Category Archives: ORIGINAL ARTICLE

Deciphering the inheritance of fertility restoration and influence of environmental factors on maldandi source of male sterility in rabi sorghum [Sorghum bicolor (L.) Moench]

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Abstract

This study aimed to investigate the inheritance pattern of fertility restoration in hybrids resulting from crosses between a male sterile line (M31-2A), a maldandi cytoplasm, and two promising restorers (DSMR-4 and DSMR-8). The evaluation of hybrids was conducted in two sets of experiments, including the F2, BC1F1 and F2, F3 generations. The segregation pattern was analysed in the F2 and BC1F1 generations, resulting in a 54:10 ratio of fertile to sterile plants and a 1:1 ratio of fertile to sterile plants, respectively. This indicated the involvement of three genes, at least two of which must be in a dominant condition for restoration to occur, acting in a duplicate complementary manner. In the F3 generation, both crosses were grown to confirm the stability of restorers, and they segregated in the ratio of 10 true-breeding families and 44 segregating families, which was consistent with the F2 ratio. Additionally, this study observed the influence of rainfall on the partial restoration pattern over seasons, as restorer genes are up or down-regulated depending on the availability of water.

Evaluation of different antimicrobial agents for laboratory and field against Pantoea agglomerans, the causative agent of bacterial leaf blight disease on oat (Avena sativa)

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Evaluation of different antimicrobial agents for laboratory and field against Pantoea agglomerans, the causative agent of bacterial leaf blight disease on oat (Avena sativa)

Laboratory and field experiments on the efficacy of 13 antimicrobial agents against oat leaf blight disease (Pantoea agglomerans) found that zhongshengmycin and ethylicin have excellent control efficacy.


Abstract

Leaf blight disease (LBD) caused by Pantoea agglomerans is a newly emerged oat disease in China that causes great economic and yield losses of oat production. Laboratory and field experiments were conducted to evaluate the efficacy of 13 antimicrobial agents against P. agglomerans and recommend agents with better control efficacy for use. The antibacterial potential of four concentrations of each agent was evaluated under in vitro conditions. Zhongshengmycin and ethylicin were the most effective in inhibiting the growth of P. agglomerans; their bacteriostatic rates (85.0% and 84.8%, respectively) were higher while EC50 lower (0.31 and 0.90, respectively) than other agents. The greenhouse and field experiment suggested that the greatest fresh weight per plant (57.26 g and 57.93 g), forage yield (22.53 t/ha and 22.21 t/ha) and control efficacy (>75%) were obtained after spraying twice with zhongshengmycin or ethylicin in the LBD occurrence phase, with lower yields and control by kasugamycin + dicopper chloride trihydroxide, kasugamycin + oxine copper, benziothiazolinone, copper hydroxide, phenanthrenecarboxylicacid, copper, picoxystrobin, chloroisobromine cyanuric acid, oxathiapiprolin or azoxystrobin. Foliar application of zhongshengmycin or ethylicin can therefore be used for the effective management of LBD of oat.

Genomic prediction of seed nutritional traits in biparental families of oat (Avena sativa)

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Abstract

Selection for more nutritious crop plants is an important goal of plant breeding to improve food quality and contribute to human health outcomes. While there are efforts to integrate genomic prediction to accelerate breeding progress, an ongoing challenge is identifying strategies to improve accuracy when predicting within biparental populations in breeding programs. We tested multiple genomic prediction methods for 12 seed fatty acid content traits in oat (Avena sativa L.), as unsaturated fatty acids are a key nutritional trait in oat. Using two well-characterized oat germplasm panels and other biparental families as training populations, we predicted family mean and individual values within families. Genomic prediction of family mean exceeded a mean accuracy of 0.40 and 0.80 using an unrelated and related germplasm panel, respectively, where the related germplasm panel outperformed prediction based on phenotypic means (0.54). Within family prediction accuracy was more variable: training on the related germplasm had higher accuracy than the unrelated panel (0.14–0.16 and 0.05–0.07, respectively), but variability between families was not easily predicted by parent relatedness, segregation of a locus detected by a genome-wide association study in the panel, or other characteristics. When using other families as training populations, prediction accuracies were comparable to the related germplasm panel (0.11–0.23), and families that had half-sib families in the training set had higher prediction accuracy than those that did not. Overall, this work provides an example of genomic prediction of family means and within biparental families for an important nutritional trait and suggests that using related germplasm panels as training populations can be effective.

