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Studies on the nutritive value of lucerne for dairy cowsDu Toit, Francois (Francois Johannes) 12 1900 (has links)
Thesis (MScAgric)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: An experiment was conducted to determine whether the quality of lucerne hay could be
improved by artificial drying in a forced air bulk dryer (FABD) in comparison to lucerne
hay produced by natural drying in the field. Lucerne fields were divided into four blocks
of equal size and blocks were randomly assigned to each of the two treatments (natural or
artificial drying). Lucerne was harvested at an early to mid flowering stage on six
occasions. In two blocks, cut lucerne was left in the field to dry. Material in the
remaining two blocks were left in the field for an initial drying period of no longer than
24 hours, after which it was transferred to a FABD. Samples oflucerne were taken at the
time of harvest and then at regular intervals (on average 0, 4, 8,22,26,29,47,50,53, 56,
58,69, 72, 76 and 80 hours after cutting) in the field and in the FABD until the material
was dry enough for baling (ca. 15-18% moisture). Collected lucerne samples were dried
in a forced draught oven until constant mass to determine moisture content. The rate of
moisture loss was compared. Samples of the lucerne hay in the field and in the FABD
were taken after baling to determine forage quality by means of chemical analysis.
Samples were analysed for crude protein (CP), total digestible nutrients (TDN), digestible
organic matter (DOM), acid detergent fibre (ADF) and neutral detergent fibre (NDF)
content. Good weather conditions for natural drying during the trial period resulted in
lucerne hay of similar chemical composition. Naturally dried lucerne hay had CP, ADF
and NDF contents of 17.3, 41.2 and 48.0%, respectively, while values for artificially
dried lucerne were 17.6, 40.6 and 47.3%. It was concluded that artificial drying of
lucerne does probably not produce lucerne of a better quality than field drying under
good weather conditions.
In the following trials eight ruminally cannulated cows (four Jerseys and four Holsteins)
were used to compare protein and fibre degradability of lucerne harvested at different stages of maturity (ie. 4, 5 and 6 weeks' regrowth), and of different lucerne products (ie.
lucerne hay, lucerne leaves and 8% leaves added to hay), dried in a forced air bulk dryer.
All cows received a total mixed lactation diet for the duration of the trial period. The first
in situ rumen degradability trial was conducted with lucerne harvested at three stages of
maturity namely after 4,5 and 6 weeks' regrowth. Bags were incubated in the rumen for
time intervals of 0, 2, 4, 8, 16, 24, 48 and 72 hours. Samples were analysed for dry matter
(DM), crude protein (CP) and neutral-detergent fibre (NDF) content.
The effective DM, protein and NDF degradabilities of lucerne hay did not differ (P>0.05)
between Holstein and Jersey cows. In Holsteins, DM degradability values calculated at
an outflow rate of 0.05/h for lucerne harvested after 4, 5 and 6 weeks' regrowth were
63.1, 57.1 and 55.0%, respectively. Values of 64.6, 58.6 and 55.7% were obtained in
Jerseys. CP degradability values for lucerne harvested after 4, 5 and 6 weeks' regrowth
were 81.7, 77.2 and 77.6% in Holsteins and 81.3, 78.2 and 79.4% in Jerseys. NDF
degradability values for lucerne harvested after 4, 5 and 6 weeks' regrowth were 35.8,
45.5 and 23.2% respectively in Holsteins and 35.1, 45.9 and 24.8% in Jerseys.
Analysis of the effective DM, protein and NDF degradabilities across breeds indicated
differences between lucerne harvested after 4, 5 and 6 weeks' regrowth. Rumen
degradability of DM and protein was the highest for lucerne harvested after 4 weeks'
regrowth. DM degradability values oflucerne harvested after 4,5 and 6 weeks' regrowth
calculated at a flow rate of 0.05/h were 63.9, 57.9, 55.4%, respectively, while protein
degradability values were 81.5, 77.7 and 78.5%. The lowest ruminal NDF degradability
values were found for lucerne harvested after 6 weeks' regrowth. Values for NDF
degradability calculated at a flow rate of 0.05/h for lucerne harvested after 4, 5 and 6
weeks' regrowth were 35.5, 45.7 and 23.7%, respectively. These results indicated that
lucerne quality decreased in terms of DM, protein and NDF degradability as the plants
mature.
