Resistant Germplasm Research Articles

Evaluation of Onion Germplasm for Resistance to Leaf Blight Caused by Stemphylium vesicarium

Leaf blight of onion caused by Stemphylium vesicarium is the most destructive fungal disease worldwide, which leads to decrease quality and seed production of onion. This study was conducted to evaluate the resistance degree of 110 onion germplasm against S. vesicarium. To investigate resistance to leaf blight, the genetic resources of onion were tested by following method. Onion seedlings at four-leaf stage were rubbed with nonabsorbent cotton and inoculated with spore suspension (1.0×105 spores/ml of potato dextrose broth) of S. vesicarium by spray method. Five to 7 days after inoculation, infected leaf area (%) of onion seedling was measured. Our results showed that IT274921, IT304144, IT274929, and IT274930 lines exhibited the highest resistance against S. vesicarium. And IT330615 and IT288913 lines was identified as moderately resistant to leaf blight, whereas IT299972, IT327434, IT337262, and IT337275 lines were the most susceptible cultivars to the fungus. On the basis of the results, we suggest that the resistant genetic resources can be used a basic material for resistant onion breeding system against leaf blight.

Phenotypic and genotypic insights into rice germplasm resistance against a biotype of the brown planthopper Nilaparvata lugens (stal)

This study explores the resistance of rice landraces, genotypes, and wild rice to the South Asian brown planthopper (BPH) population, a significant pest affecting rice crops. Phenotypic screening identified a few landraces, genotypes, and wild rice varieties with resistance to the South Asian biotype, including, PTB-33, Oryza officinalis, O. nivara, Adukkan, Vellai Kombi Samba and Onamuttan which exhibited damage scores ? 3 Moderate resistance was observed in IR 36, ARC 10550, T12, Manvilayan, Rathu Heenati, CR 2711, Mysore Malli, Swarnalata, Pokkali, Babawee, and ASD 7, while other varieties demonstrated varying levels of susceptibility. Molecular analysis using SSR markers revealed the presence of BPH resistance genes across these genotypes. Notably, Onamuttan and Vellai kombi samba exhibited a broad resistance gene profile, while Adukkan, Manvilayan possess two BPH-resistant genes. Conversely, ASD 7 and Rathu Heenati, despite possessing several resistance gene markers, displayed moderate resistance. This study underscores the potential of integrating resistant genotypes into breeding programs, employing SSR markers for precise gene mapping and marker-assisted selection. The combined phenotypic and genotypic data provide valuable insights for advancing rice breeding strategies for sustainable BPH management and improved pest resistance.

Comparative Review of Fusarium graminearum Infection in Maize and Wheat: Similarities in Resistance Mechanisms and Future Directions.

Fusarium graminearum is one of the most important plant-pathogenic fungi that causes disease on wheat and maize, as it decreases yield in both crops and produces mycotoxins that pose a risk to human and animal health. Resistance to Fusarium head blight (FHB) in wheat is well studied and documented. However, resistance to Gibberella ear rot (GER) in maize is less understood, despite several similarities with FHB. In this review, we synthesize existing literature on the colonization strategies, toxin accumulation, genetic architecture and potential mechanisms of resistance to GER in maize and compare it to what is known regarding FHB in wheat. There are several similarities in the infection and colonization strategies of F. graminearum in maize and wheat. We describe multiple types of GER resistance in maize and identify distinct genetic regions for each resistance type. We discuss the potential of phenylpropanoids for biochemical resistance to F. graminearum. Phenylpropanoids are well characterized, and there are many similarities in their functional roles for resistance between wheat and maize. These insights can be utilized to improve maize germplasm for GER resistance and are also useful for FHB resistance breeding and management.

