Research findings, and updates on work in progress: ICARDA scientists publish in some of the world’s top agricultural journals. Here’s a glimpse of recent research papers. The authors will be happy to provide more information.
Genotype X environment interactions and grain yield stability of haricot bean varieties in Northwest Ethiopia. W.Tadesse and Others. Published by Scientific Research and Essays
Haricot bean is one of the most important and widely cultivated species of bean in Ethiopia. It plays a key role in human nutrition and the market economies of many areas, and is widely grown by smallholder farmers in the country’s central rift valley.
Limited efforts have been made to promote improved bean technologies, and productivity remains low due to the fact that high yielding varieties adapted to diverse ecological conditions are not being widely used by smallholders.
Several improved varieties that could potentially meet local consumption and export needs exist, but the performance of these varieties has not been evaluated under conditions prevalent in northwest Ethiopia.
The lack of information about the response of crop varieties to variable environmental conditions limits accurate yield estimates and fails to identify suitability for a given region or climate.
The objective of this study was to evaluate how grain yields from several varieties of haricot beans responded to multi-environment trials across divergent ecological locations.
The study was conducted over two successive years at three locations in Ethiopia - Fenote Selam, Zema and Addis Zemen - which represent different haricot bean growing ecologies.
Statistical models were used at each location to evaluate seven haricot bean varieties - Melkie, Mexican-142, Atendaba, Awash-1, Besh Besh, Brown Speckled and Roba-1 - which had previously been released in central and southern parts of Ethiopia.
Results of all models in this study identified Atendaba and Roba-1 as the two best performing and most stable varieties. Researchers therefore recommend these varieties for further production in the region.
Simulating the effects of zero tillage and crop residue retention on water relations and yield of wheat under rainfed semiarid Mediterranean conditions
Although studies have shown that zero tillage and surface crop residue – two components of conservation agriculture – can improve soil water retention, research has not fully quantified the effects of these interventions in rainfed semi-arid Mediterranean conditions.
This research studied the soil water dynamics of wheat grown after barley in northern Syria under different conditions: two contrasting tillage regimes (zero tillage vs. conventional tillage), two levels of surface residue retention (partial and full), and early and late planting.
Researchers applied a crop-soil simulation model – CropSyst – for the season under study covering the period 1980-2010.
Results showed that planting dates had a notable impact on crop performance and yield: planting wheat immediately after the first sufficient autumn rainfall minimized the risks of crop failure; whereas late planting was affected by unproductive soil evaporation.
In contrast, zero tillage and residue management had minimal impacts on yields – although these practices have the potential to reduce the costs of agronomic management compared to conventional tillage.
Since approximately 55% of seasonal precipitation is lost to evaporation because of late planting - even though early planting bears little risk of crop failure - researchers believe farmers should be encouraged to plant early as this seems to be the main factor responsible for maximizing yields.
Although many developing regions have excellent agricultural potential, populations have become so concentrated in these regions that acute poverty and malnutrition are a serious concern.
The food science response to chronic nutrition has often been to subsidize diets through nutritional supplements or crop varieties with higher nutrient levels. However, in areas where significant numbers suffer from inadequate nutrition intake, as in the highlands of Ethiopia, supplements are neither financially realistic nor sustainable.
A combination of approaches is therefore needed to improve nutrition and household income. Using criteria defined by farmers as constraints, this study used a mathematical model to analyze the effects of different potential combinations of technologies and supporting agricultural policies on household nutrition gaps and farmer income.
The constraints identified by farmers included access to storage to avoid seasonal price reductions, the availability of soil inputs, and especially crop losses due to Striga, a parasitic plant and the biggest limiting biological factor in the production of sorghum in Sub-Saharan Africa.
This study evaluated a strategy to introduce Striga resistant sorghum varieties alongside other interventions in the Qobo Valley of Ethiopia: inorganic fertilizers, tied ridges, and an inventory credit financial system.
It concluded that a multi-solution approach, which increased overall income, as well as maize productivity, is necessary since better Striga resistance alone would not have a strong enough overall effect on nutrition, unless it was combined with fertilization, water harvesting, and an improved credit program.
The study recommended the adoption of an inventory credit financial system rather than the existing sell-at-harvest method which would enable the farmer to store produce in order to take advantage of seasonal price changes.
Researchers calculated that a multi-solution approach, involving all of the aforementioned strategies, would increase farm household income by 31%. This approach would also eliminate under-nutrition completely - except in extreme drought years.
Agronomic Performance of Elite Stem Rust Resistant Spring Wheat Genotypes and Association among Trial Sites in the Central and West Asia and North Africa Region. W. Tadesse and others. Published in Crop Science.
Wheat is the dominant crop in the Central and West Asia and North Africa region, covering an annual production area of about 52 million ha. However, its productivity in the region is very low due to stresses like drought, extreme temperatures, and pests. Perhaps most alarming is the new stem rust disease Ug99, which is able to overcome many of the genes that are known to resist it.
This study identified high yielding wheat cultivars for direct release by the National Agricultural Research Systems (NARS) and for parentage purposes for the wheat breeding program at ICARDA. It also determined criteria and identified key locations for wheat yield trials in the region.
