International Crops Research Institute for the Semi-Arid Tropics
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Combatting drought: a multi-dimensional challenge
Get PDFWater will be a major limitation to food production in
the 21st century, and drought issues already prevail in
many parts of the world. Finding solutions to ensure that
farmers harvest profitable crops, and secure food supplies for families and feed for animals that will provide for
them through to the next season are urgent necessities.
The Interdrought community has been addressing this
issue for almost 30 years in a series of international conferences, characterized by a multi-disciplinary approach
across the domains of molecular biology, physiology, genetics, agronomy, breeding, environmental and social sciences, policy, and systems modeling. This special issue
presents papers from the 7th edition of the conference,
the first to be held in Africa, that paid special attention
to drought in a smallholder context, adding a ‘system’ dimension to the crop focus from the previous Interdrought
events (Varshney et al., 2018; Hammer et al., 2021)
Vision-Based Point Cloud Processing Framework for High Throughput Phenotyping
No full textHigh throughput phenotyping is an emerging field that aims to bring rapid, non-invasive sensing technology in agriculture to accelerate the estimation of plant traits significantly. This paper presents a computer vision-based automated 3D point cloud processing framework for accurate estimation of essential phenotypic traits. The framework relies on three steps involving sub-plot detection, extraction of the crop from each sub-plot, and estimating the required trait. Four essential phenotypic traits are estimated as a use case of the proposed framework, namely, plant height, leaf area index (LAI), leaf inclination, and plant count. The crop of interest is mung bean. The obtained estimates for plant height, leaf area index (LAI), and leaf inclination are statistically validated by comparing the results with ground truth data in terms of coefficient of determination, root mean squared error (RMSE), and correlation coefficient. These metrics are found to be, on average, 0.87, 0.05, and 0.93 respectively. The regression analysis has also been performed to gain analytical insights into the data. For plant count, deep learning based segmentation method have been explored and the best accuracy achieved is 86%
Urbanization and food security: evidence from Mali
Get PDFIncome poverty remains the main root of urban food insecurity as purchased food represents a major component of the spending of urban residents. The rapid and increasing urbanization and urban sprawl are major concerns for food security in Mali. In Mali, 3.6% of households, are severely food insecure and the food insecurity prevalence rate for urban households is 7.5%. The effect of urbanization on households’ food security was assessed in the literature using only a single measure of food security. In this regard, this study analyzed the effect of urbanization on both objective and subjective measures of food security in Mali, using data from the national survey on food security and nutrition (ENSAN). The data collection was conducted by the Early Warning System against Famine (SAP) on 9,782 households in February 2018. For the objective measure of food security, the study used an OLS model to estimate the effect of urbanization on household food expenditure per capita. Using the household hunger scale (HHS) score, the study estimated two models (logit and ordered probit) to capture the effect of urbanization on subjective measures of food security. The results of the OLS and logit models showed that households living in urban areas are less food secure compared to their counterparts living in rural areas. The results from the ordered probit also confirmed that urban households are more food insecure (mildly and moderately) compared to their counterparts living in rural areas. Based on these results, the study recommends to decision-makers to take into account urban poor households when setting up food safety net programmes
Codon Usage Provide Insights into the Adaptation of Rice Genes under Stress Condition
Get PDFPlants experience different stresses, i.e., abiotic, or biotic, and to combat them, plants re-program the expression of growth-, metabolism-, and resistance-related genes. These genes differ in their synonymous codon usage frequency and show codon usage bias. Here, we investigated the correlation among codon usage bias, gene expression, and underlying mechanisms in rice under abiotic and biotic stress conditions. The results indicated that genes with higher expression (up- or downregulated) levels had high GC content (≥60%), a low effective number of codon usage (≤40), and exhibited strong biases towards the codons with C/G at the third nucleotide position, irrespective of stress received. TTC, ATC, and CTC were the most preferred codons, while TAC, CAC, AAC, GAC, and TGC were moderately preferred under any stress (abiotic or biotic) condition. Additionally, downregulated genes are under mutational pressure (R2 ≥ 0.5) while upregulated genes are under natural selection pressure (R2 ≤ 0.5). Based on these results, we also identified the possible target codons that can be used to design an optimized set of genes with specific codons to develop climate-resilient varieties. Conclusively, under stress, rice has a bias towards codon usage which is correlated with GC content, gene expression level, and gene length
Production and genetic characterization of interspecific hybrids between pearl millet Pennisetum glaucum (L.) × Napier grass Pennisetum purpureum (K.)