The second in situ rumen degradability trial was conducted with three different lucerne
components dried in a forced air bulk dryer, namely lucerne hay, lucerne leaves and
lucerne hay + 8% leaves. The procedure followed was the same as in the first in situ trial. Dacron bags, containing samples of the lucerne components were incubated in the rumen
for time intervals of 0, 2, 4, 8, 16,24,48 and 72 hours. Samples were also analysed for
DM, CP and NDF content and compared both between breeds and across breeds.
DM and protein degradability values (rate and effective degradability) of the artificially
dried lucerne hay were higher in Jerseys than in Holsteins. DM degradability values
calculated for Holsteins at a flow rate of 0.05/h for lucerne hay, lucerne leaves and
lucerne hay + 8% leaves were 57.6, 66.5 and 61.4%, respectively, while protein
degradability values of 76.9, 75.5 and 77.9% were obtained. DM degradability values
calculated for Jerseys were 62.9, 69.1 and 61.7%, respectively, while protein
degradability values of 82.4, 77.6 and 78.5% were obtained.
Analysis of the mean disappearance values across breeds indicated that protein
degradability of lucerne hay in the rumen was higher than that of lucerne leaves. Protein
degradability values calculated at a flow rate of 0.05/h for lucerne hay and lucerne leaves
were 80.1 and 76.5% respectively. The NDF degradability of lucerne hay was, however,
lower than what it was for lucerne leaves (24.6 vs. 29.7%). / AFRIKAANSE OPSOMMING: Studies omtrent die voedingswaarde van lusern vir
melkkoeie. 'n Eksperiment is uitgevoer om te bepaal of die kwaliteit van lusernhooi verbeter kan
word deur gebruik te maak van kunsmatige droging in plaas van die tradisionele
landdroging. Lusernlande is in vier blokke verdeel en blokke is ewekansig aan elk van
die twee behandelings (kunsmatige en landdroging) toegeken. Gesnyde materiaal in twee
van die blokke is op die land gelaat vir die duur van die drogingsproses. Die materiaal in
die oorblywende twee blokke is op die land gelaat vir 'n aanvanklike drogingsperiode
van maksimum 24 uur, waarna dit in 'n massa-droogoond geplaas is. Lusernmonsters is
net na sny op die land geneem en daarna met gereelde (gemiddeld 4,8,22,26,29,47,50,
53, 56, 58, 69, 72, 76 en 80 uur na sny) intervalle op die land en in die droër totdat die
materiaal droog genoeg was om te baal. Lusernmonsters is in 'n droogoond gedroog
totdat 'n konstante massa bereik is vir die bepaling van die voginhoud van die materiaal.
Die tempo van vogverlies van die materiaal in die massadroër en op die land is bepaal.
Monsters van die lusernhooi wat op die land en in die oond gedroog is, is na baal geneem
en die chemiese samestelling van die lusernhooi is bepaal. Monsters is ontleed vir
ruprotein- (RP), totale verteerbare voedingstof- (TVV), verteerbare organiese materiaal-
(VOM), suur bestande vesel (SBV) en neutraal bestande vesel (NBV)-inhoud.
