International Crops Research Institute for the Semi-Arid Tropics
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Understanding the Relationship between Water Availability and Biosilica Accumulation in Selected C4 Crop Leaves: An Experimental Approach
Get PDFBiosilica accumulation in plant tissues is related to the transpiration stream, which in turn depends on water availability. Nevertheless, the debate on whether genetically and environmentally controlled mechanisms of biosilica deposition are directly connected to water availability is still open. We aim at clarifying the system which leads to the deposition of biosilica in Sorghum bicolor, Pennisetum glaucum, and Eleusine coracana, expanding our understanding of the physiological role of silicon in crops well-adapted to arid environments, and simultaneously advancing the research in archaeological and paleoenvironmental studies. We cultivated ten traditional landraces for each crop in lysimeters, simulating irrigated and rain-fed scenarios in arid contexts. The percentage of biosilica accumulated in leaves indicates that both well-watered millet species deposited more biosilica than the water-stressed ones. By contrast, sorghum accumulated more biosilica with respect to the other two species, and biosilica accumulation was independent of the water regime. The water treatment alone did not explain either the variability of the assemblage or the differences in the biosilica accumulation. Hence, we hypothesize that genetics influence the variability substantially. These results demonstrate that biosilica accumulation differs among and withi
A New Formulation for Strigolactone Suicidal Germination Agents, towards Successful Striga Management
No full textStriga hermonthica, a member of the Orobanchaceae family, is an obligate root parasite of staple cereal crops, which poses a tremendous threat to food security, contributing to malnutrition and poverty in many African countries. Depleting Striga seed reservoirs from infested soils is one of the crucial approaches to minimize subterranean damage to crops. The dependency of Striga germination on the host-released strigolactones (SLs) has prompted the development of the “Suicidal Germination” strategy to reduce the accumulated seed bank of Striga. The success of aforementioned strategy depends not only on the activity of the applied SL analogs, but also requires suitable application protocol with simple, efficient, and handy formulation for rain-fed African agriculture. Here, we developed a new formulation “Emulsifiable Concentration (EC)” for the two previously field-assessed SL analogs Methyl phenlactonoate 3 (MP3) and Nijmegen-1. The new EC formulation was evaluated for biological activities under lab, greenhouse, mini-field, and field conditions in comparison to the previously used Atlas G-1086 formulation. The EC formulation of SL analogs showed better activities on Striga germination with lower EC50 and high stability under Lab conditions. Moreover, EC formulated SL analogs at 1.0 µM concentrations reduced 89–99% Striga emergence in greenhouse. The two EC formulated SL analogs showed also a considerable reduction in Striga emergence in mini-field and field experiments. In conclusion, we have successfully developed a desired formulation for applying SL analogs as suicidal agents for large-scale field application. The encouraging results presented in this study pave the way for integrating the suicidal germination approach in sustainable Striga management strategies for African agriculture
An APSIM-powered framework for post-rainy sorghum-system design in India
Get PDFSorghum contributes to the livelihoods of millions of food-insecure households in semi-arid agri-systems. Annual production widely fluctuates throughout India due to erratic rainfall and suboptimal agronomic practices. Our novel approach utilizes the digital reflection of post-rainy (rabi) sorghum production systems in India to help better understand its spatio-temporal variations and enable the designing of geography-specific, climate-responsive system interventions (Genotype × Management; GxM). For this, we evaluated a range of farmer-relevant agronomic management practices across three soil types (shallow, medium, and deep vertisols) in combination with observed ranges of biological variability in sorghum cultivar characteristics. We used the crop growth simulation model Agricultural Production Systems sIMulator (APSIM) to identify GxM combinations that can support the enhancement/ stability of post-rainy sorghum production systems in India. In general, we found the post-rainy sorghum systems would benefit from early-season sowing (16th - 23rd September), short crop duration (compared to Maldandi (M35–1), commonly grown crop type), and medium fertilizer inputs (70–70 kg urea ha−1 as basal and top-dress application). In addition, site-specific crop management (M) and crop characters (G) optimizations would further enhance/ stabilize sorghum production. Simulations highlighted that in the poorly-endowed environmental context (i.e. shallow soils and low-rainfall areas), optimal G×M targets might involve water conservation GxM combinations, such as low plant populations and low fertilization along with low crop vigor and limited transpiration responsiveness. Details on site-specific optimum GxM are available in a web application at https://ls40.pef.czu.cz/maps/. To enable the use of the study outputs for certain applications (e.g. breeding), we separated the examined geographies based on similarities in optimum production characteristics and similarities in system response to GxM interventions into four “homogeneous system units” (HSU; i.e. geographical units within which reduced GxM interactions are expected). These HSUs intended to offer geography-specific targets to prioritize, test, and introduce distinct G×M interventions. We conclude that the APSIM-powered framework presented provides region-specific Genotype × Management options that could become a blueprint for defining quantitative breeding targets that achieve enhanced productivity/ stability of dry-season sorghum cultivation throughout India
The African Eggplant
