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The Colby Echo (2024-03-07), Colby College

The Colby Echo

Published by the students of Colby College since 1877, The Colby Echo is the weekly, editorially independent student-run newspaper of Colby College in Waterville, Maine. Published monthly, 1877-1886; semi-monthly, 1886-1897; and weekly during the academic year, 1898-present.

Low Similarity Between Parasite Communities Of Ten Sympatric Carangid Species, Juan M. Osuna-Cabanillas, Emigdio Marín-Enríquez, Ana P. Martínez-Falcón, Juan T. Timi, Francisco N. Morales-Serna

Harold W. Manter Laboratory of Parasitology: Library Materials

Host phylogeny and ecological convergence are two factors thought to influence the structure of parasite communities. The aims of this study were to determine the diversity of metazoan parasites of 10 sympatric fish species of the family Carangidae from the southeastern Gulf of California, and to analyze their similarity at infracommunity and component community levels, in order to determine if the host species, particularly those congeneric with similar ecological characteristics, exhibit similar assemblages of parasites. In total, 874 fish specimens were examined and 40 parasite species were identified. The component community was composed by 21 parasite species in Caranx caninus …

A Revisited History Of Cacao Domestication In Pre-Columbian Times Revealed By Archaeogenomic Approaches, Claire Lanaud, Hélène Vignes, José Utge, Gilles Valette, Bénédicte Rhoné, Mariella Garcia Caputi, Natalia Sofía Angarita Nieto, Olivier Fouet, Sarah M. Rowe, Guy S. Duke

Anthropology Faculty Publications

Humans have a long history of transporting and trading plants, contributing to the evolution of domesticated plants. Theobroma cacao originated in the Neotropics from South America. However, little is known about its domestication and use in these regions. In this study, ceramic residues from a large sample of pre-Columbian cultures from South and Central America were analyzed using archaeogenomic and biochemical approaches. Here we show, for the first time, the widespread use of cacao in South America out of its native Amazonian area of origin, extending back 5000 years, likely supported by cultural interactions between the Amazon and the Pacific …

Montana Kaimin, March 7, 2024, Students Of The University Of Montana, Missoula

Montana Kaimin, 1898-present

Student newspaper of the University of Montana, Missoula.

Assessing Forage Research And Education Needs Of Organic Dairy Farms In The United States, Eric Hatungimana, Heather M. Darby, Kathy J. Soder, Sara E. Ziegler, Andre F. Brito, Lisa Kissing Kucek, Heathcliffe Riday, E Charles Brummer

Faculty Publications

The viability of organic dairy operations in the United States (US) relies on forage production. The objectives of this study were to (1) assess producer and farm information regarding current forage production practices and producer knowledge gaps and (2) identify forage research and educational needs of organic dairy producers across the US. A survey was distributed to 643 organic dairy producers across the US, with 165 respondents (26% response rate). A focus group consisting of extension professionals, university researchers and staff, consultants, dairy industry representatives and organic dairy producers was also consulted for forage research needs. Results showed that approximately …

March 7, 2024, The Daily Mississippian

Daily Mississippian (all digitized issues)

No abstract provided.

Variants In Zfx Are Associated With An X-Linked Neurodevelopmental Disorder With Recurrent Facial Gestalt\, James L Shepherdson, Katie Hutchison, Dilan Wellalage Don, George Mcgillivray, Tae-Ik Choi, Carolyn A Allan, David J Amor, Siddharth Banka, Donald G Basel, Laura D Buch, Deanna Alexis Carere, Renée Carroll, Jill Clayton-Smith, Ali Crawford, Morten Dunø, Laurence Faivre, Christopher P Gilfillan, Nina B Gold, Karen W Gripp, Emma Hobson, Alexander M Holtz, A Micheil Innes, Bertrand Isidor, Adam Jackson, Panagiotis Katsonis, Leila Amel Riazat Kesh, Genomics England Research Consortium;, Sébastien Küry, François Lecoquierre, Paul Lockhart, Julien Maraval, Naomichi Matsumoto, Julie Mccarrier, Josephine Mccarthy, Noriko Miyake, Lip Hen Moey, Andrea H Németh, Elsebet Østergaard, Rushina Patel, Kate Pope, Jennifer E Posey, Rhonda E Schnur, Marie Shaw, Elliot Stolerman, Julie P Taylor, Erin Wadman, Emma Wakeling, Susan M White, Lawrence C Wong, James R Lupski, Olivier Lichtarge, Mark A Corbett, Jozef Gecz, Charles M Nicolet, Peggy J Farnham, Cheol-Hee Kim, Marwan Shinawi

