International Crops Research Institute for the Semi-Arid Tropics
ICRISAT Open Access RepositoryNot a member yet
12134 research outputs found
Sort by
Laboratory protocol for induction of sporulation in Phytophthora cajani causing phytophthora blight in pigeonpea
No full textBackground
Phytophthora blight (PB), caused by Phytophthora cajani is a prominent disease in the low laying areas combined with intermittent rainfall. Induction of zoospores and sporangia of P. cajani in culture plate is troublesome and also limited information is available on the protocol for sporulation of sporangia and zoospores in the laboratory, The study developed and validated the protocol for induction of sporangia and zoospore of P. cajani.
Methods
The Protocol using 5–7 days old culture, diluted tomato extract broth and other culture conditions like the temperature of 30°C, alternate 12 hours of fluorescent light (2000 Lx) and dark can induce abundant sporangia and zoospores in vitro.
Result
The study developed and validated the new protocol for uniform and profuse induction of sporangia and zoospores of P. cajani. Diplanetism mechanism of Phytophthora spp. was recorded with P. cajani the findings are the first of its kind. Additionally, the study revealed the concentration of 1×10−5 zoospores/ml is optimum to develop the infection in plants with the shortest incubation period of 24 hours
Invasiveness, biology, ecology, and management of the fall armyworm, Spodoptera frugiperda
Get PDFThe fall armyworm (FAW), Spodoptera frugiperda (JE Smith, 1797), is a serious pest of several crops, particularly
maize and other cereals. It has long been known as a pest in the Americas and has invaded most of Africa and parts
of the Middle East, Asia, and Australia in the last six years. Its new status as an invasive species causing serious damage in many regions worldwide has highlighted the need for better understanding and has generated much research. In this article, we provide a comprehensive review of FAW covering its (i) taxonomy, biology, ecology, genomics, and microbiome, (ii) worldwide status and geographic spread, (iii) potential for geographic expansion and quarantine measures in place, and (iv) management including monitoring, sampling, forecasting, biological control, biopesticides, agroecological strategies, chemical control, insecticide resistance, effects of insecticides on natural enemies, as well as conventional and transgenic resistant cultivars. We conclude with recommendations for research to enhance the sustainable management of FAW in invaded region
Genetic, Phenotypic, and Pathogenic Variation Among Athelia rolfsii, the Causal Agent of Peanut Stem Rot in China
No full textPeanut stem rot caused by Athelia rolfsii is a serious soilborne disease worldwide and is becoming increasingly important in China. A total of 293 A. rolfsii isolates were collected from four representative peanut producing provinces in northern, central, and southern China. These isolates were assigned to 45 mycelial compatibility groups (MCGs) through pairing testing. The MCG diversity among isolates was greater in the southern sampled provinces compared with the northern provinces. A high level of genetic variability was found among the isolates from Guangdong Province in southern China. Variations were found in mycelial growth rate and sclerotial number, size, and dry weight of isolates sampled from places in different latitudes. Size and dry weight of sclerotia were positively correlated with latitude (P < 0.01), but the number of sclerotia was negatively correlated with latitude (P < 0.01). All tester isolates were pathogenic on peanut but varied in disease index. Inter-simple sequence repeat analysis and unweighted pair-group method with arithmetic average clustering resulted in three distinct clusters that were associated with the geographical location of the collection sites and sclerotial traits but were not associated with virulence of these isolates. These findings imply that genetic diversity, morphological traits, and virulence among A. rolfsii isolates varied in diverse geographical regions in China, and genetic diversity and sclerotial traits might be affected by latitude
Identifying Suitable Watersheds across Nigeria Using Biophysical Parameters and Machine Learning Algorithms for Agri–Planning
Get PDFIdentifying suitable watersheds is a prerequisite to operationalizing planning interventions for agricultural development. With the help of geospatial tools, this paper identified suitable watersheds across Nigeria using biophysical parameters to aid agricultural planning. Our study included various critical thematic layers such as precipitation, temperature, slope, land-use/land-cover
(LULC), soil texture, soil depth, and length of growing period, prepared and modeled on the Google Earth Engine (GEE) platform. Using expert knowledge, scores were assigned to these thematic layers, and a priority map was prepared based on the combined weighted average score. We also validated priority watersheds. For this, the study area was classified into three priority zones ranging from ‘high’ to ‘low’. Of the 277 watersheds identified, 57 fell in the high priority category, implying that they are highly favorable for interventions. This would be useful for regional-scale water resource planning for agricultural landscape development
