Meike S. Andersson

Impact of management intensity on non-vascular epiphyte diversity in cacao plantations in western Ecuador

A first study on the biodiversity of non-vascular epiphytes in cacao (Theobroma cacao L.) plantations in western Ecuador yielded 112 species (51 bryophytes, 61 lichens). Epiphyte assemblages of cacao plantations resembled those of tropical rain forests but species richness was usually lower and individual species were found at lower heights on the trunks. The vast majority of the species are widespread neotropical or pantropical species; one species, Spruceanthus theobromae (Spruce) Gradst., is endemic to cacao plantations of western Ecuador. Differences in management intensity, by manual removal of epiphytes from tree trunks (‘limpia’), had a significant impact on epiphyte species diversity. Total species richness was significantly reduced in plantations with high management intensity, due mainly to the decreased diversity of lichens and liverworts; moss diversity was not affected by management regime. Total percentage cover of bryophytes was highest in plantations with low management intensity, while lichen cover was greatest in plantations with high management intensity. Crustose lichens and smooth mats growing closely appressed to the substrate were little affected by the limpia and their growth may have been promoted when larger-sized species were removed, by reducing competition. Cacao plantations with low and moderate management intensity serve as an important substitute habitat for ecological specialists (sun epiphytes, shade epiphytes) of the rain forest and are of considerable significance for their conservation.

Water, food and livelihoods in river basins

Conflicting demands for food and water, exacerbated by increasing population, increase the risks of food insecurity, poverty and environmental damage in major river systems. Agriculture remains the predominant water user, but the linkage between water, agriculture and livelihoods is more complex than “water scarcity increases poverty”. The response of both agricultural and non-agricultural systems to increased pressure will affect livelihoods. Development will be constrained in closed basins if increased demand for irrigation deprives other users or if existing agricultural use constrains non-agricultural activities and in open basins if agriculture cannot feed an expanding or changing population or if the river system loses capacity due to degradation or over-exploitation.

Assessing the importance of livestock water use in basins

Recent concern over food prices has triggered a renewed interest in agricultural production systems. While attention is focused mainly on cropping, a complete analysis of food production systems should recognise the importance of livestock as major consumers of resources – in particular water – and as providers of food and other products and services. We propose that there is a need to examine not just food systems in isolation, but combined food and water systems, both of which are described as in a critical condition. From this broader perspective, it appears even more important to understand livestock systems because first, a total evaluation of agricultural water productivity – the gain from water consumed by agriculture – cannot be made without understanding the complexities of livestock-containing systems and; second, because in most tropical river basins, livestock systems are the major consumers of water. To identify total water productivity of livestock-containing systems, we describe concepts of agricultural water productivity and review the complexities of tracking the flow of water through livestock-containing systems: from inputs as evapotranspiration (ET) of forage and crops to outputs of valued animal products or services. For the second part, we present preliminary results from water use accounts analysis for several major river basins, which reveal that for Africa at least, livestock systems appear to be the major water consumers. Yet, little is known about the fate of water as it passes through these systems. We propose that livestock-containing systems offer substantial scope for increasing total water productivity and that there is considerable merit in improving the capacity to analyse water consumption and water productivity through such systems. Without removing this major source of uncertainty, the potential for systemic improvement to meet the world food and water crisis remains undefined and hence under-acknowledged.

Phenological, agronomic and forage quality diversity among germplasm accessions of the tropical legume shrub Cratylia argentea