Duncan NRI Faculty and Staff Publications

Pathogenic variants in multiple genes on the X chromosome have been implicated in syndromic and non-syndromic intellectual disability disorders. ZFX on Xp22.11 encodes a transcription factor that has been linked to diverse processes including oncogenesis and development, but germline variants have not been characterized in association with disease. Here, we present clinical and molecular characterization of 18 individuals with germline ZFX variants. Exome or genome sequencing revealed 11 variants in 18 subjects (14 males and 4 females) from 16 unrelated families. Four missense variants were identified in 11 subjects, with seven truncation variants in the remaining individuals. Clinical findings included …

Protein Biomarkers And Alternatively Methylated Cell-Free Dna Detect Early Stage Pancreatic Cancer, Roni Ben-Ami, Qiao-Li Wang, Jinming Zhang, Julianna G Supplee, Johannes F Fahrmann, Roni Lehmann-Werman, Lauren K Brais, Jonathan Nowak, Chen Yuan, Maureen Loftus, Ana Babic, Ehsan Irajizad, Tal Davidi, Aviad Zick, Ayala Hubert, Daniel Neiman, Sheina Piyanzin, Ofer Gal-Rosenberg, Amit Horn, Ruth Shemer, Benjamin Glaser, Natalia Boos, Kunal Jajoo, Linda Lee, Thomas E Clancy, Douglas A Rubinson, Kimmie Ng, John A Chabot, Fay Kastrinos, Michael Kluger, Andrew J Aguirre, Pasi A Jänne, Nabeel Bardeesy, Ben Stanger, Mark H O'Hara, Jacob Till, Anirban Maitra, Erica L Carpenter, Andrea J Bullock, Jeanine Genkinger, Samir M Hanash, Cloud P Paweletz, Yuval Dor, Brian M Wolpin

Faculty, Staff and Student Publications

Objective: Pancreatic ductal adenocarcinoma (PDAC) is commonly diagnosed at an advanced stage. Liquid biopsy approaches may facilitate detection of early stage PDAC when curative treatments can be employed.

Design: To assess circulating marker discrimination in training, testing and validation patient cohorts (total n=426 patients), plasma markers were measured among PDAC cases and patients with chronic pancreatitis, colorectal cancer (CRC), and healthy controls. Using CA19-9 as an anchor marker, measurements were made of two protein markers (TIMP1, LRG1) and cell-free DNA (cfDNA) pancreas-specific methylation at 9 loci encompassing 61 CpG sites.

Results: Comparative methylome analysis identified nine loci that were differentially …

Early Estimate Of Nirsevimab Effectiveness For Prevention Of Respiratory Syncytial Virus-Associated Hospitalization Among Infants Entering Their First Respiratory Syncytial Virus Season - New Vaccine Surveillance Network, October 2023-February 2024., Heidi L. Moline, Ayzsa Tannis, Ariana P. Toepfer, John V. Williams, Julie A. Boom, Janet A. Englund, Natasha B. Halasa, Mary Allen Staat, Geoffrey A. Weinberg, Rangaraj Selvarangan, Marian G. Michaels, Leila C. Sahni, Eileen J. Klein, Laura S. Stewart, Elizabeth P. Schlaudecker, Peter G. Szilagyi, Jennifer E. Schuster, Leah Goldstein, Samar Musa, Pedro A. Piedra, Danielle M. Zerr, Kristina A. Betters, Chelsea Rohlfs, Christina Albertin, Dithi Banerjee, Erin R. Mckeever, Casey Kalman, Benjamin R. Clopper, New Vaccine Surveillance Network Product Effectiveness Collaborators, Meredith L. Mcmorrow, Fatimah S. Dawood

