Browsing by Subject "alfalfa"

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Advances in Horse Health and Management: Estimating Bodyweight and Grazing Legumes
(2016-07) Catalano, Devan
The role of the horse (Equus caballus L.) has evolved since it first appeared four million years ago (Hunt, 1995). According to a survey conducted by the United States Department of Agriculture (USDA), 45.7% of farms use horses for pleasure, 24.8% use horses for farm or ranch work, and 15.9% use horses for breeding (USDA, 2007). Within the sector of horses used as pleasure, workloads can vary drastically from minimal work (maintenance) to intense work (horses participating at the highest levels of competition). Within this range of workload, there are also horses described as hard keepers or easy keepers. The range of energy output of horses varies drastically; therefore, there is not a single ratio or feedstuff that applies to all horses. These different categories of horses have led to two different management problems; how to keep bodyweight (BW) off easy keepers and maintenance horses, and how to keep BW on hard keepers and performance horses. The objectives of the following studies were: 1. to determine the forage nutritive value, yield, and preference of legumes when grazed by adult horses and 2. to assess the accuracy of previously derived BW estimation equations, and if warranted, develop new BW estimation equations for adult draft and warmblood horse breeds using morphometric measurements. To determine objective 1, research was conducted in 2014 and 2015 in St. Paul, MN. Legumes were established as monocultures and in binary mixtures with cool-season grasses in a randomized complete block design with four replicates. Stands were established on May 16, 2014 and April 27, 2015. Adult horses grazed eight alfalfa (Medicago sativa L.) varieties, one red clover (Trifolium pratense L.), and one white clover (Trifolium repens L) when legumes reached the pre-bud stage. Legumes were measured for yield and samples to determine forage nutritive values were harvested prior to grazing. Plots were visually assessed for the percentage of forage removal on a scale of 0 to 100 to determine horse preference. White clover had the greatest amount of equine digestible energy (DE; 2.58 to 2.75 Mcal/kg) in monocultures and mixtures in 2014 and in monoculture in 2015. Digestible energy of all legumes exceeded equine DE requirements for adult horses at maintenance. In both years, alfalfa varieties yielded more compared to white clover (P < 0.0001). The top alfalfa variety yielded 17.4 and 12.9 Mt/ha in 2014 and 2015, respectively. In both years, horses had similar preference for all legumes and removed between 72 to 99% of available forage. This research helps to confirm that legumes are a nutrient dense, high yielding and preferred forage when grazed by adult horses. To determine objective 2, morphometric measurements were collected on adult (≥3 yr), non-pregnant draft (n = 138) and warmblood (n = 89) horse breeds at two separate shows in Minnesota in 2014. Trained personnel assessed body condition score (BCS) on a scale of 1 to 9, measured wither height at the third thoracic vertebra, body length from the point of the shoulder to the point of the buttock (BL wrap), body length from the point of the shoulder to a line perpendicular to the point of the buttock (BL straight), neck circumference at the midway point between the poll and the withers, and girth circumference at the third thoracic vertebra. Each horse was weighed using a portable livestock scale. Individuals were grouped into breed types using multivariate ANOVA analysis of morphometric measurements. Bodyweight estimations equations were developed using linear regression modeling. For estimated BW, the model was fit using all individuals and all morphometric measurements, except BL wrap. For ideal BW, the model was fit using individuals with a BCS of 5 and morphometric measurements not affected by adiposity; BL straight and height. Mean (± SD) BCS was 6.3 (± 0.9) and 5.2 (± 0.6) for draft and warmblood horses, respectively. BW (kg) was estimated by taking [girth (cm)1.528 x BL straight (cm)0.524 x height (cm)0.246 x neck (cm)0.261] / 1,181 (draft) or 1,209 (warmblood)] (R2 = 0.96; rMSE = 28 kg). This is an improvement over the previous BW estimation equation for light-breed horses, which utilized BL wrap and girth circumference to estimate BW (R2 = 0.94; rMSE = 34 kg). Ideal BW (kg) was estimated by [(4.92 x BL straight (cm)) + (4.64 x height (cm)) – 951 (draft) or 1,016 (WB)] (R2= 0.90 and rMSE = 33 kg). Morphometric measurements were successfully used to develop new and improved BW-related equations for draft and warmblood horses. The equations will assist draft and warmblood horse owners and professionals with managing horse BW, nutrition and health.