An analysis was done to quantify the main contributors to variability in grain yield for 24 wheat genotypes in 15 environments. This analysis showed that wheat grain yield was significantly affected by environments, genotypes, and genotype × environment interaction: the environment controlled 90.1% of grain yields, environmental interaction 8.3%, and improved genotypes 1.6%.
According to ICARDA findings, two genotypes, Baasha-14 and Amir-2, with mean grain yield levels of 5168 and 5127 kg per ha, respectively, were identified as the best Ug99 resistant varieties with high yield potential across a wide range of environments.
Researchers recommend that these high yielding and Ug99 resistant genotypes be released as replacements for the susceptible varieties currently in use.
Rainwater harvesting is crucially important in dryland areas, where land and water resources are often scarce. The practice can improve productivity and help communities cope with climate change in dry, marginal environments.
Accurately determining suitable locations for rainwater harvesting is therefore crucially important for maintaining and strengthening the livelihoods of dryland farmers.
Land suitability assessments are key to the effective implementation of rainwater-harvesting schemes – yet arid areas suffer from a scarcity of detailed soil information and the preparation of this data can be costly and time consuming.
This research aims to overcome these constraints by examining the utility of soil-landscape modeling techniques, and their ability to provide soil and topographic information for improved land suitability assessments.
A test site in Northwest Jordan was evaluated for two types of rainwater harvesting interventions: contour ridges and runoff strips.
Two methods were used: the Soil-Landscape Prediction Method (SLPM), which uses terrain characteristics derived from a digital elevation model, and the Systematic Random Survey Method (SRSM), which estimates terrain characteristics between 108 random field observation points over a 500m2 grid.
Compared to field observations, both models demonstrated reasonable accuracy when detecting soil depth and rocky areas – landscape features that often determine land suitability for rainwater harvesting. However, the SLPM was more accurate, suggesting this approach is likely to generate more reliable suitability assessments. This method also produced a more realistic spatial distribution of landscape characteristics.
The results will help to generate reliable suitability maps that support the implementation of sustainable land use alternatives in arid environments.
A participatory GIS approach for assessing land suitability for rainwater harvesting in an arid rangeland environment. Feras Ziadat and others. Published in Arid Land Research and Management.
Despite widespread land degradation across West Asia and North Africa, the adoption of rainwater harvesting – an effective means of improving soil moisture, vegetation cover, and productivity – has been slow.
Recent research conducted in Jordan improves the understanding of regional adoption constraints, and develops options for effective and sustainable rainwater harvesting interventions.
Using field surveys and participatory GIS approaches, the project established a methodology that can successfully match harvesting requirements with bio-physical conditions.
A range of biophysical parameters – slope, soil depth, soil texture, and stoniness – were applied to assess suitability.
Recommended rainwater harvesting interventions were subsequently introduced across 62.9 hectares, increasing water productivity and reversing degradation on 41 farms.
The results demonstrate that GIS approaches can be used to identify potential areas suitable for alternative land use interventions within a reasonable cost and time.
The approach is applicable to arid areas experiencing similar conditions where rainwater harvesting plays a crucial role in the sustainable management of land and water resources.
Significance of phosphorous for agriculture and the environment in the West Asia and North Africa region. Authors: John Ryan and others. Published in Advances in Agronomy.
Fertilizers are crucial inputs driving global food production – more than half of the world’s food output is attributed to fertilizer-applied nutrients.
While research has tended to focus on nitrogen – the primary nutrient driving agricultural production – there has been less attention paid to phosphorous fertilizers, which is no less important for crop yields and may have even greater environmental implications.
If used sustainably there is significant potential to boost productivity in parts of the world where phosphorous fertilizer application is currently low or absent. The West Asia and North Africa (WANA) region is one area where phosphorous is capable of raising yields and mitigating the impacts of increasing environmental degradation due to climate change.
Despite limited fertilizer application, WANA countries contain major deposits of exploitable phosphorous, and given the region’s predominantly calcareous soils, significant capacity to increase usage.
This research paper reviews current knowledge on phosphorous application in the WANA region. It presents the results of field trials conducted over the past three decades, highlighting fertilizer usage on the region’s main crops in relation to rainfall, cropping systems, soil test levels, and efforts to identify P-efficient genotypes and enhance soil phosphorous fertility with mycorrhizae.
Results demonstrate increasing usage across the region and provide a framework for future application efforts: establishing effective phosphorous accumulation rates, residual values of phosphorous reserves, appropriate fertilization rates, and soil phosphorous sufficiency limits.
Attempts to strengthen food security through the use of phosphorous fertilization will depend upon efforts to synthesize research findings across the region and strengthen weak or non-existent extension systems.
To develop new crop varieties, plant breeders require good raw material – genotypes with specific traits such as drought tolerance or resistance to a particular disease. Often, the problem is how to identify such genotypes from a genebank collection containing tens of thousands of potential candidates. A new tool known as FIGS (Focused Identification of Germplasm Strategy) has made this identification process faster and more accurate.
The science behind FIGS continues to develop. A new research paper describes the development of effective algorithms and techniques that use agro-climatic data to predict the likely levels of a particular stress – in this case, stem rust disease in wheat – in a given environment. This is an important first step in identifying rust-resistant genotypes because rust-endemic environments are likely to contain wheat genotypes that have co-evolved with rust pathogens, and possess resistance to the disease.
