Weed Science Commons^™

Characterizing Quinclorac-Resistant Smooth Crabgrass (Digitaria Ischaemum) Control And Possible Metabolic Mechanisms Of Resistance, Atikah Dwi Putri

Theses and Dissertations

Quinclorac controls crabgrass (Digitaria spp.) post-emergence in cool- and warm-season turfgrass. A rate response study revealed that two Mississippi smooth crabgrass (Digitaria ischaemum) species (MSU1 and MSU2) are resistant to quinclorac. Following that, field experiments were carried out to evaluate programmatic approaches to control one of these populations. Despite prior study on quinclorac-resistant weeds, to date, quinclorac-resistant smooth crabgrass and its mechanism of resistance have only been reported once in California. The mechanism of resistance of MSU1 and MSU2 relative to susceptible (SMT) was then investigated. The SMT biotype accumulated three times more cyanide than the resistant …

Hymenachne Amplexicaluis [(Rudge) Nees] Genetic Resources Collection In México, A Suitable Grass For Flood Plains In Tropical Areas, J. F. Enriquez-Quiroz, A. R. Quero-Carrillo, J. Perez-Perez, A. Hernandez-Garay, E. Garcia-Moya

IGC Proceedings (1977-2023)

Hymenachne amplexicaluis [( Rudge ) Nees; 2n= 2x= 24; Azuche, West Indian marsh grass] is a native Central and South America C₃ grass that grows well under intermittent flooding conditions. It produces good seed set and stolons to thrive on new areas assuring its survival, combined with an efficient N metabolism to promote vigorous new growing leaves and tillers (Antel et al., 1998). Azuche is a dual attribute species when introduced to new areas; it has valuable forage attributes but also is a potential weed (Hill, 2000). As Azuche is a native species, one must deal with in …

Critical Analysis Of Tropical Forage Breeding In Brazil, J. A. Usberti Jr., P. B. Alcantara

IGC Proceedings (1977-2023)

Forage grasses account for 90% of the Brazilian forage seed market while the genera Brachiaria, Panicum and others are responsible for 85, 10 and 5% of the traded grass seeds, respectively. Most of the forage grass and legume cultivars available for sowing in Brazil were selected in germplasm banks during the last 20 years, while few of them were derived from artificial crossings, followed by selection for desirable forage traits. The selection of new genetic materials in germplasm banks (exploitation of naturally-occurring genetic variability) is still feasible but the chances of success are decreasing through time. From now on, …

Protecting Wa Crops Issue 30 - May 2023, Department Of Primary Industries And Regional Development, Western Australia

Protecting WA Crops

Protecting WA Crops Issue 30 - May 2023 contents:

• GRDC Perth Research Updates – Pathology – Part 2
• Impact of fungicide product, rotation and timing on Net form net blotch in Planet barley in southern WA
• Economical management of Spot form net blotch in low rainfall environments
• Meet crop protection team member – Jason Bradley

Seasonal Phenology And Starch Allocation Patterns Of Cuban Bulrush (Oxycaryum Cubense) Growing In Mississippi, Usa, Madeline Clarke, Ryan M. Wersal, Gray Turnage

Biological Sciences Department Publications

Seasonal patterns of biomass and starch allocation for the aquatic invasive species (AIS) Cuban bulrush were quantified in populations from Lake Columbus on the Tennessee-Tombigbee Waterway in Mississippi. Monthly samples of Cuban bulrush were harvested from five plots from May 2019 to April 2021. During each sampling event, water pH, water temperature, air temperature, and photosynthetically active radiation (PAR) were recorded. Average peak total biomass was 309.0 g DW m−2, 290.0 g DW m−2, and 129.3 g DW m−2 in 2019, 2020, and 2021 respectively and usually occurred in late fall or early winter months (November to January). Biomass allocation …

Evaluating Planting Green And Herbicides For Integrated Weed Management And Their Effect On Soil Properties In Corn And Soybean In Nebraska, Trey Parker Stephens

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Producers across the Midwest are finding new ways to implement cover crops into cropping systems and the practice of “Planting Green” is one of the newest uses of cover crops. When planting green, producers plant their row crops into actively growing cover crops and terminate the cover crop at time of planting or shortly after planting. This practice would allow for higher biomass accumulation of the cover crop and could aid in weed management of herbicide-resistant weeds. The objective of the first two studies was to evaluate planting green and its effect on soil-applied residual herbicides, weed management, dicamba/glyphosate-resistant soybean …

The Intersection Of Herbicide Policy, Exposure, And Health At The University Of Connecticut, Katherine Hayward

Honors Scholar Theses

Pesticides play an extremely complicated role in our everyday lives. From the water you use to make your coffee, to the breastmilk your neighbor provides for their child, to the lake your dog swims in, chemical pesticides or their byproducts have been found in nearly every corner of our lives. The chemicals used in synthetic herbicides, a subcategory of pesticides, have far reaching negative impacts on human health, biodiversity, and water quality. Despite there being numerous published studies on the relationships between pesticide exposures and health, there is still ongoing discord and controversy surrounding their role in our lives. After …

The Bellarmine Bee Bed: Organizing A Native Plant Garden Using Feedback From The Local Community, Kate Moran

Undergraduate Theses

Animal pollinators are the cornerstone of healthy ecosystems. Their survival is essential for the persistence of entire food chains: from the flowers they cross-pollinate directly, to the animals who depend on those plants for nutrition. The establishment of pollinator gardens—particularly ones that consist of native plants—is an effective way to enhance their biodiversity, abundance, and well-being.

