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Performance Of Ley Farming Systems Including Annual Legumes And Mixtures Of Legumes With Grasses At Cukurova In Turkey, V Tansi, T Saglamtimur, H Baytekin Mar 2025

Performance Of Ley Farming Systems Including Annual Legumes And Mixtures Of Legumes With Grasses At Cukurova In Turkey, V Tansi, T Saglamtimur, H Baytekin

IGC Proceedings (1977-2023)

Ecological conditions in Cukurova are favourable for production of various crops, including cotton and wheat, so cotton monoculture or cotton-wheat rotation systems have been common for many years. These monoculture systems have brought some soil and pest problems into .Cukurova. To improve the livestock production, intensive dairy units were established, However, half of these were later liquidated since the livestock husbandry was unprofitable, compared with cash cropping. The most limiting factor was the high purchase cost of fodder. Ley fanning is an alternative system in which crops are alternated on the same land to obtain fodder without reducing yields of …

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Effect Of Tillage On Regeneration Of Annual Pasture Legumes In Cereal-Livestock Farming Systems, E D. Carter, P G. Fulwood Mar 2025

Effect Of Tillage On Regeneration Of Annual Pasture Legumes In Cereal-Livestock Farming Systems, E D. Carter, P G. Fulwood

IGC Proceedings (1977-2023)

The self-regenerating annual pasture legumes, mainly Medicago spp. (medics) and Trifolium spp, (clovers), are important components of annual pastures on millions of ha in the mediterranean climatic zones of the world. We have shown that tillage practices for cereals and other crops have a severe effect by reducing legume density and productivity after a cropping sequence. Deep-burial of pasture legume seed by disc ploughing and mouldboard ploughing is most detrimental, as a high percentage of seed is buried too deeply to allow emergence, while normal scarifying at 6-8 cm causes little loss of potential legume seed germination and seedling emergence. …

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Predicting The Emergence Of Annual Pasture Legumes In Cereal-Livestock Farming Systems Of South Australia, E D. Carter, P G. Oorter Mar 2025

Predicting The Emergence Of Annual Pasture Legumes In Cereal-Livestock Farming Systems Of South Australia, E D. Carter, P G. Oorter

IGC Proceedings (1977-2023)

Annual pasture legumes (mainly Medicago spp. and Trifolium spp.) are the basis of sustainable farming systems in the cereal-livestock distcicts of South Australia. However, several factors in the cropping and pasture phases deplete legume seed reserves. While total legume seed reserves measured during summer and autumn after a cropping sequence are a useful guide to legume regeneration, the readily germinable seed (i.e., soft seed) is a much beUer guide. We have developed a simple but accurate method of predicting natural regeneration of legume pastures based on the controlled watering of representative sites on stubble paddocks during the summer-autumn period as …

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Potential Suitability Of Spontaneously Reseeing Stylosanthes Spp. For Ley Farming In The Central Chaco Of Paraguay, A Glatzle Mar 2025

Potential Suitability Of Spontaneously Reseeing Stylosanthes Spp. For Ley Farming In The Central Chaco Of Paraguay, A Glatzle

IGC Proceedings (1977-2023)

Continuously cropped regosols in the semi-arid Central Chaco are deficient in organic matter and prone to wind erosion. Ley-farming with self-regenerating legumes may be a sustainable alternative land use. In a 2-year field trial Stylosanthes hamata cv. Verano (V) and a 1: 2 mixture of S. humllis cv. Paterson and S. guianeuis var. intermedia cv. Oxley (P+O) were tested for their: preceding crop values to silage sorghum (S) as compared with continuously cropped S; and potential to recover spontaneously after a reduced tillage intermediate crop of S with weed control (we) or with the voluntary style underseed allowed to grow …

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Potential Of Crotalaria Ochroleuca (Marejea) In Traditional Crop And Livestock Production Systems In Tanzania, S V. Sarwatt Mar 2025

Potential Of Crotalaria Ochroleuca (Marejea) In Traditional Crop And Livestock Production Systems In Tanzania, S V. Sarwatt

IGC Proceedings (1977-2023)