No full textThe African eggplant (Solanum aethiopicum L.) is a promising nutritious African vegetable that is also grown in South and Central America and certain parts of Italy and France. There are four known cultivar groups of the African eggplant, which together with its progenitor, Solanum anguivi, form the hypervariable scarlet eggplant complex. Despite its
importance as food, medicine, and source of disease resistance genes, there has been limited research investment in the improvement of the African eggplant and it remains an
orphan crop. We review the botanical description of the cultivar groups, the available genetic and genomic resources, and the germplasm conservation efforts within the
primary and secondary genepools. We present the recently published draft genome sequence and make detailed comparisons of the genome with other genomes within the Solanaceae family. We further demonstrate the immediate
utilization of the draft genome for gene discovery by retrieving orthologous seed dormancy candidate genes that can be characterized to improve this trait in the African
eggplant. We finally provide evidence of why the African eggplant is underutilized and make some recommendations for future breeding, research investment, and marketing
efforts that promise to enhance its utilization
GWAS identifies genetic loci underlying nitrogen responsiveness in the climate resilient C4 model Setaria italica (L.)
Get PDFIntroduction: N responsiveness is the capacity to perceive and induce morpho-physiological adaptation to external and internal Nitrogen (N). Crop productivity is propelled by N fertilizer and requires the breeding/selection of cultivars with intrinsically high N responsiveness. This trait has many advantages in being more meaningful in commercial/environmental context, facilitating in-season N management and not being inversely correlated with N availability over processes regulating NUE. Current lack of
its understanding at the physio-genetic basis is an impediment to select for cultivars with a predictably
high N response. Objectives: To dissect physio-genetic basis of N responsiveness in 142 diverse population of foxtail millet, Setaria italica (L.) by employing contrasting N fertilizer nutrition regimes
Micronutrient-sensitive food value chains: A systematic review of intervention strategies and impact pathways to nutritional outcomes
Get PDFKnowledge and evidence on how food value chains can deliver nutrition, especially micronutrients, are limited. A deeper understanding of the food value chains as part of agri-food systems approaches addressing hunger and malnutrition through agricultural development may provide pathways for
nutrition and health outcomes.. This systematic review was undertaken using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) to assess the broad topic of value chains and micronutrients, focusing on interventions and their related impact pathways. Impact
pathway interventions improving micronutrient delivery and consumption were classified as production, accessibility, marketing, income, knowledge and behavioral, and finally, women’s empowerment pathways. However, the case study evidence on the micronutrient-sensitive value chains for nutritional outcomes is very scant. This review identified that making value chains micronutrient-sensitive requires a multi-stakeholder, integrated approach as a basis for concerted action among various stakeholders in terms of policy, research, strengthening partnerships and coordination, and information sharing. The review illustrates the scarcity of literature with a focus
on the micronutrients in the context of food value chains and developing countries. The food value chain approach offers great potential to unpack the complexity of food systems and identify entry points and pathways for improving nutrition outcomes, especially the micronutrients. Additionally, this review identifies multiple entry points and calls for strong advocacy of nutrition-sensitive value
chain approaches to combat hidden hunger
Phytoliths as indicators of plant water availability: The case of millets cultivation in the Indus Valley civilization
Get PDFThe interpretation of crop water management practices has been central to the archeological debate on agricultural
strategies and is crucial where the type of water strategy can provide fundamental explanations for the adoption and use of specific crops. Traces of water administration are difficult to detect and are mostly indirect, in the form of water harvesting or distribution structures. Attempts have been made to infer plant water availability directly fromarchaeobotanical remains. Current evidence suggests that the ratio of sensitive to fixed phytolith morphotypes can be used as a proxy for water availability in C₃ crops, as well as in sorghum and maize. Nevertheless, the controversy on whether genetically and environmentally controlled mechanisms of biosilica deposition are directly connected towater availability in C₄ crops is open, and several species remain to be tested for their phytolith production in relation to water levels. This research aims at clarifying whether leaf phytolith assemblages and concentration, silica skeleton size and ratio of sensitive to fixed morphotypes can be related to different water regimes in Eleusine coracana Gaertn., Pennisetum glaucum (L.) R. Br., and Sorghum bicolor (L.) Moench.We cultivated 5 traditional landraces for each species in lysimeters, under differentwatering conditions and analyzed their phytolith content/production in leaves. Results show higher proportions of long cells, bulliforms and stomata produced inwell watered conditions. The model built on the basis of phytolith composition has been then applied to interpret archeological phytolith assemblages recovered froma single phase at four different sites of the Indus Civilisation: Harappa, Kanmer, Shikarpur and Alamgirpur. The results show thatmost probably C4 crops grew under water stress conditions, providing new data on the interpretation of ancient agricultural management in the Indus Valley
Generation mean analysis of Striga hermonthica resistance in pearl millet (Pennisetum glaucum [L.] R. Br.)