The authors of the paper experimented with different modeling techniques and statistical tools to quantify the relationship between target trait and agro-climate. Their results provide interesting insights into the distribution of stem rust resistance in wheat. Resistant genotypes are confined to certain environments or areas, and susceptible genotypes to other areas, with overlap.
This research will help select, from a huge genebank collection, a small, manageable subset that is likely to include resistant genotypes. The results will improve our understanding of how crop plants adapt to environmental conditions, enable more effective use of genebanks, and accelerate the flow of useful genes to plant breeders.
Partners in FIGS development include ICARDA, the Vavilov Research Institute in Russia, the Australian Winter Cereals Collection, the NordGen Genebank and the Grains Research and Development Corporation, Australia.
For more information contact Dr Abdullah Bari, e-mail a.bari@cgiar.org
Genomic resources for improving food legume crops. Authors: J. Kumar and others. Published online in the Journal of Agricultural Science, Cambridge.
Food legumes ― lentil, faba bean, chickpea, soybean and others ― are the main source of dietary protein for a large majority of the world’s population. However, legume breeding programs have been unable to match the spectacular yield gains achieved in rice, wheat and other cereal crops. The main reason: large genotype × environment (G×E) interactions that influence the expression of traits and limit the gains from traditional plant breeding methods. A broad-ranging literature review, published recently, looks at how genomics and modern biotechnology tools can help overcome these challenges.
Molecular markers allow geneticists to ‘dissect’ yield and other complex traits (those governed by multiple genes). Quantitative trait loci (QTL) analysis can help identify genotypes with more stable responses across environments (wide adaptation and/or high yield stability); or those that interact significantly with a particular kind of environment (e.g. high response to irrigation).
A number of genomic resources have been developed in several legume species during the last two decades: linkage maps, high-throughput sequencing technologies, expression sequence tag (EST) databases, genome sequences, DNA chips, targeting induced local lesions in genomes (TILLING), bacterial artificial chromosome (BAC) libraries and others. The paper summarizes what resources are available, how they are being used, and how their application might expand in the near future. It also discusses problems with some of the current genomics tools – for example difficulties of using certain kinds of molecular maps – and suggests alternative approaches.
A huge range of genomic resources are available in the public domain, but only a few are used routinely in legume breeding programs. Their use is expected to increase rapidly, with the availability of high-throughput and cost-effective genotyping platforms, combined with automation in phenotyping methodologies.
Partners in this study included ICARDA, the Indian Institute of Pulses Research, and Agriculture and Agri-food Canada.
A special edition of the journal Field Crops Research, examining in detail the subject of Conservation Agriculture (CA) in Dry Areas, has just been published on line and will be available in hard copy next month (June 2012) . It was edited by ICARDA’s Director of Diversification and Sustainable Intensification of Production Systems – Dr Rachid Serraj, alongside Professor Kadambot H.M. Siddique of The University of Western Australia.
“The positive impacts of CA can be harnessed through innovative systems research and development, to enhance agricultural systems productivity, profitability and sustainability for the future.”
This publication is very timely. The global area currently under CA is approaching 120 M ha, corresponding
to about 8.5% of arable cropped land, spread across all continents and agro-ecologies, including the dry Mediterranean type. Growing scientific and empirical evidence shows that significant productivity, economic, social and environmental benefits can be gained through the adoption of CA principles for sustainable production intensification in dry environments. Crop yield potential under CA management practices in rainfed systems is often greater than with conventional tillage (CT) systems; particularly in dry environments where sub-optimal rainfall often limits yield.
The editors say the objective of this special issue is to enrich the ongoing debate on the role of CA, especially in smallholder farming systems, by synthesizing the recent research findings of CA in dry areas, by analyzing agronomic, socio-economic, and agro-ecological determinants leading to its success or failure, and by identifying potential entry points for priorities for future research on CA in dry areas.
They conclude that the principles that underlie CA are well known and have been tested and validated in various regions around the world, but CA components for crop and agro-ecological resource management are complex and location-specific, including crop residue management, cultivar selection and crop choice for rotation, strategies for nutrient management, tactics for weed management, disease and pest management, and soil water management practices.
These components must be managed and fine-tuned for relevant cropping systems, so that the practices are compatible with the principles of CA and that ,most importantly, they meet the requirements of and are feasible as a practical solution for farmers. Future research and development should focus on better understanding the effects and interaction among all these systems components and to develop site-specific CA options, they say. The critical need for an active farmer participatory approach in the comprehensive assessment of ecological and socio-economic conditions in which CA could be adapted especially under smallholder farming systems is emphasized.
Sources of resistance to stem rust (Ug99) in bread wheat and durum wheat identified using focused identification of germplasm strategy (FIGS). Authors: Dag Terje Filip Endresen,* Kenneth Street, Michael Mackay, Abdallah Bari, Ahmed Amri, Eddy De Pauw, Kumarse Nazari, and Amor Yahyaoui
A computer modeling trial at ICARDA has validated the focused identification of germplasm strategy (FIGS) for use in predictive simulation studies, to predict and test against previously known trait scores.
The team involved is therefore recommending that the FIGS approach can be used as a complement to expert knowledge and experience when selecting accessions for plant breeding and crop research activities.
The study itself was designed as a “blind” procedure where the person calculating the computer model did not know the actual trait scores. This approach has provided a more realistic test of the predictive capacity of the FIGS approach compared to previous studies, says the team.