In experiments to study the role of Crolalaria ochrroleuca (marejea) in traditional farming systems, the plant was used in the following way: (l) broadcast alone at a rate of 10 kg/ha of seed to determine dry matter (DM) yield, nutritive value and kg N/ha it can fix at different stages of growth, i.e., 2, 4, 6, 8, IO, 12, 14 and 16 weeks. (2) sown under after 3 weeks on alternate ridges with maize and maize alone as control. (3) the leaves at 10 weeks were harvested and supplemented to young sheep grazing 8 h/day. 12 male sheep …

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Effect Of Gliricidia Provenances On The Yield Of Soybean And Cassava In An Alley-Cropping System, I M. Nitis, W Puger, M Suarna, W Sukanten, K Lana Mar 2025

Effect Of Gliricidia Provenances On The Yield Of Soybean And Cassava In An Alley-Cropping System, I M. Nitis, W Puger, M Suarna, W Sukanten, K Lana

IGC Proceedings (1977-2023)

An alley-cropping experiment was carried out for 3 years in a dry land farming area in Bali to study the effect of Gliricidia sepium (gliricidia) on soybean and cassava yields. Sixteen provenances of gliricidia were compared, in a completely randomised block design with 6 blocks and 12 plants/provenance. Six of the provenances originated from Mexico (M), 4 from Guatemala (G), I each from Costa Rica (R), Nicaragua (N), Panama (P), Colombia (C), Venezuela (V) and Indonesia (I). Plant spacings were 0.5 m within the alley, with 4 m between alleys. Soybean seeds and cassava sticks were planted between the alley …

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Role Of Ley Farming In Crop Rotations In The Tropics, M A. Mohamed Saleem, M J. Fisher Mar 2025

Role Of Ley Farming In Crop Rotations In The Tropics, M A. Mohamed Saleem, M J. Fisher

IGC Proceedings (1977-2023)

Is there a role for ley farming in the agricultural changes desired across the tropics? Hopes were high after the identification of suitable traits for leys in tropical legumes, Despite agroclimatic-suitability similarities for a wide range of tropical crops and forages, socioeconomic conditions vary across the tropics. Increasing debt problems and low prices for agricultural commodities constrain many countries, particularly in tropical Africa, to achieve the needed agricultural growth rates at the current levels of inputs and subsistence land-use practices, Tropical agriculture's inability to meet the growing demand for food is further compounded by declining land productivity and rapid population …

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Is Ley Farming In Mediterranean Zones Just A Passing Phase?, T G. Reeves, M A. Ewing Mar 2025

Is Ley Farming In Mediterranean Zones Just A Passing Phase?, T G. Reeves, M A. Ewing

IGC Proceedings (1977-2023)

Ley farming in southern Australia has changed dramatically in the past decade or so. The present version is a more flexible, adaptive one that includes crop legumes, nitrogen fertiliser, direct drilling, and stubble retention. This has resulted in much longer phases of cropping between pasture periods, causing some to designate the new system as "phase farming". Su.ch changes are critical not only in Australia, but also elsewhere, when considering the development and adoption of ley farming in mediterranean-type regions. While the effects of traditional Icy-farming on soil fertility and crop, pasture and livestock production have been well established, there is …

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Sesbania Sesban: A Promising Forage Legume In Semi-Arid Central Tanzania, D N. Msariri, M L. Kusekwa Mar 2025

Sesbania Sesban: A Promising Forage Legume In Semi-Arid Central Tanzania, D N. Msariri, M L. Kusekwa

IGC Proceedings (1977-2023)

Seventy-four accessions of Sesbania sesban were evaluated alongside 7 of S. goetzel for forage production at Mpwapwa, In Tanzania. The former was promising while the latter was generally unsuccessful. For S. sesban, germination of scarified inoculated seed in nursery was 34%. Survival of the seedlings was 96% at transplanting at 8 weeks. Growth in the field, measured in terms of mean incremental height, was 2.9 m at l year of establishment. On average, 50% of the plants flowered and formed pods at 158 and 190 days, respectively. Seed yield averaged 348 g per plant, while forage yield averaged 4.5 t …

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Increasing The Germination Of Seed Of Fine-Stem Stylo (Stylosanthes Guianesis Var. Intermedia) Using A Heated, Rotating Cylinder, Colin J. Paton Mar 2025

Increasing The Germination Of Seed Of Fine-Stem Stylo (Stylosanthes Guianesis Var. Intermedia) Using A Heated, Rotating Cylinder, Colin J. Paton

IGC Proceedings (1977-2023)