Weersomstandighede was ideaal vir natuurlike droging van lusern en dit het aanleiding
gegee daartoe dat die chemiese samestelling van die kunsmatig- en natuurlik gedroogde
lusernhooi nie veel verskil het nie. Die RP, ADF en NDF inhoud van natuurlik
gedroogde lusernhooi was 17.3,41.2 en 48.0% terwyl waardes van 17.6,40.6 en 47.3%
vir kunsmatig gedroogde lusernhooi verkry is. Daar is bevind dat die kunsmatige droging
van lusern nie 'n hoër kwaliteit hooi lewer as wat verkry kan word tydens landdroging
wanneer weersomstandighede gunstig is nie. Hierna is twee degradeerbaarheidstudies gedoen. Agt koeie (vier Holsteins en vier
Jerseys) met rumenkannulas, is gebruik om die proteïen- en veseldegradeerbaarheid van
verskillende lusernkomponente te vergelyk. Lusern op verskillende groeistadia gesny,
asook verskillende lusernprodukte wat kunsmatig gedroog is, is vergelyk. Al die koeie
het gedurende die proeftydperk 'n hoë-konsentraat laktasierantsoen ontvang.
Die eerste in situ degradeerbaarheidstudie is gedoen met lusern wat na 4-, 5- en 6 weke
hergroei gesny is. Sakkies met lusernmonsters is in die rumen geplaas vir 0, 2, 4, 8, 16,
24,48 en 72 uur onderskeidelik. Monsters is na inkubasie in die rumen vir die DM-, RPen
NBV -inhoud daarvan ontleed.
Daar is bevind dat die DM-, proteïen en NBV degradeerbaarhede van lusernhooi nie
verskil het (P.0>05) tussen Holstein- en Jerseykoeie nie. DM degradeerbaarhede wat by
'n deurvloeitempo van 0.05/h in Holsteinkoeie bereken is vir lusern wat na 4-,5- en 6
weke hergroei gesny is, was onderskeidelik 63.1, 57.1 en 55.0%. Die waardes wat vir
Jerseys bereken is, was onderskeidelik 64.6,58.6 en 55.7%. Vir lusern wat na 4-,5- en 6
weke hergroei gesny is, was RP degradeerbaarhede 81.7, 77.2 en 77.6%, onderskeidelik,
vir Holsteinkoeie en 81.3, 78.2 en 79.4%, onderskeidelik, vir Jerseys. NDFdegradeerbaarhede
vir lusern wat na 4-,5- en 6 weke hergroei gesny is, was 35.8,45.5 en
23.2%, onderskeidelik, vir Holsteins en 35.1, 45.9 en 24.8%, onderskeidelik, vir Jerseys.
'n Vergelyking van die DM-, proteïen- en NBV-degradeerbaarhede wat gedoen is met die
saamgevoegde data van al die diere, het daarop gedui dat verskille bestaan tussen die
lusern wat na 4-, 5- en 6 weke hergroei gesny is. Die lusern wat na 4 weke hergroei
gesny is, het die hoogste DM- en proteïendegradeerbaarheid in die rumen getoon. DMdegradeerbaarhede
wat bereken is teen 'n deurvloei tempo van 0.05/h vir lusern wat na 4,
5- en 6 weke hergroei gesny is, was onderskeidelik 63.9,57.9 en 55.4% en proteindegradeerbaarhede
was 81.5, 77.5 en 78.5%. Lusern wat na 6 weke hergroei gesny is het
die laagste NDF-degradeerbaarheid gehad. Waardes wat bereken is teen 'n
deurvloeitempo van 0.05/h vir lusern wat na 4-,5- en 6 weke hergroei gesny is, was
onderskeidelik 35.5, 45.7 en 23.7%. Hierdie resultate dui daarop dat die kwaliteit van lusern afneem in terme van DM-, protein- en NBV-degradeerbaarhede namate die plante
meer volwasse raak.
Die tweede rumendegradeerbaarheidstudie is gedoen met 3 lusernprodukte wat in 'n
massadroër gedroog is nl. lusernhooi, lusernblare en lusernhooi waarby 8% lusernblare
gevoeg is. Dieselfde proefprosedure as tydens die eerste degradeerbaarheidstudie is
gevolg. Sakkies met lusernmonsters, is in die rumen geplaas vir 0, 2, 4, 8, 16, 24, 48 en
72 uur. Monsters is ontleed vir DM-, proteïen- en NBV inhoud.