Alfalfa Hay: Evaluating its Quality by Performance of Dairy Animals and Laboratory Procedures
(Minnesota Agricultural Experiment Station, 1972) Donker, J. D.; Marten, G. C.
Alfalfa leaf protein concentrate: A sustainable protein source for aquaculture feeds
(2019) Samac, Deborah A; Coburn, Jessica E M; Phelps, Nicholas; Wells, M Scott
Interest in local, sustainable aquaculture is continuing to expand across the United States. To ensure profitability and high consumer acceptance, a plant-based non-GMO source of protein is needed for replacing fishmeal in aquaculture diets. Most replacements in current use are derived from seeds, and often contain undesirable antinutritional components. Alfalfa (Medicago sativa) is a high biomass perennial legume that is grown across the U.S. for use in animal feeds. We evaluated the yield and composition of protein concentrates derived from fresh alfalfa foliage. Furthermore, a commercial alfalfa protein concentrate (APC) was used to replace fishmeal in diets for yellow perch (Perca flavescens) and rainbow trout (Oncorhynchus mykiss). Weight gains, growth rate, and feed conversion ratios were measured.
Antibacterial Activity of Plant Defensins Against Alfalfa Crown Rot Pathogens
(2017) Sathoff, Andrew; Velivelli, Siva; Shah, Dilip; Samac, Deborah A
Alfalfa (Medicago sativa) is the fourth most widely grown crop in the United States. Alfalfa crown rot is a disease complex that severely decreases alfalfa stand density and productivity in all alfalfa-producing areas. Currently, there are no viable methods of disease control. Plant defensins are small cationic antimicrobial peptides with a conserved signature of cysteines. The in vitro and in planta antifungal activity of plant defensins has been extensively studied. However, their antibacterial activity has been less well characterized. Defensins have a γ-core motif, a cluster of cationic and hydrophobic residues, which is essential for antimicrobial activity. The γ-core motifs of five synthetic defensins were tested for antibacterial activity against the bacterial pathogens in the alfalfa crown rot disease complex. Full length defensins, expressed using a Pichia pastoris expression system, were tested to compare antibacterial activity. A spread plate method was used to quantify antibacterial activity of defensins. Bacteria were grown out to an OD600 value of 0.1, and a 200 μL culture was incubated with shaking for 3 hours with concentrations of defensin peptide up to 30 μg/mL. The bacteria were serially diluted, and 100 μL was plated on to NBY plates. After 48 hours of incubation, the bacterial colonies were counted. The amount of defensin needed to inhibit growth of pathogen strains by 50% (IC50) was calculated. The core motif of MtDef4 was shown to be the most effective truncated peptide with IC50 values of 3.4 μM against Pseudomonas syringae pv. syringae and 4.52 μM against Xanthomonas alfalfae. Also, the corresponding full length MtDef4 peptide was found to be active against P. syringae pv. syringae and X. alfalfae with IC50 values of 0.43 μM and 0.68 μM, respectively. These experiments show the previously overlooked high biological activity of plant defensins against bacterial pathogens. Additionally, these results indicate that the γ-core-motif can be used to predict biological activity of the full-length defensin, and that transgenic expression of plant defensins in alfalfa has the potential to lead to improved crown rot resistance.