Scarifying pasture legume seed to reduce hard seed content can improve pasture establishment. A heated, rotating cylinder suitable for treating large quantities of seed was used to test the effect of a range of heat doses (measured in cumulative degree-seconds of treatment above 90°C and expressed as degsecs>90°C) on seed of fine-stem stylo (Stylosanthes gulianensis var. lmermedla), Heat doses ranged from O to 1500 degsecs>90°C, A heat dose of 450 degsecs>90°C, achieved by heating seed at 120°C for 15 seconds in the cylinder, gave the highest germination without increasing the proportion of dead seed. This treatment …

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Development Of New Stylosanthes Cultivar For Australia From Naturally Occurring Genotypes, L A. Edye, T J. Hall Mar 2025

Development Of New Stylosanthes Cultivar For Australia From Naturally Occurring Genotypes, L A. Edye, T J. Hall

IGC Proceedings (1977-2023)

The productivity and persistence of Stylosamhes hamata cvs, Verano and Amiga and S. scabra cv. Seca were compared in small swards in 20 dry tropical environments over periods of 2-4 years, For consistently high production Verano and Amiga appear to require tropical environments with >760 mm average annual rainfall even though they survive in regions with 500 mm. Seca is much more widely adapted than S. hamata, being highly productive and drought resistant in tropical and subtropical environments, but will not survive lieavy frosts. The opportunities for further plant improvement through selection within these species is described. However, the most …

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Pasture Legumes In Cuba: Past, Present, And Future, F Funes, Marta Monzote Mar 2025

Pasture Legumes In Cuba: Past, Present, And Future, F Funes, Marta Monzote

IGC Proceedings (1977-2023)

Before 1960 the utilisation of pasture legumes was scarce. During the decade 1960-1970 more than 10 thousand hectares of Medicago sativa. Neonolonia wightii, Cajanus cajan and Pueraria phaseoloides were sown, but interest decreased later. In the mid 1970s, research was reorganised and since 1980 results were attained showing outstanding performance of the species: N. wightii (10 t DM/ho/ year), ·Teramnus labialis (11.5 t), Lencaena leucocephala (12 I), Medicago sativa (12,5 t), Pueraria phaseoloides (14 t), Stylosanthes guianensis (IS I) and others. Results on ecological adaption, sowing, establishment, rhizobiology, seed production, pest and diseases and other agronomic aspects are …

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Establishment And Animal Production Based On Tropical Grass-Legume Pastures, Marta Monzote, F Funes Mar 2025

Establishment And Animal Production Based On Tropical Grass-Legume Pastures, Marta Monzote, F Funes

IGC Proceedings (1977-2023)

Different experiments were carried out to study the establishment of grass-legume swards and animal performam;e from the pastures. Grasses were: Digitarla decumbens, Dichantum sp,, Botriocliloa sp,, Panicum maximum, Cllloris gayana, Cynodon dactylon, Cenchrus setigerus and Cenchrus ciliaris; legumes were: Neonotonia wightti, Macroptllium atropurpuretm, Desmodium intortum, Stylosanthes guianensis and Centrosema pubescens. Good establishment were obtained with minimum tillage of harrowing on the grass cover after heavy grazing or harvesting close to the ground, Broadcast sowing at 2-3 kg/ha was carried out. Growth was slow at I plant/m1 but rapid at S-10 plant/m1, In prepared …

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Analysis Of Growth Characteristics And Evaluation As Fodder Resources Of Tropical Leguminous Browses In Subtropical Area In Japan, Y Kawamoto, M Honma Mar 2025

Analysis Of Growth Characteristics And Evaluation As Fodder Resources Of Tropical Leguminous Browses In Subtropical Area In Japan, Y Kawamoto, M Honma

IGC Proceedings (1977-2023)

To evaluate the potential of several tropical leguminous browse species as fodder plants in the subtropical area of Japan, the dry matter yield and quality and resistance to clipping and drought in the first year were examined and compared in browse species. Species such as Deamodiwn tortuoaum, Desmodium discolor, Aeschynomene villosa and herbaceous Stylosanthes guianensis, had relatively high water stress tolerance, All the species were resistant to clipping. The species such as Desmodium tortuosum. Desmodium discolor among Desmodium genus have high potential for dry matter production and nutritive value in this region.

