for Growth Reduction in Perennial Ryegrass". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001. http://hdl.handle.net/10150/216366.

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PROXY (ethephon) and PRIMO (trinexepac-ethyl) were applied to ryegrass (as overseeded turf) in winter and early spring of 1999. PGR effect was assessed as reduction in clipping weight between mowings on eleven harvest dates. From March to April, the greatest percentage reductions were realized from all PGR treatments. Over the entire test period (March 5 to May 15), clipping reduction was rate dependent for PROXY with the 10.0 ounce rate producing a greater PGR effect (less clippings than that of PROXY at the 5.0 ounce rate). PRIMO treated turf (at the highest label rate of 1.0 ounce/product/1000 ft) generally produced the greatest clipping reductions, but lost affect in the middle of May when suppression (broke) was released. PROXY at the 10.0 ounce rate was closer to that of PRIMO for PGR effect than was PROXY at the 5.0 rate. All treatments produced less clippings than that of the control on nine of the eleven harvest events. PRIMO produced on average a noticeably darker color turf than PROXY treated turfs and that of the control plots as well. PROXY treated turf at the 10.0 ounce rate generally had similar overall quality turf when compared to PRIMO treated turf throughout the test. This was due to a high degree of plant uniformity among PROXY treated turf, versus the darker color enhancement realized from PRIMO. No PGR affected the initial stages of spring transition from ryegrass to bermuda by late May 1999.

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27

Wetherall, Jane Ann. "The characterisation of perennial ryegrass proteases and their inhibition during ensilage". Thesis, University of Newcastle Upon Tyne, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308366.

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28

Yang, Bicheng. "Investigations of self-incompatibility (SI) in perennial ryegrass (Lolium perenne L.)". Thesis, University of Birmingham, 2009. http://etheses.bham.ac.uk//id/eprint/1097/.

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Perennial ryegrass (Lolium perenne L.) is one of the most economically and environmentally important grass species for the temperate zone. It maintains effective self-incompatibility (SI), which promotes outbreeding as well as limits the efficient production of inbred lines and hybrids. SI in L. perenne is controlled by the S and Z loci, mapping to linkage groups 1 and 2, respectively. None of the gene products has been identified so far. Comparative mapping has identified regions on rice chromosomes 5 (R5) and 4 with synteny to regions of L. perenne genome containing the S and Z loci, respectively. Markers were developed from the syntenic rice genomic region to refine the S and Z maps. The closest flanking markers had a map distance of 2 cM from S and 0.2 cM from Z. SI cDNA libraries were developed from in-vitro pollinated stigma subtracted with unpollinated stigma to identify SI components and SI response related genes. Through a BLAST search, candidates identified from the SI libraries that were orthologous to sequences on the S and Z flanking regions on rice R4 and R5 were the prime candidate SI genes. Altogether ten SI candidate genes were identified with incompatible response associated differentially expression pattern: a rapid increase in expression within two minutes after pollen-stigma contact and reaching a maximum between 2-10 minutes, implying their roles in the SI response. Attempts were carried out to determine the linkage relationships between the identified candidates and the S or Z loci. Large fine scale mapping populations were developed individually for the S and Z loci to generate high resolution maps of S and Z towards map-based cloning. Tightly linked markers were identified mapping at a distance of 1.4 cM from S and 0.9 cM from Z. The studies performed in this project have implications on both the underlying genetic control and the associated biochemical responses involved in L. perenne SI. The closely linked markers for S or Z could be applied in future marker assisted selection breeding programmes and map-based cloning.

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29

Babu, Jacob. "Bioactive Chemicals of Importance in Endophyte-Infected Grasses". The University of Waikato, 2009. http://hdl.handle.net/10289/2608.

