This is a guide to the techniques required to produce pure and vigorous seed from varieties of this cross-pollinated crop. Multiplication rates, through sequential breeder, foundation, and certified seed stages, are high:3 kg of seed are adequate for sowing 1 ha, subsequently producing 1 tonne of clean seed. Nucleus seed plots (stage 0), sown for regeneration once every 4 years, should be effectively is o- lated . They should be between 0,1 and 0.2 ha in size, and contain at least 3000 plants. Plots of breeder seed(stage1)should similarly be well isolated, and rigorously inspected and rogued, and not more than 1% of off – types should be permit tedatfinal inspection. Plot sizes are normally between 0.1 and 0.5 ha, according to how much certified seed is required, using a conservative multiplication factor of X200. At the end of the foundation seed stage (stage 2), through protective perimeter planting, inspection, and rogueing, off-types should be less than 2%. At the final certified seed stage(3), the permitted level of off-types is 5%. Six points of guidance are given for extension staff to pass on to farmers who(as may be expected) at tempt to multiply their own improved seed.
Tag: plant breeding
Agroforestry trees: to domesticate or not to domesticate?
The improvement of agroforestry is as much a social and political challenge as a biological one. To encourage tree planting amonst a diverse client group of resource poor farmers requires better understanding of farmer’s decision-making processes. The modest resources for domestication efforts will have to be focused on priority species which have been determined following objective methodologies. Common to the domestication of all species is a need to accelerate the process to deliver appropriate imorovement early on. The proactive multiplication of germplasm is required to reduce the lag phase between identification and adoption of improved material.
Tree improvement research for agroforestry: a note of caution
Tree improvement is increasingly considered as an important research direction for the development of more productive agroforestry systems. In these systems trees have multiple economic uses and ecological functions that should be taken into account in tree improvement programmes in order for these programmes to ensure that the improved species, the end-result of their research, is adapted to agroforestry. The key issue here may be for tree improvement specialists involved in agroforestry programmes to be able to differentiate, from the range of characters that could be selected for improvement of a given species, characters that are absolutely necessary to improve whatever agroecosystem the tree may be grown in – the primary targets and characters for which improvement would only be appropriate for particular agro ecosystems – the secondary targets.
Alternatives to slash-and burn: above ground biodiversity assessment working group summary report 1996-1999 – impact of different land uses on biodiversity, annex i-v
This report covers the contractual requirement of ASB to the Global Environment Facility (GEF) to meet Goal 2 “Assessment of the impact on biodiversiry of d4fferenr land uses” as outlined in the aims and objectives of Phase 112. It also meets the broader goals of the ASB consortium to explore the dynamic linkages among biodiversity, carbon sequestration and productivity for human needs. The approach has been to establish a series of ecoregional biophysicai baselines to first identify and then to evaluate, via intensive field studies, some of the key predictive relationships among plant and animal species and functional types and the physical environment. The size of this task required that it be tackled at two levels: first, to identify broad distributional patterns of key plant groups along gradients of land use at the ecoregiona] scale, as these are usually closely associated with both plant and animal performance overall; and second, to explore finer scale patterns of both plant and animal performance along an intensive land-use gradient within a specified ecoregion. The assumption has been that the information derived from the intensive study could reveal indicators of biodiversity response to land use that could be extrapolated and subsequently tested within the broader spatial ecoregional framework. Once identified, such indicators would be examined to assess their potential use by managers and planners in ongoing assessment and monitoring of biodiversity and as an aid to decision support for adaptive management. While this report deals mainly with above-ground biodiversity according to the TOR of the GEF contract, close attention has been given as well to below-ground elements in the intensive study in order to better understand the dynamic between biodiversity and land use. Funding for additional survey work in Cameroon and Indonesia was supplied by DANIDA and more recent, ongoing work exploring linkages between biodiversity and profitability in Thailand and Indonesia has been funded by ACIAR.
Operationalizing an innovative systems approach for breeding agroforestry trees
Key messages
- ‘Systems approach’ plant breeding is about considering multiple global challenges together within the breeding process, to make sustainable progress in addressing those challenges.
- For a systems approach to tree breeding to be successful, the starting point is a broad set of measures that define breeding success. The values applied should extend beyond the traditional ones of productivity and profitability, and embrace resilience, sustainability, nutritional security, local cultures and conservation.
- Policy interventions that encourage a systems approach to tree breeding should provide incentives for tree researchers and breeders to embrace these broader values during tree characterization and genetic improvement. There should also be specific incentives for tree breeders to bring together existing breeding methods in novel ways to ensure that multiple values are addressed.
Comparison of resilience of different plant teams to drought and temperature extremes in Denmark in sole and intercropping systems
Intercropping (IC) can reduce nitrogen fertilizer requirements, supress weeds, and improve crop yields and yield stability. Three field trials were conducted in Denmark in 2018 with intercropping and sole crops (SC) using spring wheat, barley, faba bean and field pea to compare productivity under five fertilizer levels. The trials were carried out using in a split-plot design with four. Anomalous weather during the 2018 cropping season created drought conditions and high temperatures above 31°C. No effect of fertilizer treatment was found, and total dry matter and grain yields were supressed in all systems. Wheat grain yields averaged 2.14 t ha−1 across systems, ranging from 1.58 t ha−1 as a component of the IC to 2.44 t ha−1 as SC, and barley grain yields averaged 2.35 t ha−1. Faba bean yielded 1.78 t ha−1 as SC, but failed in the IC. Pea failed in both systems. Intercropping barley with cover crops had no effect on grain yield or total dry matter. These results suggest that intercropping provided no production advantage during a drought and illuminate the need to continue conducting research and breeding on drought-resistant cultivars.
A scoping review on tools and methods for trait prioritization in crop breeding programmes
Trait prioritization studies have guided research, development and investment decisions for public-sector crop breeding programmes since the 1970s, but the research design, methods and tools underpinning these studies are not well understood. We used PRISMA-ScR (Preferred Reporting Items for Systematic review and Meta-Analysis Protocols) to evaluate research on trait ranking for major crops over the past 40 years (1980–2023). Data extraction and descriptive analysis on 657 papers show uneven attention to crops, lack of systematic sex disaggregation and regional bias. The lack of standardized trait data taxonomy across studies, and inconsistent research design and data collection practices make cross-comparison of findings impossible. In addition, network mapping of authors and donors shows patterns of concentration and the presence of silos within research areas. This study contributes to the next generation of innovation in trait preference studies to produce more inclusive, demand-driven varietal design that moves beyond trait prioritization focused on productivity and yield.