Weed Science Commons^™

Physiological And Morphological Advances For Forage Improvement, J P. Cooper

IGC Proceedings (1977-2023)

Forage production basically involves the conversion of environmental inputs to provide digestible energy and other nutrients for ruminant livestock. The plant breeder needs to consider the seasonal inputs or constraints in his particular environment, the efficiency of the crop in responding to these factors, those features of the plant that contribute to this efficiency, and the degree to which those features can be modified by selection and breeding. Forage production basically involves the conversion of environmental inputs to provide digestible energy and other nutrients for ruminant livestock. The plant breeder needs to consider the seasonal inputs or constraints in his …

Multiple Use Of Grassland Resources (Grasslands To Provide Natural Resource Conservation And A Quality Environment For Mankind), P J. Edwards

IGC Proceedings (1977-2023)

The grasslands of the world ( and communities closely akin to them, such as shrub and savanna types) provide not only a very effective mantle for protection of the soil, but also the main source of feed for herbivores. They also cater to many other needs of mankind. Increasing population results in competition between types of grassland use for specific sites. Sound planning is necessary to resolve this conflict in the way most beneficial to mankind. In order to plan logically it is necessary to make an inventory of the resources, to consider the various uses to which grasslands can …

Nitrogen Relationships In Grassland Ecosystems, A Lazenby

IGC Proceedings (1977-2023)

Some recent findings affecting nitrogen (N) cycling in grassland ecosystems are discussed, and an indication is given of major problems requiring research and development. The importance of modern techniques is stressed to enable further quantification of the pathways and processes of the nutrient in grassland; such data are needed both to improve understanding and to enable more efficient use of N in practice. A brief description of the N in soil organic matter is followed by an account of symbiotic N fixation by legumes, including estimated levels and rates of fixation and factors affecting the process. Data are presented on …

Practical Livestock-Forage Systems: Model To Manager, R W. Brougham

IGC Proceedings (1977-2023)

The developments in practical livestock-forage systems research during this century are outlined, and present-day approaches are discussed. Some examples of production levels presently being obtained from research stations, top farmers, and average farmers in different regions of the world are presented. These indicate that production levels being obtained from livestock­forage systems research remain appreciably higher than levels being obtained from the best farmers. Comments are made on the many different research techniques used to demonstrate these levels in both developed and developing countries. The value of this type of research to the farm adviser and farmer is also noted. Some …

Contribution Of Forages To Worldwide Food Production: Now And In The Future, E F. Henzell

IGC Proceedings (1977-2023)

Herbivorous livestock provided during the 1970s an estimated minimum 7%-17% of the total dietary protein in Asia and Africa compared with about 30 % in Latin America and just over 30 % in the developed countries. Cattle accounted for approx­imately 70% of the world's domestic animals (calculated in units weighted for size), buffaloes for 10%, and sheep and goats for 11 % . About 69 % of these animal units were in the developing countries, but productivity was higher in the developed coun­tries. Forages, defined broadly to include all edible plant materials except grains and concentrates, provided more than 90% …

Potential Productivity Of Temperate And Tropical Grassland Systems, G O. Mott

IGC Proceedings (1977-2023)

Grasses of temperate regions of the world belong primarily to the subfamily Festucoideae, whereas tropical regions are populated by tribes of the Panicoideae subfamily. Temperate grasses have a C3 biochemical pathway of photosynthesis in con­trast to tropical grasses, which have a C4 photosynthetic mechan-ism. Both tropical and temperate legumes are C3 plants. Com­patible mixtures of legumes and grasses have long been successful in many temperate regions, but combining C4 grasses and C3 legumes as mixtures in the tropics has been only moderately successful. Maximum net primary productions of temperate and tropical grasslands are in the order of 25 and 80 …

Use Of Genetic Resources For Improvement Of Forage Species, J R. Harlan

IGC Proceedings (1977-2023)

The use of genetic resources of forage species poses some special problems because of the number of species involved, the in­adequacy of our knowledge about them, the fact that they are often used in combination and should be evaluated in terms of livestock product, and so on. Collections should be as comprehensive as possible at the outset of improvement programs; other­wise, there may be much use of inferior material and much waste of time and effort. Most of the forage species in use come from (1) Europe (excluding Mediterranean zones), (2) Mediterranean Basin and Near East, (3) African savannas (mostly …