Characterization of the bacterial stem blight pathogen of alfalfa, Pseudomonas syringae pv. syringae ALF3
(2014) Samac, Deborah A; Studholme, David J; Ao, Samadangla
Bacterial stem blight of alfalfa occurs sporadically in the central and western U.S. Yield losses of up to 50% of the first harvest can occur with some cultivars. Developing resistant cultivars is hampered by lack of information on the pathogen and a standard test for evaluating plant germplasm. Bacteria producing a fluorescent pigment were isolated on King’s B agar from alfalfa with symptoms of bacterial stem blight from near Cheyenne, WY. The strain ALF3 was tentatively identified as Pseudomonas syringae pv. syringae based on 16S rDNA sequence and PCR amplification of syrB for lipodepsinonapeptide toxin production. Multilocus sequence analysis indicated that ALF3 falls within a clade containing strains of P. syringae pv. syringae with closest affinity to FF5 from pear. Comparison of a draft whole-genome sequence of ALF3 further confirmed that ALF3 most closely resembles FF5 (~96% sequence identity) and P. syringae pv. aptata DSM50252 from beet. Approximately 60 genes were unique to ALF3, including several predicted genes in the T3SS cluster such as a type III helper protein HrpZ (Pto) and phage-associated genes. ALF3 was highly pathogenic to snapbean pods but caused only mild symptoms on leaves of snapbean, pear, and sugarbeet. A standardized method for evaluating disease resistance in alfalfa was developed. Cultivars with fall dormancy ratings of 1 and 2 had higher percentages of resistant plants than cultivars with fall dormancy ratings of 8-11.
Consider Cutting Alfalfa in October
(University of Minnesota Extension, 2002-09-26) Peterson, Paul
Development of genetic mapping and DNA markers for tolerance to bacterial stem blight caused by Pseudomonas syringae pv. syringae in alfalfa
(2023-06) Sierra Moya, Yeidymar
Alfalfa, Medicago sativa, is a legume with an important role in agriculture, livestock nutrition, and human health. It has high nutritive content, providing vitamins, minerals, protein, and antioxidants not only for livestock but also for humans. As a perennial forage crop, it is cultivated worldwide and is considered the third most valuable field crop in the USA. In addition, it is important for sustainable agriculture due to its role in biological nitrogen fixation and the improvement of soil fertility. Unfortunately, even though it is an excellent forage crop, it is constantly facing biotic and abiotic challenges.Pseudomonas syringae is a gram-negative bacterial pathogen capable of affecting a wide range of plants around the world. Pseudomonas syringae pv. syringae is the causal agent of bacterial stem blight (BSB) of alfalfa and losses can reach 50% of the forage production in some cultivars. Yield losses are due to both frost injury and disease. The bacterium promotes frost through ice nucleation then enters plants through frost injury sites and causes water-soaking, chlorosis, and necrosis 7 to 10 days after the frost injury. Currently, multiple strains have been isolated from Australia, Europe, western Iran, and the USA. Although there is a better understanding of the epidemiology of P. syringae infecting model plants, there is a gap in knowledge on the interactions between legumes and this bacterium. For this reason, it is crucial to find genes that provide tolerance, resistance, or susceptibility to this infection to develop efficient genotypic selection tools such as marker-assisted selection for the development of germplasm resistant to BSB in alfalfa. Chapter 1 includes an extensive literature review of alfalfa and P. syringae, as well as the grounding base for our study. Chapter 2 contains the development of standardized methods for the detection and quantification of Pseudomonas syringae pv. syringae causing BSB of alfalfa, as well as a scoring system to evaluate disease severity. Adapting molecular techniques for the detection, identification, and quantification of this pathogen is key understand the epidemiology of the disease. By understanding the disease progression and bacterial load after infection we can provide insights into the plant response against the pathogen. Results from this research showed that alfalfa leaves scored as resistant with few to no symptoms at 9 days post-inoculation had a similar bacterial load as those with severe symptoms, indicating a tolerance response to the foliar phase of BSB. Chapter 3 contains a genome-wide identification study of genes for tolerance to BSB. The scoring guide of host responses and quantification methods from Chapter 2 were employed to classify plants into different levels of response and used to conduct quantitative trait loci (QTL) mapping for genes involved in BSB disease phenotypes. This is the first study to identify DNA markers associated with tolerance to this pathogen, to increase understanding of defense mechanisms, and advance progress in the development of improved alfalfa cultivars. These results will provide a better insight into the genes involved in BSB resistance and facilitate the mapping of other disease-tolerance/resistance QTL for the development of commercial varieties. The investigations of these chapters have significant implications for the understanding of disease resistance mechanisms for BSB in alfalfa.
