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Background: Sterility mosaic is the most destructive disease of pigeon pea causing yield losses up to 95 per cent. Pigeon pea genotypes are found to vary in different biochemical characteristics, thereby playing a crucial role in resistance to sterility mosaic disease. The best approach to manage the disease is by adopting resistant genotypes for cultivation, which is highly necessary in the areas with high sterility mosaic incidence. Methods: Field screening of 41 pigeon pea genotypes was conducted during Kharif 2021 and 2022 at the Indian Institute of Pulse Research, Regional Research Center, Dharwad, to identify the resistance sources to Pigeon pea sterility mosaic virus. All the test genotypes were artificially inoculated by leaf stapling technique at 15-20 days after sowing and the infector hedge row technique was also employed to develop high disease pressure. Observation on per cent disease incidence was recorded at the peak period of the disease. The study also focused on biochemical components that confer resistance in pigeon pea. Further, the leaf samples were collected from the selected pigeon pea genotypes showing resistance and susceptible reactions and statistically analysed for total phenol content, peroxidase and polyphenol oxidase activity. The genotypes showing resistance and susceptible reactions were analysed for leaf chlorophyll content using SPAD Meter. Result: Seven genotypes were found resistant to sterility mosaic disease with a mean disease incidence of 1.9-8.86 per cent. SPAD chlorophyll meter reading revealed that chlorophyll content remained high in all resistant/moderately resistant genotypes as compared to susceptible genotypes. The resistant genotypes were shown to have higher phenol content, peroxidase and polyphenol oxidase activity in comparison to susceptible genotypes suggesting their crucial role in imparting resistance. [ABSTRACT FROM AUTHOR]

Scald caused by the fungal pathogen Rhynchosporium commune is a significant foliar disease affecting barley production on a global scale, and it leads to substantial reductions in both yield and quality of barley. In the current study, the reactions of 40 Turkish barley (Hordeum vulgare L.) varieties to scald were evaluated under natural conditions in Çanakkale and Kırşehir in 2021–2022, and Antalya and Siirt locations in 2022–2023 growing seasons. Field trials were conducted according to randomized block design with three replications in each year; the spore concentration was 1 × 106 spores per mL, and it was applied to the varieties three times at different growth stages. The reactions of barley varieties were assessed using a newly designed two-digit scale ranging from 11 to 99. Based on their scale values, the varieties were categorized as immune (0), resistant (11–35), moderately resistant (36–55), moderately susceptible (56–75), and susceptible (76–99). In addition, genotype plus genotype-by-environment (GGE) interactions of scale values were analyzed through GGE Biplot and explained 97.65% of the total variation. The ranking of genotypes based on scale groups generally showed consistency with GGE Biplot results, but GGE Biplot offered a more detailed classification, especially for moderately susceptible varieties. The relationship between the two methods indicated the relative stability of variety reactions, as GGE Biplot analysis also considered genotype stability. In conclusion, the use of the newly developed scale for evaluating scald reactions in barley gives reliable results. In addition, identified resistant varieties can serve as valuable genetic resources for further breeding studies. [ABSTRACT FROM AUTHOR]