Get PDFPearl millet grains are valued as human food while its dry stover makes important livestock ration in crop–livestock farming system. Interspecific hybrids between cultivars of pearl millet Pennisetum glaucum (L.) with 2n = 2x = 14 and its wild relative Napier Grass Pennisetum purpureum (K.) Schum with 2n = 4x = 28, which have multicut behaviour, perennial nature, high biomass and drought tolerance traits for crop improvement, were obtained by cross hybridization. Several hybrid progenies were obtained and then examined based on the morphological traits at RVC, BAU, Ranchi. The F1 seed of each combination was harvested at maturity and the F1 seed was planted on raised nursery bed to remove the bajra like plants. The row to row and plant to plant spacing was 60 cm. All the recommended cultural practices were followed to raise the healthy crop. Thin napier lines were procured from PAU, Ludhiana. Several yield and yield and yield attributing traits were recorded The highest no. of slips were obtained by LN 3 (24) followed by LN 1 (20). In bajra, 10 forage A lines (male sterile lines) and 18 forage pollinators (OPVs) (recurrent lines) were procured from ICRISAT, Hyderabad. The characters recorded were days to 50% flowering, plant height, no. of tillers/plant, spike length and green fodder yield (q/ha). In case of male sterile line, the highest green fodder yield (q/ha) was recorded by ICMA 00444A4 (545 q/ha) followed by ICMA 07999A5 (430 q/ha) while in case of Forage pollinators (OPVs), the highest green fodder yield (q/ha) was recorded by ICMV 05222 (684 q/ha) followed by ICMV 1710 (623 q/ha). Different Hybrids were developed from crossing of Bajra x Bajra and Bajra x Napier on two different dates of sowing. The interspecific hybrids between Bajra x Napier in first date of sowing (16.8.20) were BxN1 (384 q/ha) BxN2 (379 q/ha) and BxN3 (456 q/ha). The Number of crosses developed between Bajra x Bajra on two different dates of sowing i.e. 16.8.20 and 30.8.20. Several crosses were developed. Out of them, B2xB23 (656 q/ha) recorded highest yield followed by B2xB25 (546 q/ha). In the second date of sowing B6xB12 (634 q/ha) recorded highest yield followed by B2xB23 (578 q/ha)
Improving fertilizer response of crop yield through liming and targeting to landscape positions in tropical agricultural soils
Get PDFNutrient management research was conducted across locations to investigate the influence of landscape position (hill, mid-, and foot slope) in teff (Eragrostis tef) and wheat (Triticum aestivum) yield response to fertilizer application and liming in the 2018 and 2019 cropping seasons. The treatments included 1) NPS fertilizer as a control treatment (42 N + 10P + 4.2S kg ha−1 for teff and 65 N + 20P + 8.5S kg ha−1 for wheat); 2) NPS and potassium (73 N + 17P + 7.2S + 24 K kg ha−1 for teff and 103 N + 30P + 12.7S + 24 K kg ha−1 for wheat) and 3) NPSK and zinc (73 N + 17P + 7.2S + 24K + 5.3Zn kg ha−1 for teff and 103 N + 30P + 12.7S + 24K + 5,3Zn kg ha−1 for wheat) in acid soils with and without liming. Results showed that the highest teff and wheat grain yields of 1512 and 4252 kg ha−1 were obtained at the foot slope position, with the respective yield increments of 71% and 57% over the hillslope position. Yield response to fertilizer application significantly decreased with increasing slope owing to the decrease in soil organic carbon and soil water content and the increase in soil acidity. The application of lime with NPSK and NPSKZn fertilizer increased teff and wheat yields by 43–54% and 32–35%, respectively compared to the application of NPS fertilizer without liming where yield increments were associated with the application of N and P nutrients. Orthogonal contrasts revealed that landscape position, fertilizer application, and their interaction effects were significant on teff and wheat yields. Soil properties including soil pH, organic carbon, total N, and soil water content were increased down the slope, which might be attributed to sedimentation down the slope. However, available P is yet very low both in acidic and non-acidic soils. We conclude that crop response to applied nutrients could be enhanced by targeting nutrient management practices to agricultural landscape features and addressing other yield-limiting factors such as soil acidity and nutrient availability by conducting further research
Scenarios of sustainable fodder production in the conflict-affected Kerio Valley of Kenya
No full textCommunities that keep livestock depend on forages. Understanding the potential futures of livestock forages in regions affected by climate change and resource conflict is critical for climate security and peace. However, often there is limited data on future fodder developments and their drivers. This article presents the results of a scenario development process to identify livestock forage options against conflict scenarios in the Kerio Valley in Kenya. The Valley is of interest because of ongoing communal conflicts, whereby one of the triggers is disputes over pasture during drought emergencies. Given the absence of data, we underwent a participatory scenario development process to co-design fodder futures with representatives of warring communities, market players, the local administration and researchers from Egerton University who worked in the region to mitigate drought risks in the area. Through this process, the representatives developed six strategic fodder scenarios and examined them against four likely stability contexts. The findings from the scenario workshops identify strategies to support the most promising scenarios. Kerio Valley actors could adopt those fodder scenarios that mitigate the risk of resource conflicts, especially in preparation for reoccurring droughts emergencies. Finally, our research suggests that where conflict parties jointly search for fodder solutions, scenario planning could contribute to peace-building