Efficiency of indirect selection for fusarium head blight resistance and mycotoxin accumulation in winter wheat (Triticum aestivum L.)

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Abstract

Fusarium head blight (FHB) is one of the most devastating diseases of wheat and can lead to significant yield losses as well as a contamination of the crop with mycotoxins that are a major concern in cereal-based food and feed products. The aims of this study were thus to investigate the relationship between resistance against multiple Fusarium species and to assess the potential of an indirect phenotypic and genomic selection for the resistance against the accumulation of several mycotoxins in wheat. Strong phenotypic and genetic correlations between the mycotoxin contents, FHB severity and FHB-associated traits were observed, irrespective of if traits were assessed in trials inoculated with a DON or HT-2/T-2 producing Fusarium species. A multi-stage phenotypic or genomic selection with low anther retention being used for an indirect selection among early generation selection candidates, followed by an evaluation of the pre-selected set in disease nurseries, and lastly by assessing the mycotoxin content of the most promising genotypes is suggested as a suitable strategy to breed for wheat cultivars with reduced risk of mycotoxin accumulation.

Contrasting interactions of the aggressive Verticillium longisporum lineage A1/D1 and the non‐aggressive A1/D2 lineage with roots of oilseed rape

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Contrasting interactions of the aggressive Verticillium longisporum lineage A1/D1 and the non-aggressive A1/D2 lineage with roots of oilseed rape

The non-aggressive lineage A1/D2 of Verticillium longisporum penetrates roots of oilseed rape, however, without inducing typical disease symptoms, indicating tolerance in oilseed rape to A1/D2.


Abstract

Verticillium longisporum is a soilborne fungal vascular pathogen of Brassica crops. Three hybrid lineages originating from three independent hybridization events of four haploid Verticillium parents are known. V. longisporum lineage A1/D2 has only been found in horseradish and previous pathogenicity tests have shown that it is non-aggressive on oilseed rape (Brassica napus). The aim of this study was to investigate the interaction of the non-aggressive lineage A1/D2 with oilseed rape in comparison with the aggressive A1/D1 lineage. Although A1/D2 did not cause severe disease symptoms, the study revealed restricted root infection and systemic colonization by this lineage, as assessed by quantitative PCR of fungal DNA. Assessment of root surface colonization by confocal laser microscopy indicated early sporulation, disorganized loosely attached hyphal growth and hyphal coiling of A1/D2. By contrast, A1/D1 showed organized hyphal growth tight to the root surface, as well as hyphal swellings at points of penetration. Vascular colonization was studied with transmission electron microscopy, which revealed less vessel colonization, higher intensity of vascular responses and lower plant cell wall degradation in A1/D2-treated plants in comparison with A1/D1. Vascular responses consisted of strong coating of vessel walls and fungal hyphae with an electron-dense material, indicating higher intensity of plant defence in comparison with A1/D1. The results, for the first time, demonstrate stem colonization and thus a basic level of pathogenic interaction of non-aggressive strains of A1/D2 with oilseed rape associated with a lack of severe disease symptoms, which indicate tolerance in oilseed rape to lineage A1/D2.

Colletotrichum acericola sp. nov. from seeds of the invasive alien tree species Acer negundo in Poland

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Colletotrichum acericola sp. nov. from seeds of the invasive alien tree species Acer negundo in Poland

Colletotrichum acericola sp. nov. was found in Wrocław, Poland on the seeds of an invasive alien boxelder. Based on comparisons with US prairie sequences, it is likely that it originated in North America and was introduced to Europe.