Thwarting the Blight: A Comprehensive Review of Traditional and Molecular Germplasm Screening Techniques for Black Spot Resistance in Roses

Diplocarpon rosae causing rose black spot disease, is one of the most devastating pathogens, that affect the quality of roses, and is responsible for huge yield losses, worldwide. Many approaches have been applied to control this disease including developing resistance variety. However, this review widely evaluates different screening germplasm methods to control the black-spot disease in rose. Additionally, in this review, many major issues influencing the black-spot disease resistance, including environmental factors, plant-pathogen interaction and genetic diversity, providing a complete thoughtful of the multifaceted nature of this disease. Moreover, the variety of screening technique ranging from conventional field assessment to contemporary molecular approaches, emphasizing their respective benefits and restrictions. But, the finding and employing new resistance genes is very difficult due to highly genetic diversity of this pathogen, especially, when their interaction of this pathogen to plant are not completely understood. Because, various isolates and strains of pathogen can relate in diverse ways with different germplasm, making it challenging to identify uniform resistance among all strains. Furthermore, many environmental factors including light, temperature and humidity support to increase the disease development, leading reduce the resistance and tolerance of plant against pathogen. Whereas, developing resistance germplasm might be helpful to control this disease and reduce pathogen infection in plants. In this regard, many plant-omics studies such as transcriptome, genome re-sequencing and proteomics have been widely studied to find out candidate resistance (R) protein and genes, which related to the black-spot disease. This review seeks to provide researchers as well as growers and breeders with a through recourse that combine recent information on the assessment of rose germplasm against black spot disease resistance. By employing newly approaches, we aimed to accelerate the growth of rose varieties, that are beautifully attractive and strong in the appearance on this determined blight. In the last, our collective finding to addresses the issues could be increase the sustainability and visual attractiveness of rose cultivation for future generations.

Transcriptome Analysis Reveals the Molecular Mechanisms of Carrot Adaptation to Alternaria Leaf Blight.

Carrot (Daucus carota L.) is an important vegetable crop that is rich in carotenoids and is widely cultivated throughout the world. Alternaria leaf blight (ALB), caused by infection with Alternaria dauci (A. dauci), is the most serious fungal disease in carrot production. Although several quantitative trait loci associated with ALB resistance have been identified, the genetic mechanisms underlying this resistance remain largely unelucidated. The aim of the present study was to clarify the infection mode of A. dauci and examine the molecular mechanisms underlying carrot cultivar adaptation to ALB by RNA sequencing. Microscopic observation revealed that A. dauci invades leaf tissues by entering through stomata, and resistant germplasms may significantly inhibit the infection and colonization of A. dauci. In addition, transcriptomic analyses were performed to detect the key pathways and genes associated with the differential responses between ALB-resistant (HB55) and ALB-susceptible (14088) carrot cultivars. These results suggest that the secondary metabolic process, phenylpropanoid biosynthesis, and tyrosine metabolism might play important roles in the resistance of carrots to A. dauci. Three candidate genes (LOC108208301, LOC108215577, and LOC108224339) that were specifically upregulated in the resistant carrot cultivar 'HB55' after A. dauci infection were identified as the key resistance response genes. These findings provide insights into the resistance mechanism of carrots to ALB, as well as key candidate genes and information on expression regulation for the molecular breeding of carrot disease resistance.

Identification of resistance sources and genomic regions regulating Septoria tritici blotch resistance in South Asian bread wheat germplasm.