Daar is gevind dat die proteïen degradeerbaarheid (tempo en effektiewe
degradeerbaarheid) van kunsmatig gedroogde lusernhooi, hoër was by Jerseys as by
Holsteins. DM degradeerbaarhede wat in Holsteinkoeie teen 'n deurvloeitempo van
0.05/h bereken is vir lusernhooi, lusernblare en lusernhooi + 8% blare, was 57.6, 66.5 en
61.4%, onderskeidelik, terwyl proteïen degradeerbaarhede 76.9, 75.5 en 77.9%,
onderskeidelik, was. Vir Jerseys is DM-degradeerbaarhede van 62.9,69.1 en 61.7%,
onderskeidlik, bereken terwyl proteïendegradeerbaarhede 82.4, 77.6 en 78.5% was.
Gemiddelde verdwyningswaardes, wat bereken is deur data van al die diere saam te
gebruik, dui daarop dat die proteïen degradeerbaarheid van lusernhooi in die rumen hoër
was as in die geval van lusernblare. Die proteïen degradeerbaarhede wat bereken is teen
'n deurvloeitempo van 0.05/h, was 80.1 en 76.5%, onderskeidelik, vir lusernhooi en
lusernblare. Die NBV -degradeerbaarheid van lusernhooi was egter laer as vir lusernblare
(24.6 vs. 29.7%).
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Die gebruik van 'n swaainet vir die monitering en diversiteitsbepaling van insekte op lusern in die Wes-KaapDe Villiers, M. (Marelize) 03 1900 (has links)
Thesis (MScAgric)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Lucerne is the most important pasture and fodder crop in the winter rainfall area of
South Africa. Various pests are known to cause damage to this crop. The use of the
sweep net for monitoring pests is a cheap, easy and quick technique. If the sweep net
is suitable for the lucerne pests in South Africa, potential pest status can be
determined easily and quickly and the necessary precautionary measures taken to
prevent crop losses. From a managerial point of view, it is also important to know
the composition of the insect community in order to follow practices in which the
number of beneficial insects can be increased and the injurious insects decreased.
Therefore a study was done to quantify the use of the sweep net as a survey
technique for monitoring pests on established lucerne stands. Insect diversity was
also determined to obtain information on the insect families and guilds on lucerne.
The redlegged earth mite, due to its importance as a pest, and the Anystis mite,
important as a predator, were also included.
The sweep net proved to be suitable for the sampling of the main lucerne pests. If a
29 cm diameter sweep net is swiped once per pace for six long paces, twelve
systematically chosen sampling units are recommended for the lucerne earth flea and
aphids. It is not necessary to differentiate amongst the three aphid species, or
between the winged and unwinged aphids. Actual counts should be used instead of
absence-presence data. Instead of counting all the insects in a sample, sub-samples
can be taken. Operational characteristic curves can be used to determine the risk
involved in the decision not to intervene, for example by spraying or grazing.
Recommendations for monitoring and the accuracy of control decisions for the
redlegged earth mite, Sitona weevil and lucerne butterfly can only be made after
threshold values have been determined.
The pea aphid, bluegreen aphid and lucerne earth flea showed peaks in their
population levels during spring. Peak numbers of the spotted alfalfa aphid occurred
during late summer and autumn. The Sitona weevil and lucerne butterfly numbers
reached peak levels during late spring and early summer. For all pests population levels were dramatically reduced after grazing or cutting of the plantings. Therefore,
these cultivation practices provided good control.
The herbivores made up more than 85% of the insect community in lucerne. The
largest herbivorous families, in terms of the number of individuals per family, were
the Aphididae and Sminthuridae. These two families contain the main lucerne pests,
the pea aphid, bluegreen aphid, spotted alfalfa aphid and the lucerne earth flea. The
largest predatory family was the Anystidae, represented by the Anystis mite, the
most important predator of the red legged earth mite and lucerne earth flea. Another
well represented predatory family was the Coccinellidae, containing natural enemies
of the aphids. The dryland plantings had a higher percentage of predators than the
irrigated lucerne.
