International Crops Research Institute for the Semi-Arid Tropics
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Assessment of the spatial distribution and identification of potential risk areas for the sterility mosaic disease of pigeonpea (Cajanus cajan L. Huth) in Southern India
Get PDFSterility mosaic disease (SMD) is an emerging biotic risk to the cultivation of pigeonpea throughout the Indian subcontinent. The prevalence and distribution of SMD documented from diverse agro-climatic zones are still poorly known. In this investigation, we determined the spatial distribution of SMD covering major pigeonpea-growing states of Southern India namely, Karnataka, Telangana, Tamil Nadu, Maharashtra, and Andhra Pradesh by considering 2 years of exploratory survey data. Geospatial approaches were employed to determine the SMD incidence levels at unvisited locations using neighboring observations. The results indicated enormous variability in disease incidence ranging from 0 to 82.64% and 0 to 36.84%, respectively, in Kharif 2021–22 and 2022–23 in pigeonpea-growing states. Spatial autocorrelation analysis and Ripley’s K function established the presence of average clustering over sampling locations. Two main clusters were identified via agglomerative hierarchical cluster analysis. From the Local Moran’s I spatial autocorrelation (LISA) analysis, most of the districts were clustered together at (I25%) above the threshold level and must be closely monitored to restrict and minimize further disease spread across the studied areas in Southern India. In pigeonpea, this is the first study in India that attempted to understand the spatial pattern of SMD using geostatistical methodologies. The results of the study will aid in the design and dissemination of specific management practices and curb the further spread of SMD
Multi-environment testing for G×E interactions and identification of high-yielding, stable, medium-duration pigeonpea genotypes employing AMMI, GGE biplot, and YREM analyses
Get PDFPigeonpea [Cajanus cajan (L.) Millspaugh] is a widely grown pulse with high seed protein content that contributes to food and nutritional security in the Indian subcontinent. The majority of pigeonpea varieties cultivated in India are of medium duration (<180 days to maturity), which makes it essential for breeders to focus on the development of stable high-yielding varieties. The diverse agroecological regime in the Indian subcontinent necessitates an efficient multi-environment study by taking into consideration genotype (G) × environment (E) interaction (GEI) that has a significant impact on traits like grain yield (GY) in developing high-yielding and widely adaptable varieties. In the present study, 37 pigeonpea genotypes were evaluated during the 2021 rainy season at ARS Badnapur, ARS Tandur, BAU Ranchi, GKVK Bengaluru, and ICRISAT Patancheru. The GEI was significant on the grain yield (p < 0.01), and hence, genotype + genotype × environment (GGE) and additive main effects and multiplicative interaction (AMMI) biplots along with AMMI stability value (ASV) and yield relative to environmental maximum (YREM) statistics were used to identify stable high-yielding genotypes. The interaction principal component analysis 1 and 2 (IPC1 and IPC2) explained 40.6% and 23.3% variations, respectively. Based on the rankings of genotypes, G37 (ICPL 20205), G35 (ICPL 20203), G8 (ICPL 19404), G17 (ICPL 19415), and G9 (ICPL 19405) were identified as ideal genotypes. Discriminativeness vs. representativeness identified GKVK Bengaluru as an ideal environment for comprehensive evaluation of test genotypes. However, ICPL 19405 was identified as the potentially stable high-yielding genotype for further testing and release across the test environments based on its mean grain yield (1,469.30 kg/ha), least ASV (3.82), and low yield stability index (YSI) of 13
Mapping and Monitoring Of Water Hyacinth In Lake Victoria Using Polarimetric Radar Data