The Septoria tritici blotch (STB) [Zymoseptoria tritici (Desm.)] of wheat (Triticum aestivum L.) is characterized by its polycyclic and hemibiotrophic nature. It is one of the most dangerous diseases affecting wheat production worldwide. Durable resistance is largely decided by the combined effect of several quantitative trait loci (QTLs) having a minor effect. Currently, STB is not important in South Asia. However, STB expanding and wider adaptability, changing climatic conditions, and agronomic practices can create a situation of concern. Therefore, dissection of the genetic architecture of adult-plant resistance with genome-wide association mapping and selection of resistant sources for adult plant STB resistance were carried out on a panel of South Asian germplasm. We discovered the 91 quantitative trait nucleotides (QTNs) associated with STB resistance; 23 QTNs were repetitive across the different years and models. Many of these QTNs could differentiate the mapping panel into resistant versus susceptible groups and were linked to candidate genes related to disease resistance functions within linkage disequilibrium blocks. The repetitive QTNs, namely, Q.CIM.stb.2DL.2, Q.CIM.stb_dh.2DL.3, Q.CIM.stb.2AL.5, and Q.CIM.stb.7BL.1, may be novel due to the absence of co-localization of previously reported QTLs, meta-quantitative trait loci, and STB genes. There was a perfect negative correlation between the stacking of favorable alleles and STB susceptibility, and STB resistance response was improved by ∼50% with the stacking of ≥60% favorable alleles. The genotypes, namely, CIM20, CIM56, CIM57, CIM18, CIM44, WK2395, and K1317, could be used as resistant sources in wheat breeding programs. Therefore, this study could aid in designing the breeding programs for STB resistance before the onset of the alarming situation of STB in South Asia.

Axant™ Flex cotton response to topramezone applied early- or mid-postemergence

Abstract The continued development of herbicide-resistant weeds, such as Palmer amaranth, represents a growing concern across the United States Cotton Belt. To mitigate this issue, BASF Corporation developed Axant™ Flex cotton, the first quadruple-stacked herbicide resistance germplasm to improve the control of troublesome weed species in cotton. Field studies were conducted in 2022 and 2023 at the Texas Tech University Research Farm near New Deal, TX, to evaluate the response of Axant Flex cotton to topramezone applied alone or in combinations when applied to 3-leaf cotton (early-postemergence (EPOST)) or to 7-leaf cotton (mid-postemergence (MPOST)). No difference in cotton stand was observed between isoxaflutole or prometryn PRE treatments compared to the nontreated control. In 2022, no EPOST treatment caused greater than 6% crop response at 7 and 14 d after application (DAA). When treatments were made to 7-leaf cotton, crop response did not exceed 18% at 7 and 14 DAA. In 2023, crop response was ≤ 2% at 28 DAA regardless of application timing. No differences in lint yield were observed following any herbicide treatment when compared to the nontreated control in either year. Additionally, fiber length and strength were not adversely affected by treatments containing topramezone EPOST or MPOST in 2022 and 2023. These results support the potential use of topramezone in Axant Flex cotton to help manage troublesome weeds without detrimental effects on yield and fiber quality.

Development of rapid, efficient and cost effective screening technique for testing arecanut against Phytophthora meadii incitant of fruit rot disease

To accelerate identification of disease resistant arecanut germplasm or hybrids against Phytophthora, it is very much imperative to develop bioassays which could differentiate resistant and susceptible cultivars efficiently. Here, a cost effective and rapid technique, called the “Detached Leaf Assay”, was developed to identify resistant germplasm at the seedling stage itself. Zoospore production in highly virulent Phytophthora meadii (P19) was standardized by incubating under a 12 hours light and dark regime. Zoospore suspension was adjusted to 105 spores ml-1 in Petri plates. Subsequently, surface sterilized arecanut leaves were floated in zoospore suspension and incubated at temperature of 24±1 °C. Disease symptoms, including water-soaked lesions, were recorded three days after inoculation. Infection lesion increased from 1 to 7.3 cm2. The pathogen was re-isolated and confirmed with the original culture. The assay was successfully validated to screen arecanut accessions, wild types and hybrids against P. meadii. This technique is the first to be developed, and it is simple, cost-effective, and faster. It also provides consistent infection and could be effectively utilized to screen arecanut germplasm or hybrids against P. meadii in the seedling stage itself.•Developed a cost effective, efficient and rapid screening technique•The technique was validated to identify resistant arecanut genotypes against Phytophthora meadii at the seedling stage.