The most important parasitaids were those in the superfamily Chalcidoidea and in
the family Braconidae. The main detritivores were springtails in the suborder
Arthropleona, insects in the families Mycetophilidae on irrigated lucerne, and
Mycetophagidae on dryland lucerne. The most abundant visitors were in the families
Chironomidae, Drosophilidae and Tephritidae. The dryland plantings had a lower
percentage of visitors than the irrigated plantings.
The number of insect families, as well as the number of individuals per family, was
lower at the dryland plantings than at the irrigated plantings. The vast majority of
insect families found on lucerne were collected during the one-year sampling period.
A lower diversity was found where grazing was more severe, and there was a
negative relationship between diversity and evenness. / AFRIKAANSE OPSOMMING: Lusern is die belangrikste wei- en voergewas 10 die winterreëngebied van Suid-
Afrika. Hierdie gewas word deur 'n verskeidenheid plae aangeval. Die gebruik van
die swaainet vir die monitering van plae is 'n goedkoop, maklike en vinnige tegniek.
lndien die swaainet geskik is vir die betrokke plae in Suid-Afrika, kan potensiële
plaagstatus van die plae dus maklik en vinnig bepaal word en die nodige
voorsorgmaatreëls getref word om verliese te voorkom. Vanuit 'n bestuursoogpunt
is dit ook belangrik om te weet wat die samestelling van die insekgemeenskap is
sodat praktyke gevolg kan word waardeur die getal voordelige insekte verhoog en
nadelige insekte verlaag word. Gevolglik is 'n studie uitgevoer om die gebruik van
die swaainet te kwantifiseer as 'n monsternemingsmetode vir die monitering van plae
op gevestigde lusernstande. Insekdiversiteit is ook bepaal ten einde inligting te
bekom oor die insekfamilies en -gildes op lusern. Die lusernerdvlooi en
swartsandmyt, vanweë hul belang as plae, en die Anystis-roofmyt, vanweë sy belang
as predator, is ook ingesluit.
Die swaainet blyk geskik te wees vir die monitering van die. vernaamste lusernplae.
Wanneer 'n 29 cm deursnee swaainet vir ses lang treë een keer per tree geswaai
word, word 12 sistematies gekose steekproefnemingseenhede vir die lusernerdvlooi
en plantluise aanbeveel. Daar hoef nie onderskeid tussen die plantluisspesies en
tussen gevleuelde en ongevleuelde plantluise getref te word nie. Daar moet gebruik
gemaak word van werklike insektellings en nie van aanwesigheid-afwesigheid data
nie. In plaas van om al die insekte in 'n monster te tel, kan submonsters geneem
word. Operasionele karakteristieke kurwes kan gebruik word om die risiko verbonde
aan die besluit om nie op te tree, deur byvoorbeeld te spuit of bewei nie, te bepaal.
Vir die swartsandmyt, Sitona-snuitkewer en lusernskoenlapper moet drempelwaardes
eers vasgestel word voordat aanbevelings vir monitering en die akkuraatheid van
besluite rakende beheer, gegee kan word.
Vir die ertjieluis, blougroenluis en lusernerdvlooi het die bevolkingsvlakke 'n piek in
die lente bereik. Die gevlekte lusernluis se piekgetalle was hoofsaaklik in die laat
somer en herfs. Die Sitona-snuitkewer en lusernskoenlapper het piekgetalle gehad in die laat lente en vroeë somer. Vir al die plae het bevolkingspieke drasties afgeneem
nadat die aanplantings bewei of gesny is. Hierdie verbouingspraktyke blyk dus goeie
beheer te verskaf.
Die herbivore op lusern het meer as 85% van die insekgemeenskap beslaan. Die
grootste herbivoorfamilies, in terme van aantal individue per familie, was die
Aphididae en Sminthuridae. Hierdie twee families bevat die vernaamste lusernplae,
naamlik die ertjieluis, blougroenluis, gevlekte lusernluis en lusernerdvlooi. Die
grootste predatoriese familie was die Anystidae, wat verteenwoordig is deur die
Anystis-roofmyt. 'n belangrike predator van die swartsandmyt en lusernerdvlooi.