Manuscripts, Articles, Book Chapters and Other Papers

Respiratory syncytial virus (RSV) is the leading cause of hospitalization among infants in the United States. In August 2023, CDC's Advisory Committee on Immunization Practices recommended nirsevimab, a long-acting monoclonal antibody, for infants agedtrials, nirsevimab efficacy against RSV-associated lower respiratory tract infection with hospitalization was 81% (95% CI = 62%-90%) through 150 days after receipt; post-introduction effectiveness has not been assessed in the United States. In this analysis, the New Vaccine Surveillance Network evaluated nirsevimab effectiveness against RSV-associated hospitalization among infants in their first RSV season during October 1, 2023-February 29, 2024. Among 699 infants hospitalized with acute respiratory illness, …

Safety, Tolerability, And Dose-Limiting Toxicity Of Lacosamide In Patients With Painful Chronic Pancreatitis: Protocol For A Phase 1 Clinical Trial To Determine Safety And Identify Side Effects, Evan L Fogel, Jeffrey J Easler, Ying Yuan, Dhiraj Yadav, Darwin L Conwell, Santhi Swaroop Vege, Samuel Y Han, Walter Park, Vanessa Patrick, Fletcher A White

Faculty, Staff and Student Publications

Background: Chronic abdominal pain is the hallmark symptom of chronic pancreatitis (CP), with 50% to 80% of patients seeking medical attention for pain control. Although several management options are available, outcomes are often disappointing, and opioids remain a mainstay of therapy. Opioid-induced hyperalgesia is a phenomenon resulting in dose escalation, which may occur partly because of the effects of opioids on voltage-gated sodium channels associated with pain. Preclinical observations demonstrate that the combination of an opioid and the antiseizure drug lacosamide diminishes opioid-induced hyperalgesia and improves pain control.

Objective: In this phase 1 trial, we aim to determine the safety, …

One Form And Two Functions: Mbd Of Setdb2 Is A Protein-Interacting Domain, Jujun Zhou, Taiping Chen, Xiaodong Cheng

Faculty, Staff and Student Publications

In this issue of Structure, Mahana et al.1 present their structural characterization of an annotated methyl-CpG-binding domain (MBD) from the histone H3 lysine 9 methyltransferase SETDB2. This study reveals that, rather than binding DNA as previously hypothesized, this domain instead interacts with a cystine-rich domain from C11orf46, highlighting its involvement in protein-protein interactions.

Reconstruction Of The Talus And Calcaneus Using A Three-Dimensional (3d)-Printed Custom Implant Following A Shotgun Wound: A Case Report, Dino Fanfan, Cary Chapman

All Publications

We present a case detailing the successful reconstruction of the hindfoot in a 15-year-old male patient who suffered a self-inflicted shotgun wound. The patient had multiple complex fractures in these bones, resulting in considerable bone loss and the destruction of the articular surface. Considering the extent of the injuries and the failure of prior intervention from an outside surgeon, traditional reconstruction methods would not have adequately addressed the severity of the damage. Consequently, the treating physician opted to address the deformity using a three-dimensional (3D)-printed custom implant to salvage the limb. The treatment involved a two-stage surgical plan. The first …

Young Dictators—Speaking About Oneself Decreases Generosity In Children From Two Cultural Contexts, Sandra Weltzien, Lauren Marsh, Patricia Kanngiesser, Bruce Hood

School of Psychology

Sharing of resources is a common feature of human societies. Yet, there is substantial societal variation in children’s generosity, and this variation emerges during middle childhood. Societal differences in self-construal orientation may be one factor influencing the ontogeny of generosity. Here, we examine anonymous Dictator Game sharing in 7-and-8-year-olds from two distinct societies: India and the UK (N = 180). We used self-construal manipulations to investigate whether priming self- or other-focused conversations would differentially influence children’s generosity. There were no differences in generosity between populations. While a significant reduction in generosity was found following self-priming in both societies, other-priming was …

