International Crops Research Institute for the Semi-Arid Tropics
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Exploring Novel Sources of Resistance to Late Leaf Spot in Groundnut (Arachis hypogaea L.)
No full textPeanut (Arachis hypogaea L.), commonly known as groundnut, is a significant oilseed crop cultivated in over 100 countries worldwide. Late leaf spot (LLS) is a severe disease affecting groundnut, leading to yield losses of up to 50%. Development of resistant varieties is considered a preferred strategy to manage LLS due to its cost-effectiveness and reduced environmental damage compared to other control methods. To date, GPBD 4, derived from
Arachis cardenasii, is the sole source of resistance against LLS globally, serving as a basis for developing disease-resistant or tolerant varieties. However, encouragingly, other wild species have been identified with high resistance. Introgression lines, developed from synthetic crosses with these wild species (A. kempffmercadoi, A. hoehnei, A. duranensis, A. batizocoi and A. ipaensis) have shown a disease score of 2, outperforming GPBD 4. SNP-based allele mining of these introgression lines, using markers from GPBD 4 for LLS resistance (Chr13_142435734 (C/T), Chr13_144038674 (T/C), Chr13_143296024 (AG/A)) which
encode for the proteins receptor like protein 29 and Pentatricopeptide repeat-containing protein revealed the absence of those alleles, suggesting the presence of additional significant alleles for resistance from the wild species. Identifying the genes responsible for resistance present in these new sources is critical. A total of 705 introgression lines, developed through backcrossing
(ICGV91114 × ISATGR 121250, ICGV87846 × ISATGR 265-5A, ICGV87846 × ISATGR-278-18, TMV2 × ISATGR 121250) and advanced to BC2F10 and BC2F7, were screened for resistance, and the best-performing lines, superior to GPBD 4, were selected during rainy 2024. These best performing ILs will again phenotype during rainy 2025 for trait confirmation, followed by making these available to global research community
It is Better to Procure Food from the Field than the Market: Youth Perspectives and Engagement in Agri-Food Systems in Mali and Nigeria
Full text linkYouth engagement in agri-food systems (AFS) is crucial for sustainable food production, economic stability, and rural development. This study examines the perspectives of young people in the drylands of Mali and Nigeria regarding their participation in agriculture, focusing on aspirations, challenges, and opportunities within AFS. A key finding is the growing recognition among youth that investing in agriculture—through labor, inputs, and capacity building—ensures reliable food supplies and economic resilience, reducing dependence on market purchases. A study conducted across six regions in Mali and Nigeria explored these dynamics using a mixedmethods approach, incorporating surveys and interviews with 1,224 respondents, evenly split by gender. The findings reveal remarked opportunities and constraints influencing youth participation in agriculture. Notably, young women have greater access to credit and financial support (21.04%) compared to young men (9.70%), largely due to women-targeted financial schemes. While both genders benefit from AFS employment opportunities, female youth appear to have an advantage in financial inclusion. However, structural barriers remain significant, with
limited access or user rights to land, agricultural equipment, credit and low technological adoption being key challenges affecting youth participation. The study underscores the need for targeted policies and investments that support youth engagement in agriculture, promote
innovation, and strengthen local food systems. Addressing gender disparities and structural constraints through inclusive financial mechanisms, land access reforms, and technology-driven solutions can enhance youth participation and drive agricultural transformation in the study country and by extension to most parts of West and Central Africa (WCA). By building the capacities of youth – both female and male youth, enhancing their agency to make strategic choices and fostering an enabling environment, governments and development partners can harness the potential of young people to build resilient and sustainable food system
Agroecology and circular food systems: decoupling natural resource use from rural development in sub-Saharan Africa?