Context: Among biotic factors, bean anthracnose caused by Colletotrichum lindemuthianum (Sacc. & Magnus) Briosi & Cavara is one of the most destructive diseases of common bean (Phaseolus vulgaris L.). Resistance in common bean genotypes is controlled by anthracnose resistance loci (designated Co). Aims: The objective of this study was to evaluate the presence of Co resistance genes in common bean genotypes from Turkey and to examine promising genotypes as candidates for parent plants in breeding studies. Methods: The presence of Co resistance genes in 693 common bean genotypes from 35 provinces of Turkey was determined by 12 SCAR (sequence characterised amplified region), RAPD (random amplified polymorphic DNA), STS (sequence-tagged site) and CAPS (cleaved amplified polymorphic sequence) markers. The disease reaction of 40 agronomically promising genotypes to different pathogen isolates was evaluated in a pot study. Key results: The results indicated the presence of Co-1 , Co-1 4 , Co-1 5 , Co-2 , Co-3 3 , Co-4 , Co-4 2 , Co-6 , Co - 10 , Co - 11 and Co - 13 resistance genes, alone or in combination; Co - 5 was not detected in any of the genotypes. Among the genotypes, Co-1 5 was the most frequent resistance source, followed by Co-4 , Co-6 and Co-11 , respectively. Common bean genotypes carrying Co-1 4 , Co-2 , Co-3 3 , Co-11 and Co-13 have been identified for the first time in Turkish germplasm. Five genotypes carrying the various combinations of Co-1 , Co-1 5 , Co-4 , Co-6 , Co-10 , Co-11 and Co-13 were resistant to all isolates in pathogenicity tests. Conclusions: This study is the most comprehensive to date on Co genes linked to the resistance of common bean genotypes throughout Turkey and provides an important gene pool for breeding studies into bean anthracnose. Resistant genotypes identified will be useful as parent plants in resistance breeding studies. Implications: Resistance genotypes carrying different Co genes to bean anthracnose will contribute significantly to the disease management strategy. Host plant resistance is the most economical and environmentally friendly method of protection against plant disease. This study examined Co genes in Turkish common bean genotypes linked to resistance to bean anthracnose. The study provides an important gene pool for breeding studies and identifies genotypes resistant to the pathogen. [ABSTRACT FROM AUTHOR]

Angular leaf spot (ALS) caused by Pseudocercospora griseola is a major disease of french bean (Phaseolus vulgaris L.) worldwide. A good diversity of French bean is present in the Garhwal Himalayas of Uttarakhand, India, which is unexplored. The purpose of this study was to identify ALS-resistant accessions among local landraces of French bean in this region. One hundred seventy-six local accessions were collected from different villages of Garhwal, Uttarakhand. All the accessions were screened by four SCAR primers SN02 (Phg- 2), SAA19, SM02, SBA16 (Phg- 3), one STS primer TGA1.1 (Phg-1) and one SSR primer Pv-at006 (Phg- 5). All the accessions were also screened for ALS resistance under field condition in the years 2019 and 2020. The disease-resistant score was recorded on 1–9 scale. After field screening, 48 accessions (19 resistant, 24 moderately resistant and five susceptible) were selected for in-vitro screening under screen house condition. These 46 accessions were artificially inoculated by two different isolates of P. griseola P5 and P9, which are the most virulent pathotype characterized by microbiology lab, College of Forestry, Tehri, Uttarakhand. After in-vitro screening, seven accessions (GFB-25, GFB-26, GFB-30, GFB-32, GFB-93, GFB-97 and GFB-136) were found resistant to both the isolates P5 and P9. The P. griseola -resistant accessions may further be used in future breeding programmes to develop new and more resistant varieties of French bean against ALS. [ABSTRACT FROM AUTHOR]

Anthracnose caused by Colletotrichum lindemuthianum is one of the major diseases of common bean (Phaseolus vulgaris L.) worldwide. The aim of this study was to analyze common bean cultivars in Turkey for Co resistance genes using different molecular markers (SC08, SBB14, OPAZ04, SF10, OPF10, OPA18, SB12, TGA1, SAB3, SCAreoli, SZ04, and OPV20) linked with anthracnose resistance genes and evaluate the reaction of these cultivars to the pathogen isolates. The results showed the presence of Co-1, Co-14, Co-15, Co-2, Co-4, Co-42, Co-6, Co-10, Co-11, and Co-13 resistance genes, alone or combination except for Co-33and Co-5, in common bean cultivars. These cultivars carried predominantly Co-6 and Co-4 genes for anthracnose resistance. Five cultivar (Sazova, Zülbiye, Akın, Önceler and Karacaşehir 90), carrying Co-1, Co-14, Co-15, Co-2, Co-10, Co-13, Co-4, and Co-6 resistance genes were resistant to the pathogen isolates. These cultivars, showing a high level of resistance to the pathogen can be used as resistance sources in common bean breeding programs for resistance to anthracnose disease. These markers will provide significant benefit in breeding strategies. [ABSTRACT FROM AUTHOR]

