Faba bean in cropping systems

The grain legume (pulse) faba bean (Vicia faba L.) is grown world-wide as a protein source for food and feed. At the same time faba bean offers ecosystem services such as renewable inputs of nitrogen (N) into crops and soil via biological N₂ fixation, and a diversification of cropping systems. Even though the global average grain yield has almost doubled during the past 50 years the total area sown to faba beans has declined by 56% over the same period. The season-to-season fluctuations in grain yield of faba bean and the progressive replacement of traditional farming systems, which utilized legumes to provide N to maintain soil N fertility, with industrialized, largely cereal-based systems that are heavily reliant upon fossil fuels (=N fertilizers, heavy mechanization) are some of the explanations for this decline in importance. Past studies of faba bean in cropping systems have tended to focus on the effect of faba bean as a pre-crop in mainly cereal intensive rotations, whereas similar information on the effect of preceding crops on faba bean is lacking. Faba bean has the highest average reliance on N₂ fixation for growth of the major cool season grain legumes. As a consequence the N benefit for following crops is often high, and several studies have demonstrated substantial savings (up to 100–200 kg N ha⁻¹) in the amount of N fertilizer required to maximize the yield of crops grown after faba bean. There is, however, a requirement to evaluate the potential risks of losses of N from the plant–soil system associated with faba bean cropping via nitrate leaching or emissions of N₂O to the atmosphere as a consequence of the rapid mineralization of N from its N-rich residues. It is important to develop improved preventive measures, such as catch crops, intercropping, or no-till technologies, in order to provide farmers with strategies to minimize any possible undesirable effects on the environment that might result from their inclusion of faba bean in cropping system. This needs to be combined with research that can lead to a reduction in the current extent of yield variability, so that faba bean may prove to be a key component of future arable cropping systems where declining supplies and high prices of fossil energy are likely to constrain the affordability and use of fertilizers. This will help address the increasing demand by consumers and governments for agriculture to reduce its impact on the environment and climate through new, more sustainable approaches to food production. The aims of this paper are to review the role of faba bean in global plant production systems, the requirements for optimal faba bean production and to highlight the beneficial effects of faba bean in cropping systems.     

Control of Fusarium verticillioides,cause of ear rot of maize,by Pseudomonas fluorescens

BACKGROUND: Maize is one of the staple food crops grown in India. Fusarium verticillioides (Sacc.) Nirenberg is the most important fungal pathogen of maize, associated with diseases such as ear rot and kernel rot. Apart from the disease, it is capable of producing fumonisins, which have elicited considerable attention over the past decade owing to their association with animal disease syndromes. Hence, the present study was conducted to evaluate ecofriendly approaches by using a maize rhizosphere isolate of Pseudomonas fluorescens (Trev.) Mig. and its formulation to control ear rot disease and fumonisin accumulation, and also to study the capacity to promote growth and yield of maize. In vitro assays were conducted to test the efficacy of P. fluorescens as a seed treatment on seed germination, seedling vigour and also the incidence of F. verticillioides in different maize cultivars. The field trials included both seed treatment and foliar spray. For all the experiments, P. fluorescens was formulated using corn starch, wheat bran and talc powder. In each case there were three different treatments of P. fluorescens, a non‐treated control and chemical control. RESULTS: Pure culture and the formulations, in comparison with the control, increased plant growth and vigour as measured by seed germination, seedling vigour, plant height, 1000 seed weight and yield. P. fluorescens pure culture used as seed treatment and as spray treatment enhanced the growth parameters and reduced the incidence of F. verticillioides and the level of fumonisins to a maximum extent compared with the other treatments. CONCLUSION: The study demonstrates the potential role of P. fluorescens and its formulations in ear rot disease management. The biocontrol potential of this isolate is more suited for fumonisin reduction in maize kernels intended for human and animal feed. Copyright © 2009 Society of Chemical Industry     

The world's richest tadpole communities show functional redundancy and low functional diversity: ecological data on Madagascar's stream-dwelling amphibian larvae

Background  

Functional diversity illustrates the range of ecological functions in a community. It allows revealing the appearance of functional redundancy in communities and processes of community assembly. Functional redundancy illustrates the overlap in ecological functions of community members which may be an indicator of community resilience. We evaluated patterns of species richness, functional diversity and functional redundancy on tadpole communities in rainforest streams in Madagascar. This habitat harbours the world's most species-rich stream tadpole communities which are due to their occurrence in primary habitat of particular interest for functional diversity studies.     