Nog 'n predatoriese familie wat goed verteenwoordig was, was die Coccinellidae,
natuurlike vyande van plantluise. Die droëland aanplantings het 'n hoër persentasie
predatore gehad as die besproeide lusern.
Die belangrikste parasitoïede aanwesig was dié in die superfamilie Chalcidoidea en
familie Braconidae. Die vernaamste detritivore was erdvlooie in die suborde
Arthropleona, insekte in die families Mycetophilidae by besproeide lusern, en
Mycetophagidae by droëland lusern. Die volopste besoekers was lede van die
families Chironomidae, Drosophilidae en Tephritidae. Die droëland aanplantings het
'n laer persentasie besoekers gehad as die besproeide lusern.
Die aantal insekfamilies, asook die aantal individue per familie, was laer by die
droëland aanplantings as by die besproeide aanplantings. Die oorgrote meerderheid
insekfamilies wat op lusern voorkom, is gedurende die een jaar opnameperiode
waargeneem. 'n Laer insekdiversiteit is gevind waar beweiding strawwer was, en
daar was 'n negatiewe verband tussen diversiteit en gelykmatigheid.
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SPECTRAL REFLECTANCE OF CANOPIES OF RAINFED AND SUBSURFACE IRRIGATED ALFALFAHancock, Dennis Wayne 01 January 2006 (has links)
The site-specific management of alfalfa has not been well-evaluated, despite the economic importance of this crop. The objectives of this work were to i) characterize the effects of soil moisture deficits on alfalfa and alfalfa yield components and ii) evaluate the use of canopy reflectance patterns in measuring treatment-induced differences in alfalfa yield. A randomized complete block design with five replicates of subsurface drip irrigation (SDI) and rainfed treatments of alfalfa was established at the University of Kentucky Animal Research Center in 2003. Potassium, as KCl, was broadcast on split-plots on 1 October 2004 at 0, 112, 336, and 448 kg K2O ha-1. In the drought year of 2005, five harvests (H1 - H5) were taken from each split-plot and from four locations within each SDI and rainfed plot. One day prior to each harvest, canopy reflectance was recorded in each plot. Alfalfa yield, yield components, and leaf area index (LAI) were determined. In 2005, dry matter yields in two harvests and for the seasonal total were increased (Pandlt;0.05) by SDI, but SDI did not affect crown density. Herbage yield was strongly associated with yield components but yields were most accurately estimated from LAI. Canopy reflectance within blue (450 nm), red (660 nm) and NIR bands were related to LAI, yield components, and yield of alfalfa and exhibited low variance (cv andlt; 15%) within narrow ( 0.125 Mg ha-1) yield ranges. Red-based Normalized Difference Vegetation Indices (NDVIs) and Wide Dynamic Range Vegetation Indices (WDRVIs) were better than blue-based VIs for the estimation of LAI, yield components, and yield. Decreasing the influence of NIR reflectance in VIs by use of a scalar (0.1, 0.05, or 0.01) expanded the range of WDRVI-alfalfa yield functions. These results indicate that VIs may be used to estimate LAI and dry matter yield of alfalfa within VI-specific boundaries.