Aim of study: To evaluate genetic variability and population structure of C. lindemuthianum isolates in Turkey and to record the reactions of some common bean cultivars to the pathogen isolates representing different genetic groups. Area of study: The study was performed in seven provinces of Turkey. Material and methods: Genetic diversity of 91 C. lindemuthianum isolates obtained from different provinces of Turkey was characterized by 27 iPBS and 30 ISSR primers. Also, the resistance of 40 common bean cultivars was scored against three isolates representing different genetic groups. Main results: The dendrogram based on the combined dataset of iPBS and ISSR markers classified the isolates into two main groups with a genetic similarity of 72%, which closely associated with the geographic distribution of the isolates. The dendrogram of Nei’s genetic distances and Structure analysis supported the clustering of C. lindemuthianum isolates according to the geographical provinces. The results indicated that high level of genetic diversity (GST= 0.4) and low level of gene flow (NM=0.748) exist among the populations. AMOVA analysis showed that 58.7% of total genetic variability resulted from genetic differences between the isolates within populations, while 41.29% was among populations. Four cultivars showed resistant reaction to three isolates, while the other cultivars were susceptible to at least one isolate. Research highlights: The results indicated that iPBS and ISSR markers were reliable and effective tools for analyzing population structure of C. lindemuthianum and revealed high level of genetic and pathogenic diversity among pathogen populations in Turkey.

Common bean (Phaseolus vulgaris L.) is the most important grain legume. Crop production of common bean is affected by a number of diseases, such as Rhizoctonia root rot, being detected worldwide. Herein, we aimed to genetically and pathologically characterize Rhizoctonia solani isolates obtained from different provinces in Turkey. Anastomosis groups (AG) and subgroups of isolates were identified based on the sequence analysis of the rDNA-ITS region. The most prevalent subgroup was AG-4 HGIII, according to BLAST analysis and the phylogeny of resultant sequences, followed by AG-4 HGI and AG-4 HGII, respectively. iPBS retrotransposons highly supported the phylogenetic tree and provided a high level of genetic variability among isolates to discriminate AG subgroups. The results indicated that the iPBS DNA marker system based on retrotransposons could be used to discriminate Rhizoctonia isolates relying on AG grouping. The virulence of the pathogen isolates changed from 3.67 to 5 based on the agar-plate assay on the susceptible cv. Gina. The reactions of thirty common bean cultivars were also evaluated against the most aggressive isolate in each subgroup. The reaction assay showed significant differences among both isolates and cultivars; the highest disease severity among cultivars was observed to AG-4 HGI, followed by AG-4 HGIII and AG-4 HGII, respectively. None of the cultivars showed resistance to all AG subgroups. Screening of AGs among the isolates and selecting cultivars are critical to managing Rhizoctonia disease due to the range of host suitability according to AG subgroups. • IPBS is as effective as DNA sequence analysis in distinguishing R. solani subgroups. • Among cultivars, AG-4 HGI showed the highest disease severity, followed by AG-4 HGIII, AG-4 HGII. • Seher Yıldızı, Sarıkız, Perolar were resistant to AG-4 HGII-HGIII, sensitive to HGI. [ABSTRACT FROM AUTHOR]

Spot blotch caused by Bipolaris sorokiniana is a destructive disease of wheat worldwide. This study investigated the aggressiveness of B. sorokiniana isolates from different wheat-growing areas of Bolu province in Turkey on the cultivar Seri-82. Host susceptibility of 55 wheat cultivars was evaluated against the most aggressive isolate. Our results indicated that the cultivars Anafarta and Koç-2015 were the most resistant. A specific and sensitive qPCR assay was developed for detecting the pathogen in plant tissues and evaluating wheat plants with different resistance levels. Three primer sets, BsGAPDHF/BsGAPDHR, BsITSF/BsITSR, and BsSSUF/BsSSUR, were designed based on glyceraldehyde-3-phosphate dehydrogenase, internal transcribed spacers, and 18S rRNA loci of B. sorokiniana with detection limits of 1, 0.1, and 0.1 pg of pathogen DNA, respectively. The qPCR assay was highly sensitive and did not amplify DNA from the other closely related fungal species and host plants. The protocol differentiated wheat plants with varying degrees of resistance. The assay developed a useful tool for the quantification of the pathogen in the early stages of infection and may provide a significant contribution to a more efficient selection of wheat genotypes in breeding studies. In the present study, expression levels of PR proteins, phenylalanine ammonia-lyase, catalase, ascorbate peroxidase, and superoxide dismutase enzymes were upregulated in Anafarta (resistant) and Nenehatun (susceptible) cultivars at different post-infection time points, but more induced in the susceptible cultivar. The results showed considerable variation in the expression levels and timing of defense genes in both cultivars.