Get PDFWater hyacinth, an invasive species originating from South America, has become a significant concern since its introduction in Lake Victoria (Kenya), particularly in the Winam Gulf, where large annual blooms are observed. Monitoring the occurrence and location using in situ methods is expensive and challenging due to the lake's vastness. Remote sensing monitoring methods offer an alternate option due to the ability to cover vast areas. This study explores the potential of polarimetric Synthetic Aperture Radar (PolSAR), specifically utilising Sentinel-1 VV-VH data to map and monitor water hyacinth cover. The change detection method based on Optimisation of Power Difference (OPDiff) and minimum eigenvalue selection achieves a remarkable accuracy of 98.89% in separating clear and water hyacinth-infested water. Using polarimetric data offered better separability, enabling spatial and temporal monitoring. The analysis reveals that in 2018 water hyacinth cover peaked, spanning over 200 km 2 . Temporal variability showcases a seasonal rise and peak from September to December. This research demonstrates the capability of using PolSAR data to accurately map and monitor water hyacinth's spatial and temporal dynamics, offering valuable insights for effective management strategies
Molecular Basis and Engineering Strategies for Transcription Factor-Mediated Reproductive-Stage Heat Tolerance in Crop Plants
Get PDFHeat stress (HS) is a major threat to crop productivity and is expected to be more frequent and severe due to climate change challenges. The predicted increase in global temperature requires us to understand the dimensions of HS experienced by plants, particularly during reproductive stages, as crop productivity is majorly dependent on the success of plant reproduction. The impact of HS on crop productivity is relatively less-studied than the other abiotic stresses, such as drought and salinity. Plants have evolved diverse mechanisms to perceive, transduce, respond, and adapt to HS at the molecular, biochemical, and physiological levels. Unraveling these complex mechanisms underlying plant HS response and tolerance would facilitate designing well-informed and effective strategies to engineer HS tolerance in crop plants. In this review, we concisely discuss the molecular impact of HS on plant reproductive processes and yield, with major emphasis on transcription factors. Moreover, we offer vital strategies (encompassing omics studies, genetic engineering and more prominently gene editing techniques) that can be used to engineer transcription factors for enhancing heat tolerance. Further, we highlight critical shortcomings and knowledge gaps in HS tolerance research that should guide future research investigations. Judicious studies and a combination of these strategies could speed up the much-needed development of HS-resilient crop cultivars
HOMEOBOX2, the paralog of SIX-ROWED SPIKE1/HOMEOBOX1, is dispensable for barley spikelet development
Get PDFThe HD-ZIP class I transcription factor Homeobox 1 (HvHOX1), also known as Vulgare Row-type Spike 1 (VRS1) or Six-rowed Spike 1, regulates lateral spikelet fertility in barley (Hordeum vulgare L.). It was shown that HvHOX1 has a high expression only in lateral spikelets, while its paralog HvHOX2 was found to be expressed in different plant organs. Yet, the mechanistic functions of HvHOX1 and HvHOX2 during spikelet development are still fragmentary. Here, we show that compared with HvHOX1, HvHOX2 is more highly conserved across different barley genotypes and Hordeum species, hinting at a possibly vital but still unclarified biological role. Using bimolecular fluorescence complementation, DNA-binding, and transactivation assays, we validate that HvHOX1 and HvHOX2 are bona fide transcriptional activators that may potentially heterodimerize. Accordingly, both genes exhibit similar spatiotemporal expression patterns during spike development and growth, albeit their mRNA levels differ quantitatively. We show that HvHOX1 delays the lateral spikelet meristem differentiation and affects fertility by aborting the reproductive organs. Interestingly, the ancestral relationship of the two genes inferred from their co-expressed gene networks suggested that HvHOX1 and HvHOX2 might play a similar role during barley spikelet development. However, CRISPR-derived mutants of HvHOX1 and HvHOX2 demonstrated the suppressive role of HvHOX1 on lateral spikelets, while the loss of HvHOX2 does not influence spikelet development. Collectively, our study shows that through the suppression of reproductive organs, lateral spikelet fertility is regulated by HvHOX1, whereas HvHOX2 is dispensable for spikelet development in barley
Genome‑wide screening and characterization of phospholipase A (PLA)‑like genes in sorghum (Sorghum bicolor L.)