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Map-based Cloning of an Anthracnose Resistance Gene in <i>Medicago truncatula</i>Yang, Shengming 01 January 2008 (has links)
Anthracnose, caused by the fungal pathogen Colletotrichum trifolii, is one of the most destructive diseases of alfalfa worldwide. Cloning and characterization of the host resistance (R) genes against the pathogen will improve our knowledge of molecular mechanisms underlying host resistance and facilitate the development of resistant alfalfa cultivars. However, the intractable genetic system of cultivated alfalfa, owing to its tetrasomic inheritance and outcrossing nature, limits the ability to carry out genetic analysis in alfalfa. Nonetheless, the model legume Medicago truncatula, a close relative of alfalfa, provides a surrogate for cloning the counterparts of many agronomically important genes in alfalfa. In this study, we used genetic map-based approach to clone RCT1, a host resistance gene against C. trifolii race 1, in M. truncatula. The RCT1 locus was delimited within a physical interval spanning ~200 kilo-bases located on the top of M. truncatula linkage group 4. Complementation tests of three candidate genes on the susceptible alfalfa clones revealed that RCT1 is a member of the Toll-interleukin-1 receptor/nucleotide-binding site/leucine-rich repeat (TIR-NBS-LRR) class of plant R genes and confers broad spectrum anthracnose resistance. Thus, RCT1 offers a novel resource to develop anthracnose-resistant alfalfa cultivars. Furthermore, the cloning of RCT1 also makes a significant contribution to our understanding of host resistance against the fungal genus Colletotrichum.
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Common Insect Contaminants Found in Arizona LettuceKerns, David L. 02 1900 (has links)
2 pp. / This publication describes the common insects found in Arizona lettuce through the use of pictures. The insects include; lepidopterous larva, striped flea beetle, leafminer fly, leafminer mine, adult western flower thrips, winged adult aphid, false chinch bug, lygus bug, potato leafhopper, and threecornered alfalfa hopper.
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TISSUE CULTURE AND RADICLE EXCISION TECHNIQUES FOR EVALUATION OF SALT TOLERANT ALFALFA (MEDICAGO SATIVA L.).SEITZ, MORENA HOLLY. January 1983 (has links)
Tissue culture and radicle excision techniques were employed to evaluate salt tolerance in alfalfa (Medicago sativa L.). Plant suspension cultures of either seedling root or shoot origin were studied in media with or without supplemental NaCl (3.54 g liter⁻¹). In most cases, the growth rates of root-derived cultures were stimulated by this low level of supplemental NaCl while most shoot-derived cultures were not stimulated by NaCl. Excised radicles of three populations of alfalfa which possessed widely differing ranges of germination salt tolerance were screened in four salts (NaCl, KCl, Na₂SO₄, and K₂SO₄) at six varying concentrations. As was observed in the tissue culture experiments, low levels of NaCl (7.09 g liter⁻¹) stimulated radicle elongation of all populations as compared to the elongation levels of the control solutions (no supplemental salts). In general, for NaCl, the population that posessed the highest degree of germination salt tolerance (Az-St 1982) also displayed the greatest rates of radicle elongation especially in the highest salt concentrations. Additionally, this population along with the moderately germination salt tolerant population (Az-ST 1979) maintained higher rates of elongation in KCl, K₂SO₄ and Na₂SO₄ than did the control germplasm which has little germination salt tolerance (Mesa Sirsa Control). Examinations of each individual population in all four salts simultaneously, indicated that the sulfate salts reduced radicle elongation to a greater extent than did the chloride salts. Evaluation of both osmotic effects and specific ion effects showed that the specific ion effects attributed to the anions were more detrimental to radicle elongation than were the osmotic effects.