Assessment of Cropland Changes Due to New Canals in Vientiane Prefecture of Laos using Earth Observation Data
Get PDFThe lower catchment area of a Mak Hiao river system is vulnerable to flash floods and water stress. So it is
important to construct irrigation structures in this area to minimize floods during the rainy season and store
water for the winter season. The Asian Development Bank (ADB) has been supporting the Government of Laos in
constructing such small reservoirs like Donkhuay schemes 1 & 2, Mak Hiao, Nalong 3 and Sang Houabor projects
in lower catchment areas. Our study evaluated the impacts of small irrigation schemes in terms of land-use/landcover
(LULC), crop intensity, and productivity changes, using high resolution satellite imagery, socioeconomic,
and ground data. We analyzed the temporal cropping pattern in the Vientiane prefecture of Laos using Planet and
Sentinel-2 data. On the other hand, crop intensity and cropland changes were mapped using Sentinel-2 data and
spectral matching techniques (SMTs). The crop classification accuracy based on field-plot data was 88.6%. Our
results show that irrigation projects in the lower catchment areas brought about significant on-site changes in
terms of cropland expansion and increased crop intensity. Remarkable changes in LULC were observed especially
in the command areas owing to an increase of about 300% in crop area with access to irrigation and increase of
water bodies by 31%. Our study found that interventions at the level of the command area do improved on-site
soil, water and environmental services. They study emphasized underline the role of land-use regulations in
reducing pressure on natural land-use systems and thereby serving the major goal of up-scaling sustainable
natural resource management. The study documented the vital role of small/medium irrigation projects in
restoring ecosystem services such as cropping patterns and LULC conversio
Three-Way Top-Cross Hybrids to Enhance Production of Forage with Improved Quality in Pearl Millet (Pennisetum glaucum (L.) R. Br.)
Get PDFThree-way top-cross hybrids of pearl millet were evaluated along with a popular single- cross check hybrid (PAC 981) for forage yield and quality traits under a multi-cut (three cuts) system across multiple years, seasons and sites in India. Total green forage yield (TGFY) varied from 36 to 53 t ha−1, and two hybrids outyielded the check hybrid for both total dry forage yield (TDFY) and forage quality (CP; Crude protein, and IVOMD; In vitro organic matter digestibility) traits. A set of promising three-way top-cross hybrids evaluated along with a set of promising open-pollinated varieties (OPVs) and top-cross hybrids for forage-related traits over two years under a multi-cut system revealed that the mean TDFY of three-way top-cross hybrids was higher than the mean TDFY of top-cross hybrids, followed by OPVs. Also, three-way top-cross hybrids had higher/or at par forage quality traits such as CP and IVOMD in comparison to other types of cultivars. TDFY had no correlation with CP and IVOMD across cuts in three-way top-cross hybrids, indicating that forage quantity and quality traits can be improved independently of each other. Overall, three-way top-cross hybrids were found to be a better pearl millet cultivar option than other types of cultivars
Identification of Candidate Genes Regulating Drought Tolerance in Pearl Millet
Get PDFPearl millet is an important crop of the arid and semi-arid ecologies to sustain food and fodder production. The greater tolerance to drought stress attracts us to examine its cellular and molecular mechanisms via functional genomics approaches to augment the grain yield. Here, we studied the drought response of 48 inbreds representing four different maturity groups at the flow-ering stage. A set of 74 drought-responsive genes were separated into five major phylogenic groups belonging to eight functional groups, namely ABA signaling, hormone signaling, ion and osmotic homeostasis, TF-mediated regulation, molecular adaptation, signal transduction, physiological ad-aptation, detoxification, which were comprehensively studied. Among the conserved motifs of the drought-responsive genes, the protein kinases and MYB domain proteins were the most conserved ones. Comparative in-silico analysis of the drought genes across millet crops showed foxtail millet had most orthologs with pearl millet. Of 698 haplotypes identified across millet crops, MyC2 and Myb4 had maximum haplotypes. The protein–protein interaction network identified ABI2, P5CS, CDPK, DREB, MYB, and CYP707A3 as major hub genes. The expression assay showed the presence of common as well as unique drought-responsive genes across maturity groups. Drought tolerant genotypes in respective maturity groups were identified from the expression pattern of genes. Among several gene families, ABA signaling, TFs, and signaling proteins were the prospective con-tributors to drought tolerance across maturity groups. The functionally validated genes could be used as promising candidates in backcross breeding, genomic selection, and gene-editing schemes in pearl millet and other millet crops to increase the yield in drought-prone arid and semi-arid ecol-ogies