Get PDFSorghum bicolor (L.) Moench is the fifth most cultivated crop worldwide, and it is used in many ways, but it has always gained less popularity due to the yield, pest, and environmental constraints. Improving genetic background and developing better varieties is crucial for better sorghum production in semi-arid tropical regions. This study focuses on the phospholipase A (PLA) family within sorghum, comprehensively characterising PLA genes and their expression across different tissues. The investigation identified 32 PLA genes in the sorghum genome, offering insights into their chromosomal localization, molecular weight, isoelectric point, and subcellular distribution through bioinformatics tools. PLA-like family genes are classified into three groups, namely patatin-related phospholipase A (pPLA), phospholipase A1 (PLA1), and phospholipase A2 (PLA2). In-silico chromosome localization studies revealed that these genes are unevenly distributed in the sorghum genome. Cis-motif analysis revealed the presence of several developmental, tissue and hormone-specific elements in the promoter regions of the PLA genes. Expression studies in different tissues such as leaf, root, seedling, mature seed, immature seed, anther, and pollen showed differential expression patterns. Taken together, genome-wide analysis studies of PLA genes provide a better understanding and critical role of this gene family considering the metabolic processes involved in plant growth, defence and stress response
Crop traits and production under drought
No full textDrought limits crop productivity and threatens global food security, with moderate drought stress — when crops grow at a reduced rate — commonly experienced. Increasing plant tolerance to moderate drought is a key target for adaptation and management, but efforts to understand and increase drought tolerance often focus on more extreme drought that causes complete crop failure and only consider crop genetics. In this Review, we discuss the influence of moderate drought on crop productivity and the role of physiological traits in drought tolerance and adaptation. Traits related to crop water use, water capture, water availability, transpiration efficiency and phenology impact drought adaptation, but their overall effect varies situationally. For example, early restrictions in transpiration, higher transpiration efficiency or altered tillering increase water availability during grain filling and can double yield in some drought scenarios. However, these same traits under less severe drought scenarios can also lead to yield penalties. To assess when and under what conditions traits will be beneficial, crop models are used to integrate the effects of genetics, the environment and management, estimating the expected yield responses under these combinations of scenarios and traits. More robust characterization of moderate drought tolerance and better integration between plant genetic information and modelling will enable the local selection of crop varieties suited to the expected drought scenarios
Complexity-aware principles for agri-food system interventions: Lessons from project encounters with complexity
Get PDFCONTEXT
Complexity has long been recognised as a key feature of agri-food systems. Yet, it remains largely theoretical or poorly addressed in practice, hampering the potential of international development projects to address agriculture and food-related challenges in the Global South.
OBJECTIVE
The paper identifies and examines six sources of complexity that can manifest in projects, namely: unpredictability; path dependencies; context-specific dynamics; power relations; multiple temporal and spatial scales. It then proposes and tests six agri-food system principles that could be drawn upon to more successfully navigate this complexity. The aim of the paper is to illustrate how these principles could help projects respond to the changing circumstances and unpredictable turns of agri-food systems contexts in a different way, which flexibly embraces complexity. This flexibility is essential in an age of uncertainty and transformation.
METHODS
Comparative case study analysis of six projects implemented by the CGIAR: aflatoxin control in groundnuts in Malawi (1), pigeonpea in Eastern and Southern Africa (2), sorghum beer in Kenya (3), sweet sorghum for biofuel in India (4), precooked beans in Uganda and Kenya (5), Smart Foods in India and Eastern Africa (6). The projects aimed to either increasing smallholder farmers' incomes or addressing food and nutrition security, or both. They were specifically selected as all they were affected by some of the sources of complexity, which hampered the projects to different extents. This makes the cases relevant for not only illustrating manifestations of complexity, but also help reflect on alternative strategies to tackle it.
RESULTS AND CONCLUSION
The analysis of the case studies reveals how complexity can frustrate objectives of development interventions under several aspects. It also serves to discuss how complexity can be more successfully navigated (within but also beyond the selected cases) by applying the set of proposed agri-food system principles. The principles are also presented as ways future interventions could avoid clinging to what is “known to work” and instead venture into more powerful pathways of change.