The Many Scales Of Pelagic Habitats, Abigail Mcquatters-Gollop, Rowena Stern, Angus Atkinson, Michael Best, Eileen Bresnan, Veronique Creach, Michelle Devlin, Matt Holland, Clare Ostle, Katrin Schmidt, Lawrence Sheppard, Glen Tarran, E. Malcolm S. Woodward, Paul Tett

School of Biological and Marine Sciences

"This fact sheet is intended to help explain the extreme variation in both abundance and body size exhibited by marine plankton and why those characteristics make them challenging to understand.Plankton in pelagic (open ocean) habitats vary greatly in abundance and body size, presenting significant challenges for assessing the state of pelagic habitats.There are also vast differences in the spatial and temporal scale of events and pressures impacting pelagic habitats, adding complexity and making pelagic habitats challenging to understand.This project was funded by the Department for Environment, Food and Rural Affairs (Defra) as part of the marine arm of the Natural …

Assessing Forage Research And Education Needs Of Organic Dairy Farms In The United States, Eric Hatungimana, Heather M. Darby, Kathy J. Soder, Sara E. Ziegler, Andre F. Brito, Lisa Kissing Kucek, Heathcliffe Riday, E Charles Brummer

Faculty Publications

The viability of organic dairy operations in the United States (US) relies on forage production. The objectives of this study were to (1) assess producer and farm information regarding current forage production practices and producer knowledge gaps and (2) identify forage research and educational needs of organic dairy producers across the US. A survey was distributed to 643 organic dairy producers across the US, with 165 respondents (26% response rate). A focus group consisting of extension professionals, university researchers and staff, consultants, dairy industry representatives and organic dairy producers was also consulted for forage research needs. Results showed that approximately …

De Novo Variants In Dennd5b Cause A Neurodevelopmental Disorder, Marcello Scala, Valeria Tomati, Matteo Ferla, Mariateresa Lena, Julie S Cohen, Ali Fatemi, Elly Brokamp, Anna Bican, John A Phillips, Mary E Koziura, Michael Nicouleau, Marlene Rio, Karine Siquier, Nathalie Boddaert, Ilaria Musante, Serena Tamburro, Simona Baldassari, Michele Iacomino, Paolo Scudieri, Undiagnosed Diseases Network, Jill A Rosenfeld, Gary Bellus, Sara Reed, Hind Al Saif, Rossana Sanchez Russo, Matthew B Walsh, Vincent Cantagrel, Amy Crunk, Stefano Gustincich, Sarah M Ruggiero, Mark P Fitzgerald, Ingo Helbig, Pasquale Striano, Mariasavina Severino, Vincenzo Salpietro, Nicoletta Pedemonte, Federico Zara

Faculty, Staff and Students Publications

The Rab family of guanosine triphosphatases (GTPases) includes key regulators of intracellular transport and membrane trafficking targeting specific steps in exocytic, endocytic, and recycling pathways. DENND5B (Rab6-interacting Protein 1B-like protein, R6IP1B) is the longest isoform of DENND5, an evolutionarily conserved DENN domain-containing guanine nucleotide exchange factor (GEF) that is highly expressed in the brain. Through exome sequencing and international matchmaking platforms, we identified five de novo variants in DENND5B in a cohort of five unrelated individuals with neurodevelopmental phenotypes featuring cognitive impairment, dysmorphism, abnormal behavior, variable epilepsy, white matter abnormalities, and cortical gyration defects. We used biochemical assays and confocal …

Early Estimate Of Nirsevimab Effectiveness For Prevention Of Respiratory Syncytial Virus-Associated Hospitalization Among Infants Entering Their First Respiratory Syncytial Virus Season - New Vaccine Surveillance Network, October 2023-February 2024, Heidi L Moline, Ayzsa Tannis, Ariana P Toepfer, John V Williams, Julie A Boom, Janet A Englund, Natasha B Halasa, Mary Allen Staat, Geoffrey A Weinberg, Rangaraj Selvarangan, Marian G Michaels, Leila C Sahni, Eileen J Klein, Laura S Stewart, Elizabeth P Schlaudecker, Peter G Szilagyi, Jennifer E Schuster, Leah Goldstein, Samar Musa, Pedro A Piedra, Danielle M Zerr, Kristina A Betters, Chelsea Rohlfs, Christina Albertin, Dithi Banerjee, Erin R Mckeever, Casey Kalman, Benjamin R Clopper, Meredith L Mcmorrow, Fatimah S Dawood