The Effect of Trace Elements on Alfalfa and Oats in Minnesota
(Minnesota Agricultural Experiment Station, 1955-03) MacGregor, John M.; Mulvehill, John F.
Factors Affecting the October Alfalfa Harvesting Decision
(University of Minnesota Extension, 2005-09-21) Peterson, Paul
Genome editing in alfalfa (Medicago sativa) to hyper-accumulate phosphate
(2019) Samac, Deborah A; Miller, Susan S; Dornbusch, Melinda R; Curtin, Shaun J
Rock phosphate, the main source of phosphate (P) for crop fertilizers, is a finite resource that is predicted to be depleted in 50-100 years. P is a critical nutrient in agriculture and its application can dramatically improve plant productivity. However, many soils have excess amounts of P from application of animal manures and runoff of phosphate from agricultural lands is the major source of nonpoint water pollution in the Midwestern US. The goal of this project is to create mutations by gene editing in the ubiquitin E2 conjugating enzyme PHO2, involved in P signaling and P homeostasis in alfalfa so that plants hyper-accumulate phosphate. Such plants could be used to reduce soil P levels and reclaim P for use as a fertilizer. From a draft diploid Medicago sativa genome scaffold sequence and the alfalfa transcriptome database (AGED), three PHO2 genes were identified. The genes, two of which are >99% homologous (a/b), each have seven exons interspersed by six introns. The open reading frames are 912 amino acids except when an alternate splice site is used in a/b gene transcript resulting in a 902 amino acid sequence. Alfalfa plants grown under P limiting conditions expressed low levels of the a/b transcripts with higher levels seen for PHO2c, while application of higher P induced increased expression mainly of the a/b transcripts. Under high P conditions, roots and shoots accumulated 4.1x and 2.5x more P than in low P conditions, respectively. An initial CRISPR/Cas9/Cys4 reagent targeting all three genes was generated and used to transform alfalfa cv. RegenSY. A total of 67 verified transgenic plants were screened by acrylamide gel shift assays, cloning, and sequencing to identify plants with mutations. Mutations ranging from a 1 bp insertion to a 25 bp deletion were identified in a total of 10 plants and some plants had multiple targets hit. Recently, a second attempt at CRISPR/Cas9 mutation utilized a cassette vector system with either the tRNA or Cys4 splicing system and exonuclease components. Initial screening results indicate that the tRNA splicing system may have yielded greater numbers of mutations. TaqMan probes were designed to identify plants with changes in the target sites and were verified by restriction digestions, cloning, and sequencing. Data on inheritance of mutations and phosphate accumulation in edited plants will be presented. The results of these experiments demonstrate that editing of multiple targets can be accomplished in alfalfa, although the tetraploid inheritance of genes complicates analysis.
Identification of markers associated with race-specific resistance to Aphanomyces root rot in alfalfa, Poster at the 2017 APS meeting
(2017) Samac, Deborah; Bucciarelli, Bruna; Dornbusch, Melinda; Miller, Susan; Yu, Long-Xi
Aphanomyces root rot, caused by Aphanomyces euteiches, is one of the most important diseases of alfalfa in the United States. Two races of the pathogen are recognized and although most cultivars are resistant to race 1, fewer have resistance to race 2, the predominant race in North America. Molecular markers are needed to facilitate breeding for resistance and to clarify race/resistance gene structure. Resistant and susceptible seedlings were identified from three resistant cultivars, WAPH1, WAPH5 and 53V52, and used as parents to produce F1 populations. Severity of symptoms corresponded with amount of pathogen DNA and oospore density in roots. Race-specific resistance involves a hypersensitive response of individual epidermal or cortical cells upon pathogen attack followed by suberization of cells surrounding the stele and strong autofluorescence in cortical cells, indicating the presence of phenolic compounds. Segregation ratios of F1 populations suggested that resistance to race 1 in WAPH1 is conditioned by a single gene but resistance to race 1 is multigenic in WAPH5 and 53V52, and resistance to race 2 is multigenic in all three cultivars. Segregation for resistance to seven strains of A. euteiches in 70 F1 full-sib plants derived from 53V52 suggested the presence of clustered resistance genes and multiple race types. Identification of resistance gene loci is in progress using genotyping by sequencing and genetic mapping of F1 populations.