Eight isolates of Sclerotium rolfsii from four strategically geographical sites of Bangladesh were characterized and their cultural properties like average linear mycelial growth, colony colour, colony consistency, growth pattern and sclerotia formation were studied. Isolates varied in mycelial growth and other growth characteristics and were grouped into three. The highest linear growth was displayed by S8. DNA concentration of eight isolates varied from 1150-7200 ng/μl. DNA fingerprinting by RAPD prompted the grouping of isolates. Selected 3 primers generated 20 bands with size ranging from 100-1500 bp. Out of the 20 bands, 9 bands (45%) were polymorphic and 11 bands (55%) were monomorphic among the eight isolates of Sclerotium rolfsii. The co-efficient of gene differentiation (Gst) was 1.000 reflecting the existence of high level of genetic variations among the 8 isolates. The lowest genetic distance and highest inter isolate similarity was found in S1 and S2 which would be homogeneous. The highest genetic distance and lowest inter isolate similarity found in S3, S7 and S3, S8 pair which would be most divergent isolates. The cluster analysis also revealed that S3, S7 and S8 belong to different clusters. All five varieties of eggplant and tomatoes were graded as susceptible when inoculated with eight isolates. Plant mortality 93.33% was recorded in S4, S6 and in S8. Considering the isolate factor the most virulent isolate would be S8 whereas the less virulent isolate would be S2 and S7. Host plant of S8 was tomato collected from Thakurgaon. S2 and S7 were collected from BAU farm and Dinajpur and host plants were lentil and tomato respectively. It is evident that Sclerotium rolfsii from Thakurgaon on host tomato is more virulent.

Cashew powdery mildew, caused by Erysiphe quercicola , is one of the main disease problems of cashew trees in Brazil. Thus, research to study the reaction of commercial cashew clones under different epidemiological stages of the disease is very important for identifying resistant clones. The objective of this research was to evaluate the reaction of commercial clones of cashew to powdery mildew by monitoring the disease during three disease cycles. The study was carried out at Embrapa Agroindústria Tropical, Pacajus Experimental Field, Ceará, Brazil, during 2012, 2013 and 2014 using eleven commercial clones of cashew (CCP 09, CCP 76, CCP 100, CCP 06, EMBRAPA 51, EMBRAPA 50, BRS 265, BRS 189, BRS 274, BRS 275 and BRS 226). Powdery mildew severity on inflorescences was estimated using a descriptive scale of severity consisting of scores ranging from 0 to 4. The transformed data were used to estimate the area under the disease progression curve (AUDPC) and the rate of infection. Based on similarities in disease severity estimates with time, clones were clustered using multivariate clustering analysis. Epidemics of cashew powdery mildew differed between the three cycles in terms of duration and severity. The clones were classified into four clusters of similar clones, defined by the graphical analysis on the basis of the powdery mildew severity. Clones BRS 274, BRS 275, CCP 1001 and BRS 226 attained lower AUDPC and clones BRS 189 and CCP 06 showed higher AUDPC. The results show evidence of partial resistance to powdery mildew among commercially grown cashew clones. Clones BRS 274, BRS 275, BRS 226 and CCP 1001 were the most resistant, while CCP 06 and BRS 189 clones were the most susceptible to powdery mildew. The AUDPC seems to be suitable for discriminating between genotypes, whereas the rate of disease progression may be used for establishing a threshold in the evaluation of other control methods, as it does not clearly differentiate between disease reactions. [ABSTRACT FROM AUTHOR]