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Janthitrems are believed to be involved in the observed sporadic cases of AR37- infected perennial ryegrass staggers. Investigations into the role of janthitrems in perennial ryegrass staggers are difficult as isolation of the compounds from the ryegrass is hindered by the inherent instability of these compounds. Therefore attempts were made to isolate janthitrems from an alternative source, allowing these janthitrem analogues to be used as surrogates for endophyte produced janthitrems. Analysis of a series of Penicillium janthinellum cultures revealed the presence of janthitrems in a number of strains, including janthitrem B, janthitrem C and two novel janthitrem compounds. Detailed one- and two-dimensional NMR and mass spectral techniques identified the two novel compounds as 11,12- epoxyjanthitrems B and C, which were subsequently given the trivial names janthitrems A and D, respectively. Janthitrems B and C were isolated and identified by NMR and revisions of some previously reported chemical shift assignments were proposed. In addition to the janthitrems, penitrems were also identified in two strains of P. janthinellum. The isolated janthitrem B was utilised for the development of efficient extraction procedures, and for the determination of ideal storage conditions for janthitrem compounds. A method for the extraction and isolation of janthitrem B from a P. janthinellum culture was developed and optimised to yield 6 mg of janthitrem B from 900 mL of fungal culture in two days. Stability studies of janthitrem B indicated the ideal storage condition which minimised degradation was dry at −80 C where only 7% sample loss was observed over 300 days. Bioactivity studies of janthitrems A and B found these compounds to be tremorgenic to mice, with janthitrem A (an epoxyjanthitrem) inducing more severe tremors than janthitrem B. Insect testing also showed that both janthitrems A and B displayed anti-insect activity to porina larvae. Since the epoxyjanthitrems, which are associated with AR37 endophyte-infected ryegrass, were also shown to be tremorgenic and to display anti-insect activity, the insect resistance and the sporadic cases of ryegrass staggers displayed by AR37 may be related to the presence of epoxyjanthitrem compounds. LC-UV-MS analysis of janthitrems A-D, penitrems A-F, lolitrem B, paspalinine, paxilline and terpendole C found these indole-diterpenoids to be more sensitive by analysis using an APCI source as opposed to an ESI source. APCI negative ion LC-UV-MS required source induced dissociation in combination with increased collision energy to suppress an acetate adduct peak, sourced from the acetic acid buffer. Negative ion MS2 and MS3 data produced more informative fragments compared to the conventional positive ion MS2 and MS3 data. The availability of both positive and negative ion LC-UV-MS methodologies will allow future endophyte products to be more thoroughly screened for different classes of secondary metabolites. Extracts of mouldy walnuts were analysed for the presence of tremorgenic mycotoxins after a dog was found to exhibit symptoms characteristic of tremorgenic mycotoxicosis. LC-UV-MS analysis of the mouldy walnuts identified the tremorgenic mycotoxins penitrems A-F, thus confirming the veterinarian's tentative diagnosis of canine tremorgenic mycotoxicosis the first reported case in New Zealand.

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30

Lowes, Wendy. "A molecular analysis of the factors affecting frost tolerance in Lolium perenne". Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299054.

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31

Jupp, A. P. "Some effects of severe drought on the roots of Lolium perenne". Thesis, University of Bristol, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375027.

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32

Dunaway, Chad W. "IN VITRO DIGESTIBILITY OF RYEGRASS SUPPLEMENTED WITH HAY, CORN, OR SOYBEAN HULLS". MSSTATE, 2009. http://sun.library.msstate.edu/ETD-db/theses/available/etd-10292009-093405/.

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Abstract (sommario):

An in vitro continuous culture rumen fermentation experiment was conducted to evaluate digestibility of annual ryegrass either fed alone or annual ryegrass supplemented with hay, corn, or soybean hulls. Nutrient disappearance of feedstuffs offered were not different (P > 0.05) as a percentage of the diet however there were differences (P < 0.05) in amounts of individual nutrients digested for each treatment. Ammonia-N concentrations of culture samples were less (P < 0.05) for vessels fed corn as a supplement however there was no difference (P > 0.05) among vessels fed either ryegrass alone or supplemented with hay or soybean hulls. This may indicate a more efficient use of available nutrients from annual ryegrass when corn was supplemented.

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33

Malleson, Evelyn Rhoda. "Fishmeal supplementation to high producing Jersey cows grazing ryegrass or kikuyu pasture". Diss., Pretoria : [s.n.], 2008. http://upetd.up.ac.za/thesis/available/etd-06272008-130048.