Interestingly, the location and year of the experiment in which the previously known evaluation data were obtained were seen to influence the predictive power of the models. Another factor requiring further consideration was the size and perhaps the ratio of resistant to susceptible expression of the training set. It was also noted that the FIGS approach requires the accessions to be geo-referenced before an association between the germplasm and the environment (in which it evolved and was subject to selection) can be established.
The study also explored the suitability of FIGS for the identification of resistance in bread wheat (Triticum aestivum L. subsp. aestivum) and durum wheat [Triticumturgidum L. subsp. durum (Desf.) Husn.] to Ug99—a strain of stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & Henn.) and typified to race TTKSK. The predictions were validated against a dataset with the screening of wheat accessions conducted in Yemen in 2008. Only a small training set representing 20% of the trait screening results was disclosed to the person conducting the data analysis for the calibration of the prediction model.
The hit rate for identification of Ug99-resistant accessions was more than twice as high when using the FIGS approach compared to a random selection of accessions. These results suggest that FIGS is well suited to the identification of samples with resistance to fungal pathogens and show that further research into refinement is justified.
For more information contact Dr Abdulla Barij, email A.Bari@cgiar.org
Assessment of long-term barley–legume rotations in a typical Mediterranean agro-ecosystem: grain and straw yields. Authors John Ryan, Murari Singh and Scott Christiansen
Published in Archives of Agronomy and Soil Science Volume 58, Issue 3, 2012
In recent years, land-use pressures across the dry land areas of WANA and elsewhere have led to a decrease in the use of fallowing and an increase in cereal monoculture. This is a risky move, with increased potential for disease build-up and crop failure leading to a real threat in food security. Given the well-recognized agronomic benefits of crop rotations, a revival of interest in legume-based rotations has begun.
Food or forage legumes in rotation with cereals are a sustainable, alternative sustainable cropping system. But how to prove their effectiveness as complex cropping systems can only be assessed by long-term trials?
ICARDA scientists set about this 11-year rain-fed, barley-based rotation trial in northern Syria to assess rotation effects on yields of barley and legumes, with particular emphasis on the management of vetch. The mean order of barley grain yields from the rotations was led by vetch for hay, vetch for grazing with continuous barley delivering the lowest. Straw yields followed a similar pattern. Nitrogen (60 kg/ha) increased grain (39%) and straw (65%) yields. The N fertilization of barley had no carryover effect on the alternative legume crops.
Although there were no significant differences in seed or straw yield between lentil and vetch, seasonal rainfall influenced overall yields. Total biomass yields descended in the order of vetch, medic and lentil.
There is then a compelling case for annual vetch paired with barley in rotations for the Mediterranean region, says the ICARDA team. They point out that barley/vetch rotations can potentially enhance barley yields and improve soil quality, as well as provide valuable fodder for small ruminants (sheep and goats) in the region’s traditional farming systems.
For more information contact Dr John Ryan, email J.Ryan@cgiar.org
New high-yielding winter wheat genotypes demonstrate resistance to stripe rust disease
Improved winter wheat genotypes for Central and West Asia. R. C. Sharma and others. Published in Euphytica.
A new study has found that high grain yields and resistance to stripe rust – a new aggressive strain of wheat rust disease – are the most important traits for the successful adoption of winter wheat varieties in Central and West Asia.
Stripe rust disease has decimated harvests in recent years – losses of 10-90 per cent have been recorded across Central and West Asia – threatening 40 per cent of the region’s food calorie intake and 20 per cent of its protein consumption.
Researchers determined the stripe rust response and agronomic performance of a set of breeding lines recently developed by the International Winter Wheat Improvement Program (IWWIP).
Field studies were conducted in 2010 and 2011 across several sites in Kazakhstan, Tajikistan, Uzbekistan, and Azerbaijan. In total, 38 experimental varieties, one regional variety, and one local variety were tested.
Although responses were varied during initial trials, several genotypes were not only resistant to stripe rust but generated yields that were higher or equal to local varieties.
Subsequent trials of these successful genotypes were extremely promising: five in particular were consistently resistant to stripe rust disease across all sites in both years, and several also demonstrated high grain yields and superior agronomic performance.
The findings indicate that new IWWIP varieties – available within the region – can help farmers tackle the threats posed by stripe rust disease.
Given the current limitations of research, extension, and seed production systems, however, directly placing these new varieties in the hands of farmers in a short time frame requires new ways of dissemination.
View our presentations
Trials underway to improve bean production in Ethiopia
Genotype X environment interactions and grain yield stability of haricot bean varieties in Northwest Ethiopia. W.Tadesse and Others. Published by Scientific Research and Essays
Haricot bean is one of the most important and widely cultivated species of bean in Ethiopia. It plays a key role in human nutrition and the market economies of many areas, and is widely grown by smallholder farmers in the country’s central rift valley.
Limited efforts have been made to promote improved bean technologies, and productivity remains low due to the fact that high yielding varieties adapted to diverse ecological conditions are not being widely used by smallholders.
Several improved varieties that could potentially meet local consumption and export needs exist, but the performance of these varieties has not been evaluated under conditions prevalent in northwest Ethiopia.