Northwestern Himalayan common beans: A treasure trove for breeding resistant bean cultivars for multiple foliar pathogens

Common bean (Phaseolus vulgaris. L) is attacked by a lot of important foliar diseases like anthracnose, bean common mosaic virus, angular leaf spot, bean golden yellow mosaic virus, and common bacterial blight. In the present study, we exploited anthracnose resistant germplasm of 122 common bean genotypes for the identification of broad spectrum and durable resistance for multiple foliar diseases. We utilized linked molecular markers and found some promising genotypes with 11 resistance genes. These genotypes possess significant potential as parental lines for gene pyramiding strategies, to enhance disease resistance in common beans. We also highlighted the need for new generation markers over SCAR markers to streamline genotypic screening and expedite the breeding of disease-resistant common bean varieties. Our phenotypic studies identified a few bean landraces highly resistant to the new BCMV NL-1n strain. Consequently, the genome wide association study also confirms the presence of already identified resistance genes. Additionally, our study reconfirms the presence of the recently identified bc-urgene in our material. The bean landraces of northern India contain novel regions associated with BCMV resistance on Pv03, Pv05, Pv04, Pv06, Pv07, Pv09, and Pv11. This study provides the list of bean genotypes that can be used to breed resistant cultivars and may also contain new resistance genes to a most important viral disease of common beans.

Exploring the hemp virome and assessing hemp germplasm for resistance to an emerging pathogen

Hemp (Cannabis sativa L., <0.3% tetrahydrocannabidiol, THC) as a crop has been widely adopted throughout the United States. However, there is little support or guidance on disease identification and management for growers. This study aimed to describe the diversity and distribution of viruses infecting hemp in Colorado and determine if there is genetic resistance to pathogens in hemp. Throughout 2021 and 2022, leaf tissues from symptomatic and asymptomatic plants were sampled during three phenological stages (early vegetative, late vegetative, and mature flowering) in four regions of Colorado. High Throughput Sequencing (HTS) revealed a total of seven viruses across both years from 48 pooled samples: alfalfa mosaic virus, beet curly top virus (BCTV), cannabis cryptic virus, cannabis sativa mitovirus 1, grapevine line pattern virus, opuntia umbra-like virus, and tomato bushy stunt virus. These viruses had >97% nucleotide identity to their nearest GenBank accessions. As the growing season progressed, viral incidence and the number of viral species increased. We observed similar and unique viromes between individual cultivars from the same field. Given the prevalence of BCTV in the virome and its prevalence across the western United States, 13 genotypes of hemp were screened for resistance to this pathogen. Two genotypes (4587 and 4710) had a lower BCTV copy number and disease index than others. Our study provides initial evidence of the diversity of viral communities in hemp across Colorado and provides impetus for developing accurate detection methods and screening for host resistance.

Progress in the resistance mechanism and breeding of Camellia oleifera with resistance to anthracnose

Camellia oleifera is an important woody oil crop in China, and its seed oil has a high economic value. Anthracnose, one of the main diseases in C. oleifera, occurs in a wide range in the production areas, limiting the growth and development of plants and causing serious losses of oil production. With the rapid development of the C. oleifera industry in recent years, great progress has been achieved in the research on anthracnose in C. oleifera. This paper summarized the resistance mechanisms, the mining of resistance genes, and the evaluation of resistant germplasm resources, aiming to provide a theoretical basis for the prevention and control of anthracnose and the breeding of C. oleifera germplasm with resistance to anthracnose.

Introgression and Mapping of Cotton Leaf Curl Disease (CLCuD) Resistance from Wild Gossypium armourianum Kearney into Upland Cotton (G. hirsutum L.).

