Molecular Characterization and Tissue Culture Regeneration Ability of the USA \u3ci\u3eArachis Pintoi\u3c/i\u3e (Krap. and Greg.) Germplasm Collection

Arachis pintoi Krap. and Greg. is a herbaceous, perennial legume, exclusively native to Brazil. It is considered a multiple use legume, being grown for forage; ground cover in fruits orchards, forest, and low tillage systems; erosion control; and ornamental purposes. Although several cultivars have been released in different countries, little is known about the genetic diversity of the germplasm stored in world genebanks. Our objective was to characterize and evaluate the genetic diversity of the germplasm of 35 accessions of Arachis pintoi at molecular level using RAPD markers. Concurrently, two tissue culture protocols were evaluated for their organogenesis ability. Further, variation in band profile was analyzed by comparing “Parent Plants” and tissue culture regenerated plants

Development of Red Clover with High Levels of Resistance to Root-Knot Nematodes

Red clover (Trifolium pratense L.), is grown in many areas of the world, but production in subtropical regions may be limited by susceptibility to root-knot nematodes (Meloidogyne spp.) (RKN). Selection for early vigor in RKN infested soils resulted in moderate RKN tolerance in ‘Cherokee’. However, improved RKN resistance in red clover was needed. Seven additional cycles of greenhouse selection using Cherokee as a base population developed a population (FLMR7) with high RKN resistance. When FLMR7 was infested with M. arenaria, M. hapla, M. incognita, or M. javanica, numbers of galls and egg masses were lower than on Cherokee or an earlier cycle of selection (FLMR6). The resistance mechanisms appeared to delay and reduce RKN maturation at all life stages, including reduction in number of egg masses per plant. Preliminary evidence suggests that resistance may interact with higher soil temperatures

Tissue Damage and Nutritive Value of Warm-Season Grasses Following a Freeze

Bahiagrass (Paspalum notatum Flugge) is a major forage for livestock in the subtropics of the U.S.A. However, it is subject to freeze damage with minimal winter regrowth, and is generally considered a poor grass for stockpiling due to poor quality of the residue. Bahiagrass genotypes have been found showing a range of leaf freezing tolerance in the in the field (-30 C) (Blount et al., 2001). Other C4 grasses have been reported to have genotype-specific tolerances to below-freezing temperatures ranging from -3 to -100 C (Sakai & Larcher, 1987). This research was begun to try to understand the processes that take place following freeze injury to bahiagrass. Three grasses native to the Midwest, big bluestem (Andropogon gerardii Vitman cv Alamo), Indiangrass (Sorghastrum nutans (L.) Nash cv Lometa), and switchgrass (Panicum virgatum L. cv Kaw) and commonly used for stockpiling were used for comparison

Rhizoma Peanut: More Than a ‘Lucerne’ for Subtropical USA

Rhizoma peanut (Arachis glabrata) was introduced to Florida from South America in the 1930s. Selections \u27Arb\u27 (PI 118457) and \u27Arblick\u27 (PI 262839) were released in the 1960s, but their use was very limited due to slow establishment and low productivity. The University of Florida released \u27Florigraze\u27 (PI 421707) in 1978 and \u27Arbrook\u27 (PI 262817) in 1986. These cultivars produced much higher dry matter yields. Thereafter, rhizoma peanut began to gain commercial acceptance. These cultivars are used throughout the Gulf Coast region of the USA for commercial hay production, pasture, creep grazing, silage, balage, and living mulch (French et al., 1994). It is estimated that circa 8 Kha of rhizoma peanut have been planted (Quesenberry, 1999). \u27Ecoturf\u27 (PI 262840), an A. glabrata introduction that is gaining wide spread acceptance as a low maintenance turf or ornamental, is the latest development with rhizoma peanut breeding at the University of Florida. In 2002, perennial peanut was selected as the Plant of the Year by the Florida Nurserymen and Growers Association. Current estimates are that rhizoma peanut sales (mainly hay, but also includes planting material and ornamental production) exceed $7M USD

Selection of morphological traits to improve forage characteristics of Setaria sphacelata grown in Florida.

A genetically diverse population of Setaria sphacelata was developed at Gainesville, Florida by intercrossing the cultivars ?Narok?, ?Kazungula? and ?Solander? and a local persistent population. To determine heritability of traits that may improve setaria as a forage plant in Florida, progeny of the intercrossed population underwent two cycles of selection for inflorescence number and one cycle for leaf width. The selected populations, together with cultivars and introductions, were evaluated for morphological characters, yield and forage quality in field experiments with close- and wide-spaced plants. Increase of inflorescence number was not obtained by selection but resulted in decreased plant height, inflorescence length, yield, leaf width, and leafiness. Leaf width was increased by selection and was associated with increased leafiness and whole-plant crude protein content. The results suggest good prospects for selection of setaria cultivars suited to Florida with improved yield and quality providing they tolerate winter cold and reliably produce seed

Evaluation of Limpograss (\u3cem\u3eHemarthria altissima\u3c/em\u3e) Breeding Lines under Different Grazing Managements