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The Aeschynomene Genus As A Source Of Pasture Legumes For Tropical And Subtropical Australia, H G. Bishop, T B. Hilder Mar 2025

The Aeschynomene Genus As A Source Of Pasture Legumes For Tropical And Subtropical Australia, H G. Bishop, T B. Hilder

IGC Proceedings (1977-2023)

Three Aeschynomene cultivars are currently used as pasture legumes for tropical and subtropical Australia; A. falcata·cv, Bargoo released in 1973, A. americana cv, Glenn released in 1983 and A. americana cv. Lee released in 1991. Five other Aeschynomene accessions from 2 species are on "pre-release" registration with the Queensland Herbage Plant Liaison Committee pending additional data on adaptation and animal production: A. brasiliana CPI 92519 and CPI 93592 and A. villosa CPI 37235, 91209 and 93621. A collection of over 300 Aesc/1y1wme11e accessions was grown at Mackay, Queensland, in 1982-83 to describe the diversity within this genus. This diversity supports …

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Characterization And Prelimiary Evaluation Of A Large Germplasm Collection Of The Tropical Forage Legume Stylosanthes Scabra Vog., Brigitte L. Maass, R Schultze-Kraft Mar 2025

Characterization And Prelimiary Evaluation Of A Large Germplasm Collection Of The Tropical Forage Legume Stylosanthes Scabra Vog., Brigitte L. Maass, R Schultze-Kraft

IGC Proceedings (1977-2023)

Within the genus, Stylosamhes scabra Vog. has the second largest number of collected accessions worldwide. This tropical forage legume has potential to improve extensive, tropical pastures in subhumid to semi-arid regions with acid and infertile soils, Characterisation and preliminary evaluation of 557 accessions were carried out at Quilichao, Colombia. The main objectives were to characterise. variability within the species and to guide further agronomic evaluation. Wide ranges of morphological, phenological, and agronomic variation exist within the germplasm collection, Accessions originated from north-east and south-east Brazil gave the highest forage yields in 2 cuts. Several accessions were more productive than the …

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A Flower Color Marker In The Tropical Forage Legume Centrosema Brasilianum (L.) Benth., Brigitte L. Maass, A M. Torres Mar 2025

A Flower Color Marker In The Tropical Forage Legume Centrosema Brasilianum (L.) Benth., Brigitte L. Maass, A M. Torres

IGC Proceedings (1977-2023)

Cemrosema brasillianum is a legume with high potential for pasture improvement in the semi-arid tropics with acid and infertile soils. Although genetic improvement for disease and pest resistance is taken into consideration, little is known about the species' breeding ·system. Moreover, no plant character inherited in simple Mendelian fashion has been reported for any Centrosema species. In experiments at Palmira, Colombia, 2 white-flowered accessions were hybridised with 6 violet­flowered accessions, each of a different hue. Segregation for flower colourin F2 populations fitted a single gene model,colour being dominant over white, Hence, flower colour is a useful genetic marker, Because segregation …

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Evaluation And Development Of Desmanthus Virgatus On Medium- To Heavy Textured Soils In Queensland, Australia, B G. Cook, T.W.G Graham, R L. Clem, T J. Hall, M F. Quirk Mar 2025

Evaluation And Development Of Desmanthus Virgatus On Medium- To Heavy Textured Soils In Queensland, Australia, B G. Cook, T.W.G Graham, R L. Clem, T J. Hall, M F. Quirk

IGC Proceedings (1977-2023)

Desmanthmus virgatus is a summer-growing, perennial legume comprising a wide diversity of growth forms. It is native to North and South America where it is often found on neutral to alkaline soils and in areas of low rainfall. Its potential for persistence and spread under grazing on clay soils in semi-arid environments in Queensland has been demonstrated in various experiments since 1978. Three varieties have been selected for commercial release through a state-wide co­ordinated programme of evaluation which began in 1987. These were selected on the basis of yield and persistence, and to exploit the range of growth habits and …

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Arachus Spp.: Introduction And Evaluation Of New Accessions In Seasonally Flooded Land In The Brazilian Cerrado, E A. Pizarro, J.F. M. Valls, M A. Carvalho, M.J D'Avila Charchar Mar 2025

Arachus Spp.: Introduction And Evaluation Of New Accessions In Seasonally Flooded Land In The Brazilian Cerrado, E A. Pizarro, J.F. M. Valls, M A. Carvalho, M.J D'Avila Charchar