Cotton leaf curl disease (CLCuD), caused by the whitefly transmitted geminivirus complex (Cotton leaf curl virus - CLCuV and their satellite molecules), is a serious threat to successful upland cotton production in northwest India, Pakistan, and China. The disease causes significant losses in fibre yield and the quality of cotton. Owing to the regular emergence of resistance breaking strains of CLCuV, all the previously available CLCuD resistant germplasms of upland cotton have become compromised and none of the extant upland cotton cultivars is resistant to this disease. Therefore, alternate sources of CLCuD resistance need to be explored, as genetic resistance is the only pragmatic and tenable management strategy to combat this malady. Here, we report for the first time the introgression and mapping of CLCuD resistance from a related non-progenitor wild diploid D-genome cotton species, G. armourianum into upland cotton. A backcross population (G. hirsutum/G. armourianum/G. hirsutum) was developed for this purpose. A single major QTL was found to be associated with resistance to CLCuD and was located on chromosome D01 through the genotyping-by-sequencing technique.

Identification and Characterization of Innate Immunity in Actinidia melanandra in Response to Pseudomonas syringae pv. actinidiae.

Pseudomonas syringae pv. actinidiae biovar 3 (Psa3) has decimated kiwifruit orchards growing susceptible kiwifruit Actinidia chinensis varieties. Effector loss has occurred recently in Psa3 isolates from resistant kiwifruit germplasm, resulting in strains capable of partially overcoming resistance present in kiwiberry vines (Actinidia arguta, Actinidia polygama, and Actinidia melanandra). Diploid male A. melanandra recognises several effectors, sharing recognition of at least one avirulence effector (HopAW1a) with previously studied tetraploid kiwiberry vines. Sequencing and assembly of the A. melanandra genome enabled the characterisation of the transcriptomic response of this non-host to wild-type and genetic mutants of Psa3. A. melanandra appears to mount a classic effector-triggered immunity (ETI) response to wildtype Psa3 V-13, as expected. Surprisingly, the type III secretion (T3SS) system-lacking Psa3 V-13 ∆hrcC strain did not appear to trigger pattern-triggered immunity (PTI) despite lacking the ability to deliver immunity-suppressing effectors. Contrasting the A. melanandra responses to an effectorless Psa3 V-13 ∆33E strain and to Psa3 V-13 ∆hrcC suggested that PTI triggered by Psa3 V-13 was based on the recognition of the T3SS itself. The characterisation of both ETI and PTI branches of innate immunity responses within A. melanandra further enables breeding for durable resistance in future kiwifruit cultivars.

Pathotype determination of sorghum anthracnose (Colletotrichum sublineola) isolates from Ethiopia using sorghum differentials.

Sorghum anthracnose, caused by Colletotrichum sublineola, is the most destructive disease of sorghum, which causes up to 80% grain yield loss in susceptible varieties. The use of resistance varieties is an effective, durable, and eco-friendly strategy for anthracnose control. Knowledge of the phenotypic and genetic variation in C. sublineola is vital for designing appropriate anthracnose management strategies. The present study examined the morphology and virulence of 25 C. sublineola isolates recovered from various sorghum-producing regions of Ethiopia against 18 known sorghum anthracnose differentials, 6 Ethiopian sorghum landraces, and a variety of Bonsa. Analysis of variance (ANOVA) revealed significant differences among sorghum genotypes, C. sublineola isolates, and their interactions. There was a significant difference between the isolates in virulence, with each isolate exhibiting virulence in 8-72% of the sorghum genotypes tested. Among the 25 tested isolates, the top four most virulent isolates were from Pawe, suggesting that this area is suitable for pathogen diversity studies and host plant resistance screening. The sorghum genotypes IS_18760, Brandes, and Bonsa showed resistance to all tested isolates. Consequently, they may provide potential sources of resistance genes for sorghum breeding programs to develop cultivars resistant to different C. sublineola pathotypes. However, the resistant check SC748-5 was susceptible to isolates NK73_F37, while another resistant check SC112-14 was susceptible to isolates PW123_F47 and PW122_F47. Cluster analysis grouped 22 isolates into seven clusters based on their morphological characters, whereas 24 pathotypes were identified among 25 isolates that were tested on 25 sorghum genotypes. Hence, this study revealed high variation in C. sublineola in Ethiopia suggesting the need for broad-spectrum resistance to control the disease. Sorghum genotypes resistant to various C. sublineola isolates were identified in this study, which can be used in sorghum breeding programs aiming to develop resistant cultivars to anthracnose. Highly virulent C. sublineola isolates were also identified which could be used in sorghum germplasm resistance screening. The report is the first to show the existence of C. sublineola pathotypes in Ethiopia.

