CHARACTERIZATION AND USE OF Desmodium SPECIES IN THE CARIBBEAN TROPICS AND SUBTROPICS

Forage legume research is active and cooperative in the Caribbean Basin/Central America. Large collections of many Desmodium species are available for use. Desmodium intortum and Q. uncinatum have been characterized as unadapted to our livestock production sites. Native and exotic browse species (e.g., fi. discolor. distortum. Q. tortuosum. 2. nicaracruense. E. strigillosum. fi. velutinum and Codariocalyx gyroides (syn. D. qyroides) may be valuable for stock owners with little or no land. Spontaneous species of native pastures (D. incanum. fi. uniflorum. Q. procumbens. E. scoroiurus. D. adscendens. and 2. triflorumi are not presently recommended for commercial development. Desmodium barbatum is untried. Relative adaptation of the wet tropical lowland species D. heterocaroon• Eheterophy1lum. and fi. ovalifolium varies with site; J). ovalifolium is more widely adapted. Though superior in pasture comportment, fi. ovalifolium provides poor animal performance; promising new germplasm is being characterized. An international workshop on E- ovalifolium would be timely

Contributions of in-vitro biology to cassava improvement

Cassava (Manihot esculenta Crantz) is a tough and productive survival crop of smallholder farmers in the tropics. It is often grown where other crops fail. Research can make important contribution to food security and economic development in cassava-growing areas. This can be enhanced through in-vitro propagation methods for this crop, due to its slow vegetative propagation. For useful biotechnology innovations to reach smallholder cassava farmers, a combined effort is essential, with participation of farmers and other partners in research and development. The Cassava Biotechnology Network combines forces to mobilise biotechnology as a tool for enhancing cassava's value for food security and as a means of access to economic development. In-vitro biology methods are essential to safe and efficient conservation and exchange of cassava diversity. Transgenic methods, now nearing the stage of first field trials, may offer a means of adding disease resistance or enhanced crop quality characteristics to existing preferred varieties.Le manioc (Manihot esculenta Crantz) est une culture r\ue9sistante et productive de survie de petits fermiers dans les tropiques. Il pousse souvent l\ue0 o\uf9 les autres cultures \ue9chouent. La recherche peut faire une contribution importante pour la s\ue9curit\ue9 alimentaire et le d\ue9veloppement \ue9conomique dans les zones de la culture du manioc. Ceci peut \uea accru \ue0 partir des m\ue9thodes de propagation en vitro pour cette culture suite \ue0 sa propagation v\ue9g\ue9tative lente. Pour des innovations biotechnologiques utiles afin d'atteindre les petits fermiers producteurs du manioc, un effort combin\ue9 est essentiel avec la participation des fermiers et des autres partenaires en recherche et developpement. Le R\ue9seau Biotechnologique du Manioc combine les forces pour mobiliser la biotechnologie comme un outil pour accro\ueetre la valeur du manioc pour la s\ue9curit\ue9 alimentaire et comme un moyen d'acc\ue8s au d\ue9veloppement \ue9conomique. Les m\ue9thodes biologiques en vitro sont essentielles pour une conservation s\ufbre et efficiente et pour l'\ue9change de la diversit\ue9 du manioc. Les m\ue9thodes transg\ue9niques s'approchant maintenant au stade des premiers champs d'essais peuvent offrir un moyen d'augmenter la r\ue9sistance \ue0 la maladie ou d'am\ue9liorer les caract\ue9ristiques augment\ue9es qualitatives des vari\ue9t\ue9s actuelles pr\ue9f\ue9r\ue9es

Production of plantlets from tissue cultures of Lotononis, a southern African veld legume.

A simple procedure is described for the production of large numbers of rooted plantlets from callus cultures of Lotononis bainesii Baker. Highest frequency of shoots was obtained from somatic embryos formed in initiation cultures on Murashige & Shoog medium plus 1 mg/l benzylaminopurine plus 1 mg/l naphtaleneacetic acid. The somatic embryos from these initiation cultures were transferred to media containing 0, 5, 10 or 20 mg/l isopentenyladenine or 0, 1 of 5, 0 mg/l kinetin (1, 8 to 3, 1 shoots per culture) where they re-callused and produced shoots. All shoots obtained from the cultures on media containing 0, 5, 10 or 20 mg/l isopentenyladenine or 0, 1 mg/l kinetin were rooted; 35% of shoots from the cultures on medium containing 5, 0 mg/l kinetin were rooted. Rooting of unrooted shoots from other treatments was readily induced on medium containing 0, 1 mg/l indoleacetic acid.Keywords: callus cultures; forage legume improvement; legumes; lotononis bainesii; plantlets; procedure; rooting; somatic embryos; tissue cultur

Season progression, ontogenesis, and environment affect Lespedeza cuneata herbage condensed tannin, fiber, and crude protein concentrations

© Crop Science Society of America. Sericea lespedeza [Lespedeza cuneata (Dumont de Courset) G. Don., SL] is a perennial, warm-season forage legume with wide adaptation, freeze tolerance, establishment ease, and persistence under grazing. It has high condensed tannin (CT) concentrations (g kg−1), which could be useful for methane mitigation and rumen bypass protein, as well as insect pest and gastro-intestinal nematode suppression. However, CT concentration is variable. Our objective was to test CT, crude protein (CP), and fiber concentrations at five locations (Georgia, Alabama, North Carolina, Louisiana, and Texas) during a growing season. Established ‘AU Grazer’ SL regrowth and accumulated herbage in separate trials was sampled starting late April 2010 every 35 d for four dates. Regrowth CP concentration ranged (P ≤ 0.05) from 127 g kg−1 in North Carolina on date 3 up to 221 g kg−1 in Alabama on date 1. Sericea lespedeza regrowth in the warmest latitude (Louisiana) consistently contained among the greatest (P ≤ 0.05) acid detergent fiber. In regrowth herbage, we recorded a wide (P ≤ 0.05) total CT range, from 133.5 mg kg−1 in Texas on date 3 to 46.1 mg kg−1 in Louisiana on date 1, reflecting variability in fiber-bound, protein-bound, and especially extractible CT. Results from accumulated herbage reflected (P ≤ 0.05) herbage ontogenesis with less CP and greater fiber concentration with maturity but showed the same lack of CT concentration pattern as the regrowth herbage. These results indicate that SL herbage nutritive value and CT concentration is variable, so that any hay or pellets sold commercially for CT content should be assayed by environment and crop maturity