Abstract

The boxelder maple (Acer negundo, Sapindaceae) is one of the most common tree species of the genus Acer natively growing in North America. In the 17th century, A. negundo was introduced to Europe as an ornamental plant, and from this time, it started an uncontrolled expansion into new territories, threatening local ecosystems. Fungal development on invasive alien species' seeds and pedicels was observed in 2017 and 2021 in the municipality of Wrocław (Poland), outside of the native occurrence of the host. Morphological analyses combined with multilocus phylogenetic analyses (internal transcribed spacer [ITS], gapdh, act, tub2, chs-1 and his3 sequences) showed that isolates belonged to a new species of Colletotrichum, from the rare C. agaves species complex. The name Colletotrichum acericola is proposed for this fungus. Based on comparisons with sequences from NCBI GenBank originating from prairie plants in the United States, it is likely that C. acericola is native to North America.

Characterization of Xanthomonas hortorum isolates causing leaf spot on Primula vulgaris

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Characterization of Xanthomonas hortorum isolates causing leaf spot on Primula vulgaris

A new pathovar, Xanthomonas hortorum pv. primulicola, was identified as the causative agent of leaf spot in Primula vulgaris based on taxonomic analysis, and distinct host ranges in comparison to other X. hortorum pathovars.


Abstract

The bacterial leaf spot of Primula vulgaris was reported from forest locations in Mazandaran province, Iran in 1995. The causative bacterium was initially identified as Xanthomonas campestris based on sequences of ITS and 16S rRNA regions. On the basis of sequences of gyrB and dnaK housekeeping genes, the isolates resembled strains of Xanthomonas hortorum. The present study was performed to clarify the taxonomic status of the incitant bacterium. Samples of P. vulgaris with leaf spot symptoms were collected from the Darabkola forest (Mazandaran province) and the bacterial strains were isolated on plates of glucose nutrient agar. Some isolates only induced hypersensitive reaction on geranium (Pelargonium × hortorum) leaves but a few isolates incited leaf spot symptoms when inoculated on P. vulgaris, P. heterochroma and P. × polyantha plants. The isolates were Gram stain, oxidase and urease negative but positive in tests for catalase and hydrolysis of gelatin, aesculin and Tween 80. Several unique nonpathogenic isolates were recovered with varying carbon source utilization profiles and different molecular features, including distinct ERIC-PCR profiles. Representative gyrB, rpoD, dnaK and fyuA housekeeping genes were amplified by PCR and sequenced for comparison with Xanthomonas species in the GenBank database using maximum-likelihood, maximum-parsimony and Bayesian algorithms to construct phylogenetic trees. The pathogenic and nonpathogenic strains were closely related to X. hortorum pathovars. Therefore, it is likely that these isolates belong to a new pathovar of X. hortorum. Based on previous studies and our findings, we propose naming the strain causing primrose leaf spot as X. hortorum pv. primulicola.

Identification of Piper species that are resistant to Phytophthora capsici, Meloidogyne incognita, and waterlogging in Vietnam

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Identification of Piper species that are resistant to Phytophthora capsici, Meloidogyne incognita, and waterlogging in Vietnam

Two Piper accessions P. divaricatum and P. hancei in Vietnam demonstrated high levels of resistance to pathogenic Phytophthora capsici, the root-knot nematode Meloidogyne incognita and tolerance towards waterlogged conditions.