Increasing Sustainability Of Agricultural Systems Through Adaptive Crop Management Practices And Technologies
(2017-06) Noland, Reagan
Cover crops can provide ecological services and improve the resiliency of annual cropping systems; however, cover crop use is low in corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotations in the upper Midwest due to challenges with establishment. Our objective was to compare three methods to establish five cover crops in corn at the seven leaf collar stage. Establishment methods included directed broadcast of seed into the inter-row (DBC), directed broadcast with light incorporation (DBC+INC), and a high-clearance drill (DRILL). Fall cover crop biomass was greater with the DRILL method than DBC for all cover crops except pennycress, and the DRILL and DBC+INC methods resulted in greater spring biomass for red clover and hairy vetch than DBC. Cover crop biomass and N uptake in the spring was among the greatest with winter rye (means = 971 kg DM ha-1 and 25 kg N ha-1, respectively). Cover crop treatments did not affect corn grain or silage yield, and reduced seed yield of the subsequent soybean crop by 0.4 Mg ha-1 (10%) only when poor termination of hairy vetch occurred at Lamberton. Soil nitrate N was reduced by winter rye at both locations and by hairy vetch, red clover, and pennycress at Waseca, compared to the no cover control. These results demonstrate that cover crops can be interseeded into corn at the seven leaf collar stage in the upper Midwest to reduce residual soil nitrate N while maintaining corn and subsequent soybean yields; however; appropriate timing and method of cover crop termination is critical to avoid competition with the subsequent soybean crop. Winterkill of alfalfa (Medicago sativa L.) causes substantial yield losses in northern environments, requiring alternative forages to meet livestock needs. This study explores the forage crop yield, nutritive value and N response of seven annual forage species and one grass-legume biculture, no-till planted into spring-terminated alfalfa. Forages were planted in late-May with split-plot factors of three N fertilizer rates (0, 56, and 112 kg N ha-1) and were harvested on approximately 30-d intervals. When successfully established, teff [Eragrotis tef (Zuccagni) ‘Summer Lovegrass’] and sudangrass [Sorghum bicolor (L.) subsp. drummondii (Nees ex Steud.) ‘PCS 3010’] were among the highest-yielding species, with yields ranging from 4.2 to 9.9 Mg DM ha-1 and 6.8 to 8.9 Mg DM ha-1, respectively. Fertilizer N increased yields of all species at Rosemount in 2014; however, N needs were met by terminated alfalfa at both locations in 2015. Weed biomass increased with the addition of fertilizer N in site-years when weeds were present. Nitrogen fertilization did improve forage nutritive value through decreased neutral detergent fiber concentration and increased crude protein concentration and neutral detergent fiber digestibility (48-hr in-vitro) in all site-years. However, N fertilization had no effect on economic net return in two of three site-years. Annual ryegrass [Lolium multiflorum (Lam.) ‘Jumbo’] most consistently resulted in the greatest net return. No-till planting annual forages into terminated alfalfa can provide forage to offset losses and utilize alfalfa N in situations of alfalfa winterkill. In-field estimations of alfalfa yield and nutritive value can inform management decisions to optimize forage quality and production. However, acquisition of timely information at the field scale is limited using traditional measurements such as destructive sampling and assessment of plant maturity. Remote sensing technologies (e.g. measurement of canopy reflectance) have the potential to enable rapid measurements at the field scale. Canopy reflectance (350‐2500 nm) and LiDAR-estimated canopy height were measured in conjunction with destructive sampling of alfalfa across a range of maturity at Rosemount, MN in 2014 and 2015. The full range of reflectance data was processed with stepwise regression using the Bayesian Information Criterion to identify individual wavebands most correlated with alfalfa nutritive value. Models were reduced by spectral range and number of wavebands to improve model utility., and cumulative Growing Degree Units (GDUs) and canopy height were added as predictors. Optimum predictions of R2 = 0.89, 0.91, 0.89, 0.87 for yield, crude protein, neutral detergent fiber, and neutral detergent fiber digestibility (48-hr in-vitro). This research establishes potential for remote sensing measurements to be integrated with environmental information to achieve rapid and accurate predictions of alfalfa yield and nutritive value at the field scale for optimized harvest management.
