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Development of Rhizoma Peanut for Forage in Lower South, USA
Full text linkRhizoma (perennial) peanut (Arachiis glabrata Benth.) (RP) is n perennial, warm-season legume, adapted to well-drained soils of humid tropics and subtropics. It is grown in Florida and warmer portions of the south-eastern USA up to about 32°N. Cultivar Florigraze was released in 1978 and cv. Arbrook in 1986. Commercial hectarage of RP has increased about 40% annually to approximately 2000 ha in 1992. Propagated vegetatively from rhizomes, RP Is slow to establish. Rhizoma peanut is drought-tolerant, persistent, grows well on droughty, low-fertility soils, requires moderate to excessive soil drainage and requires no N and usually no P fertiliser. It is longlived, highly resistant to diseases, insects and nematodes, and produces high quality palatable forage similar to alfalfa (Medicago saliva L), Rhizoma peanut can be grazed or harvested as hay, haylage and silage. Continuous interaction between researchers, extensionists and producers has developed the technology needed for growing RP
Recurrent Selection for Partial Resistance to Anthracnose Disease in Shrubby Stylo (Stylosanthes scabra)
Full text linkThree cycles of crossing have been completed in a recurrent selection programme for partial resistance to anthracnose disease of shrubby stylo (Stylosanthes scabra) In a field study of a subset of 40 F2 populations from the first cycle, highly significant differences (P\u3c0.001) in anthracnose resistance were found for both male and female effects and for the female x male interaction, In a subsequent F3 progeny test of 99 families selected for disease resistance and yield, 92 of the families were resistant to highly resistant with leaf damage \u3c1% (cf, \u3e50% damage for the susceptible cultivar, Fitzroy). Strong discrimination for resistance was also obtained in a second subset of 23 F2 populations using combined glasshouse and field selection for resistance. Further improvement in anthracnose resistance was achieved in the second and third cycles of recurrent selection. The broadly based resistance of selections from the third cycle should ensure stability of field resistance to the damaging anthracnose fungus
Effects of Phosphogypsum, Phsophorus and Lime on Andropogon gayanus Kunth
Full text linkThere are several factors which determine the low animal productivity in the tropics. Among these factors, inadequate nutrition is the most limiting one followed by the low natural fertility and high acidity of the soils in these regions. Previous findings have shown important soil nutrient deficiencies in some Brazilian cerrado soils. Malavolta (1952) demonstrated sulfur (S) deficiencies, while Werner et al. (1967) found plant response to S. Responses to phosphorus addition are very common in this kind of soil and in tropical America there are rates of phosphorus being applied, which sometimes are uneconomical for the formation and maintenance of pastures. The combination among tolerant varieties to the low phosphorus disponibility, the correct application of phosphatic fertilizers and the correction of the soil acidity, to reduce phosphorus fixation, would be an effective mean for its economical utilization in many tropical soils with high fixing capacity. In many cases, tropical grasses have shown little or no response to liming (Emrich, 1967). Being adapted to high acidity, they respond only to calcium and/or magnesium fertilization, when used at rates that are not enough to affect pH and the exchangeable aluminium (Ciat, 1977); however, there is a differential tolerance to soil acidity among forages, each species or variety in the same species having a different behavior. The purpose of this paper was to investigate possible deficiencies and responses of andropogon grass to rates of sulfur, phosphatic fertilization, and liming on cerrado soil
Determination of Predictive Zones for the Evaluation of Herbage Grasses in Cuba
Full text linkRegional studies that evolve a high quantity of environment are made nowadays in order to define the behaviour of a genotype in different environments, but the workers of introduction programmes can not prove their varieties in all environments. Therefore, it is necessary to select a wide range to represent production conditions. This topic has been studied by several writers (Rambling et al., 1980; Brown et al., 1983). The objective of our study is to reduce test sites due to the high source in income needed in these studies
Genotypic Differences in Seedling Vigor in Sericea Lespedeza
Full text linkSlow seed germination and poor seedling establishment have been considered major problems in sericea lespedeza [Lespedeza cuneata (Dumont de Courset) G. Don.], a summer perennial legume grown in the southeastern United States for forage and soil conservation (Logan et al., 1969). Wright et al. (1978) considered sericea lespedeza a nonaggressive species because of the low number of seedlings that emerge and the long time needed for emergence as compared to other species. Hoveland et al. (1971) indicated that sericea lespedeza seedlings are weak and compete poorly with weeds. Recommended planting time of sericea is early spring as soon as there is not a risk of a heavy frost. In Alabama, this period is from March to early April (Ball and Donnelly, 1985). The estimated daylength during this time of year in Alabama is between 11 and 13 h (Anonymous, 1984). Pieters (1939) first observed that the growth of sericea lespedeza plants was strongly affected by daylength. Similar results were obtained by Bates (1955), who found that 5 cm plants exposed to daylengths less than 13 h grew very little. The objectives of the present study were to measure the influence of temperature and daylength on early growth of sericea lespedeza genotypes