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34

Kopec, David M., e Jeffrey J. Gilbert. "Response of Perennial Ryegrass under Desert Conditions to Applications of Sulfentrazone Herbicide". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001. http://hdl.handle.net/10150/216356.

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Abstract (sommario):

Sulfentrazone was applied to perennial ryegrass turf as single applications at 0.125, 0.250 and 0.375 lb. AI/A, and split application combinations of 0.125/0.125, 0.250/0.250 and 0.375/0.125 AI/A. Respective treatments were applied on June 28 and July 31, 1996. Sulfentrazone caused a decrease in turfgrass color, which was most noticeable at the 0.375 lb. AI/A rate. Decreases in color were generally dependent on application rate. Sulfentrazone caused a slight "pocking" of the turf, which resulted from leaf twisting/cupping. This injury was most evident at seven days after the first application. There was no foliar burning or uneven discoloration however. The turf exhibited a lesser amount of discoloration and injury following the second (split) application.

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35

Kopec, David M., D. P. Jensen e Jeffrey J. Gilbert. "Ethephon Potential for Spring Transition of Perennial Ryegrass back to Common Bermudagrass". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2001. http://hdl.handle.net/10150/216367.

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Abstract (sommario):

Spring transition of ryegrass back to the underlying bermudagrass has become problematic for turfgrass managers in the Southwest. This is in part do to increased heat tolerance and shoot densities of newer ryegrass cultivars which predominate the market place. The chemical ethephon (Proxy for turf) was evaluated for use as a plant growth regulator (PGR) to enhance transition from perennial ryegrass to bermudagrass. Proxy was applied at either 5 or 10 ounce rates/1000 square ft, either before, during or after soil moisture stress was imposed on the overseeded turf. On the dates of July 6, 21, 19 and August 9 the greatest visible difference occurred among treatments for percent bermudagrass. These responses were not not statistically significant, however. The greatest transition response was achieved (in general) from Proxy applied at 10 the ounce rate, when applied "pre-stress". This treatment combination generally ranked highest for percent bermudagrass throughout the test. The second most beneficial treatment (in general) was that of Proxy at the 10 ounce rate when applied under "medium stress". From July 21 to August 9 this treatment essentially ranked second for the ryegrass to bermudagrass transition. The third most beneficial treatment (in general) was Proxy applied at the 10 ounce rate , applied "post stress". This treatment was applied the latest in the season ( June 16), which was 22 days after the entire test was fully irrigated (at the start of the test on May 23). Proxy applied "post stress" at the 10 ounce rate excelled in enhancing the ryegrass to bermudagrass transition from July 21 to July 29. When applied at either the 5 or 10 ounce product rates, the "low stress" application treatments had minimal affect for transition. These treatments ranked similar in response to that of the untreated - well watered controls. The "medium" stress plots receiving Proxy exhibited a greater affect on the ryegrass to bermuda transition, depending on the date of bermudagrass evaluation. Further testing should be conducted on lower mowed perennial ryegrass with a more aggressive underlying bermudagrass base, such as the popular Tifway 419.

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36

Neylan, David. "Operational modes for effective recovery of energy from ryegrass using anaerobic digestion". Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/210411/.

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Abstract (sommario):