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Characterization of the Early Host-nematode Relationship of Meloidogyne Incognita Infecting Resistant and Susceptible Alfalfa CultivarsFlores-Lara, Yolanda January 2005 (has links)
Plant parasitic nematodes cause billons of dollars in annual crop losses. One of the most damaging is the root-knot nematode, Meloidogyne incognita, which is known to attack more than 3000 plants. This research will contribute to the understanding of host-plant resistance through characterization of the early infection processes of Meloidogyne incognita race 3 in susceptible (Lahontan) and resistant (Moapa) alfalfa cultivars by light microscopy and transmission electron microscopy. Neither differential penetration of M. incognita J2 into Lahontan, nor migration of J2 from Moapa, played a significant role in the resistance mechanism(s). Coiled nematodes in the cortex were observed in greater numbers in the Moapa 48 hours after inoculation. This position was interpreted as a sign of disorientation and starvation. By 96 hours after inoculation, no coiled nematodes were observed in Lahontan. In Moapa, resistance probably depends not only on the failure of the J2 to identify a suitable feeding site and initiate giant cells, but also on its inability to maintain the giant cells, once they are initiated. At the ultrastructural level, 48 hours after inoculation, the most evident change in both cultivars was the appearance of a uniform interstitial material (IM) between the nematode cuticle and the root cell wall. At 96 hours, IM in Moapa was completely agglutinated while in Lahontan it was still uniform or only slightly agglutinated. Due to these clear differences between both cultivars I propose that the IM plays a role in the resistance of Moapa to M. incognita. Immunolabeling techniques were employed to determine if the distribution of the nematode's surface coat, deposited in host tissues, differs in resistant and susceptible alfalfa cultivars. At 72 hours after inoculation, labeling of surface coat epitopes in Moapa was stronger than at 24 and 48 hours after inoculation. Labeling was observed on the nematode's cuticle, the plant cell wall, and the IM. In Lahontan, 72 and 96 hours after penetration, labeling of the surface coat epitopes was observed on the nematode's cuticle, the root cell walls, and the cell wall junctions of cells near the nematode, but not in direct contact with the cell.
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RUMEN PASSAGE RATES AND FIBER DIGESTIBILITIES FOR WHEAT STRAW, ALFALFA HAY AND FLAKED SORGHUM GRAIN IN MIXED DIETS FOR STEERSPoore, Matthew H. (Matthew Henry), 1959- January 1987 (has links)
No description available.
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Chromosome number, fertility, and mitochondrial genome of backcross populations derived from Medicago sativa x Medicago dzhawakhetica hybridsChaulk, Christine Annie, 1964- January 1989 (has links)
Backcross populations (BC) from Medicago sativa L. x M. dzhawakhetica Bordz. hybrids were analyzed for chromosome number, fertility and morphological characteristics. Previously obtained F1 hybrids were recovered when diploid (2n = 2x = 16) M. sativa was crossed with tetraploid (2n = 4x = 32) M. dzhawakhetica. Resulting F1 hybrids were triploid (2n = 3x = 24), completely male sterile and had low levels of female fertility. Subsequent populations were obtained by successive backcrossing to unrelated (4x) M. sativa clones. The BC1 plants were pentaploid (2n = 5x = 40) and both male and female fertile. BC2 populations had chromosome numbers ranging from 2n = 32 to 48, and most plants (94% were male and female fertile. BC3 populations were tetraploid (2n = 32) or near tetraploid (2n = 33) and were morphologically similar to M. sativa. Preliminary analysis of mitochondrial nucleic acids by agarose gel electrophoresis, indicated biparental inheritance of this organelle in the F1 hybrids; however, further analysis provided inconclusive results.
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AN ANALYSIS OF FACTORS IMPACTING HAY AUCTION PRICES AND THE POTENTIAL FOR NAP TO REDUCE ALFALFA REVENUE RISKDant, Madeline L. 01 January 2017 (has links)
Hay auctions have generally been understudied due to their unique market structure. Therefore, the factors that influence the price of hay at auction markets are not well-known. The price of hay at auction markets reflects the various characteristics that differentiate each lot of hay sold. This study is aimed at analyzing the determinants of Central Kentucky hay prices. A hedonic price model is estimated using data collected from a Central Kentucky hay auction. Known hay attributes include forage species, form, bale weight, and nutritive value. An important aspect of this analysis is to determine whether the quality measures of the hay are significant factors in determining hay prices in this auction setting. While price discovery of hay is important, it is also important to know about the insurance that is available to producers. Insurance for hay production is very limited with only two insurance programs available to Kentucky producers. An evaluation of the Noninsured Crop Disaster Assistance Program is conducted by simulating yields from an alfalfa producer and alfalfa trials from University of Kentucky Agriculture Research Centers in Princeton and Lexington, Kentucky. This analysis reveals the effectiveness of the coverage levels offered through the program for alfalfa producers in Kentucky.
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