SUMMARYCratylia argentea (Desv.) O. Kuntze is a drought-tolerant tropical shrub legume that can helpto ensure continuity of forage supply in smallholder systems either through direct grazing or as acut-and-carry plant for fresh foliage or silage. A collection of 38 accessions was characterized agro-nomically and nutritionally. High diversity was detected between accessions. Time to floweringranged from 217–329 days after transplanting seedlings to the field and from 129–202 days aftercutting. Flowering is probably induced by reduction of day length. Seed production was high butvariable. Dry matter production ranged from 190–382 g/plant in the rainy and from 124–262 g/plantin the dry season, content of in vitro digestible dry matter from 589–690 g/kg, crude protein contentfrom184–237g/kgandfibrecontentfrom403–528 g/kg(neutraldetergent fibre,NDF),240–335 g/kg(acid detergent fibre, ADF), and 9–13 g/kg (acid detergent fibre-bound nitrogen, N-ADF).Accessions CIAT 18674 and CIAT 22406 were identified as promising for further study. They weresuperior to the commercial cultivar in terms of dry matter (DM) production, particularly in the dryseason. Further research is required to determine the prevailing reproduction strategy of C. argenteaand to quantify outcrossing-rates. Multilocational trials with a selected set of accessions should beconducted under different environmental conditions.INTRODUCTIONLivestock productivity in the tropics is severelyaffected in the dry season by low availability andquality of fodder (NAS 1979; Ranjhan 1986;Enri´quez et al. 2003). High-protein legumes, in par-ticular shrub species, can contribute to improvedproductivity of livestock during dry seasons and atthe same time maintain and even restore soil fertility(Brewbaker 1986; Schultze-Kraft & Peters 1997;Peters et al. 2001; Shelton 2001). Cratylia argentea(Desv.) O. Kuntze (syn. C. floribunda Benth., Diocleaargentea Desv.) is a shrub legume which was selectedas promising for dry-season supplementation, par-ticularly in regions with acid soils and extended dryseasons(Argel MArgelLPeters & Schultze-Kraft 2002).Cratylia argentea belongs to the familyLeguminosae, subfamily Papilionoideae, and is themostwidely distributed ofthe fivespecies in the genus(de Queiroz & Coradin 1996; Pizarro et al. 1997). Theleafy shrub usually reaches 1.5–3 m, but there aretrees up to 10 m tall. It is found in a broad range ofhabitats from Western Peru to the state of Ceara´ inBrazil, and is well adapted to acid soils of low tomedium fertility and altitudes up to 1200 m asl(Xavieretal.1995;Maass1996;Schultze-Kraft1996;Peters & Schultze-Kraft 2002). Its nutritive value ishigher than thatof most other shrublegumes adaptedto acid soils. Plants contain only trace amounts oftannins(Lascano1996;Shelton2001).Ithasexcellentregrowthcapacityaftercuttingandcanbeusedassoilcover, mulch and green manure. The species is verydrought tolerant and remains green and productive

Extent and structure of genetic diversity in a collection of the tropical multipurpose shrub legume Cratylia argentea (Desv.) O. Kuntze as revealed by RAPD markers

The tropical multipurpose shrub legume Cratylia argentea is well adapted to acid soils of low to medium fertility and has excellent drought-tolerance. Due to its high nutritive value it is particularly suited as forage for dry-season supplementation. A collection of 47 C. argentea accessions in a collection, derived from seed replicating of original accessions with differing geographic origin and morphological and agronomic characteristics was investigated using molecular markers (RAPD (random amplified polymorphic DNA)). Genetic diversity ( H T = 0.145) in the collection was low, with 30% of differentiation among groups and high genetic similarity among accessions ( GS = 0.805). Within-accession variability was high. One taxonomic mismatch and five possible duplicate accessions were identified. Our results suggest that the genetic diversity in the C. argentea accessions studied is relatively homogeneously distributed, indicating the likelihood of extensive outcrossing. The genetic diversity of original accessions should be assessed to determine if outcrossing has occurred during or before ex situ storage. This might also support any decision on whether accessions should be bulked rather than maintaining them individually.

Availability, production, and consumption of crops biofortified by plant breeding: current evidence and future potential

Biofortification is the process of increasing the density of vitamins and minerals in a crop through plant breeding—using either conventional methods or genetic engineering—or through agronomic practices. Over the past 15 years, conventional breeding efforts have resulted in the development of varieties of several staple food crops with significant levels of the three micronutrients most limiting in diets: zinc, iron, and vitamin A. More than 15 million people in developing countries now grow and consume biofortified crops. Evidence from nutrition research shows that biofortified varieties provide considerable amounts of bioavailable micronutrients, and consumption of these varieties can improve micronutrient deficiency status among target populations. Farmer adoption and consumer acceptance research shows that farmers and consumers like the various production and consumption characteristics of biofortified varieties, as much as (if not more than) popular conventional varieties, even in the absence of nutritional information. Further development and delivery of these micronutrient‐rich varieties can potentially reduce hidden hunger, especially in rural populations whose diets rely on staple food crops. Future work includes strengthening the supply of and the demand for biofortified staple food crops and facilitating targeted investment to those crop–country combinations that have the highest potential nutritional impact.

Enhancing Nutritional Quality in Crops Via Genomics Approaches

Micronutrient malnutrition—also known as hidden hunger—is a growing public health concern that affects especially women and children in the developing world. Worldwide, at least 2 billion people suffer from vitamin A, iron, and zinc deficiencies. Here we review recent advances in the application of genomic approaches for biofortification of staple crops to enhance their nutritional quality and thus reduce ‘hidden hunger’. The application of genomic tools such as marker-assisted selection in conventional breeding or genetic modification offers sustainable and cost-effective ways to provide essential micronutrients (here provitamin A or iron) to people in developing countries. To maximize the benefits of genomic approaches for biofortification, we need to extend our understanding of the genetic control mechanisms and relative contribution from different rate-limiting steps for both provitamin A and iron accumulation in edible plant parts.