The main goal of this thesis is to construct a pollinator garden that maximizes the benefits for animal pollinators using feedback from local gardeners. A survey was used to gather information about the popularity and preferences of 40 flowering plants, and after analyzing the …

Differential Behaviour Of Guineagrass (Panicum Maximum Jacq.) Hybrids, With Different Al+3 Reactions, As To Major Nutrient Translocations To The Leaves, R. S. Paterniani, J. A. Usberti Jr., J. C. Werner

IGC Proceedings (1977-2023)

Most of the Brazilian cultivated pasture fields presents soils with high Al⁺³ levels and liming is economically unfeasible. So, there is an urgent need for grasses with good forage yielding potentials that can withstand Al⁺³ deleterious effects (abnormal root development: short, thick and poorly branched roots, which are unable to effectively translocate water and essential nutrients to the leaves) (Foy, 1984); as a consequence, susceptible genetic materials have their field persistences greatly affected, mainly during drought periods. Researches on Al⁺³ reaction are usually compare supposedly resistant/tolerant genotypes with a resistant control check; doing so, the genotypic effect …

Animal Performance And Productivity Of New Ecotypes Of Brachiaria Brizantha In Brazil, Valéria P. B. Euclides, Manuel C. M. Macedo, Cacilda B. Do Valle, R. Flores, M. P. Oliveira

IGC Proceedings (1977-2023)

Brazil has the competitive advantage of a very dynamic and cost effective animal production system on pastures over other countries. The pursuit for more productive forages that will result in higher quality beef at a lower cost is then justified. Brachiaria is the most important forage genus utilised in Brazil, thus an intense search for new cultivars amongst collected and introduced ecotypes from Africa is underway. Following agronomic evaluation of this material in plots, 8 pre-selected Brachiaria ecotypes were tested under intermittent grazing in paddocks (Euclides et al., 2001). Continuing on the process of cultivar development, two out of …

Development Of A Bahiagrass Paspalum Notatum Flugge With Increased Short-Day Biomass, P. Mislevy, Ann R. Blount, T. R. Sinclair

IGC Proceedings (1977-2023)

Low herbage productivity of subtropical grasses during the short-day winter months of October through to March can place a severe burden on livestock producers in Southeastern U.S. Researchers at the University of Florida (Sinclair et al., 2001) hypothesised that the decrease in forage production might result from physiological dormancy induced by short day length. A study using artificial lights to extend the day length demonstrated that maintaining the day length at 15 hr during the short-day length period increased 'Pensacola' bahiagrass P. notatum Flugge saure Parodi forage yield 122% when compared with normal photoperiod (Mislevy et al., 2001). …

Genetic And Molecular Characterization Of Temperate And Tropical Forage Maize Inbred Lines, B. Alarcón-Zúñiga, E. Valadez-Moctezuma, T. Cervantes-Martinez, T. Cervantes-Santana, M. Mendoza‐Rodriguez

IGC Proceedings (1977-2023)

The livestock feeding in the Central highland of Mexico is based on harvest, grazing and annual forage conservation, being forage maize the most important silage crop (Alarcón, 1995). Even though forage maize is extensively bred in Europe, USA and Asia since 1900's, this started in Mexico in the 1960's, and little is known about the genetic diversity in both agronomic and nutritive value traits. Our breeding program goals are to analyze combining ability of biomass and quality predictors and to study the genetic relationship of inbred lines between lowland tropical and temperate races from Mesa Central, by genetic and molecular …

Preliminary Performance Of Panicum Maximum Accessions And Hybrids In Brazil, Liana Jank, Rosangela M. S. Resende, S. Calixto, M. M. Gontijo Neto, V. A. Laura, Manuel C. M. Macedo, Cacilda B. Do Valle

IGC Proceedings (1977-2023)

Due to the lack of high quality forages adapted to the distinct ecosystems in Brazil, a national network to evaluate 14 accessions, 4 hybrids and 5 commercial standards of Panicum maximum was established in 2002, in 5 regions of Brazil (states of Mato Grosso do Sul, Acre, Rondônia, Minas Gerais and in the Federal District). Staff of the Embrapa Beef Cattle group co-ordinated the network and pre-selected the accessions and hybrids (Jank, 1995; Jank et al., 2001; Resende et al., 2004). We present their performance as to leaf dry matter yield (LDMY) and leaf percentage (LP) obtained from …

Effect Of Applied Biosolids To Bahiagrass Pastures On Copper Status Of Cattle, M. E. Tiffany, L. R. Mcdowell, G. A. O'Connor, N. S. Wilkinson

IGC Proceedings (1977-2023)