Forage Quality: Assessing The Plant-Animal Complex, D J. Minson

IGC Proceedings (1977-2023)

At the VI International Grassland Congress held at Pennsylvania State College in 1952, the late Dr. C.P. McMeekan re­viewed the many problems associated with the plant-animal complex. Great stress was placed on the need to measure forage in­take accurately as a prerequisite to an under-standing of the plant-animal complex. Progress in the development of more accurate :methods of estimating the forage intake of grazing animals is reviewed, in­cluding the introduction of different methods of administering chromic oxide, the esophageal fistula for obtaining samples of selectively grazed material, the in-vitro technique for estimating the digestibility of the forage eaten, and the …

Competitive, Adaptive, And Evolutionary Process In Grassland Ecosystems, B D. Patil

IGC Proceedings (1977-2023)

In the tropics, grasslands or grazing lands are found where the forest vegetation climax has been subjected to fire, grazing, felling, or other disturbances. Grazing lands in the tropics form various ecosystems under the major climatic types. Delineation of such ecosystems is possible through remnants of the climax vegetation of undisturbed or least-disturbed areas. Several subecosystems exist as seral stages under each ecosystem, the floristic composition of which is a reflection of the edaphic and soil­moisture-fertility conditions. Biological production in terms of energy for grazing animals varies among these ecosystems and subecosystems. Reconstruction of the adaptable competitive flora with woody …

Summer Dormancy In Italian Populations Of Dactylis Glomerata L., F Lorenzetti, A Panella, E Falistocco

IGC Proceedings (1977-2023)

Mediterranean types of perennial grasses are winter-growing and summer-dormant, while central and northern European types arc winter-dormant and aummer•growing. Dormancy severely limits the annual production and largely determines the seasonal distribution pattern of the perennial grass. Summer dormancy wa• studied in 81 Italian populations of Dac!)llit glomtTata. L. collected from north (48°N) to south (38°N) on the Italian pt:ninaula. Dormancy was measured at Perugia (43°O5'N) on 60 plant.'i for each population. The percentage of summer-dormant plants was negatively correlated with the mean score for summer growth (r = -0.75**). The results distinguish three main groups of populations with increasing levels …

Growth And Development Of Two Echinochloa Millet Species In A Warm Temperate Climate, D K. Muldoon

IGC Proceedings (1977-2023)

Most summer forage crops fall into either the sorghum or the millet species group. Included in the millet group are two species, Echinochloa utilis and Echinochloa frumentacea, commonly known as Japanese barnyard millet and Indian barnyard millet, respectively. These species have a negligible HCN potential and higher nutritive value than Sorghum species. However, they generally flower early, yield less than forage sorghum , and lack vigor in regrowth. In this study the pattern of growth and development of two Echinochloa millets was examined as part of a larger program of improving the production of these forage species. E. utilis …

Test Adaptation And Evaluation Trials Of Forage Plants In Major Ecological Regions Of Ethiopia And Kenya, K M. Ibrahim, A Orodho

IGC Proceedings (1977-2023)

Kenyan and Ethiopian natural grazing Ian.cl. support more than 20% of the cattle population of the African continent. Many of the natural pastures of these countries are severely overgrazed, as unfavorable grazing conditions prevail for over half the year. Objectives of adaptation trials were to evaluate and identify introduced or indigenous forage and fodder species or ecotypes having genetic potential for high production of digestible dry matter for direct pasture and range improvement and for future use in breeding programs. Over 4,000 indigenous and 3,000 introduced ecotypes were evaluated for 24 vegetative characters in six ecological regions between 1971 and …

Collections Of Western Wheatgrass And Blue Grama And Associated Nematode Genera In The Western Dakotas, R E. Barker, J D. Berdahl, J M. Krupinsky, E T. Jacobson

IGC Proceedings (1977-2023)