Limpograss (Hemarthria altissima (Poir.) Stapf et C.E. Hubb.) is a stoloniferous, warm-season perennial grass from South Africa. It is frequently used to extend the grazing season in poorly drained soils of subtropical regions (Quesenberry et al. 2004). The cold tolerance of limpograss allows it to grow at temperatures below which other commonly used warm-season grasses (e.g. bermudagrass) remain productive. Use of limpograss has helped to reduce forage shortfall during winter, therefore, reducing feeding costs. In the past 30 years, the area planted to limpograss in Florida, USA has grown faster than that of any other forage grass species. It is estimated that over 0.2 million ha are planted to limpograss (Quesenberry et al. 2004). Recent University of Florida research with limpograss has focused on developing new hybrids which incorporate the persistence of the most widely used cultivar ‘Floralta’ with the digestibility of ‘Bigalta’. Preliminary clipping and grazing trials evaluated 50 breeding lines and identified 5 lines (designated 1, 4F, 10, 32 and 34) with superior performance. With an overall program goal of identifying the best limpograsses for cultivar release, the specific objective of this experiment was to investigate the forage productivity and sward canopy characteristics of these 5 breeding lines, compared to Floralta, in response to different grazing management strategies

Herbage Accumulation and Nutritive Value of Limpograss Breeding Lines Under Stockpiling Management.

Supplements or conserved forage are often used to overcome forage quantity deficits for beef cattle, but stockpiled forage can be more economical. Limpograss [Hemarthria altissima (Poir.) Stapf & C.E. Hubb.] is the best available species for stockpiling in Florida because it is productive in autumn and maintains greater digestibility than other grasses at advanced stages of maturity. New limpograss hybrid breeding lines have been developed, but they have not been tested under stockpiling. Three limpograss breeding lines (1, 4F, and 10) and the most-used cultivar, Floralta, received 50 or 100 kg N ha?1 at initiation of stockpiling and herbage accumulated for 8, 12, or 16 wk. Entry 4F had greater herbage accumulation (7.3 Mg ha?1) than Entries 10, 1, and Floralta (6.1, 6.0, and 5.4 Mg ha?1, respectively). Entry 4F also had greater in vitro digestible organic matter (IVDOM) concentration (530?594 g kg?1) than Entries 1 and Floralta, but 4F was not different from Entry 10 (519?531 g kg?1) after 12 and 16 wk of accumulation. As stockpiling period increased from 8 to 16 wk, herbage accumulation increased from 5.3 to 7.4 Mg ha?1, dead material proportion increased from 1 to 10%, and herbage crude protein (CP) decreased from 44 to 32 g kg?1. Limpograss hybrids 4F and 10 are superior to Floralta for stockpiling, stockpiling period should not be longer than 12 wk, and protein supplement will be required to achieve satisfactory animal performance on stockpiled limpograss

Plant yields and fodder quality related characteristics of millet-stylo intercropping systems in the Sahel

In trials at Sadoré, Niger in 1988-90, Pennisetum glaucum cv. Composite Inter-Varietal de Tarna, Stylosanthes fruticosa cv. ILCA 13860 and S. hamata cv. Verano were grown for 1 or 2 years as pure stands or as cereal-legume intercrops with different row ratios. In the 2-year intercrop, P. glaucum was resown on land on which the legume would regrow from the previous crop stubble. Intercropping the legumes with P. glaucum for 1 year in alternate single rows did not affect P. glaucum grain yield because of poor legume competition. Total DM yield of the intercrop was similar to pure P. glaucum, while CP concentration increased significantly with intercropping. During the 2nd year of association the legumes were more competitive, depressing P. glaucum yield by 67% in 1989 and 48% in 1990 compared with pure stands. Yield was decreased more by S. hamata than by S. fruticosa in 1990 but not in 1989, and alternate triple-row sowing of P. glaucum with the legumes gave higher grain yields than alternate single-row sowing in 1990 while the reverse pattern occurred in 1989. Total DM and CP yields, and CP concentration of the harvested fodder were, respectively, 1.4, 3.0 and 2.3 times greater in intercrops than in pure P. glaucum stand

Evaluating early selection in perennial tropical forages.

Perennial grass hybrids of Urochloa are evaluated for at least two years during the screening stage trials (SS) and advanced trials (AD) in breeding programs, an expensive and time-consuming process. In this study, we aimed to evaluate the potential for early selection of cultivars in this breeding scheme. We used multiple measurements of agronomic and nutritive value traits of Urochloa humidicola and Urochloa decumbens in the SS, and Urochloa ssp. in the AD. Repeatability coefficient, genetic correlation, selection efficiency (SE), and Spearman correlations were estimated. The results indicated that reliable early selection could be applied, decreasing the evaluation period to one year and a half for SS, and to one year for AD. These results were confirmed by high genetic and rank correlations, and overall SE above 50%. This proposed change in the breeding scheme could save considerable time, labor, and resources and accelerate the release of improved cultivars

\u3ci\u3eSnowedOut Atlanta\u3c/i\u3e: Examining digital emergence on facebook during a crisis

Individuals in emergencies form spontaneous, emergent groups to respond and recover. With the rise of social media use in crises, academics and professionals must be aware of how groups digitally coordinate emergent response efforts. This paper examines digital emergence through the case of SnowedOut Atlanta, a Facebook group formed during the 2014 ice storms in Atlanta. The posts and actions of the group members are in line with those of traditional emergent groups. For example, group members shared informational, material, and emotional support. The findings also provide implications for practitioners and insight into the communication of such groups. In particular, emergency managers have an opportunity to seek out and partner with these types of groups in future similar events