In the United Kingdom a large proportion of agricultural land is laid to grass which is used for grazing and also harvested for animal feed. Grass is also potentially the crop most suited to energy production in the UK because of its high yield, low maintenance and suitability for growing under the climatic conditions. Anaerobic digestion is a potential technology for conversion of grass to energy and the current work looks at the design and operation of digester types that could be used to maximise the energy yield per hectare of crop and take advantage of the requirement to store harvested material over the winter period. Initial experiments established the methane potential of ryegrass (Lolium perenne) to be 0.245 m3 kg-1 VS added. This was determined in a series of conventional batch digestion studies at different inoculum to substrate ratios using an anaerobic sludge taken from a municipal wastewater digester. The research then went on to examine potential energy losses through the use of conventional continuous stirred tank reactor (CSTR) digester design and from this began to focus on plug flow designs that could be simulated through a batch digestion model. Experimental work used a batch feed cycle to simulate a continuous fed plug flow reactor, although the results are equally applicable to a cyclic batch feeding regime. The minimum feed cycle length to gain 70% of the methane potential was found to be six days at an initial substrate loading rate (ISLR) of 10 g VS L-1 and twelve days at an ISLR of 20 g VS L-1; in both cases this was equivalent to an Organic Loading Rate (OLR) of 1.7 g VS L-1 day-1. In a batch or plug flow system it is necessary to add an inoculum, and experiments were designed to show the advantages and disadvantages associated with using the liquid or solid fractions derived from separated digestate material for this purpose. Both proved to be suitable as an inoculum at a 10 g VS L-1 batch loading, but a higher gas yield was achieved from the separated solids inoculum due to the capturing of residual VS by increasing the solids retention time of the system. Results from a number of experiments indicated that in a ryegrass digestion system mechanical stirring could be problematic, and there were indications that this type of mixing might not be necessary for optimal performance. At an ISLR of 20 g VS L-1 some small advantages were found as a result of stirring during acclimation of the inoculum to the feedstock but this could be compensated for by the adoption of once per day liquid recirculation around the digester. This mixing strategy was therefore adopted in subsequent experiments. 30L digesters were used to test a digester operating mode in which solids were allowed to accumulate over a number of feed cycles, achieved by removing only the liquor which passed a 1 mm mesh at the end of each cycle. The solids accumulation rate for ISLR of 10 g VS L-1 loading on a seven-day cycle would allow the digester to operate for 30 weeks if no solids were broken down. In practice the rate of VS destruction measured extended this by between ~24-67% depending on the initial solids make up of the digester. In a subsequent smaller-scale solids accumulation experiment a specific methane yield of 0.415 L CH4 gVS-1 was achieved over 10 feed cycles (weeks) and showed this reached an optimum at an I:S ratio of 3 – 3.5 on a VS basis

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37

Gooch, C. Bryan. "Competitive Effects of Perennial Ryegrass and Chewings Fescue on Bermudagrass Seed Establishment". Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36678.

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Abstract (sommario):

Perennial ryegrass (Lolium perenne L.) is widely used as a fairway turf on golf courses throughout the transition zone. The transition zone represents the geographical areas between the temperate and subtropical climates, where neither warm season nor cool season grasses are well adapted. The late-spring establishment of seeded bermudagrass could potentially enhance summer quality of a perennial ryegrass fairway during periods of extreme summer stress. Studies were conducted over two years on both perennial ryegrass and Chewings fescue (Festuca rubra L. ssp. commutata Gaud.) areas to assess the competitive effects of each species on bermudagrass seed establishment. The use of fungicides, herbicides and a plant growth regulator, as well as cultivation treatment prior to seeding, were evaluated for their effects on bermudagrass establishment, turfgrass quality, disease incidence and summer annual grass control. Turfgrass treated with preventative fungicide applications of propiconazole and chlorothalonil maintained high density and turf quality which inhibited successful establishment of bermudagrass during either year. Bermudagrass establishment in 1996 was moderately successful in plots not treated with fungicides; however, due to disease severity, turfgrass quality was unacceptable. MSMA applications did not influence turfgrass quality or bermudagrass establishment. Crabgrass populations were too low to ascertain the efficacy of either MSMA (1996) or oxadiazon (1997) on summer annual grass control. Oxadiazon followed by activated charcoal prior to bermudagrass seeding did not adversely affect bermudagrass establishment. In 1996, trinexapac-ethyl slightly enhanced bermudagrass seed establishment, but the competitiveness of perennial ryegrass prohibited establishment success. During 1997, glyphosate was evaluated as a means of eliminating competition and increasing bermudagrass establishment. Glyphosate applied in small strips across existing stands of perennial ryegrass and Chewings fescue significantly increased bermudagrass establishment. Preplant aerification and vertical mowing increased bermudagrass establishment, but slightly reduced turfgrass quality. Overall, bermudagrass establishment into existing stands of turfgrass was successful only where glyphosate was strip-treated over plots to eliminate competition or under circumstances where disease pressure reduced competition from the existing turfgrass.
Master of Science

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38

Grimoldi, Agustín A. "Effects of arbuscular mycorrhiza and phosphorus supply on the growth of perennial ryegrass". [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980529743.