Western wheatgrass (Agropyron smithii Rydb.) and blue grama (Bouteloua gracilis[Willd. ex H.B.K.J Lag. ex Griffiths) are widely distributed throughout the U.S.A. They arc two of the predominant native grasses in rangelands in the northern Great Plains. Because suitable cultivars are not always available for reseeding disturbed areas, we collected plants of the two species and evaluated phenotypic variability to determine potential for breeding improvement. We also sampled the nematode popula­tion associated with the collections. Sampling sites were systematically chosen by establishing a grid pattern 19 .3 km apart in the western halves of North Dakota and South Dakota. …

Neutral Detergent Fiber And Protein Levels In Diploid And Tetraploid Ryegrass Forage, L R. Nelson, F M. Rouquette Jr

IGC Proceedings (1977-2023)

Nutritive value of 18 ryegrass (Lolium multifloriumLam.) cultivars was studied at Overton, Te1

0.42-mm screen. Plots were harvested four times during each of the first 2 years and five times in the third year. In 1977-1978 and 1978-1979, NDF and protein analyses were run on samples from 2 replications. All forage samples were analyzed for pro­tein via the micro-Kjeldahl technique. Percentages of NDF were obtained via Van Soest extraction procedures. A seasonal increase in neutral detergent fiber (NDF) content and a decrease in protein percentage was observed. Differences in NDF were observed among cultivars and were most apparent during …

Forage Quality Of Barley Straw As Influenced By Genotype, D W. Meyer, D O. Erickson, A E. Foster

IGC Proceedings (1977-2023)

Cereal straw is an untapped carbohydrate source for ruminant animal feeds, but little information is available on genotypic differences in the feeding value of barleys (Hordeum vulgare L.) commonly grown in the northern Great Plains of the U.S.A. Our objective was to determine if barley genotypes differ in straw forage quality and if straw-quality parameters are associated with agronomic characters. Straw from 37 and 31 barley genotypes was sampled in 1977 and 1978, respectively. Straw from 10 barley genotypes grown at four locations was sampled in 1979. Standard laboratory procedures were used to determine the quality parameters measured. Correlations …

Alfalfa Breeding For Forage Yield And Low Saponin Content, P Rotili

IGC Proceedings (1977-2023)

The objective of our breeding program is to build alfalfa (Medicago satia L.) varieties, having good vigor and persistence, high protein level, and low ,aponin content. The: breeding method utilizes a selfing phase combined with selection in competitive conditions. Leaf-saponin content was analyzed by the Tn'choderma viridc bioassay. Parent populations (cv. Leonicena and Cantoni), S0, S1., and S2, families :1 were evaluated 11ndcr competitive and &equcnt culling conditions. In both populations, some S1, families yield more than their respective S1 family. Vuiatioo in yield and mortality increased with the level of selfing, and 1ome S2 families showed lower minimum values …

Productivity Of Forage Legumes On Rice-Paddy Walls In Northeast Thailand, R G. Gutteridge

IGC Proceedings (1977-2023)

Rice stubble left standing in paddy fields after rice harvest is the major source of forage for livestock in the dry season in northeast Thailand. Although the quantity of thi5 1tubble is generally not limiting, its quality as a forage is very low, and substantial live-weight losses in livestock usually occur by the end of the dry season. A trial was conducted to evaluate a range of forage legumes that could be grown on rice-paddy walls to supplement rice stubble as a dry-season feed. Seven legumes were planted at two sites in villages close to Khon Kaen in northeast Thailand. …

Development Of Gama Medic {Medicago Rugosa Desr.) As An Annual Leguminous Species For Dryland Farming Systems In Southern Australia, E J. Crawford

IGC Proceedings (1977-2023)

Annual medics (Medicago spp.) are the basic legume for nitrogen fixation in the alkaline soils of southern Australia. Not all in­dividual species are well adapted to all soil types, one difficult soil being the highly alkaline clay loam where annual rainfall is less than 500 mm. The first gama medic (M. rugosa) cultivar, Paragosa, was well adapted to the clay-loam soil type but proved to be susceptible to germination after summer thunderstorms, and seedlings died in the following drought. Many gama medic accessions were then grown in an attempt to select a genotype capable of maintaining seedcoat impermeability during …

Evolution Of Selection Techniques In Breeding For Bloat-Safe Alfalfa, B P. Goplen, R E. Howarth, G L. Lees, W Majak, J P. Fay, K J. Cheng

IGC Proceedings (1977-2023)