No full textStriga hermonthica [Del.] Benth. (Sh) is a noxious parasitic weed causing substantial yield loss in sub-Saharan Africa’s pearl millet. The objective of this study was to determine the gene action and inheritance of Sh resistance in newly developed pearl millet populations to guide selection and genetic advancement. Bi-parental crosses were derived from pairs of pearl millet lines by contrasting reactions to Striga infestations. The two sets of parental lines, F1s, F2s, and backcrosses, were evaluated using a randomized complete block design with three replications. Data on the number of Striga counted at 60 and 80 days after planting were collected. The analysis of the variance showed significant (P < 0.001) differences among the generations across sets for Sh parameters. Duplicate gene action controlled the inheritance of the number of emerged Sh. Unique F2 individuals with Sh resistance were selected from
the two sets for genetic advancement through recurrent selection methods for pearl millet variety development by integrating desirable agronomic and farmer-preferred traits
Research and development for sorghum and millets in Sub-Saharan Africa: What have we learned?
No full textThe past two decades of R & D for sorghum and millets in SSA have generated a wealth of new evidence. A synthesis of this evidence identified six strategic lessons. These were that demand is not being driven by ‘new uses’, that plant breeding programmes need to respond to African farmer's contexts and objectives to increase impact, that availability is a bigger constraint on the supply of certified seed than physical or economic access, that higher adoption of improved varieties does not generally result in higher yields, that technology and varietal diversity can compensate for climate change, and that commercialisation can be gender – and socially inclusive. R & D in Africa differs from the Indian model because of the low level of commercialisation and the continued dominance of own consumption. Consequently R & D gives a dominant role to the public sector in plant breeding, to farmer organisations and groups in seed supply, and to prioritising household food security over commercial uses
BSA‑seq and genetic mapping identified candidate genes for branching habit in peanut
No full textLateral branch angel (LBA) is an important plant architecture trait of peanut, which plays key role in lodging, peg soil penetration and pod yield. However, there are few reports of fine mapping and quantitative trait loci (QTLs)/cloned genes for LBA in peanut. In this project, a mapping population was constructed using a spreading variety Tifrunner and the erect variety Fuhuasheng. Through bulked segregant analysis sequencing (BSA-seq), a major gene related to LBA, named as AhLBA1, was preliminarily mapped at the region of Chr.15: 150-160 Mb. Then, using traditional QTL approach, AhLBA1 was narrowed to a 1.12 cM region, corresponding to a 136.65-kb physical interval of the reference genome. Of the nine genes housed in this region, three of them were involved in hormone metabolism and regulation, including one “F-box protein” and two “2-oxoglutarate (2OG) and Fe(II)-dependent oxygenase (2OG oxygenase)” encoding genes. In addition, we found that the level of some classes of cytokinin (CK), auxin and ethylene showed significant differences between spreading and erect peanuts at the junction of main stem and lateral branch. These findings will aid further elucidation of the genetic mechanism of LBA in peanut and facilitating marker-assisted selection (MAS) in the future breeding program