Faculty, Staff and Students Publications

Respiratory syncytial virus (RSV) is the leading cause of hospitalization among infants in the United States. In August 2023, CDC's Advisory Committee on Immunization Practices recommended nirsevimab, a long-acting monoclonal antibody, for infants agedtrials, nirsevimab efficacy against RSV-associated lower respiratory tract infection with hospitalization was 81% (95% CI = 62%-90%) through 150 days after receipt; post-introduction effectiveness has not been assessed in the United States. In this analysis, the New Vaccine Surveillance Network evaluated nirsevimab effectiveness against RSV-associated hospitalization among infants in their first RSV season during October 1, 2023-February 29, 2024. Among 699 infants hospitalized with acute respiratory illness, …

Mind The Gap – The Need To Continue Long-Term Plankton Monitoring, Matt Holland, Angus Atkinson, Mike Best, Eileen Bresnan, Michelle Devlin, David Johns, Margarita Machairopoulou, Sophie Pitois, James Scott, Rowena Stern, Callum Whyte, Claire Widdicombe, Abigail Mcquatters-Gollop

School of Biological and Marine Sciences

This policy brief argues that while it is beneficial to explore novel plankton survey technology, it is essential that we also continue to maintain traditional long-term monitoring programmes to generate the necessary information to inform policy.Changes in plankton have important implications for the continued provision of ecosystem services, including supporting commercial fish stocks, carbon sequestration, and oxygen production. Such changes can only be detected by studying long-term, consistent plankton datasets which are needed to understand the pressures driving these changes and how we can manage them. Traditional long-term plankton monitoring relies on light microscopy to identify and count plankton taxa, …

Features Of The Highway Road Network That Generate Or Retain Tyre Wear Particles, Florence N.F. Parker-Jurd, Geoffrey D. Abbott, Bill Guthery, Gustav M.C. Parker-Jurd, Richard C. Thompson

School of Biological and Marine Sciences

The environmental accumulation of microplastics poses a formidable global challenge, with tyre wear particles (TWPs) emerging as major and potentially harmful contributors to this particulate pollution. A critical pathway for TWPs to aquatic environments is via road drainage. While drainage assets are employed worldwide, their effectiveness in retaining microplastics of highly variable densities (TWP ~ 1–2.5 g cm³) remains unknown. This study examines their ability to impede the transfer of TWPs from the UK Strategic Road Network (SRN) to aquatic ecosystems. Samples were collected from the influent, effluent and sediments of three retention ponds and three wetlands. The …

Spatial Distribution And Movement Of Atlantic Tarpon (Megalops Atlanticus) In The Northern Gulf Of Mexico, Shane A. Stephens, Michael A. Dance, Michelle Zapp Sluis, Richard J. Kline, Matthew K. Streich, Gregory R. Stunz, Aaron J. Adams, R. J. David Wells, Jay R. Rooker

School of Earth, Environmental, & Marine Sciences Faculty Publications

Atlantic tarpon (Megalops atlanticus) are capable of long-distance migrations (hundreds of kilometers) but also exhibit resident behaviors in estuarine and coastal habitats. The aim of this study was to characterize the spatial distribution of juvenile tarpon and identify migration pathways of adult tarpon in the northern Gulf of Mexico. Spatial distribution of juvenile tarpon was investigated using gillnet data collected by Texas Parks and Wildlife Department (TPWD) over the past four decades. Generalized additive models (GAMs) indicated that salinity and water temperature played a significant role in tarpon presence, with tarpon occurrences peaking in the fall and increasing …