Bajo condiciones de la sabana de Bogotá (Colombia), se evaluaron 32 cultivares de fríjol voluble por componentes del rendimiento y por su reacción a una mezcla de aislamientos de Colletotrichum lindemuthianum procedentes de Boyacá y Cundinamarca. Los genotipos que presentaron un buen comportamiento en rendimiento y una reacción en campo a la resistencia de la enfermedad fueron: D. Moreno y 3198. Los que expresaron una reacción de resistencia a la antracnosis fueron: 3180, 3182, 3177 y G-2333. Aquellos que mostraron un buen comportamiento en componentes de rendimiento fueron: 3164, 3159, 3176 y Radical. Estos genotipos podrían usarse como posibles candidatos parentales ó sobresalientes en el programa de mejoramiento de fríjol. También se realizó análisis de dos marcadores moleculares tipo SCAR ligados a los genes Co-4 y Co-5 que confieren resistencia a C. lindemuthianum, ninguno de los materiales de evaluación a excepción del testigo resistente G-2333, amplificó los marcadores SCAR, asociados a los genes de resistencia de interés.Under Bogotá plateau (Colombia) conditions, 32 cultivars of climbing bean were evaluated by components of yield and by reaction with a mixture of isolations of Colletotrichum lindemuthianum coming from Boyacá and Cundinamarca. The cultivars that presented a good behavior in yield and resistance reaction to the disease were: D. Moreno and 3198. Those that expressed a resistant reaction to the anthracnose were: 3180, 3182, 3177 and G-2333. Finally those that showed a good behavior in yield components were 3164, 3159, 3176 and Radical. These genotypes could be used as excellent candidates in the breeding program of common bean. It was also carried out a test for each cultivar, by means of two markers molecular type SCAR tried to resistance genes to anthracnose Co-4 and Co-5. Any of the evaluation materials amplified for the couple of genes, except for the resistant control G-2333.

The most economically important disease of cultivated grapevines worldwide is powdery mildew caused by the biotrophic fungal pathogen Erysiphe necator . To integrate effective genetic resistance into cultivated grapevines, numerous disease resistance screens of diverse Vitis germplasm, including wild species, have been conducted to identify powdery mildew resistance, but the results have been inconsistent. Here, a new powdery mildew isolate that is infectious on grapevines, designated Erysiphe necator NAFU1 ( En. NAFU1), was identified and characterized by phylogeny inferred from the internal transcribed spacer (ITS) of pathogen ribosomal DNA sequences. Three classical methods were compared for the maintenance of En. NAFU1, and the most convenient method was maintenance on detached leaves and propagation by contact with infected leaves. Furthermore, controlled inoculations of En. NAFU1 were performed using detached leaves from 57 wild Chinese grapevine accessions to quickly evaluate powdery mildew resistance based on trypan blue staining of leaf sections. The results were compared with previous natural epidemics in the field. Among the screened accessions inoculated with En. NAFU1, 22.8% were resistant, 33.3% were moderately resistant, and 43.9% were susceptible. None of the accessions assessed herein were immune from infection. These results support previous findings documenting the presence of race-specific resistance to E. necator in wild Chinese grapevine. The resistance of wild Chinese grapevine to En. NAFU1 could be due to programmed cell death. The present results suggest that En. NAFU1 isolate could be used for future large-scale screens of resistance to powdery mildew in diverse Vitis germplasms and investigations of the interaction between grapevines and pathogens. [ABSTRACT FROM AUTHOR]

Cultivar selection is one of the most economically important decisions made by peanut producers. The development of genotypes capable of maintaining yield and quality under a wide range of conditions is important so that profitability can be maximized. Issues such as declining irrigation capacity and diseases limit production in parts of Texas. Efforts of the Texas AgriLife Peanut Breeding Program are to develop breeding lines with improved yield potential, total sound mature kernels (TSMK), and disease resistance. Cultivar trials were conducted in 2009, 2010, and 2011 to evaluate the performance of the cultivar Tamrun OL11. Trials were established in several different production areas under various field conditions and included the commercial standards Flavor Runner 458 and Tamrun OL07. Yields were similar for Flavor Runner 458 and Tamrun OL07 at 4538 and 4534 kg/ha, respectively; whereas, Tamrun OL11 averaged 4845 kg/ha ( P = 0.02). TSMK plus sound splits (SS) for Tamrun OL11 were 1.3% higher than Flavor Runner 458 and 2.4% higher Tamrun OL07. When comparing cultivars in fields with a history of severe Sclerotinia blight (caused by Sclerotinia minor) yield increases of 1240 and 2229 kg/ha were observed for Tamrun OL11 over Tamrun OL07 and Flavor Runner 458, respectively. Results from these studies illustrate the high yield potential and superior TSMK of Tamrun OL11. [ABSTRACT FROM AUTHOR]