IGC Proceedings (1977-2023)

Results are summarised from the agronomic evaluation of 33 new accessions of Arachis spp., especially of the Ca1dorhizae and Rhizomatosae sections, on seasonally flooded land with 2 levels of fertiliser (low::pasture establishment and high=crop production). Level of fertiliser had no significant effect on the dry mailer yield (DMY) of any plant component. The edible green DMY of the best 9 accessions ranged from 2-6 tlha, with an average IVDMO of 63% for the stems and 61% for the leaves, respectively. The total DMY in the wet season ranged from 2.5 to 10 tlha, The ratio of above-ground to underground DMY …

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Agronomic Evaluation Of Centrosema Germplasm On An Acid Utisol In The Humid Tropics Of Peru. Iii. Selected Centrosema Rubescens Benth. Accessions, Gerhard Keller-Grein, F Passoni Mar 2025

Agronomic Evaluation Of Centrosema Germplasm On An Acid Utisol In The Humid Tropics Of Peru. Iii. Selected Centrosema Rubescens Benth. Accessions, Gerhard Keller-Grein, F Passoni

IGC Proceedings (1977-2023)

Agronomic performance of new accessions of Centroseum pubescens on an acid ultlsol (pH 4.5, 80% Al saturation) was assessed over a 26- month period in a small-plot cutting trial near Pucallpa, Peru. 23 accessions, selected from a collection of 575 introductions, were tested along with 2 lines of C. pubescens and 3 of C. acutifolium as controls. Several new accessions of C. pubescens had significantly higher dry matter yields and better stolon root development and produced more seeds than the C. pubescens control lines, which were considerably affected by cercospora leaf spot and rhizoctonia foliar blighi. The new accessions …

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Agronomic Evaluation Of Centrosema Germplasm On Acid Utisol In The Humid Tropics Of Peru. Ii. Centrosema Tetragonolobum Schultze-Kraft & Williams, Gerhard Keller-Grein Mar 2025

Agronomic Evaluation Of Centrosema Germplasm On Acid Utisol In The Humid Tropics Of Peru. Ii. Centrosema Tetragonolobum Schultze-Kraft & Williams, Gerhard Keller-Grein

IGC Proceedings (1977-2023)

The agronomic potential of 11 accessions of Centrosema tetragonolobum was assessed In a small-plot clipping trial conducted near Pucallpa, Peru. These accessions were compared with 8 selected accessions of C. acutifolium, C, brasilianum and C. macrocarpum, and 3 accessions of the agronomically little-known C. brachypodum and C. capitatum. All C. tetragonolobum accessions were well adapted to an acid ultisol (pH 4.S, 80% Al saturation). Several of them produced dry matter and seed yields similar to those of promising lines of C. acutifolium and C. macrocarpum, The capacity to root at trailing stems was poor for C. tetragonolobum …

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Agronomic Evaluation Of Centrosema Germplasm On An Acid Utisol In The Humid Tropics Of Peru. I. Centrosema Macrocarpum Benth., Gerhard Keller-Grein Mar 2025

Agronomic Evaluation Of Centrosema Germplasm On An Acid Utisol In The Humid Tropics Of Peru. I. Centrosema Macrocarpum Benth., Gerhard Keller-Grein

IGC Proceedings (1977-2023)

As part of the search for new forage germplasm options for cleared­forest ecosystems in the humid tropics of South America, a small­plot clipping trial was conducted with 128 accessions of Centrosema macrocarpum near Pucallpa, Peru. Most of the accessions showed good adaptation to an acid ultisol with a high Al level (pH 4.4, 81% Al saturation), Considerable variation was detected among accessions for the agronomic attributes studied. On the basis of seasonal dry matter production and seed yield, the germplasm tested was classified into 8 cluster groups. All accessions proved to have a high level of pest and disease tolerance …

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Commercialization Of Arachis Pintoi Cv. Amarillo In Northern Australia, B G. Cook Mar 2025

Commercialization Of Arachis Pintoi Cv. Amarillo In Northern Australia, B G. Cook

IGC Proceedings (1977-2023)

Arachis pintoi is an herbaceous, stoloniferous perennial legume, native to river valleys of central Brazil. In 1987, the accession CPI 58113 was released in Australia as cv. Amarillo. It grows on a range of soils, produces good yields of high quality forage in Che humid tropics and subtropics, persists under heavy grazing even with competitive grasses, and is an effective shade-tolerant ground cover under ·orchard and plantation crops. New seed production and harvesting techniques were developed because conventional methods used for A. hypogaea are unsuitable, Commercial acceptance of Amarillo by extension workers and. farmers has been successfully promoted since release.