Lignin reduction in alfalfa (Medicago sativa) does not affect foliar disease resistance
(2018) Samac, Deborah A; Ao, Samadangla; Dornbusch, Melinda R; Grev, Amanda M; Wells, M Scott; Martinson, Krishona; Sheaffer, Craig C
Disruptions in the lignin biosynthetic pathway have been shown to reduce disease resistance in a number of crops. Recently, genetically modified alfalfa (Medicago sativa) varieties have been marketed with reduced lignin and improved forage quality traits, including increased digestibility by ruminants at later stages of plant maturity. The objective of this study was to compare foliar disease resistance in three reference alfalfa varieties, 54R02, DKA43-22RR, WL355.RR, and the reduced lignin variety, 54HVX41, to evaluate the effect of the reduced lignin trait on foliar disease resistance. Alfalfa plants in research plots at three locations in Minnesota were evaluated for percent defoliation caused by foliar pathogens at four maturity stages; early bud, bud, early flower, and flowering; with natural inoculum. Spring black stem and leaf spot, Leptosphaerulina leaf spot, and common leaf spot were observed from June through September in all locations on all varieties. Summer black stem and leaf spot was most prevalent in August on all varieties at one location. The amount of defoliation increased with maturity stage for all varieties. When harvest was delayed until the flowering stage, moderate to severe (32 to 64%) leaf loss occurred, depending on location. Alfalfa varieties did not differ in percent defoliation at any maturity stage indicating that the reduced lignin trait did not affect foliar disease resistance.
Managing the Rotation from Alfalfa to Corn
(University of Minnesota Extension, 2015) Yost, Matt A.; Coulter, Jeffery A.; Russelle, Michael P.
This bulletin describes management practices for alfalfa termination and the two subsequent corn crops that will help utilize the benefits of alfalfa.
Manufacture and Use of Alfalfa (Medicago sativa L.) Leaf Protein Concentrate as a Protein Supplement in Fish Culture Diets
(2019-05) Coburn, Jessica
Alfalfa protein concentrate (APC) is a high-protein, low-fiber, refined product from the legume Medicago sativa L. intended for feeding monogastric animals. The research herein extends understanding of the potential for APC use in aquaculture by conducting feeding trials with yellow perch (Perca flavescens) and rainbow trout (Oncorhynchus mykiss) and evaluating APC yield and content by producing APC with alternative methods, from reduced-lignin varieties, and from stripped alfalfa leaves. Both fish species accepted APC feeds. Growth was slowed in the perch trial where APC was included at 18% of diet, while the trout did not show significant differences among feeds when APC was included at low levels to enhance growth. APC produced with acid contained less fiber while heating produced the highest protein concentration. APC produced from stripped leaves contained less protein than APC from whole forage. APC produced from reduced-lignin varieties did not differ from APC produced from conventional varieties.