This report summarizes the Canadian breeding program to develop a bloat-safe alfalfa (Medicago sativa L.). This program has experienced an evolution of selection methods in attempting to identify bloat-safe alfalfa genotypes. In chronological order, the methods involved selection for fraction I (18S) protein, soluble proteins, foam volume, tannins (flavolans), saponins, initial rate of digestion (IRD), sonication, purified enzymes, gas production, and leaching. Although soluble herbage protein is correlated with the occurrence of pasture bloat, we have experienced slow progress in a selection program to reduce soluble-protein concentration in alfalfa. We have found that foam volume is not correlated with …

Evaluation Of Within-Half-Sub Family Selection From Leo Birdsfoot Trefoil, D T. Tomes, O U. Onokpise, B E. Twamley

IGC Proceedings (1977-2023)

This research was undertaken to evaluate the effectiveness of within-half-sib family recurrent selection for seedling vigor, seed yield, and forage yield in birdsfoot trefoil (Lotus comiculatusL. cv. Leo). The effectiveness of selection was measured by comparing progeny performance, genetic variance, and heritability in selected and unselected populations. In addition, cx­perimc.ntal synthetic• (Syn-2 generation) from the selected population were compared to Leo for forage yield and seed yield in several trials. Seedling vigor and yield in 1979, and forage yield in 1980, of polycross progeny in the selected population were significantly higher than those of similar progeny in the unselected …

Breeding Centrosema Pubescens Better Adapted To Acid Infertile Soils Of South America, E M. Hutton

IGC Proceedings (1977-2023)

Centrosema pubescen, Benth. {centro) in tropical South America depends upon the development of lines with increased tolerance to high acidity and aluminum (Al). This study classified levels of acid tolerance among Centrosema introduc­tions and crosses of promising introductions. Initially, greenhouse and field evaluations in Carimagua oxisol (pH 4.5, 90% Al saturation) were used. Introductions of C. schottii and C. pascuorom died, while most C. virginianum and C. Uutifolium and a few C. pubescens had low acid tolerance. Most C. pubescens introductions had medium acid tolerance, whereas C. macrocarpum and C. schiedanum were highly acid tolerant. The degree of acid …

Comparison Of Italian Ryegrass And Meadow Fescue With F2, F3, F4 Hybrids Of Both Grass Species, H Kaltofen, E Wojahn

IGC Proceedings (1977-2023)

In forage-grass breeding there is an increasing interest in hybrids of Italian ryegrass (Lolium multiflorum Lam.) and meadow fescue (Festuca pratensis Huds.). The objective of this study was to investigate some agronomic properties of such Festulolium hybrids with special reference to the question of whether these hybrids change from one generation to the next. In a pot experiment with four levels of nitrogen fertilization, Italian ryegrass and meadow fescue as well as F2, F3, and F4 hybrids of the two grass species were examined for 2 years. In each year four cuts were taken. All the F2, F3, …

Effective Selection For Tolerance To Grass-Killing Herbicides In Perennial Ryegrass (Lolium Perenne L.), C E. Wright, J S. Faulkner

IGC Proceedings (1977-2023)

The aim of grassland reseeding is to establish a high-quality sward of improved herbage cultivars. To obtain the maximum value from the improved sward, weed invasion should be prevented. Herbicides are the main tool available. There are many herbicides for selectively controlling dicotyledonous, but not graminaceous, weeds. The control of graminaceous weeds would be possible in swards of grass cultivars selected for tolerance to grass-killing herbicides. Two cycles of recurrent selection for glyphosate tolerance in Lolium perenne L. were carried out by spraying large seedling populations with critical dosages in the greenhouse and intercrossing the survivors. It was found that …

Selection For Specific Leaf Weight In Reed Canarygrass And Its Effects On The Plant, I T. Carlson, D K. Christensen, R B. Pearce

IGC Proceedings (1977-2023)

Specific leaf weight (SL W, dry weight/unit leaf area) may serve as a selection criterion for forage yield through a positive rela• tionship with photosynthesis. Two cycles of phenotypic selection for high and low SLW were conducted in reed canarygrass (Phalaris anmdinacea L.) to investigate direct and correlated responses, particularly those related to yield and quality of forage. In a space-planted test, average direct responses from two cycles of selection for high and low SLW were 23% and 19%, respectively. Significant correlated responses were obtained for ten traits. Compared with the low-SLW cycle-2 population, the high SLW cycle-2 population averaged …