Two decades of association mapping: Insights on disease resistance in major crops
Get PDFClimate change across the globe has an impact on the occurrence, prevalence, and severity of plant diseases. About 30% of yield losses in major crops are due to plant diseases; emerging diseases are likely to worsen the sustainable production in the coming years. Plant diseases have led to increased hunger and mass migration of human populations in the past, thus a serious threat to global food security. Equipping the modern varieties/hybrids with enhanced genetic resistance is the most economic, sustainable and environmentally friendly solution. Plant geneticists have done tremendous work in identifying stable resistance in primary genepools and many times other than primary genepools to breed resistant varieties in different major crops. Over the last two decades, the availability of crop and pathogen genomes due to advances in next generation sequencing technologies improved our understanding of trait genetics using different approaches. Genome-wide association studies have been effectively used to identify candidate genes and map loci associated with different diseases in crop plants. In this review, we highlight successful examples for the discovery of resistance genes to many important diseases. In addition, major developments in association studies, statistical models and bioinformatic tools that improve the power, resolution and the efficiency of identifying marker-trait associations. Overall this review provides comprehensive insights into the two decades of advances in GWAS studies and discusses the challenges and opportunities this research area provides for breeding resistant varieties
Bulb Yield Stability Study of Onion Lines over Locations and Seasons in Ghana and Mali
Get PDFOnion is one of the most economically and nutritionally important vegetable crops in West Africa. Onions are very important for consumers due to the antioxidants and compounds they contain that may reduce inflammation, lower triglycerides and reduce cholesterol levels, resulting in lower risks of heart disease and blood clots. However, high-yielding varieties that are accessible to farmers remain scarce. The objective of the present study was to identify adapted onion genotypes for sustainable production in Northern Ghana and Southern Mali. Nine onion lines, including a check variety, were assessed for yield stability using a randomized complete block design. The trials were carried out in “technology parks” under the joint management of farmers and researchers. Onion bulb weight was recorded for each plot after harvest. Separate analyses of variances were performed for each location and season. Analysis of variance of combined locations, seasons and lines was performed to determine the most stable varieties using the line-superiority measure and ecovalence stability coefficients. Results indicated that the lines AVON1310 and AVON1325 were most stable for yield performance over locations and seasons (Wi = 2.20 and 11.60, respectively; Pi = 1.32 and 6.56, respectively). From the genotype main effects and genotype-by-environment interaction biplots, the best performing lines were AVON1310 (33.32 t.h−1), AVON1308 (28.81 t.h−1) and AVON1325 (31.68 t.h−1). The stability of these lines makes them potential candidates for commercial release in West Africa to contribute to sustainably intensifying onion production in the region
Step-wise selection for early canopy traits followed by stress tolerance indices as an approach for improving drought tolerance in groundnut (Arachis hypogaea L.)
Get PDFRationale:
Drought stress at the pod filling stage of groundnut is a major yield constraint in the semi-arid tropics of Africa and
Asia.
Methods:
A population of 600 MAGIC lines (MLs) (F8/9generation) is studied in Leasyscan, a high throughput phenotyping
platform (HTPP) that assessed canopy growth up to 45 days after planting (DAP), and under managed stress
environment that uses drip lines for application of uniform and measured quantity of water in well-watered (WW)
and water-stress (WS) plots. Intermittent drought was imposed from 60 DAP coinciding with pod-filling stage, and
time domain reflectometry (TDR) probes measured soil moisture.
Results:
During 2018-19, the Mean Score Index (MSI) of Productivity and Resilience indices selected 20 MLs (MSI=9-10)
at par with the checks, ICGV 02266 (MSI=9.4) and ICGV 03043 (MSI=9.2). About 50% of the MLs (320) recorded a
Leaf Area Index (LAI) of <0.30 from which 12 MLs recorded high MSI. From 122 MLs that recorded superior digital
biomass (11173 to 11297 m3) at 45 DAP than the drought tolerant check ICGV 02266 (10245 m3), eight MLs recorded
high MSI. Extreme water stress of 100 mm imposed at pod filling stage in 2021-22 resulted in a yield reduction of
>70% in 402 MLs, however, 29 MLs with <20% yield reduction were selected.
Conclusions & Perspectives:
Early generation selection using HTPP (LeasyScan) for early canopy traits followed by stress index-based selections
in managed stress environment is proposed for drought tolerance breeding in groundnut. The MAGIC population is
a valuable source for improving drought tolerance