Haploinsufficiency Of Zfhx3, Encoding A Key Player In Neuronal Development, Causes Syndromic Intellectual Disability, María Del Rocío Pérez Baca, Eva Z Jacobs, Lies Vantomme, Pontus Leblanc, Elke Bogaert, Annelies Dheedene, Laurenz De Cock, Sadegheh Haghshenas, Aidin Foroutan, Michael A Levy, Jennifer Kerkhof, Haley Mcconkey, Chun-An Chen, Nurit Assia Batzir, Xia Wang, María Palomares, Marieke Carels, Zfhx3 Consortium, Bart Dermaut, Bekim Sadikovic, Björn Menten, Bo Yuan, Sarah Vergult, Bert Callewaert

Faculty, Staff and Students Publications

Neurodevelopmental disorders (NDDs) result from impaired development and functioning of the brain. Here, we identify loss-of-function (LoF) variation in ZFHX3 as a cause for syndromic intellectual disability (ID). ZFHX3 is a zinc-finger homeodomain transcription factor involved in various biological processes, including cell differentiation and tumorigenesis. We describe 42 individuals with protein-truncating variants (PTVs) or (partial) deletions of ZFHX3, exhibiting variable intellectual disability and autism spectrum disorder, recurrent facial features, relative short stature, brachydactyly, and, rarely, cleft palate. ZFHX3 LoF associates with a specific methylation profile in whole blood extracted DNA. Nuclear abundance of ZFHX3 increases during human brain development and …

Clonal Haematopoiesis Of Indeterminate Potential Predicts Incident Cardiac Arrhythmias, Art Schuermans, Caitlyn Vlasschaert, Victor Nauffal, So Mi Jemma Cho, Md Mesbah Uddin, Tetsushi Nakao, Abhishek Niroula, Marcus D R Klarqvist, Lachelle D Weeks, Amy E Lin, Seyedmohammad Saadatagah, Kim Lannery, Megan Wong, Whitney Hornsby, Steven A Lubitz, Christie Ballantyne, Siddhartha Jaiswal, Peter Libby, Benjamin L Ebert, Alexander G Bick, Patrick T Ellinor, Pradeep Natarajan, Michael C Honigberg

Faculty, Staff and Students Publications

Background and aims: Clonal haematopoiesis of indeterminate potential (CHIP), the age-related expansion of blood cells with preleukemic mutations, is associated with atherosclerotic cardiovascular disease and heart failure. This study aimed to test the association of CHIP with new-onset arrhythmias.

Methods: UK Biobank participants without prevalent arrhythmias were included. Co-primary study outcomes were supraventricular arrhythmias, bradyarrhythmias, and ventricular arrhythmias. Secondary outcomes were cardiac arrest, atrial fibrillation, and any arrhythmia. Associations of any CHIP [variant allele fraction (VAF) ≥ 2%], large CHIP (VAF ≥10%), and gene-specific CHIP subtypes with incident arrhythmias were evaluated using multivariable-adjusted Cox regression. Associations of CHIP with myocardial …

Editorial: Reviews And Advances In The Molecular Mechanisms Of Breast Cancer, A. Redfern, V. Agarwal, Suresh Alahari

School of Medicine Faculty Publications

No abstract provided.

Plenty More Fish In The Sea? Counting The Cost Of Climate Change On Marine Natural Capital, Angus Atkinson, Matt Holland, Abigail Mcquatters-Gollop, Michelle Devlin, M Best, Paul Tett, Matthew Faith

School of Biological and Marine Sciences

"This policy brief describes how predicted changes in productivity across the Atlantic will impact the amount of fish that the marine environment can support. This is bound to have important implications for marine food webs and our continued sustainable use of marine resources.Plankton form the foundation of commercially-valuable food chains to fish• Warming, stratification and reduced nutrient supply has already reduced plankton stocks• Reduced phytoplankton also means less efficient food chains• Even a modest (16-26%) continued decline in phytoplankton will magnify into a 38-55%decline in harvestable fish across the north Atlantic• Hotspots of this future decline in fish are in …

Pelcap: Natural Capital In Plankton & Pelagic Habitats, Paul Tett, Eileen Bresnan, Matthew Faith, Matt Holland, Mike Best