Genome-wide association study of cassava brown streak disease resistance in cassava germplasm conserved in South America

Cassava (Manihot esculenta Crantz) is a vital carbohydrate source for over 800 million people globally, yet its production in East Africa is severely affected by cassava brown streak disease (CBSD). Genebanks, through ex-situ conservation, play a pivotal role in preserving crop diversity, providing crucial resources for breeding resilient and disease-resistant crops. This study genotyped 234 South American cassava accessions conserved at the CIAT genebank, previously phenotyped for CBSD resistance by an independent group, to perform a genome-wide association analysis (GWAS) to identify genetic variants associated with CBSD resistance. Our GWAS identified 35 single nucleotide polymorphism (SNP) markers distributed across various chromosomes, associated with disease severity or the presence/absence of viral infection. Markers were annotated within or near genes previously identified with functions related to pathogen recognition and immune response activation. Using the SNP candidates, we screened the world’s largest cassava collection for accessions with a higher frequency of favorable genotypes, proposing 35 accessions with potential resistance to CBSD. Our results provide insights into the genetics of CBSD resistance and highlight the importance of genetic resources to equip breeders with the raw materials needed to develop new crop varieties resistant to pests and diseases.

Evaluation blackgram and greengram germplasm for resistance against tobacco streak virus (TSV) and peanut bud necrosis virus (PBNV) isolates of blackgram and greengram of Andhra Pradesh under glasshouse conditions

Evaluation blackgram and greengram germplasm for resistance against tobacco streak virus (TSV) and peanut bud necrosis virus (PBNV) isolates of blackgram and greengram of Andhra Pradesh under glasshouse conditions

An Aegilops longissima NLR protein with integrated CC-BED module mediates resistance to wheat powdery mildew

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), reduces wheat yields and grain quality, thus posing a significant threat to global food security. Wild relatives of wheat serve as valuable resources for resistance to powdery mildew. Here, the powdery mildew resistance gene Pm6Sl is cloned from the wild wheat species Aegilops longissima. It encodes a nucleotide-binding leucine-rich repeat (NLR) protein featuring a CC-BED module formed by a zinc finger BED (Znf-BED) domain integrated into the coiled-coil (CC) domain. The function of Pm6Sl is validated via mutagenesis, gene silencing, and transgenic assays. In addition, we develop a resistant germplasm harbouring Pm6Sl in a very small segment with no linkage drag along with the diagnostic gene marker pm6sl-1 to facilitate Pm6Sl deployment in wheat breeding programs. The cloning of Pm6Sl, a resistance gene with BED-NLR architecture, will increase our understanding of the molecular mechanisms underlying BED-NLR-mediated resistance to various pathogens.

Cercospora leaf spot impacts on postharvest disease and respiration of affected sugarbeet roots.