Abstract: Gummosis disease (Lasiodiplodia theobromae) is the most limiting problem for cashew production in semi-arid northeastern Brazil; nevertheless, there is no efficient method of control other than genetic resistance. Although genetically improved dwarf clones with a high resistance have been released, there is still a need for sources of resistance in wild common cashew populations. The reactions to gummosis disease of twenty cloned wild cashew genotypes were evaluated during seven consecutive years in a commercial orchard located in an area under high disease pressure in semi-arid northeast Brazil. The disease incidence and severity (0 to 4 severity scale) were assessed at 4-month intervals, and the area under the disease progress curve was estimated for each genotype. The first gummosis symptom was observed after twelve months of planting. The disease progressed very rapidly after twenty months in most of the genotypes, but three of them showed resistance. The area under the disease progress curve was found to be a good parameter to differentiate among the genotype reactions. A significant correlation between the disease incidence and severity was detected upon Pearson coefficient analyses. This is the first report on screening wild-common cashew genotypes for the resistance to gummosis. [Copyright &y& Elsevier]

Spot blotch caused by Bipolaris sorokiniana is a destructive disease of wheat worldwide. This study investigated the aggressiveness of B. sorokiniana isolates from different wheat-growing areas of Bolu province in Turkey on the cultivar Seri-82. Host susceptibility of 55 wheat cultivars was evaluated against the most aggressive isolate. Our results indicated that the cultivars Anafarta and Koç-2015 were the most resistant. A specific and sensitive qPCR assay was developed for detecting the pathogen in plant tissues and evaluating wheat plants with different resistance levels. Three primer sets, BsGAPDHF/BsGAPDHR, BsITSF/BsITSR, and BsSSUF/BsSSUR, were designed based on glyceraldehyde-3-phosphate dehydrogenase, internal transcribed spacers, and 18S rRNA loci of B. sorokiniana with detection limits of 1, 0.1, and 0.1 pg of pathogen DNA, respectively. The qPCR assay was highly sensitive and did not amplify DNA from the other closely related fungal species and host plants. The protocol differentiated wheat plants with varying degrees of resistance. The assay developed a useful tool for the quantification of the pathogen in the early stages of infection and may provide a significant contribution to a more efficient selection of wheat genotypes in breeding studies. In the present study, expression levels of PR proteins, phenylalanine ammonia-lyase, catalase, ascorbate peroxidase, and superoxide dismutase enzymes were upregulated in Anafarta (resistant) and Nenehatun (susceptible) cultivars at different post-infection time points, but more induced in the susceptible cultivar. The results showed considerable variation in the expression levels and timing of defense genes in both cultivars. [ABSTRACT FROM AUTHOR]

Isolates of X. campestris pv. sesami used in the present work behaved almost similarly on the basis of their morphological, biochemical and physiological characterization. The studies failed to differentiate any strains within the isolates. Pathogenicity of the isolates to sesame plants was proved by inoculation experiments. When other plant species were inoculated infection did not occur. The levels of resistance of some naturally selected sesame cultivars were investigated following artificial infection with the pathogen. Seven cultivars proved resistant, three (cvs Tozi 3, S-76F2-22 and K 112) were highly resistant.. [ABSTRACT FROM AUTHOR]

HSF-240, one of the elite sugarcane varieties, was observed for its reaction with sugarcane smut over three consecutive years under natural conditions. The study includes plant crop, first year ratoon and second year ratoon crops. The data revealed that in plant crop only 4.25% stools were infected with smut and crop proved to be resistant during that year. In first year ratoon 18.39% stools were infected with the disease and crop stood tolerant against the disease. However in second year ratoon the disease infected up to 38.19% of stools rendering the crop severely susceptible to this disease. This suggests a swift replacement of HSF-240 with new and promising varieties, dejection of this variety in future as a plant crop as well as a ban on keeping ratoon of this variety. [ABSTRACT FROM AUTHOR]