School of Biological and Marine Sciences

This policy brief fact sheet descries ecosystem services provided by pelagic habitats and a natural capital accounting of the the economic contribution pelagic habitats provide to the UK, as estimated by the Office of National Statistics.Plankton is vital for the functioning of marine ecosystems but is hard to value monetarily. According to the Office of National Statistics, plankton in UK waters provides services valued at up to 3.4 £ billion per year. PHEG members think that this is an underestimate.This project was funded by the Department for Environment, Food and Rural Affairs (Defra) as part of the marine arm of …

The World Must Rethink Plans For Ageing Oil And Gas Platforms, Antony Knights, Anaëlle Lemasson, Matthew Frost, Paul Somerfield

School of Biological and Marine Sciences

Earth’s oceans are awash with ageing energy infrastructure. A change in the law is needed to ensure that these structures are decommissioned in ways that maximize environmental and societal benefits.

Program: 2024 Featured Lecture, "Tell Her Story: How Women Led, Taught, And Ministered In The Early Church", Nijay Gupta

Frank Pack Distinguished Christian Scholar Lecture Program

Program for the Nineteenth Annual Frank Pack Distinguished Christian Lecture Program with featured lecturer Nijay Gupta, Professor of New Testament at Northern Seminary.

Identification Of Alfalfa Chromosomes Using Giemas Banding And Image Analysis Techniques, G R. Bauchan, M A. Hossain

IGC Proceedings (1977-2023)

Chromosomes of two diploid (2n=2x=16) subspecies of Medicago sativa, ssp. caerulea and ssp. falcata, their hybrid and tetraploid (2n=4x=32) cultivated alfalfa (M. sativa, ssp. sativa) were studied. Feulgen’s staining, C- and N-banding techniques and an image analysis system were used. The chromosomes of ssp. falcata have only centromeric bands, however, a multitude of bands were observed in both the C- and N-banding pattern of ssp. caerulea and ssp. sativa enabling the precise identification of each of the eight sets of chromosomes and development of a karyotype. The differences in banding patterns between the diploid subspecies makes it possible …

Advances In Breeding Apomictic Brachiaria In Tropical America, J W. Miles, C B. Do Valle

IGC Proceedings (1977-2023)

Prior to 1988 Brachiaria improvement was based exclusively on the collection, introduction, and evaluation of natural germplasm from Africa. Breeding programs in Brachiaria have been possible only in the past 10 years with the creation of a sexual, tetraploid B. ruziziensis cross-compatible with B. decumbens and B. brizantha. Applied Brachiaria breeding projects are underway both in Colombia (International Center for Tropical Agriculture, CIAT) and Brazil (National Centre for Beef Cattle Research - Brazilian Corporation for Agricultural Research, CNPGC/EMBRAPA). These seek to combine the broad edaphic adaptation and other desirable agronomic attributes of B. decumbens cv. Basilisk with spittlebug resistance. An …

Evaluating Cultivars Of Subterranean Clover In Monoculture Or With Perennial Ryegrass, K F.M. Reed, S G. Clark, W M. Feely

IGC Proceedings (1977-2023)

Over four years, sowing perennial ryegrass (Lolium perenne) with a range of subterranean clover (“sub clover”, Trifolium subterraneum) cultivars was found to reduce the yield of clover per se by 31% and increase pasture yield by 11%. For one high-producing experimental variety, the presence of grass did not reduce clover yield (P<0.001). Clover yield in monoculture plots was poorly correlated with that measured in mixed swards (r = 0.44), but clover yield (± grass) was correlated with total herbage yield (r = 0.94). Clover seed yield was not reduced by the presence of grass. However, in year 2 - but not in the establishment year - grass reduced seed weight. Irrespective of grass treatment, the new late maturing cultivar, Leura outyielded the other commercial cultivars (P<0.05). Enfield and Enfield x Daliak crosses set the most seed and regenerated with a greater density than other cultivars (P<0.05) - apart from Leura. It was concluded that the winter-active, late maturing cultivar, Leura, will compete most successfully with perennial ryegrass.