Genome-wide association analysis for emergence of deeply sown rice (Oryza sativa) reveals novel aus-specific phytohormone candidate genes for adaptation to dry-direct seeding in the field
Get PDFDry direct-seeded rice (dry-DSR) is typically sown deeply to circumvent the need for irrigation, and thus seedling emergence is a crucial trait affecting plant stand and yield. To breed elite cultivars that use less water and are climate-resilient, an understanding of the genomic regions and underlying genes that confer emergence in deeply sown dry-DSR would be highly advantageous. A combined diversity panel of 470 rice accessions (RDP1 plus aus subset of 3K RGP) was evaluated with 2.9 million single nucleotide polymorphisms (SNPs) to identify associations with dry-DSR traits in the field and component traits in a controlled-environment experiment. Using genome-wide association study (GWAS) analyses, we identified 18 unique QTLs on chromosomes 1, 2, 4, 5, 6, 7, 9, 10, and 11, explaining phenotypic variance ranging from 2.6% to 17.8%. Three QTLs, namely, qSOE-1.1, qEMERG-AUS-1.2, and qEMERG-AUS-7.1, were co-located with previously reported QTLs for mesocotyl length. Among the identified QTLs, half were associated with the emergence of aus, and six were unique to the aus genetic group. Based on functional annotation, we identified eleven compelling candidate genes that primarily regulate phytohormone pathways such as cytokinin, auxin, gibberellic acid, and jasmonic acid. Prior studies indicated that these phytohormones play a critical role in mesocotyl length under deep sowing. This study provides new insight into the importance of aus and indica as desirable genetic resources to mine favorable alleles for deep-sowing tolerance in rice. The candidate genes and marker-tagged desirable alleles identified in this study should benefit rice breeding programs directly
Consortium of Management Practices in Long‑Run Improves Soil Fertility and Carbon Sequestration in Drylands of Semi‑Arid Tropics
No full textA continuously declining carbon in soils of drylands has increasingly become a source of concern and needs integrated solutions to achieve global food security and sustainability goals. This study analysed the impact and sustainability of management practices for climate change mitigation and food security in dryland tropics using long-term field trials. We compared a consortium of interventions, comprised four treatments, viz. traditional farming, improved practice, and regenerative treatments. Additionally, we presented the results of regeneration practices aimed at maintaining the soil macro and micro-aggregates. Results showed significantly higher soil organic carbon (SOC) in the topsoil layer (0–15 cm) of regeneration areas compared
to the precision farming area. Our long-term experiments with a consortium of interventions resulted in a promising increase in soil carbon and crop yields. We selected shared socioeconomic pathways for scenarios in future climates and simulated the effect of improved practices in the near and distant future. Our simulation results revealed that adopting improved practices enhanced soil carbon at the rate of 0.7% per year and provided additional income from the yield of pulses in the 2-year rotation. Similarly, we observed an increasing trend in SOC building for improved practices in all future climate scenarios. However, the traditional practice showed a clear decline (0.20–0.15%) in SOC stock for all shared-socio-economic pathways
CRISPR/Cas9-Mediated Mutation in XSP10 and SlSAMT Genes Impart Genetic Tolerance to Fusarium Wilt Disease of Tomato (Solanum lycopersicum L.)
Get PDFFusarium wilt is a major devastating fungal disease of tomato (Solanum lycopersicum L.) caused by Fusarium oxysporum f. sp. lycopersici (Fol) which reduces the yield and production. Xylem sap protein 10 (XSP10) and Salicylic acid methyl transferase (SlSAMT) are two putative negative
regulatory genes associated with Fusarium wilt of tomato. Fusarium wilt tolerance in tomato can be developed by targeting these susceptible (S) genes. Due to its efficiency, high target specificity, and versatility, CRISPR/Cas9 has emerged as one of the most promising techniques for knocking out disease susceptibility genes in a variety of model and agricultural plants to increase tolerance/resistance to various plant diseases in recent years. Though alternative methods, like RNAi, have been attempted to knock down these two S genes in order to confer resistance in tomato against Fusarium wilt, there has
been no report of employing the CRISPR/Cas9 system for this specific intent. In this study, we provide a comprehensive downstream analysis of the two S genes via CRISPR/Cas9-mediated editing of single (XSP10 and SlSAMT individually) and dual-gene (XSP10 and SlSAMT simultaneously). Prior to directly advancing on to the generation of stable lines, the editing efficacy of the sgRNA-Cas9 complex was first
validated using single cell (protoplast) transformation. In the transient leaf disc assay, the dual-gene editing showed strong phenotypic tolerance to Fusarium wilt disease with INDEL mutations than single-gene editing. In stable genetic transformation of tomato at the GE1 generation, dual-gene CRISPR transformants of XSP10 and SlSAMT primarily exhibited INDEL mutations than single-gene-edited lines. The dual-gene CRISPR-edited lines (CRELs) of XSP10 and SlSAMT at GE1 generation conferred a strong phenotypic tolerance to Fusarium wilt disease compared to single-gene-edited lines. Taken together, the reverse genetic studies in transient and stable lines of tomato revealed that, XSP10 and SlSAMT function together as negative regulators in conferring genetic tolerance to Fusariumwilt disease