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39

Clifford, Veronica Rose. "Mechanisms regulating the thermal acclimation of dark respiration in snow tussock and ryegrass". Thesis, University of Canterbury. Biological Sciences, 2007. http://hdl.handle.net/10092/1445.

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Abstract (sommario):

The aim of this research was to identify the mechanisms that underpin changes in respiratory capacity during acclimation to temperature. Dark respiration, enzyme activities and leaf ultrastructure were measured from ryegrass (Lolium perenne) in controlled environmental chambers and two species of native grass (Chionochloa rubra & C. pallens) growing at different altitudinal ranges on Mount Hutt, Canterbury, New Zealand. The overall hypothesis was that the changes in both mitochondrial numbers and enzyme activity underpin the greater respiratory capacity observed in response to decreasing temperatures. Gas exchange measurements were carried out to measure rates of dark respiration (Rd) in leaves of both ryegrass and tussocks. Respiratory homeostasis (full acclimation) was achieved in ryegrass leaves but only partial acclimation in both species of tussock plants. Dark respiration rates for warm-grown ryegrass were greatly reduced compared to cool-grown grasses. Rd was lower for C. rubra growing at the base of the mountain (450m) compared to plants at a higher altitude (1060m). The dark respiration rates were also lower for C. pallens growing at 1070m than at 1600m. When comparing Rd between high and low altitude plants, it was significantly lower in low altitude plants at 450m than at 1600m. Oxygen consumption was measured in intact leaves and roots, crude mitochondria and isolated mitochondria from ryegrass to investigate whether a change in respiratory capacity was involved with changes in Rd. Mitochondrial respiratory capacity was slightly reduced in warm leaves and roots (not significantly). The respiratory capacity results from isolated mitochondria for C. rubra (at 450m and 1060m) and C. pallens (at 1070m and 1600m) were consistent with the hypothesis that plants from warm sites have lower respiratory capacity in comparison to plants from cool sites. Based on these results and those of previous studies, it was concluded that respiratory flux for any given temperature is not simply determined by maximal capacities of the respiratory apparatus but rather a combination of the availability of substrate supply, the demand for respiratory products (i.e. ATP) and/or the maximal capacity of respiratory enzymes. Utilizing transmission electron micrographs, it was found that mitochondria were significantly less abundant in warm-grown than cool-grown ryegrass mesophyll cells. Mitochondria dimensions increased slightly between the cool and warm treatment. At lower altitudes (C. rubra), there was a significant decrease in mitochondria numbers with decreasing elevation. At higher altitudes (C. pallens), there was no noticeable change in mitochondria numbers between 1070m and 1600m. It was concluded that mitochondrial abundance for the controlled and field experiments, and mitochondrial sizes in the field, were associated with changes in Rd. The maximal activities of fumarase and succinate dehydrogenase (SDH) in isolated mitochondria from leaves of ryegrass and tussock were measured spectrophotometrically. The results in the controlled experiment indicate that enzymes other than fumarase and SDH could be responsible for the increased respiratory capacity observed in cold acclimated leaves of ryegrass. However, fumarase maximal activity was significantly reduced in C. rubra at low altitude compared with C. pallens growing at high altitude - this suggests that it may be involved in the differences in respiratory capacity and Rd between the two sites. Succinate dehydrogenase did not differ significantly in response to altitude. The large difference between the two field sites for fumarase activity is comparable to the large difference in Rd and reduction in mitochondrial abundance and dimensions seen between the two sites. This supports the overall hypothesis that cool-grown plants keep up with energy demands at low temperatures by increasing enzyme concentrations/capacity. The results of this study are supportive of the hypothesis that growth in low altitudes and warm conditions will result in the reduction of Rd as a consequence of: (1) temperature sensitivity of the respiratory apparatus, resulting in the reduction of the respiratory capacities of mitochondria; (2) a reduction in mitochondria size and numbers; and as a consequence of this (3) a reduction in the activities of mitochondrial enzymes. However, these responses are species specific and vary according to the range of temperatures experienced by plants in the field and controlled environments.