SIGNIFICANCE
The following complexity-aware principle are proposed: Welcome surprises and openly discuss trade-offs; Shun orthodoxies; Engage with context-specificity; Expose patterns of power; Embrace the lengthy nature of change; Understand the multi-scale (in terms of space and time) nature of agri-food systems contexts. These principles could be used by project designers and implementors to cope with the complexity and uncertainty that will inevitably be encountered in agri-food system interventions, and can no longer be ignored
Introgression of Δ1-pyrroline-5-carboxylate synthetase (PgP5CS) confers enhanced resistance to abiotic stresses in transgenic tobacco
Get PDFΔ1-pyrroline-5-carboxylate synthetase (P5CS) is one of the key regulatory enzymes involved in the proline biosynthetic pathway. Proline acts as an osmoprotectant, molecular chaperone, antioxidant, and regulator of redox homeostasis. The accumulation of proline during stress is believed to confer tolerance in plants. In this study, we cloned the complete CDS of the P5CS from pearl millet (Pennisetum glaucum (L.) R.Br. and transformed into tobacco. Three transgenic tobacco plants with single-copy insertion were analyzed for drought and heat stress tolerance. No difference was observed between transgenic and wild-type (WT) plants when both were grown in normal conditions. However, under heat and drought, transgenic plants have been found to have higher chlorophyll, relative water, and proline content, and lower malondialdehyde (MDA) levels than WT plants. The photosynthetic parameters (stomatal conductance, intracellular CO2 concentration, and transpiration rate) were also observed to be high in transgenic plants under abiotic stress conditions. qRT-PCR analysis revealed that the expression of the transgene in drought and heat conditions was 2–10 and 2–7.5 fold higher than in normal conditions, respectively. Surprisingly, only P5CS was increased under heat stress conditions, indicating the possibility of feedback inhibition. Our results demonstrate the positive role of PgP5CS in enhancing abiotic stress tolerance in tobacco, suggesting its possible use to increase abiotic stress-tolerance in crops for sustained yield under adverse climatic conditions
Identification of stable restorers and high-yielding hybrids using diverse sorghum male sterile cytoplasmic sources and established pollen parents under different water regimes
No full textSorghum hybrids demonstrated increased productivity and helped offset the decreasing cultivated areas, particularly in Asia. The diversity in cytoplasmic male sterility systems, stability of restorers and high yield of sorghum is an important factor for achieving food security and sustainability. In sorghum, hybrid production has been limited to A1 cytoplasmic source to date, primarily due to limited number of restorers on other cytoplasmic sources. This work aimed at filling this gap through diversifying and assessing the producibility and stability of cytoplasmic backgrounds across environments, evaluating the stability of restorers across cytoplasms and environments, and evaluating the performance of the hybrid F1 products under different water regimes across cropping seasons. The effects of genotypes and interactions between the genotypes and the tested environments were shown visually using GGE biplot, which also categorized the genotypes based on performance per se and stability. Analysis of variance revealed significant (PA1>A3 >A4. The A2 cytoplasm can therefore reliably offer seed producibility advantage to commercial seed producers. Furthermore, the which-won–where model for hybrid grain yield revealed specific adaptations of hybrid genotypes G143, G195 and G215 to first mega environment (E1 and E3), whereas G167, G110, and G112 were adapted to the second mega-environment (E2 and E4). With a GGE biplot goodness of fit of 70% the best possible yield- and stability-based ranking of hybrid genotypes was G143, G215, G189, G200, G69, G162, G119, G54, and G81. The newly uncovered hybrid products should therefore be considered for downstream testing stages and candidates for release and commercial cultivation. Clearly, this work resulted in novel findings particularly in terms of seed producibility, universal restorers across the 4 cytoplasms and environments, and superior and stable hybrid products, all of which are expected to add value to conventional and heterosis breeding in the process of sorghum cultivar development