The lack of information about the response of crop varieties to variable environmental conditions limits accurate yield estimates and fails to identify suitability for a given region or climate.
The objective of this study was to evaluate how grain yields from several varieties of haricot beans responded to multi-environment trials across divergent ecological locations.
The study was conducted over two successive years at three locations in Ethiopia - Fenote Selam, Zema and Addis Zemen - which represent different haricot bean growing ecologies.
Statistical models were used at each location to evaluate seven haricot bean varieties - Melkie, Mexican-142, Atendaba, Awash-1, Besh Besh, Brown Speckled and Roba-1 - which had previously been released in central and southern parts of Ethiopia.
Results of all models in this study identified Atendaba and Roba-1 as the two best performing and most stable varieties. Researchers therefore recommend these varieties for further production in the region.
Measuring the impacts of conservation agriculture on wheat yields
Simulating the effects of zero tillage and crop residue retention on water relations and yield of wheat under rainfed semiarid Mediterranean conditions
R. Sommer and others. Published in Field Crops Research
Although studies have shown that zero tillage and surface crop residue – two components of conservation agriculture – can improve soil water retention, research has not fully quantified the effects of these interventions in rainfed semi-arid Mediterranean conditions.
This research studied the soil water dynamics of wheat grown after barley in northern Syria under different conditions: two contrasting tillage regimes (zero tillage vs. conventional tillage), two levels of surface residue retention (partial and full), and early and late planting.
Researchers applied a crop-soil simulation model – CropSyst – for the season under study covering the period 1980-2010.
Results showed that planting dates had a notable impact on crop performance and yield: planting wheat immediately after the first sufficient autumn rainfall minimized the risks of crop failure; whereas late planting was affected by unproductive soil evaporation.
In contrast, zero tillage and residue management had minimal impacts on yields – although these practices have the potential to reduce the costs of agronomic management compared to conventional tillage.
Since approximately 55% of seasonal precipitation is lost to evaporation because of late planting - even though early planting bears little risk of crop failure - researchers believe farmers should be encouraged to plant early as this seems to be the main factor responsible for maximizing yields.
Increasing Income and Nutrition in the Highlands of Ethiopia
Introducing New Agricultural Technologies and Marketing Strategies: A Means for Increasing Income and Nutrition of Farm Households in Ethiopia. Yigezu, AY and Sanders, JH. Published in the African Journal of Food, Agriculture, Nutrition and Development.
Although many developing regions have excellent agricultural potential, populations have become so concentrated in these regions that acute poverty and malnutrition are a serious concern.
The food science response to chronic nutrition has often been to subsidize diets through nutritional supplements or crop varieties with higher nutrient levels. However, in areas where significant numbers suffer from inadequate nutrition intake, as in the highlands of Ethiopia, supplements are neither financially realistic nor sustainable.
A combination of approaches is therefore needed to improve nutrition and household income. Using criteria defined by farmers as constraints, this study used a mathematical model to analyze the effects of different potential combinations of technologies and supporting agricultural policies on household nutrition gaps and farmer income.
The constraints identified by farmers included access to storage to avoid seasonal price reductions, the availability of soil inputs, and especially crop losses due to Striga, a parasitic plant and the biggest limiting biological factor in the production of sorghum in Sub-Saharan Africa.
This study evaluated a strategy to introduce Striga resistant sorghum varieties alongside other interventions in the Qobo Valley of Ethiopia: inorganic fertilizers, tied ridges, and an inventory credit financial system.
It concluded that a multi-solution approach, which increased overall income, as well as maize productivity, is necessary since better Striga resistance alone would not have a strong enough overall effect on nutrition, unless it was combined with fertilization, water harvesting, and an improved credit program.
The study recommended the adoption of an inventory credit financial system rather than the existing sell-at-harvest method which would enable the farmer to store produce in order to take advantage of seasonal price changes.
Researchers calculated that a multi-solution approach, involving all of the aforementioned strategies, would increase farm household income by 31%. This approach would also eliminate under-nutrition completely - except in extreme drought years.
Increasing the Performance of Stem Rust Resistant Spring Wheat
Agronomic Performance of Elite Stem Rust Resistant Spring Wheat Genotypes and Association among Trial Sites in the Central and West Asia and North Africa Region. W. Tadesse and others. Published in Crop Science.
Wheat is the dominant crop in the Central and West Asia and North Africa region, covering an annual production area of about 52 million ha. However, its productivity in the region is very low due to stresses like drought, extreme temperatures, and pests. Perhaps most alarming is the new stem rust disease Ug99, which is able to overcome many of the genes that are known to resist it.
This study identified high yielding wheat cultivars for direct release by the National Agricultural Research Systems (NARS) and for parentage purposes for the wheat breeding program at ICARDA. It also determined criteria and identified key locations for wheat yield trials in the region.
An analysis was done to quantify the main contributors to variability in grain yield for 24 wheat genotypes in 15 environments. This analysis showed that wheat grain yield was significantly affected by environments, genotypes, and genotype × environment interaction: the environment controlled 90.1% of grain yields, environmental interaction 8.3%, and improved genotypes 1.6%.
According to ICARDA findings, two genotypes, Baasha-14 and Amir-2, with mean grain yield levels of 5168 and 5127 kg per ha, respectively, were identified as the best Ug99 resistant varieties with high yield potential across a wide range of environments.