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40

Devereaux, Alissa Corrine. "Transformation and overexpression of a MnSOD gene in perennial ryegrass (Lolium perenne L.)". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ61891.pdf.

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41

Brewer, Marin Talbot. "Effects of Biological Control and a Ryegrass Rotation on Rhizoctonia Disease of Potato". Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/BrewerMT2003.pdf.

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42

McKay, A. C. "Investigations to develop methods to control the nematode associated with annual ryegrass toxicity /". Title page, contents and summary only, 1985. http://web4.library.adelaide.edu.au/theses/09PH/09phm153.pdf.

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43

Pilbeam, C. J. "Comparative studies of populations of perennial ryegrass differing in their rate of respiration". Thesis, University of Reading, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376256.

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44

Hoiberg, Andrew Hansen. "Seeding rates of annual ryegrass that maximize turf cover when sown during traffic". [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1464213.

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45

Weedon, C. M. "Biosynthesis of indole-diterpenoids and other isoprenoids by the ryegrass endophyte, Acremonium loliae". Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47298.

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46

Morgan, Sarah Ann. "Relationships between fatty acids, lipids and other characteristics of perennial ryegrass (Lolium perenne)". Thesis, Aberystwyth University, 2015. http://hdl.handle.net/2160/faf97ebd-42b4-447d-bda5-71d41d14c031.

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Abstract (sommario):

Production and consumption of ruminant products is partly being held accountable for the increasing global challenges of human health and climate change. Also, increasing demand for food, feed and fuel is placing growing pressure on land availability. One area under investigation in response to these challenges is fatty acid content of forages. This thesis sets out to investigate the variation and relationships between fatty acids, lipids, chlorophyll and other nutritional aspects of perennial ryegrass. Additionally, it will investigate alternative methods to predict fatty acids in forage. The core experiment involved twenty-four genotypes from two perennial ryegrass populations. Fatty acids were found to increase in leaf material during a growing season. Genotype differences in fatty acid content and composition were found which were broadly consistent across the growing season. Fatty acids correlated positively with crude protein but negatively with water-soluble carbohydrates. A positive and consistent relationship was found between chlorophyll and fatty acids across the growing season. The use of a chlorophyll meter to estimate fatty acid content did not perform very well, due to poor relationships with in vitro chlorophyll, however near-infrared reflectance and Fourier-transform mid-infrared spectroscopy had acceptable prediction accuracies for use as a screening tool. The accuracies of these prediction methods could be improved with further development using larger datasets. Investigation of the lipid composition revealed that galactolipid proportion was the main contributor to increased total fatty acid content in the high FA genotypes. While phospholipid proportion was minimally affected and neutral lipid negatively affected by increased total fatty acid content. Further work is needed to determine the underlying genetic control of fatty acid and lipid synthesis in perennial ryegrass. Additionally, a great deal more research is needed to establish environmental and genetic effects on lipid composition of forages.

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47

Baxter, Charles James. "The role of sucrose phosphate synthase in plant carbohydrate metabolism". Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324445.

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48

Ferris, David Glen. "Evolutionary differentation in Lolium L. (Ryegrass) in response to the Mediterranean-type climate and changing farming systems of Western Australia /". Connect to this title, 2007. http://theses.library.uwa.edu.au/adt-WU2008.0040.

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49

Christopher, John T. "Mechanisms of resistance to herbicides which inhibit acetolactate synthase in annual ryegrass (Lolium rigidum)". Adelaide, 1993. http://hdl.handle.net/2440/21646.

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Abstract (sommario):

AThesis (Ph.D.) -- University of Adelaide, Faculty of Agricultural Natural Resource Sciences, [1993]
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.

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50

Labuschagne, Johan. "Nitrogen management strategies on perennial ryegrass - white clover pastures in the Western Cape Province /". Thesis, Link to the online version, 2005. http://hdl.handle.net/10019.1/1385.

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