Full text linkThis paper proposes transitioning food systems in sub-Saharan Africa to circularity and greater diversity, using agroecology principles and shifting mental models of development from scale to scope. We argue that integrated dryland and irrigated agroecosystems can increase production efficiencies when aligned with local food demands and cultures. Synergies between food enterprises, their products, byproducts and waste will generate further enterprises and tighten resource cycles, closing nutrient, water and energy loops while reducing reliance on external inputs. This will generate more economic benefits per unit of land, labour and water, decoupling local economies from natural resource use and environmental impact
Non-targeted metabolomics reveals fatty acid and associated pathways driving resistance to whitefly and tomato leafminer in wild tomato accessions
Full text linkWild tomato species exhibit natural insect resistance, yet the specific secondary metabolites and underlying mechanisms governing the resistance remain unclear. Moreover, defense expression dynamically adapts to insect herbivory, causing significant metabolic changes and species-specific secondary metabolite accumulation. The present study aims to identify the resistance-related metabolites in wild tomato accessions that influence the defense mechanism against whitefly (Bemisia tabaci Asia II 7) and leafminer (Phthorimaea absoluta). In this study, LC-HRMS-based non-targeted metabolomics of resistant wild (Solanum cheesmaniae and Solanum galapagense) and susceptible cultivated (Solanum lycopersicum) accessions following 6- and 12-h post-infestation (hpi) by B. tabaci Asia II 7 and P. absoluta revealed distinct sets of resistance-related constitutive (RRC) and induced (RRI) metabolites. The key resistance-related metabolites were those involved in the fatty acid and associated biosynthesis pathways (e.g., triacontane, di-heptanoic acid, dodecanoic acid, undecanoic acid, N-hexadecanoic acid, pentacosane, monogalactosyldiacylglycerols, sphinganine, and 12-hydroxyjasmonic acid), which are recognized for their direct or indirect role in mediating plant defense against insects. Additionally, the differential accumulation of metabolites was evident through partial least squares-discriminant analysis (PLS-DA), highlighting differences in metabolite profiles between resistant and susceptible accessions at 6 and 12 hpi of B. tabaci and P. absoluta. Volcano plot analysis revealed a higher number of significantly upregulated metabolites in wild accessions following herbivory. Moreover, wild tomato accessions responded uniquely to B. tabaci and P. absoluta, highlighting species-specific metabolic responses of tomato accessions to the two feeding guilds. This study uncovered biochemical mechanisms governing resistance in wild tomato accessions, elucidated the influence of dual herbivory on the plant metabolome, and offered well-characterized parent materials and candidate metabolites for breeding insect-resistant varieties
Geospatial Analysis of Crop Residue Burn Areas and Their Dates for Emission Mitigation Strategies
Full text linkMitigating the environmental impact of agricultural practices, particularly intensive rice farming, is critical in the face of climate change. This study focuses on mapping rice residue burn areas and their dates while estimating the greenhouse gas (GHG) emissions associated with residue burning and rice cultivation. By using Sentinel-2 satellite imagery, machine learning algorithms, and ground truth data, we analyzed changes in rice cultivation patterns before and after the Kaleshwaram intervention. The Near-Infrared Region (NIR) band was instrumental in accurately identifying residue burn areas and pinpointing burn dates, enabling timely alerts for decision-makers to act. Detailed quantifications of CO2, CH4, and N2O emissions from crop residue burning, alongside methane emissions from rice cultivation, highlight the significant contribution of these practices to overall GHG emissions. Key findings reveal a significant 82.1% increase in rice cultivation area from 2018–2019 to 2022–2023, accompanied by a worrying rise in residue burning, with some regions experiencing up to a 276% increase in burn areas. This research not only reveals the dual challenges of residue burning and GHG emissions but also emphasizes the importance of integrating precise burn date monitoring with emission data. The findings provide a strong foundation for implementing sustainable crop residue management strategies and developing informed policies to mitigate the adverse environmental effects of rice farming