In Michigan, sugarbeets (Beta vulgaris) are stored for up to 200 days post-harvest, during which sugar loss may occur due to energy use from respiration and factors like rot. Cercospora leaf spot (CLS) has been considered a potential predisposing factor for increased storage rot. To investigate these impacts, field and postharvest studies evaluated storage rot symptom development in sugarbeets with designated 'high' or 'low' in-season CLS severity. Root slices of sugarbeets from each CLS level were inoculated with Fusarium graminearum, Botrytis cinerea, or Penicillium vulpinum and symptoms assessed after seven days. Across three CLS-susceptible commercial varieties, there were no significant differences between storage rot susceptibility to any of the tested pathogens in hand-harvested sugarbeets, regardless of CLS level, at any storage timepoint in 2020 or 2021 (P > 0.05). In studies using CLS-susceptible and -resistant germplasm and varieties, CLS effects were inconsistent and only significant in one parameter at two of six storage timepoints across years (P < 0.05). Across storage pathogens, prior CLS level also did not impact root respiration or the change in respiration rate from initial to final storage timepoint in either 2021 or 2023 (P > 0.05). Of note, B. cinerea caused more severe symptoms than other pathogens in these studies (P < 0.05). Finally, varietal responses differed significantly to storage pathogens (P < 0.05) and may be of interest to future cultivar development efforts. This research increases our understanding of factors contributing to potential storage losses, which will improve yield and profit for sugar growers.

Evaluation of bread wheat germplasm for adult plant resistance to stem rust using artificial inoculation

Wheat stem rust, caused by Puccinia graminis f.sp. tritici, is a major biotic threat to wheat (Triticum aestivum L.) in many wheat-producing countries worldwide, including Ethiopia. The pathogen is capable of continuously evolving new fungal races with high reproductive potential. It can be easily dispersed by wind over large geographic areas, allowing it to attack resistant varieties. Under optimal environmental conditions, it can cause epidemics leading to severe yield losses (up to 100%). A total of 91 germplasms, comprising 81 advanced bread wheat lines and 10 varieties, including the susceptible check Morocco, were planted using an augmented design. The experiment was conducted with artificial inoculation on spreaders to evaluate their slow rusting response against four virulent stem rust races viz. TTKTF, TKKTF, TTKTT, and TTTTF under field conditions at the Kulumsa Agricultural Research Center during the 2022-2023 offseason. Slow rusting resistance at the adult-plant stage was assessed by measuring the final rust severity (FRS) and the average coefficient of infection (ACI). Accordingly, 50 (61.7%) of the advanced lines and 6 (60%) of the released varieties namely Boru, Abay, Shaki, Kakaba, Deka, and Dursa exhibited low levels of FRS and ACI. In contrast, 31 (48.3%) of the advanced lines and 4 (40%) of the varieties showed high FRS and ACI values. The germplasms with low FRS and ACI values were considered to exhibit good slow rusting resistance and could be recommended for release into production and/or used in breeding programs aimed at achieving durable stem rust resistance in Ethiopia.

Understanding the origins, impacts, and remedies for mungbean yellow mosaic virus

Mungbean (Vigna radiata) is a crucial crop worldwide, especially in Asian countries, where it significantly contributes to agricultural yields. However, the Mungbean Yellow Mosaic Virus (MYMV), a begomovirus, causes substantial yield reductions. Despite ongoing efforts to identify resistant cultivars, most available varieties remain susceptible, potentially resulting in yield losses of up to 100%. In Pakistan, challenges such as inadequate irrigation, disease outbreaks, and poor-quality seed stocks exacerbate the impact of MYMV on mungbean production. Whiteflies (Bemisia tabaci) are the primary vectors for MYMV. Molecular characterization reveals that virus particles aggregate in the host nuclei, disrupting cell structure and leading to yield losses, with early infection stages resulting in more severe reductions. Efforts to manage MYMV include evaluating mungbean germplasm for resistance and emphasizing the importance of genetic resistance in disease control. Despite difficulties in developing resistant cultivars, ongoing research aims to reduce the impact of MYMV on mungbean production. This review explores the effect of MYMV on mungbean production, particularly in Pakistan, and examines the associated economic consequences. It also investigates the genetic susceptibility of mungbean cultivars, the influence of environmental conditions, and the dynamics of whitefly populations, which collectively contribute to MYMV incidence. The review highlights the correlation between whitefly populations and disease incidence and discusses strategies for managing MYMV and its vector. This paper provides a comprehensive overview of current approaches to develop sustainable and effective methods for mitigating MYMV-induced yield losses in mungbean cultivation.