Molecular characterization ofPseudomonas syringae pv.tomato isolates from Tanzania

Bacterial speck caused byPseudomonas syringae pv.tomato is an emerging disease of tomato in Tanzania. Following reports of outbreaks of the disease in many locations in Tanzania, 56 isolates ofP. syringae pv.tomato were collected from four tomato- producing areas and characterized using pathogenicity assays on tomato, carbon source utilization by the Biolog Microplate system, polymerase chain reaction and restriction fragment length polymorphism (RFLP) analysis. All theP. syringae pv.tomato isolates produced bacterial speck symptoms on susceptible tomato (cv. ‘Tanya’) seedlings. Metabolic fingerprinting profiles revealed diversity among the isolates, forming several clusters. Some geographic differentiation was observed in principal component analysis, with isolates from Arusha region being more diverse than those from Iringa and Morogoro regions. The Biolog system was efficient in the identification of the isolates to the species level, as 53 of the 56 (94.6%) isolates ofP. syringae pv.tomato were identified asPseudomonas syringae. However, only 23 isolates out of the 56 (41.1%) were identified asPseudomonas syringae pv.tomato. The results of this work indicate the existence ofP. syringae pv.tomato isolates in Tanzania that differ significantly from those used to create the Biolog database. RFLP analysis showed that the isolates were highly conserved in theirhrpZ gene. The low level of genomic diversity within the pathogen in Tanzania shows that there is a possibility to use resistant tomato varieties as part of an effective integrated bacterial speck management plan. http://www.phytoparasitica.org posting August 8, 2008.     

Problems with disseminating information on disease control in wheat and barley to farmers

Plant pathologists have traditionally worked in the area of clarifying and understanding the disease cycles of specific diseases, factors influencing epidemiology, yield loss potential and host-pathogen interactions in order to be able to minimise the disease risk, build warning systems or recommend specific control thresholds in relation to the application of fungicides. The decision support system Crop Protection Online (CPO) is an example of a threshold-based system that determines economically viable fungicide strategies. The system is based on using appropriate doses aimed at minimising the overall pesticide input. CPO is used widely by advisors and many of the thresholds are generally accepted and disseminated through newsletters. The national figures for the use of fungicides in cereals have shown a major reduction during the last 20 years and their use today is much in line with the level that can be achieved from using CPO as indicated from validation trials. The number of end-users among farmers has been stable at around 3% during the last 10 years (800–1,000 farmers). Major hurdles in increasing the number of users are believed to be: (1) the requirements for carrying out assessments in the field, (2) farm sizes getting larger, leaving less time for decision making for individual fields, (3) lack of economic incentives to change from standard treatments, (4) the failure of decision support systems to interact with other computer-based programmes on the farm, (5) the lack of compatibility of decision support systems with farmers’ ways of making decisions on crop protection in general, (6) the need for direct interactions with advisors. A sociological investigation into the farmers’ way of making decisions in the area of crop protection has shown that arable farmers can be divided into three major groups: (a) systems-orientated farmers, (b) experienced-based farmers and (c) advisory-orientated farmers. The information required by these three groups is different and has to be looked at individually from the end-user’s perspective rather than from the scientist’s perspective. New ways of entering the decision support system where specific field inspections are omitted and where regional disease data are relied on, have been investigated and tested in field trials. The results show possibilities for further developments in that direction, which might be one way of gaining more end-users.     

Sinap Orlovsky triploid apple cultivar: Its origin and cytoembryological characteristic

This paper gives the development history of the best apple cultivar of the temperate zone of Russia— the Sinap Orlovsky apple cultivar with fruit of a long storage life, which has hitherto been considered to be a diploid one. The assumption of its triploidy has come into existence due to DNA-markers. Cytoembryological studies showed in 2016 that the cultivar was a triploid. It is characterized by vigorousness and regular fruit bearing. The long-term experimental data show that the cultivar is of little promise as an initial form for the development of a large hybrid fund owing to its low fruit output, hybrid seeds, and one-year seedlings relative to pollinated flowers in case of its being used as a maternal and paternal parent.