Effects of phosphorus availabilities on growth and yield of foxtail millet: insights from high-throughput phenotyping platforms
Full text linkFoxtail millet, renowned for its high nutrient content and drought resilience, faces limited breeding investment despite being cultivated in vulnerable agri-systems. Low phosphorus (P) levels affect approximately 50% of global agricultural soils, and particularly impact regions like Sub-Saharan Africa and Southeast Asia, the latter where foxtail millet is extensively grown. This study explores the effects of low P (< 5 ppm; Hedley Fractionation Method; Cross and Schlesinger 1995) on foxtail millet plant growth and yield-related traits, utilizing high-throughput platforms (HTP) with a selected subset of genotypes (n = 10) from the core collection of ICRISAT Genebank. Results uncover substantial variation in plant growth and agronomical traits at both treatment and genotype levels. Under low-P conditions, genotypic variation is noted, with a sixfold difference in tiller count, 2.4-fold in grain yield, 2.7-fold in 3D-leaf area, and 2.3-fold in root surface area. A significant relationship was found between grain yield under low-P and high-P conditions (R2 = 0.65; P < 0.01). This suggests that genetic yield potential (vigor) under high-P conditions strongly influences grain yield and tiller numbers under low-P conditions. Residual grain yield under low-P conditions, not explained by high-P conditions, had a strong positive association with tiller numbers (R2 = 0.70; P < 0.01) and showed a significant negative association with total P concentration (R2 = 0.54; P < 0.05). Conversely, under high-P conditions, grain yield (GY_LF) from Lysi-Field exhibited significant positive correlations with P use efficiency (PUE) (r = 0.94; P < 0.001) and total biomass (r = 0.84; P < 0.01). These findings underscore the critical role of P availability in influencing grain yield and related traits. Under low-P conditions, performance is primarily driven by growth potential, with tiller number serving as a reliable marker of this potential. The significant genotypic variation observed highlights the importance of selecting for growth-related traits in P-limited environments. In addition, P dilution, rather than total P concentration, appears to play a key role in determining yield under low P. Optimizing P management strategies and breeding for improved growth potential may significantly enhance crop performance in regions facing P limitation
Genomic dissection of terminal heat tolerance in synthetic hexaploid derived nested introgression libraries of wheat (Triticum aestivum L.)
Full text linkThe terminal heat stress during grain filling period is major threat to wheat productivity. Heat tolerant QTLs were harnessed from synthetic hexaploid lines (SHWs) derived from heat tolerant Ae. tauschii accessions in present study. SHWs were crossed with two heat susceptible advanced breeding lines to develop nested introgression libraries (S-NILibs). The S-NILibs were evaluated for phenotypic traits and heat tolerance index (HTI) over three years under optimum environment (OE) with sowing at normal date in mid-November and heat stressed environment (HSE) under sown late during mid-December. The panel of 354 S-NILibs was genotyped using the 35 K Axiom® Wheat Breeder’s Array. Genome-wide association study (GWAS) identified a total of 61 marker-trait associations (MTAs) across environments (OE and HSE), associated with different traits using multiple models. Of these, two MTAs AX_94985380 for plant height (PH), spikelet number (SN) and AX_94469933 for plant height (PH), thousand grain weight (TGW) were observed for more than one trait across environments and models. Another MTA for HTI (AX-94461626) mapped on 4B chromosome was observed in all four environments and three models. This MTA originated from genes for Ubiquitin carboxyl-terminal hydrolases which is known for maintenance of the circadian clock at high temperature. A subset of MTAs was validated using KASP markers suggested strong association with traits of PH, SN, flag leaf length (FL) and number of productive tillers (pTN). The S-NILib generated, and QTLs identified in this study are potential pre-breeding resource for heat stress tolerance
Dynamics of cytosolic and organellar gene transcripts in wild and cultivated genotypes of pigeon pea due to simulated herbivory