Researchers recommend that these high yielding and Ug99 resistant genotypes be released as replacements for the susceptible varieties currently in use.
Improving land suitability assessments for rainwater harvesting
Soil-landscape modeling and land suitability evaluation: the case of rainwater harvesting in a dry rangeland environment. Anwar Al-Shamiri and Feras M. Ziadat. Published in International Journal of Applied Earth Observation and Geoinformation.
Rainwater harvesting is crucially important in dryland areas, where land and water resources are often scarce. The practice can improve productivity and help communities cope with climate change in dry, marginal environments.
Accurately determining suitable locations for rainwater harvesting is therefore crucially important for maintaining and strengthening the livelihoods of dryland farmers.
Land suitability assessments are key to the effective implementation of rainwater-harvesting schemes – yet arid areas suffer from a scarcity of detailed soil information and the preparation of this data can be costly and time consuming.
This research aims to overcome these constraints by examining the utility of soil-landscape modeling techniques, and their ability to provide soil and topographic information for improved land suitability assessments.
A test site in Northwest Jordan was evaluated for two types of rainwater harvesting interventions: contour ridges and runoff strips.
Two methods were used: the Soil-Landscape Prediction Method (SLPM), which uses terrain characteristics derived from a digital elevation model, and the Systematic Random Survey Method (SRSM), which estimates terrain characteristics between 108 random field observation points over a 500m2 grid.
Compared to field observations, both models demonstrated reasonable accuracy when detecting soil depth and rocky areas – landscape features that often determine land suitability for rainwater harvesting. However, the SLPM was more accurate, suggesting this approach is likely to generate more reliable suitability assessments. This method also produced a more realistic spatial distribution of landscape characteristics.
The results will help to generate reliable suitability maps that support the implementation of sustainable land use alternatives in arid environments.
Addressing constraints and developing options for sustainable rainwater harvesting
A participatory GIS approach for assessing land suitability for rainwater harvesting in an arid rangeland environment. Feras Ziadat and others. Published in Arid Land Research and Management.
Despite widespread land degradation across West Asia and North Africa, the adoption of rainwater harvesting – an effective means of improving soil moisture, vegetation cover, and productivity – has been slow.
Recent research conducted in Jordan improves the understanding of regional adoption constraints, and develops options for effective and sustainable rainwater harvesting interventions.
Using field surveys and participatory GIS approaches, the project established a methodology that can successfully match harvesting requirements with bio-physical conditions.
A range of biophysical parameters – slope, soil depth, soil texture, and stoniness – were applied to assess suitability.
Recommended rainwater harvesting interventions were subsequently introduced across 62.9 hectares, increasing water productivity and reversing degradation on 41 farms.
The results demonstrate that GIS approaches can be used to identify potential areas suitable for alternative land use interventions within a reasonable cost and time.
The approach is applicable to arid areas experiencing similar conditions where rainwater harvesting plays a crucial role in the sustainable management of land and water resources.
Utilizing the potential of phosphorous fertilizers
Significance of phosphorous for agriculture and the environment in the West Asia and North Africa region. Authors: John Ryan and others. Published in Advances in Agronomy.
Fertilizers are crucial inputs driving global food production – more than half of the world’s food output is attributed to fertilizer-applied nutrients.
While research has tended to focus on nitrogen – the primary nutrient driving agricultural production – there has been less attention paid to phosphorous fertilizers, which is no less important for crop yields and may have even greater environmental implications.
If used sustainably there is significant potential to boost productivity in parts of the world where phosphorous fertilizer application is currently low or absent. The West Asia and North Africa (WANA) region is one area where phosphorous is capable of raising yields and mitigating the impacts of increasing environmental degradation due to climate change.
Despite limited fertilizer application, WANA countries contain major deposits of exploitable phosphorous, and given the region’s predominantly calcareous soils, significant capacity to increase usage.
This research paper reviews current knowledge on phosphorous application in the WANA region. It presents the results of field trials conducted over the past three decades, highlighting fertilizer usage on the region’s main crops in relation to rainfall, cropping systems, soil test levels, and efforts to identify P-efficient genotypes and enhance soil phosphorous fertility with mycorrhizae.
Results demonstrate increasing usage across the region and provide a framework for future application efforts: establishing effective phosphorous accumulation rates, residual values of phosphorous reserves, appropriate fertilization rates, and soil phosphorous sufficiency limits.
Attempts to strengthen food security through the use of phosphorous fertilization will depend upon efforts to synthesize research findings across the region and strengthen weak or non-existent extension systems.
Identifying plant genotypes with specific traits
Focused identification of germplasm strategy (FIGS) detects wheat stem rust resistance linked to environmental variables. Authors: Abdullah Bari and others. Published online in Genetic Resources and Crop Evolution.
To develop new crop varieties, plant breeders require good raw material – genotypes with specific traits such as drought tolerance or resistance to a particular disease. Often, the problem is how to identify such genotypes from a genebank collection containing tens of thousands of potential candidates. A new tool known as FIGS (Focused Identification of Germplasm Strategy) has made this identification process faster and more accurate.