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Perennial Arachis Germplasm For The Subtropics And Tropics, K H. Quesenberry, A E. Ruttinger-Lamperti, C A. Kelly Mar 2025

Perennial Arachis Germplasm For The Subtropics And Tropics, K H. Quesenberry, A E. Ruttinger-Lamperti, C A. Kelly

IGC Proceedings (1977-2023)

Evaluation of a limited number of perennial Aracliis plant introductions in the 1960s led to the release of the cultivars Florigraze and Arbrook of rhizoma peanut (Arachis glabrata Benth). Beginning in 1987, 110 more recently collected introductions of primarily rhizomatous perennial Arachis species were evaluated for response to 3 foliar leaf diseases, root-knot nematode (Meloidogyne arenarla) and agronomic traits related to establishment and production. Significant variability for plant spread, plant vigour, flowering, rhizome morphology and mass, leaf morphology, foliar disease response, and root-knot nematode resistance was identified. Some accessions showed small lesions in response to Cercospora arachidicola, …

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Among-Population Variation In Telomere Regulatory Proteins And Their Potential Role As Hidden Drivers Of Intraspecific Variation In Life History, Sarah E. Wolf, Mary J. Woodruff, David A. Chang Van Oordt, Ethan D. Clotfelter, Daniel A. Cristol, Elizabeth P. Derryberry, Stephen M. Ferguson, Mark T. Stanback, Conor C. Taff, Maren N. Vitousek, David F. Westneat, Kimberly A. Rosvall Mar 2025

Among-Population Variation In Telomere Regulatory Proteins And Their Potential Role As Hidden Drivers Of Intraspecific Variation In Life History, Sarah E. Wolf, Mary J. Woodruff, David A. Chang Van Oordt, Ethan D. Clotfelter, Daniel A. Cristol, Elizabeth P. Derryberry, Stephen M. Ferguson, Mark T. Stanback, Conor C. Taff, Maren N. Vitousek, David F. Westneat, Kimberly A. Rosvall

Biology Faculty Publications

Biologists aim to explain patterns of growth, reproduction and ageing that characterize life histories, yet we are just beginning to understand the proximate mechanisms that generate this diversity. Existing research in this area has focused on telomeres but has generally overlooked the telomere's most direct mediator, the shelterin protein complex. Shelterin proteins physically interact with the telomere to shape its shortening and repair. They also regulate metabolism and immune function, suggesting a potential role in life history variation in the wild. However, research on shelterin proteins is uncommon outside of biomolecular work. Intraspecific analyses can play an important role in …

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Macroevolutionary Inference Of Complex Modes Of Chromosomal Speciation In A Cosmopolitan Plant Lineage, Carrie M. Tribble, José Ignacio Márquez-Corro, Michael R. May, Andrew L. Hipp, Marcial Escudero, Rosana Zenil-Ferguson Mar 2025

Macroevolutionary Inference Of Complex Modes Of Chromosomal Speciation In A Cosmopolitan Plant Lineage, Carrie M. Tribble, José Ignacio Márquez-Corro, Michael R. May, Andrew L. Hipp, Marcial Escudero, Rosana Zenil-Ferguson

Biology Faculty Publications

The effects of single chromosome number change—dysploidy – mediating diversification remain poorly understood. Dysploidy modifies recombination rates, linkage, or reproductive isolation, especially for one-fifth of all eukaryote lineages with holocentric chromosomes. Dysploidy effects on diversification have not been estimated because modeling chromosome numbers linked to diversification with heterogeneity along phylogenies is quantitatively challenging. We propose a new state-dependent diversification model of chromosome evolution that links diversification rates to dysploidy rates considering heterogeneity and differentiates between anagenetic and cladogenetic changes. We apply this model to Carex (Cyperaceae), a cosmopolitan flowering plant clade with holocentric chromosomes. We recover two distinct modes of …