When grazing ruminants consume forages high in Mo but adequate in S, there is a risk of molybdenosis (a Mo-induced Cu deficiency). This occurs when Mo, S, and Cu join to form Cu-thiomolybdate complexes in the rumen that are not readily absorbed (Suttle, 1991). High dietary S reduces Cu absorption, possibly due to unabsorbable Cu sulphide formation, independent from its part in thiomolybdate complexes. The use of municipal sludge (biosolids) as a pasture fertiliser is of interest since some contain high Mo which may induce Cu deficiency. The objective of this study was to evaluate the performance and Cu status …

An In Vitro Investigation Of Forage Factors Which Affect The Production Of Conjugated Linoleic Acid And Trans Vaccenic Acid In The Rumen. Ii. Wilting & Cell Damage, Michael R. F. Lee, J. K. S. Tweed, Nigel D. Scollan, R. J. Dewhurst

IGC Proceedings (1977-2023)

Previous studies have shown that cis 9 trans 11 conjugated linoleic acid (CLA) concentrations are higher for summer milk produced from cows grazing fresh pastures than for winter milk when conserved forages are fed (Jahreis et al., 1997). Furthermore, Offer (2003) showed that a similar depression in milk fat CLA occurred if grass was simply cut and fed after a short wilt. This experiment investigated the effect of wilting on the production of CLA and trans vaccenic acid (TVA) in an in vitro rumen simulation, and whether any differences could be related to changes in plant structure. It was …

Effects Of Grassland Management On Herbage Lipid Composition And Consequences For Fatty Acids In Milk, Anjo Elgersma, P. Maudet, I. Witkowska, A. C. Wever

IGC Proceedings (1977-2023)

Herbage provides bulk feed and is the basis for ruminant nutrition. Herbage lipids, especially C18:3, are a major source of beneficial fatty acids (FA) in milk. These desired FA are unsaturated FA such as CLA (conjugated linoleic acid), especially the isomer rumenic acid, and also vaccenic acid, both trans omega-7 FA (Ellen & Elgersma, 2004). As information on lipids in forages is scarce, effects were studied of N application level and regrowth period on the lipid concentration and FA composition of perennial ryegrass (Lolium perenne L.), the most important forage in temperate climate zones. A linear relation had previously …

Effect Of Feeding L-Carnitine And Sunflower Seeds On Cla Content Of Pasture-Fed Beef, S. L. Scott, W. P. Mccaughey, K. E. Buckley

IGC Proceedings (1977-2023)

Pasture finishing enhances levels of conjugated linoleic acids (CLA) in beef lipids (Shanta et al. 1997). CLA (e.g., C18:2 c9, t11), formed during biohydrogenation of polyunsaturated fatty acids (PUFA) in the rumen, can reduce the incidence of heart disease, cancer and obesity in humans. However, pasture finishing cattle can reduce carcass grade. Feeding pasture-fed cattle a high-grain diet for a short finishing period (~60 d) improves grades but may reduce lipid CLA levels. A feeding regime is required that maintains the positive nutritional attributes of pasture-fed beef and improves the meat grade. The objective of this study was to investigate …

Content, Pattern And Esterification Of Fatty Acids In Fresh Grass In Relation To Extraction Solvents And Sample Storage Conditions, Marta Lourenço, Veerle Fievez

IGC Proceedings (1977-2023)

The relatively high content of linolenic acid (C18:3 n-3) in forages has lead to research on the role of forage based feeding strategies in the production of healthier milk. In these studies, forage samples are often stored, although analysis immediately after harvest has been considered to avoid oxidative deterioration and transformation of unsaturated fatty acids (FA) (Christie, 1993; Frankel, 1998). In the current study, we evaluated the effect of different storage conditions (fresh grass samples under liquid nitrogen (liq.N₂) or in a cool box during 3h or at -20ºC, -80ºC or in the extraction solvent at -20°C, during …

Traditional Cattle Feeding Stuffs: Fatty Acid Profile, A. M. Peres, L. Dias, J. Sá Morais, F. Sousa, J. M. Pires

IGC Proceedings (1977-2023)

Dietary polyunsaturated fatty acids (PUFA) are perceived to be healthier than saturated fatty acids. Therefore, in order to be able to manipulate the fatty acid profile of meat and/or milk, to respond to the consumer demands, knowledge of the fatty acid profile of feeding stuffs for cattle is of major importance (LeDoux et al., 2002; Petit, 2002). In this work a preliminary study was made of the fatty acid profile of the cow's diet in a traditional farm production system.

Finishing Effect On Fatty Acid Profile Of Intramuscular Fat In Extensively Reared Steers, N. Aldai, B. E. Murray, A. I. Nájera, K. Osoro

IGC Proceedings (1977-2023)

Both the amount and the composition of fat depots in beef may be influenced by several factors i.e. feeding system. Related to this factor, extensively reared cattle may produce beef with a more desirable fatty acid (FA) composition in terms of beneficial effect on human health, especially in relation to the content of n-3 type FAs. However, concentrate finishing improves some carcass traits and meat quality. In this sense, the objective of this work was to study the effect of concentrate finishing on intramuscular (IM) FA profile of Longissimus thoracis (LT) muscle in pasture fed steers.