Value Of White Sweet Lupin In Production Of Protein Fodder And Feeding Of Animals, O Saric, I Ramosevac

IGC Proceedings (1977-2023)

The potential of white sweet lupin (Lupinus albus L.) as a grain or forage feed for livestock was investigated in a series of ex­periments. Grain yield of lupin was greater than or equal to that of soybeans (Glycine max [L.] Merrill) in most evaluations. The quality of lupin seed compared favorably with that of soybean meal and fishmeal. Lupin is capable of producing large amounts of forage in a short period, making it a good prospect for forage production in regions that have a short growing season.

Genetic Variability For Morphological And Agronomic Characters In Desmodium Uncinatum (Jacq.) D.C. And D. Intortum (Mill.) Urb., E.M P. Oliveira, P S. Martins, A B. Cruz

IGC Proceedings (1977-2023)

Objectives of this research were to study the performance of eight populations of D. unicinatum and ten populations of D. intortum, with relation to morphological and agronomic characters to estimate the genetic variation between populations and between plants within populations, and to estimate genetic and phenotypic parameters for these characters.

White Clover: An Olde Crop With A Promising Future, P B. Gibson, W E. Knight, G W. Barnett, W A. Cope, J D. Miller

IGC Proceedings (1977-2023)

White clover (Trifolium repens L.) is a widely adapted, important forage legume for grazing in the U.S. The palatability and quality of the forage, the wide adaptation of the plants to growth in different climates and under various grazing conditions and the role it plays in supplying nitrogen to pastures make white clover our finest pasture legume. The use of adapted white clover cultivars should result in large economic gains to the livestock industry in the U.S .A. Beef and dairy farmers would profit from reduced need for nitrogen fertilizer, an extended grazing season, increased forage pro­duction and quality, better …

Performance And Variability Of Agronomic Characters In Populations Of Stylosanthes Guianensis (Aubl.) Sw., P S. Martins, N A. Vello

IGC Proceedings (1977-2023)

Stylosanthes guianens-is (Aubl.) Sw. shows wide variations in morphological and physiological characteristics, and basic infor­mation on genetic variability is needed for future breeding programs. The objectives of this paper were to evaluate 25 native Brazilian populations of S. guianensis for forage characteristics · • ;10,d • to estimate genetic and phenotypic parameters for these characters. The experiment was conducted in a duplicated 5 x 5 balanced lattice design with plots that contained 4 individuals spaced on 2-m centers. The following characters were evaluated after the beginning of flowering period: days to flowering (DF), mean diameter (MD), basal area (BA), growth …

Rhizoma Peanut: Perennial Warm-Season Forage Legume, G M. Prine

IGC Proceedings (1977-2023)

Rhizoma peanut is the common name given species in section Rhizomatosae of the genus Arachis. Florigraze rhizoma peanut (A. glabrata Benth.) has been released as a cultivar by the Florida agricultural experiment stations and the USDA Soil Conserva­tion Service. Florigraze is adapted to the well-drained soils of Florida and the warm humid tropics and subtropics around the world. Rhizoma peanuts are propagated by rhizomes, which in Florida are best planted during winter. The slowness of coverage during early establishment is the biggest shortcoming of rhizoma peanuts. If they are established first, rhizoma peanuts will grow well in mixture with bermudagrass …

Hedysarum Mongolicum Turcz.: An Important Protein Resource Legume On Dry Sandy Land, Li Min, A W. Hovin

IGC Proceedings (1977-2023)

In searching for plants that can both increase the protein production and improve the sandy-soil conservation of the grassland in the arid, windy regions of North China, so far, from among many native plants, we have identified Hedysarum mongolicum Turcz. as the best species to fulfill our dual purposes. We investigated its distribution, planted its native seeds in the Maowusu desert, and studied it under its native and cultivated growing conditions from 1957 to 1964. Chinese farmers call this perennial subbrush legume of the sweetvetcb genus "Yang Cai," meaning "sheep like to eat." It can thrive in the stable or …