The science behind FIGS continues to develop. A new research paper describes the development of effective algorithms and techniques that use agro-climatic data to predict the likely levels of a particular stress – in this case, stem rust disease in wheat – in a given environment. This is an important first step in identifying rust-resistant genotypes because rust-endemic environments are likely to contain wheat genotypes that have co-evolved with rust pathogens, and possess resistance to the disease.
The authors of the paper experimented with different modeling techniques and statistical tools to quantify the relationship between target trait and agro-climate. Their results provide interesting insights into the distribution of stem rust resistance in wheat. Resistant genotypes are confined to certain environments or areas, and susceptible genotypes to other areas, with overlap.
This research will help select, from a huge genebank collection, a small, manageable subset that is likely to include resistant genotypes. The results will improve our understanding of how crop plants adapt to environmental conditions, enable more effective use of genebanks, and accelerate the flow of useful genes to plant breeders.
Partners in FIGS development include ICARDA, the Vavilov Research Institute in Russia, the Australian Winter Cereals Collection, the NordGen Genebank and the Grains Research and Development Corporation, Australia.
For more information contact Dr Abdullah Bari, e-mail a.bari@cgiar.org
Genomic tools for legumes research
Genomic resources for improving food legume crops. Authors: J. Kumar and others. Published online in the Journal of Agricultural Science, Cambridge.
Food legumes ― lentil, faba bean, chickpea, soybean and others ― are the main source of dietary protein for a large majority of the world’s population. However, legume breeding programs have been unable to match the spectacular yield gains achieved in rice, wheat and other cereal crops. The main reason: large genotype × environment (G×E) interactions that influence the expression of traits and limit the gains from traditional plant breeding methods. A broad-ranging literature review, published recently, looks at how genomics and modern biotechnology tools can help overcome these challenges.
Molecular markers allow geneticists to ‘dissect’ yield and other complex traits (those governed by multiple genes). Quantitative trait loci (QTL) analysis can help identify genotypes with more stable responses across environments (wide adaptation and/or high yield stability); or those that interact significantly with a particular kind of environment (e.g. high response to irrigation).
A number of genomic resources have been developed in several legume species during the last two decades: linkage maps, high-throughput sequencing technologies, expression sequence tag (EST) databases, genome sequences, DNA chips, targeting induced local lesions in genomes (TILLING), bacterial artificial chromosome (BAC) libraries and others. The paper summarizes what resources are available, how they are being used, and how their application might expand in the near future. It also discusses problems with some of the current genomics tools – for example difficulties of using certain kinds of molecular maps – and suggests alternative approaches.
A huge range of genomic resources are available in the public domain, but only a few are used routinely in legume breeding programs. Their use is expected to increase rapidly, with the availability of high-throughput and cost-effective genotyping platforms, combined with automation in phenotyping methodologies.
Partners in this study included ICARDA, the Indian Institute of Pulses Research, and Agriculture and Agri-food Canada.
Rolling out conservation agriculture for the dry areas
Conservation agriculture in dry areas. Edited by Rachid Serraj and Kadambot H.M. Siddique
Published in Field Crops Research Volume 132, 2012
A special edition of the journal Field Crops Research, examining in detail the subject of Conservation Agriculture (CA) in Dry Areas, has just been published on line and will be available in hard copy next month (June 2012) . It was edited by ICARDA’s Director of Diversification and Sustainable Intensification of Production Systems – Dr Rachid Serraj, alongside Professor Kadambot H.M. Siddique of The University of Western Australia.
“The positive impacts of CA can be harnessed through innovative systems research and development, to enhance agricultural systems productivity, profitability and sustainability for the future.”
This publication is very timely. The global area currently under CA is approaching 120 M ha, corresponding
to about 8.5% of arable cropped land, spread across all continents and agro-ecologies, including the dry Mediterranean type. Growing scientific and empirical evidence shows that significant productivity, economic, social and environmental benefits can be gained through the adoption of CA principles for sustainable production intensification in dry environments. Crop yield potential under CA management practices in rainfed systems is often greater than with conventional tillage (CT) systems; particularly in dry environments where sub-optimal rainfall often limits yield.
The editors say the objective of this special issue is to enrich the ongoing debate on the role of CA, especially in smallholder farming systems, by synthesizing the recent research findings of CA in dry areas, by analyzing agronomic, socio-economic, and agro-ecological determinants leading to its success or failure, and by identifying potential entry points for priorities for future research on CA in dry areas.
They conclude that the principles that underlie CA are well known and have been tested and validated in various regions around the world, but CA components for crop and agro-ecological resource management are complex and location-specific, including crop residue management, cultivar selection and crop choice for rotation, strategies for nutrient management, tactics for weed management, disease and pest management, and soil water management practices.
These components must be managed and fine-tuned for relevant cropping systems, so that the practices are compatible with the principles of CA and that ,most importantly, they meet the requirements of and are feasible as a practical solution for farmers. Future research and development should focus on better understanding the effects and interaction among all these systems components and to develop site-specific CA options, they say. The critical need for an active farmer participatory approach in the comprehensive assessment of ecological and socio-economic conditions in which CA could be adapted especially under smallholder farming systems is emphasized.
