The evaluation of tropical legumes for use in ley pastures in central and southern Queensland

Soil fertility decline in the northern grain belt has resulted in corresponding declines in grain yield and quality. One option to overcome this decline is through the incorporation of ley or phase pastures into the cropping system. A range of tropical species are currently being evaluated as either self-regenerating annuals or perennial ley pasture legumes for central (CQ) and southern (SQ) Queensland. Several new accessions have regenerated from seedlings and may provide self -regenerating annuals for use as ley legumes. C. pascuorum has consistently been a high yielding accession in both CQ and SQ and has the ability to regenerate strongly from seed. Other accessions which are promising as regenerating annuals include V. oblongifolia CPI 121699. The most outstanding perennial species was M. bracteatum and within that species, CPI 55769 was the most promising. Other strongly persisting species were D. virgatus, C. ternatea and M. atropurpureum. Further studies are now being undertaken to develop management options for the most promising of these legumes

Butterfly pea - a legume success story in cropping lands of central Queensland

The central Queensland region is a major producer of wheat, sorghum and beef. Changes in relative values of cereals and beef, together with a market demand to finish steers at a younger age, has induced farmers to invest more resources into their beef enterprises. Soil fertility decline is seen as a major constraint to cereal production and one that can be overcome by use of pasture phases in crop rotations. Within this environment, butterfly pea (Clitoria ternatea) has emerged as a well-adapted summer-growing legume for the heavy textured cropping soils of the region. It is being sown into existing or new permanent pastures and in pasture phases within cropping rotations to improve animal production and soil nitrogen status. Butterfly pea is relatively inexpensive to establish and can provide liveweight gain of between 0.75 and 1.3 kg/head/day. The combination of farmer, extension and research inputs has resulted in widespread adoption with > 12,000 ha being successfully established over the past 3 years

An update on the global strategy for the conservation and utilisation of tropical and subtropical forage genetic resources

Tropical and sub-tropical forages (TSTF) are critically important for supplying livestock feed and environmental benefits in extensive and intensive livestock systems of developed and developing countries. There has been focused collection and conservation of forage genetic resources (FGR), and research on their diversity, adaptation and use for the past 60 years. This laid the foundations for the impacts TSTF have had, and continue to have. However, since about 1995 there has been significant reduction in forage science investment, and capability globally, and that has strangely coincided with the accelerated demand for livestock products. The status of TSTF germplasm conservation, capability and capacity are now at risk, and the decline must be reversed if the tropical and subtropical farming systems are to access the best genetic material and knowledge to meet the growing food/environmental needs. A strategy to reduce barriers to TSTF conservation, research and utilisation was developed under the Global Crop Diversity Trust in 2015 with input from across the TSTF-genetic resources community. Its aim was to build a functional network of national, regional and international genetic resource centres, introduce operational efficiencies, and enable genebanks to improve their role as knowledge managers and advisors for research and development programs. The strategy’s main objectives are: 1) Rebuild the community of TSTF genebanks and genebank users to develop closer collaboration and trust; 2) Ensure more efficient and rationalized conservation within and among genebanks; and 3) Actively support utilisation by anticipating germplasm needs and responding to users’ requests for information and seeds. Implementation of the strategy commenced in 2016, with the first aim being to win buy-in and cooperation of international and national genebanks. A new Newsletter, ‘Forages for the Future’, has >600 recipients and reports key implementation activities and the roles of forages across the tropics and subtropics. Making recent impacts more widely known indirectly helps build the body of evidence that improved forages deliver impacts and is the basis for growth in financial and human resources invested in TSTF. The CGIAR genebanks of ILRI and CIAT play key roles in TSTF research and use. In recognition of the need for greater efficiencies and better utilisation of the germplasm, ILRI and CIAT have undertaken an ambitious program to align collections to provide a one stop portal, with prioritised species/accessions for conservation and research, and a simplified germplasm request process. This change is occurring simultaneously with a TSTF strategy initiative encouraging some key national TSTF centres to work more closely together and with the CGIAR centres and with the update of the widely used TSTF database and selection tool, SoFT, with new content and ability to be used on smart phones. That new version will be released in 2019. Reversing the past downward trend requires the commitment and long-term engagement of partner countries and the donor community. The alternative is that 60 years of knowledge and expertise will have to be rebuilt, and generations of farmers and other users will not realize the production and environmental benefits that well-adapted and sustainably managed improved forages can attain

Opportunities for the development of new tropical forage cultivars

Over 100 cultivars of grasses and legumes have been released for use in the grazing industries of northern Australia over the past 36 years. However, many opportunities for new pasture plants remain in the Beef, Dairy and Cropping Industries as well as in land rehabilitation. Opportunities also exist for developing cultivars for farming systems of other tropical countries. Given these opportunities, priorities for research need to be developed in partnership with user communities, research providers and funding bodies

Pastures on cropping soils: which tropical pasture legume to use?