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Scaling Covid-19 Rates With Population Size In The United States, Austin R. Cruz, Brian J. Enquist, Joseph R. Burger Mar 2025

Scaling Covid-19 Rates With Population Size In The United States, Austin R. Cruz, Brian J. Enquist, Joseph R. Burger

Biology Faculty Publications

Using county-level data from the United States, we assessed allometric scaling relationships of coronavirus disease (COVID-19) cases, deaths and age structure within and across the first four major waves of the pandemic (wild-type, alpha, delta, omicron). Results generally indicate that the burden of cases disproportionately impacted larger-sized counties, while the burden of deaths disproportionately impacted smaller counties. This may be partially due to multiple interacting social mechanisms, including a higher proportion of older adults who live in smaller counties. Moreover, these likely social mechanisms interacting with vaccinations and virus waves created a dynamic pattern whereby the rate and magnitude of …

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The Biphasic Effect Of Lipopolysaccharide On Membrane Potential, Maria E. Hadjisavva, Robin L. Cooper Mar 2025

The Biphasic Effect Of Lipopolysaccharide On Membrane Potential, Maria E. Hadjisavva, Robin L. Cooper

Biology Faculty Publications

Lipopolysaccharide (LPS) from certain strains of Gram-negative bacteria can induce a rapid (<1 s) hyperpolarization of membrane potential, followed by a gradual depolarization exceeding the initial resting membrane potential. Through overexpression of a Drosophila ORK1 two-pore-domain K+ channel (K2P) in larval muscles and altering the external concentrations of K+ and Na+ ions, it is clear that the hyperpolarization is due to activating K2P channels and the depolarization is due to promoting an inward Na+ leak. When the external Na+ concentration is negligible, the LPS-delayed depolarization is dampened. The hyperpolarization induced by LPS can exceed −100 mV when external K+ and Na+ concentrations are lowered. These results indicate direct action by LPS on ion channels independently of immune …

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Quantifying Temporal Dynamics Of E. Coli Concentration And Quantitative Microbial Risk Assessment Of Pathogen In A Karst Basin, Shishir K. Sarker, Ryan T. Dapkus, Diana M. Byrne, Alan E. Fryar, Justin M. Hutchison Mar 2025

Quantifying Temporal Dynamics Of E. Coli Concentration And Quantitative Microbial Risk Assessment Of Pathogen In A Karst Basin, Shishir K. Sarker, Ryan T. Dapkus, Diana M. Byrne, Alan E. Fryar, Justin M. Hutchison

Earth and Environmental Sciences Faculty Publications

Karst aquifers can be highly productive water sources but are vulnerable to contamination by pathogens because of integrated surface and subsurface drainage. Our study focuses on the karstic Royal Spring basin in Kentucky, encompassing urban and agricultural land uses. The city of Georgetown distributes treated water from Royal Spring to over 33,000 customers. We examined E. coli dynamics at Royal Spring from June 2021 through June 2022, assessing variability under wet versus dry weather conditions. We also used quantitative microbial risk assessment (QMRA) to estimate potential health risks from the pathogenic bacterium E. coli O157:H7. E. coli concentrations in weekly …

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Hdl-Associated Vitamin D Binding Protein Levels Are Inversely Associated With Necrotic Plaque Burden In Psoriasis, M. P. Playford, H. Li, A. K. Dey, E. M. Florida, H. L. Teague, S. M. Gordon, N. N. Mehta Mar 2025

Hdl-Associated Vitamin D Binding Protein Levels Are Inversely Associated With Necrotic Plaque Burden In Psoriasis, M. P. Playford, H. Li, A. K. Dey, E. M. Florida, H. L. Teague, S. M. Gordon, N. N. Mehta

Physiology Faculty Publications

Background and aims: Vitamin D binding protein (DBP) serves a dual function as a vitamin D carrier and actin scavenger. Free DBP is present in high concentrations in serum, while a smaller pool is bound to lipoproteins like HDL and VLDL. The role of DBP's interaction with lipoproteins remains unclear. Given that HDL has been proposed to have both atheroprotective and anti-inflammatory properties, we sought to compare whether HDL-associated DBP and/or total serum DBP could serve as useful biomarkers for assessing disease severity in psoriasis and cardiovascular disease. Methods: Psoriasis (PSO) patients (N = 83), which were part of a …

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