For more information contact Dr Rachid Serraj, email r.serraj@cgiar.org
Tracking down sources of stem rust resistance
Sources of resistance to stem rust (Ug99) in bread wheat and durum wheat identified using focused identification of germplasm strategy (FIGS). Authors: Dag Terje Filip Endresen,* Kenneth Street, Michael Mackay, Abdallah Bari, Ahmed Amri, Eddy De Pauw, Kumarse Nazari, and Amor Yahyaoui
Published in Crop Science 52(2):764-773. doi: 10.2135/cropsci2011.08.0427; Published online 8 Dec. 2011.
A computer modeling trial at ICARDA has validated the focused identification of germplasm strategy (FIGS) for use in predictive simulation studies, to predict and test against previously known trait scores.
The team involved is therefore recommending that the FIGS approach can be used as a complement to expert knowledge and experience when selecting accessions for plant breeding and crop research activities.
The study itself was designed as a “blind” procedure where the person calculating the computer model did not know the actual trait scores. This approach has provided a more realistic test of the predictive capacity of the FIGS approach compared to previous studies, says the team.
Interestingly, the location and year of the experiment in which the previously known evaluation data were obtained were seen to influence the predictive power of the models. Another factor requiring further consideration was the size and perhaps the ratio of resistant to susceptible expression of the training set. It was also noted that the FIGS approach requires the accessions to be geo-referenced before an association between the germplasm and the environment (in which it evolved and was subject to selection) can be established.
The study also explored the suitability of FIGS for the identification of resistance in bread wheat (Triticum aestivum L. subsp. aestivum) and durum wheat [Triticum turgidum L. subsp. durum (Desf.) Husn.] to Ug99—a strain of stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & Henn.) and typified to race TTKSK. The predictions were validated against a dataset with the screening of wheat accessions conducted in Yemen in 2008. Only a small training set representing 20% of the trait screening results was disclosed to the person conducting the data analysis for the calibration of the prediction model.
The hit rate for identification of Ug99-resistant accessions was more than twice as high when using the FIGS approach compared to a random selection of accessions. These results suggest that FIGS is well suited to the identification of samples with resistance to fungal pathogens and show that further research into refinement is justified.
For more information contact Dr Abdulla Barij, email A.Bari@cgiar.org
New understanding of Mediterranean dryland cropping systems
Assessment of long-term barley–legume rotations in a typical Mediterranean agro-ecosystem: grain and straw yields. Authors John Ryan, Murari Singh and Scott Christiansen
Published in Archives of Agronomy and Soil Science Volume 58, Issue 3, 2012
In recent years, land-use pressures across the dry land areas of WANA and elsewhere have led to a decrease in the use of fallowing and an increase in cereal monoculture. This is a risky move, with increased potential for disease build-up and crop failure leading to a real threat in food security. Given the well-recognized agronomic benefits of crop rotations, a revival of interest in legume-based rotations has begun.
Food or forage legumes in rotation with cereals are a sustainable, alternative sustainable cropping system. But how to prove their effectiveness as complex cropping systems can only be assessed by long-term trials?
ICARDA scientists set about this 11-year rain-fed, barley-based rotation trial in northern Syria to assess rotation effects on yields of barley and legumes, with particular emphasis on the management of vetch. The mean order of barley grain yields from the rotations was led by vetch for hay, vetch for grazing with continuous barley delivering the lowest. Straw yields followed a similar pattern. Nitrogen (60 kg/ha) increased grain (39%) and straw (65%) yields. The N fertilization of barley had no carryover effect on the alternative legume crops.
Although there were no significant differences in seed or straw yield between lentil and vetch, seasonal rainfall influenced overall yields. Total biomass yields descended in the order of vetch, medic and lentil.
There is then a compelling case for annual vetch paired with barley in rotations for the Mediterranean region, says the ICARDA team. They point out that barley/vetch rotations can potentially enhance barley yields and improve soil quality, as well as provide valuable fodder for small ruminants (sheep and goats) in the region’s traditional farming systems.
For more information contact Dr John Ryan, email J.Ryan@cgiar.org
New high-yielding winter wheat genotypes demonstrate resistance to stripe rust disease
Improved winter wheat genotypes for Central and West Asia. R. C. Sharma and others. Published in Euphytica.
A new study has found that high grain yields and resistance to stripe rust – a new aggressive strain of wheat rust disease – are the most important traits for the successful adoption of winter wheat varieties in Central and West Asia.
Stripe rust disease has decimated harvests in recent years – losses of 10-90 per cent have been recorded across Central and West Asia – threatening 40 per cent of the region’s food calorie intake and 20 per cent of its protein consumption.
Researchers determined the stripe rust response and agronomic performance of a set of breeding lines recently developed by the International Winter Wheat Improvement Program (IWWIP).
Field studies were conducted in 2010 and 2011 across several sites in Kazakhstan, Tajikistan, Uzbekistan, and Azerbaijan. In total, 38 experimental varieties, one regional variety, and one local variety were tested.
Although responses were varied during initial trials, several genotypes were not only resistant to stripe rust but generated yields that were higher or equal to local varieties.
Subsequent trials of these successful genotypes were extremely promising: five in particular were consistently resistant to stripe rust disease across all sites in both years, and several also demonstrated high grain yields and superior agronomic performance.
The findings indicate that new IWWIP varieties – available within the region – can help farmers tackle the threats posed by stripe rust disease.
Given the current limitations of research, extension, and seed production systems, however, directly placing these new varieties in the hands of farmers in a short time frame requires new ways of dissemination.
See earlier posts