Contribution a l’etude des Especies Spontanees du Genre Trifolium L. en Algerie: Repartition en Fonction de Quelques Facturs du Milieu
Full text linkEn Algerie, le deficit chronique en lait et viande est du essentiellement a une mauvaise alimentation du troupeau. Les fourrages cultives occupent une faible superficie par rapport a !\u27ensemble des cultures herbacees et l\u27essentiel de l\u27alimentation du cheptel repose sur Jes jacheres et Jes parcours. Le genre Trifolium, sur lequel s\u27est porte notre inten��t, comporte plusieurs especes spontanees dont le role fourrager est certain. Cependant, ii est indispensable, comme cela a ete fait pour Jes genres Medicago, Scorpiurus et Hedysarum, de definir Ia repartition des differentes especes de ce genre en fonction des facteurs du milieu. Ceci constitue le but de cet article
Evaluation of Local Annual Medic Ecotypes in Morocco
Full text linkThe self regenerating annual pasture legumes are used in rotation with cereals in the so called ley farming-system launched by the Ministry of Agriculture and Agrarian Reform for improving the production of some 1,375,000 hectares of fallow lands in Morocco (Tazi et al., 1987). There have been several attempts of introducing annual medics (Medicago sp.) in North Africa and West Asia but with little success, one of the reasons being the lack of adapted cultivars (Cocks, 1985 and Francis, 1987). In Morocco, native annual medics can play an important role in providing germplasm for selecting cultivars suitable for local environmental conditions. The domestication of indigenus species and the incorporation of their useful characters into pasture and forage crops has been fully documented (Francis, 1987). Since 1983, the Plant Materials Center (P.M.C.) at El Jadida has been conducting preliminary evaluation on some 300 annual medic ecotypes from Morocco and North Africa. On the basis of those observations, 58 accessions were selected for microplots evaluation at 4 locations where the ley farming system has been introduced in Morocco: El Jadida (450 mm rainfall), Safi (584 mm), Settat (476 mm) and Meknes (560 mm). The objectives of this experiment were: 1) to select adapted ecotypes to the 4 locations and 2) to promote the best ecotypes for more intensive evaluation in advanced yield trials in other regions of the country
Genetic Variances in Crested Wheatgrass - Alfalfa Mixtures
Full text linkSince it was first successfully introduced into North America from Eurasia in 1906 (Dillman 1946), crested wheatgrass [Agropyron cristatum (L.) Gaertner, A. desertorum (Fish. ex Link) Schultes, and A.fragile (Roth) Candargy] has had more impact on revegetation of western rangelands in North America than any other grass. Much of the early crested wheatgrass seedings were made as monocultures ; however, the multiple demands now made on rangelands dictate that other grass, shrub, and forb species be included in the seeding mix. The advantages of grass-legume mixtures in terms of improved forage quality and productivity are well documented (Trenbath, 1974). Significant amounts of nitrogen are transferred from the legume to the grass component in the mixture (Brophy et al. 1984), and this can have significant economic impact as the availability of fossil fuels become more critical. Leyshorn et al. (1981) studied mixtures of grass and alfalfa (Medicago sativa L. subsp x varia) in semiarid environments of Saskatchewan, Canada. Alfalfa plus crested wheatgrass and alfalfa plus Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski] produced significantly more forage than either crested wheatgrass or Russian wildrye alone. The advantages of alfalfa in crested wheatgrass stands also were demonstrated by Rogler and Lorenz (1969). Alfalfa-crested wheatgrass mixtures were more productive than pure stands of crested wheatgrass, due not only to the productivity of the additional alfalfa but the increased vigor of the grass component as well
The Role of Root System in Tall Fescue (Festuca arundinacea Schreb.) Productivity
Full text linkDry matter production of tall fescue (Festuca arundinacea Schreb.) is usually analysed from the following aspects: 1. CO2 metabolism., 2. leaf area index., 3. morphological traits. The relationship between photosynthesis and DM production of this species is relatively complex and not yet clearly elucidated (Wilhelm and Nelson, 1978). On the other hand a close relationship between the leaf area index and DM production of this species was confirmed (Poskuta et al., 1986; Gaborcik, 1986 a). There is relatively less information about the relationship between root system characteristics and shoot DM production (Elkins et al., 1979). The aim of this research was to evaluate the relationship between root system traits and shoot DM production. Mineral concentration (N,P and K) in shoots and their uptake was also sutdied