Changes in the economics of cereal and beef production in the northern Australian cropping zone, together with a realisation that soil fertility decline is a major constraint in the production of prime hard wheat, has led to increased interest from producers in short- and long-term ley legume pasture systems. Several legumes, including lablab, leucaena, butterfly pea, caatinga style and desman-thus, are now commercially available for use in this tropical and subtropical zone. Each has advantages and drawbacks in particular farming systems. This paper outlines the best uses of these legumes within the northern cropping zone and suggests areas of research and development that must take place to improve the available suite of legume cultivars and to enhance their adoption

Geographical Patterns of Genetic Variation in Two Species of Stylosanthes Sw. Using Amplified Fragment Length Polymorphism

Understanding the extent and distribution of genetic diversity within a species is essential for the development of effective conservation strategies. The objective of this study was to assess genetic variation using amplified fragment length polymorphisms (AFLP) in two species of the tropical legume genus Stylosanthes Sw. Annual, S. humilis (2n = 20) and perennial, S. viscosa (2n = 20) are found throughout tropical America, and are sympatric for much of their range of distribution. One hundred and eleven accessions, covering a wide geographical range, were selected for AFLP analysis. Binary data matrices derived from DNA banding patterns were analysed using the software programs NTSYS-PC and ARLEQUIN. Several accessions were found to be misidentified. Of the S. humilis accessions, the overall average similarity value was (0.72) slightly higher than the value obtained for S. viscosa (0.67). Cluster analysis and principal coordinate analysis grouped accessions from both species by geographical origin, with a few exceptions. Analysis of molecular variance (AMOVA) in S. humilis revealed 59.4% of the variation among groups formed from the cluster analysis. This was highly significant (P < 0.001). For S. viscosa AMOVA also revealed more variation among than within groups (66.5%). This was also highly significant (P< 0.001). The majority of accessions of both species conserved ex situ are of Brazilian and Venezuelan origin. This study has identified areas in Central America and Mexico for which novel genetic variation may be found and where conservation activities should be focused

Measurements of nutritive value of a range of tropical legumes and their use in legume evaluation

Measurements of leaf and stem quality were taken from 4-10 legumes at 3-5 sites in each of 5 different multi-site experiments grazed by cattle. The sites were in widely separated areas in Queensland, Australia with one site in northern New South Wales. The samples, taken after a period of active growth, were from the terminal 15 cm of shoots of most legumes, although the terminal 30 cm was used for twining legumes like Siratro (Macroptilium atropurpureum). These were taken as a reasonable approximation to the 'grazed layer'. The leaf and stem components were analysed for acid detergent fibre (ADF), N and P; and the % leaf in the sample was calculated. In most sets of samples, there were consistent differences among legumes in the levels of ADF, N and P, the differences usually being greater in the leaves than in the stems. Species with consistently low ADF (ca. 20%) and high N (ca. 4%) in the leaves were Clitoria ternatea, Desmanthus spp., Aeschynomene villosa and Ae. americana whereas other species such as Stylosanthes scabra had consistently higher ADF (ca. 25-30%) and lower N levels (ca. 3%). Levels of ADF in leaf were sometimes half of the levels in new terminal stem. There were also some consistent differences in % leaf in the samples. Stylosanthes scabra and S. seabrana usually had the lowest % leaf. Thus, there were some consistent differences among the rankings of nutrient attributes in different legumes across different sites. However, it is argued that the impact of these differences on animal production will often be over-ridden by the proportions and amounts of legume leaf and stem ingested and that measurements of nutritive value should not be given priority in early stage evaluation studies. Levels of Na, K, Ca, S, Mg, Cu, Zn and Mo were also measured in most samples. The main differences were the high levels of Na (1000-1800 mg/kg) in S. scabra cv. Seca and Indigofera schimperi, which were about 10 times those in the other species