Plant Defensins: An Innovative Approach to Control Alfalfa Crown Rot
(2019-07) Sathoff, Andrew
Crown rot is a disease complex that reduces alfalfa (Medicago sativa) stand density and causes substantial losses in productivity in all alfalfa-growing areas. To evaluate plant defensins as a potential control for alfalfa crown rot, defensins were screened for antimicrobial activity. MtDef5, a defensin from Medicago truncatula, displayed high activity against both bacterial and fungal crown rot pathogens in vitro. Agrobacterium-mediated transformation was used to create transgenic lines of alfalfa constitutively expressing MtDef5. Disease bioassays demonstrated increased resistance against fungal and bacterial crown rot pathogens in the transgenic lines expressing MtDef5. Transgenic expression of defensins could be utilized to implement an eco-friendly, protein-based strategy that could provide alfalfa with enhanced resistance against crown rot and reciprocal gains in alfalfa yield. Mini-Tn5-lux mutant strains of Pseudomonas aeruginosa with Tn insertions disrupting outer membrane protective modifications were assessed for sensitivity against plant defensin peptides. Also, these strains were evaluated for lux gene expression in response to sublethal plant defensin exposure. A defensin from M. truncatula, MtDef4, induced dose-dependent gene expression of the aminoarabinose modification of LPS and surface polycation spermidine production operons. A plant pathogen, Pseudomonas syringae pv. syringae was modified through transposon mutagenesis to create mutants that are resistant to in vitro MtDef4 treatments. The transposon insertion site on defensin resistant bacterial mutants was sequenced, and modifications of ribosomal genes were identified to contribute to enhanced resistance to defensin treatments. Therefore, the MtDef4 antibacterial mode of action may also involve inhibition of translation. M. truncatula promoter regions of pathogenesis-related (PR) genes, PR5 and PR10, were identified as being highly up-regulated during the initial stages of infection by root and foliar pathogens. Theses promoters, along with the alfalfa homolog for PR10, were cloned into plant transformation vectors ahead of the beta-glucuronidase (gus) gene. Agrobacterium-mediated transformation was used to create transgenic lines of alfalfa. Quantitative PCR assays were utilized to evaluate pathogen-induced GUS expression. The MtPR10 promoter had greater fold amplifications and greater activity than the MsPR10 and MtPR5 promoters. The MtPR10 promoter is functional in alfalfa for expression of transgenes and up-regulates genes after infection by a wide range of alfalfa pathogens.
Root Structure, Biomass Allocation, And Legume Intercropping Of Intermediate Wheatgrass
(2023-08) Griffin, Alexandra
Intermediate wheatgrass (IWG; Thinopyrum intermedium) is a perennial grass undergoing domestication as a grain crop, whose deep roots can reduce soil erosion and nutrient pollution. One barrier to the viability of IWG as a grain crop is an interannual decline in seed production, the cause of which is unknown. Both experiments in this thesis aim to uncover plant density-dependent relationships associated with a decline in seed production and guide future strategies to increase yield stability. The first chapter investigates the effects of intercropping legumes on IWG in two row spacings. Intercropping legumes was not found to increase IWG seed or biomass production, however, rarely did intercropping impose net competitive effects. The second chapter investigates root structure and biomass allocation using minirhizotrons. Greater root abundance was not linked to lower aboveground productivity in IWG, which suggests that IWG does not experience a biomass allocation trade-off between above- and below-ground plant tissues.
Variances in nutritient content and yield of alfalfa protein concentrate processed with five mthods from high yielding biomass type alfalfa
(2017) Coburn, Jessica; Wells, Scott; Samac, Deborah A
The demand for protein is growing with increased populations and world affluence. A sustainable and affordable protein source is needed to support the growing aquaculture industry worldwide. Alfalfa produces high levels of protein and provides numerous environmental services, potentially making it an ideal feedstock in aquaculture. This project evaluates five methods of alfalfa protein concentrate (APC) coagulation for yield and nutritional content. A biomass-type alfalfa was harvested at full flower with a flail mower, fresh material homogenized in a laboratory blender, juice expressed by hand, and protein coagulated using five methods. The methods were: (1) heating in an 80°C water bath for 30 minutes, (2) freezing the juice at -15°C, (3) lowering the pH of the juice to 4.0 with hydrochloric acid, (4) lowering the pH of juice chilled in refrigeration with chilled hydrochloric acid, (5) first, raising the pH of the juice to 10.0 with sodium hydroxide, letting it set for 15 minutes, then lowering the pH down to 4.0 with hydrochloric acid. The temperature and pH based methods resulted in significant differences in protein yield and concentration. While the acid based coagulation methods resulted in the highest yield and lowest fiber content, temperature methods resulted in higher concentrations of protein. Extraction methods also impacted crude fat, sugar, and specific amino acids. Acid coagulation resulted in decreased fiber and fat content, which may be beneficial for aquaculture uses. Heat treatment resulted in increased concentration of limiting amino acids and lower sugar content compared to the other methods. These findings show that APC producers can adjust production methods for a specialized APC product meant for specific diets or uses.

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