No full textPigeon pea (Cajanus cajan), widely grown in India, suffers significant yield losses due to pod borers (Helicoverpa armigera and Maruca vitrata). Therefore, studying the host resistance mechanism is pivotal for crop improvement. In this study, we conducted transcriptome analysis on two wild-type (WT) Cajanus scarabaeoides accessions (ICP-15761 and ICP-15738) having high levels of resistance to pod borers and two cultivated C. cajan genotypes, ICPL-332 (moderately resistant) and ICPL-87 (susceptible), following simulated herbivory with H. armigera oral secretions (OS). Differential gene expression analysis identified 3573 and 4677 differentially expressed genes (DEGs) in ICP-15761 and ICP-15738, whereas 4149 and 3639 DEGs were documented in ICPL-332 and ICPL-87, respectively. Genes related to chloroplast biogenesis, photosynthesis, and chlorophyll metabolism exhibited significant differential expression, indicating chloroplast reprogramming under simulated herbivory. Significant upregulation of key defense genes, including chitinases and cysteine proteases, in C. scarabaeoides accessions highlighted robust defense pathway activation. A genotype-specific shift in transcription factors, phytohormones, and calcium signaling-related gene expression was noted. Higher levels of expression of aspartic proteinases and pathogenesis-related proteins in cultivated genotypes suggesting adaptive evolutionary traits. This is a novel insight on molecular mechanism of defense in a wild type, C. scarabaeoides and cultivated genotypes of pigeon pea under simulated herbivory. The information on cytosolic and organellar gene changes in pigeon pea due to H. armigera OS mediated-simulated herbivory may help develop pigeon pea varieties that are resistant to pod borer infestations
Rapid Ragi: A speed breeding protocol for finger millet
Full text linkBackground
Climate change is gradually increasing demand for resilient, nutritious crops like finger millet or ragi. Ensuring food security requires researchers to develop improved and adapted cultivars rapidly. Modern techniques such as genomics-assisted breeding have emerged in the previous decade and combined with rapid generation advancement they will offer a step change in the speed of cultivar development.
Results
In this study, we developed a repeatable and cost-effective speed breeding protocol for finger millet by modulating the agronomic and physiological components for early generation advancement. A photoperiod of 9-hours, 29 ± 2℃ temperature, 70% relative humidity, 105 plants per 1.5 sq. ft., 0.17% Hoagland’s No. 2 solution spray, restricted irrigation and harvesting at physiological maturity successfully reduced 28–54 days across the maturity groups of finger millet. The advantage was validated in segregating populations confirming up to 4–5 generations a year, instead of 1–2 under field conditions.
Conclusion
The speed breeding protocol developed reduces the breeding cycle time significantly allowing increased genetic gain. The protocol provides the advantage of rapid development of recombinant inbred lines (RILs), high-throughput phenotyping for biotic and abiotic stresses, and genotyping for early generation selections
Incorporating knowledge of allelopathic interactions can improve productivity and sustainability of crop rotations in the semi-arid tropics
Full text linkAllelopathy in rainfed crop production systems can be a boon or bane for smallholder farmers depending on their crop choices in intercrops, sequences, and rotations. Crop and weed allelopathy can lead to serious problems like poor germination, low crop stand, and reduced crop growth and productivity. Residual toxicity in soil due to allelopathic monocultures and detrimental impacts on ecosystems, human habitats and health are other problems caused by allelopathy. Allelopathy can be exploited to control weeds, reduce herbicide use, avoid herbicide resistance, stimulate crop growth, and enhance nutrient availability.
This review aims to provide practical knowledge that can improve the management of farming systems in the semi-arid tropics of the Indian subcontinent, a region prone to allelopathic effects induced by biotic and abiotic stresses. We focus on synergistic and antagonistic allelopathic effects of major cereals, legumes, oilseeds, commercial crops, and weeds and summarise the current knowledge on the mode of release and properties of allelochemicals in crops, residue management and their impacts on crops and weeds. We then list options to effectively suppress weeds, reduce risks of residual toxicity in soil and environmental hazards and outline synergistic crop rotations that reduce disease build up and eradicate parasitic weeds in rainfed production systems of the semi-arid tropics. Finally, we highlight research gaps to further improve and employ knowledge of allelopathy of weeds and crops for improved crop production, with reduced synthetic herbicide usage