Abstract

Black pepper (Piper nigrum) is a spice commonly used in kitchens throughout the world. Black pepper production is devastated by a range of pathogenic agents, including Phytophthora capsici and Meloidogyne incognita. Many efforts have been directed towards finding black pepper cultivars that are resistant to these pathogens. In this work, a 39-accession germplasm panel of species in the Piper family collected throughout Vietnam was described. Preliminary tests using P. capsici inoculation onto leaves were carried out to identify potentially resistant accessions. Next, candidate plants were inoculated with P. capsici mycelial suspension and survival rates were assessed 15, 30 and 45 days postinoculation. In addition, Piper plants were challenged with M. incognita by adding larvae/juveniles to growing pots. Resistance to M. incognita was determined by the number of root galls and the percentage of plants with yellow leaves 1, 2 and 4 months after treatment. Piper accessions were also subjected to a 4-day waterlogged treatment. Two accessions (HUIB_PH30 and HUIB_PD36) demonstrated high levels of resistance to all biological and water stresses. Micromorphological characterizations revealed that the amount of intercellular spaces in the root cortex correlated with the resistance to P. capsici and waterlogging tolerance. Hence, the abundance of intercellular spaces can serve as a guide for further selection of black pepper accessions that are resistant to common diseases and tolerant to waterlogged conditions.

Evaluation of soybean genotypes for cowpea mild mottle virus resistance through phenotypic reaction and genotypic analysis

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Evaluation of soybean genotypes for cowpea mild mottle virus resistance through phenotypic reaction and genotypic analysis

Soybean genotypes were screened under field and controlled conditions to identify and characterize, through gene-specific and SSR molecular markers, genotypes resistant against CPMMV infection.


Abstract

Cowpea mild mottle virus (CPMMV), a carlavirus nonpersistently transmitted by whiteflies, is an emerging and economically important virus of soybean. The present study aimed to identify soybean genotypes resistant to CPMMV through mechanical inoculation-based phenotyping and marker trait association using gene-specific and simple-sequence repeat (SSR) markers. A set of 500 soybean genotypes was initially screened in the field for CPMMV infection, of which 288 genotypes showing resistance were evaluated further under controlled glasshouse conditions. Among these 288 genotypes, 43 (14.9%) were resistant, 59 (20.5%) were moderately resistant while the remaining 186 (64.6%) were susceptible. A set of five gene-specific primer pairs, three of which targeted CPMMV R genes, was used for screening the 288 soybean genotypes; 96 genotypes from the 288 (based on disease score) were also genotyped with 24 SSR polymorphic markers for an association study. The mean values of major allele frequency and gene diversity were found to be 0.70 and 0.39, respectively. The polymorphism information content varied from 0.14 to 0.37. Population structure and cluster analysis revealed three subpopulations for the five gene-specific markers and two distinct subpopulations for the 24 SSR markers, respectively. Neighbour joining-based clustering analysis categorized the 288 genotypes into two major clusters. Three markers were found to be significantly associated with CPMMV resistance. The BARCSOYSSR0558 marker showed the highest phenotypic variance of 9.6%. The present study will help in identification of CPMMV R genes and breeding new resistant varieties through marker-assisted selection.

Implementing deep‐learning techniques for accurate fruit disease identification

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Implementing deep-learning techniques for accurate fruit disease identification

To overcome the problem of manual identification of fruit disease here in this work we are proposing a deep-learning model to analyse fruit images to detect diseases the fruit is suffering from.


Abstract

To overcome the problems of manual identification of fruit disease, this work proposes a deep-learning model to analyse fruit images to detect diseases in the fruit. We are proposing here a convolutional neural network (CNN)-based model for fruit disease classification. By including many layers, the proposed CNN model extracts numerous features from the fruit, deals with the large data set and finally evaluates it. With the MobileNetv2 model, the disease prediction accuracy for papaya, guava and citrus was 99.4%, 98.8% and 95.8% and the recall values were 99.4%, 98.8% and 93.8%, respectively. With VGG16, the disease prediction accuracy for papaya, guava and citrus was 97.7%, 99.6% and 94.2% and the recall values were 96.5%, 99.6% and 89.2%, respectively. Finally, with DenseNet121, the disease prediction accuracy for papaya, guava and citrus was 99.4%, 97.6% and 99.2%, and the recall values were 98.8%, 97.6% and 99.2%, respectively.