Method of assessment of red leaf blotch on soybeans used to evaluate cultivar susceptibility and chemical control

Levy, C.; Mahuku, George; Tattersfield, J.R.; Cole, Desirée L.

doi:10.1016/0261-2194(90)90095-o

Cited by 7 publications

(4 citation statements)

References 5 publications

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“…These evaluations were carried out in regions where red leaf blotch is endemic (Sinclair 1989 ). A field method to assess the infection of soybean by the pathogen was developed and used to evaluate cultivar reaction and efficacy of chemical control (Levy et al 1990 ).…”

Section: Red Leaf Blotchmentioning

confidence: 99%

Breeding for disease resistance in soybean: a global perspective

et al. 2022

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Key message This review provides a comprehensive atlas of QTLs, genes, and alleles conferring resistance to 28 important diseases in all major soybean production regions in the world. Abstract Breeding disease-resistant soybean [Glycine max (L.) Merr.] varieties is a common goal for soybean breeding programs to ensure the sustainability and growth of soybean production worldwide. However, due to global climate change, soybean breeders are facing strong challenges to defeat diseases. Marker-assisted selection and genomic selection have been demonstrated to be successful methods in quickly integrating vertical resistance or horizontal resistance into improved soybean varieties, where vertical resistance refers to R genes and major effect QTLs, and horizontal resistance is a combination of major and minor effect genes or QTLs. This review summarized more than 800 resistant loci/alleles and their tightly linked markers for 28 soybean diseases worldwide, caused by nematodes, oomycetes, fungi, bacteria, and viruses. The major breakthroughs in the discovery of disease resistance gene atlas of soybean were also emphasized which include: (1) identification and characterization of vertical resistance genes reside rhg1 and Rhg4 for soybean cyst nematode, and exploration of the underlying regulation mechanisms through copy number variation and (2) map-based cloning and characterization of Rps11 conferring resistance to 80% isolates of Phytophthora sojae across the USA. In this review, we also highlight the validated QTLs in overlapping genomic regions from at least two studies and applied a consistent naming nomenclature for these QTLs. Our review provides a comprehensive summary of important resistant genes/QTLs and can be used as a toolbox for soybean improvement. Finally, the summarized genetic knowledge sheds light on future directions of accelerated soybean breeding and translational genomics studies.

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Section: Red Leaf Blotchmentioning

confidence: 99%

Breeding for disease resistance in soybean: a global perspective

et al. 2022

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“…Several methods have been developed to assess red leaf blotch. One study rated leaves positioned at the upper four nodes (Levy et al, 1990), while another rated the lowest attached leaf . In our study, leaves from lower nodes in the canopy had more disease, but were more variable in the level of infection than leaves from the upper canopy.…”

Section: Discussionmentioning

confidence: 99%

“…Field studies on red leaf blotch including disease development and assessment have been limited. One method of assessment used the lowest attached leaf , while another used the fully expanded leaves from the upper portion of the canopy (Levy et al, 1990). Neither of these assessments accounts for defoliation, which has been reported to be an important component of the disease syndrome (Javaid & Ashraf, 1978;Hartman et al, 1987).…”

Section: Introductionmentioning

confidence: 99%

Red leaf blotch (Dactuliochaeta glycines) of soybeans (Glycine max) and its relationship to yield

Hartman

Sinclair

1996

Plant Pathology

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Red leaf blotch of soybeans, caused by Dactuliochaeta glycines, was evaluated on soybean plants in field plots located in Zambia. Two experiments were conducted in each of two seasons. Experiment 1 had four cultivars that were either fungicide-sprayed or not sprayed. Disease severity was greatest on leaves at the lowest nodes from early vegetative through the reproductive growth stages. Area under the disease progress curve (AUDPC) values and percentage of nodes defoliated at growth stage R5 were significantly (P 0 . 05) greater in unsprayed plots for all cultivars in both seasons. Yield losses ranged from 8 to 37% while reduced seed size ranged from 21 to 29% for the four cultivars. Number of pods per plant in fungicide-sprayed plots did not differ from those in unsprayed plots. However, the number of seeds per plant and seeds per pod were significantly (P 0 . 05) greater in sprayed than unsprayed plots for some cultivars. In experiment 2, cultivar Tunia was either fungicide-sprayed at different times or not sprayed. The lowest attached leaf had the most variation in the amount of disease while ratings of the most median leaf in the canopy were generally less variable. The AUDPC values calculated from the lowest attached leaf, the mean of all attached leaves, and the median attached leaf differed significantly (P 0 . 05) the number of times plants were sprayed with fungicide. Defoliation and vertical incidence of red leaf blotch from lower to higher nodes were significantly (P 0 . 05) reduced in fungicide-sprayed plots in one season, but not the other. One thousand-seed weight and yield differed significantly (P 0 . 05) with treatment as one application of triphenyltin acetate increased yields by 18% over unsprayed plots in season 1. One thousand-seed weight and yield, regressed on the AUDPC for the median leaf in the canopy, explained 92 and 72% of the variation, respectively.

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“…The stages R4 to R6 are recognized as the best fit for disease scoring in soybean production [ 24 , 25 ]. The severity of the red leaf blotch disease was evaluated using a 0–5 scale, which has previously been used to score red leaf blotch disease in soybean [ 19 , 26 , 27 ]. This scale is based on the observed damage, such as the percentage of the leaf area affected, fragmentation of the leaf, presence of pycnidia on blotches, and the color and size of the blotches ( Table 2 ).…”

Section: Methodsmentioning

confidence: 99%

Genome-Wide Association Analysis for Resistance to Coniothyrium glycines Causing Red Leaf Blotch Disease in Soybean

Lukanda,

Dramadri,

Adjei

et al. 2023

Genes

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Soybean is a high oil and protein-rich legume with several production constraints. Globally, several fungi, viruses, nematodes, and bacteria cause significant yield losses in soybean. Coniothyrium glycines (CG), the causal pathogen for red leaf blotch disease, is the least researched and causes severe damage to soybean. The identification of resistant soybean genotypes and mapping of genomic regions associated with resistance to CG is critical for developing improved cultivars for sustainable soybean production. This study used single nucleotide polymorphism (SNP) markers generated from a Diversity Arrays Technology (DArT) platform to conduct a genome-wide association (GWAS) analysis of resistance to CG using 279 soybean genotypes grown in three environments. A total of 6395 SNPs was used to perform the GWAS applying a multilocus model Fixed and random model Circulating Probability Unification (FarmCPU) with correction of the population structure and a statistical test p-value threshold of 5%. A total of 19 significant marker–trait associations for resistance to CG were identified on chromosomes 1, 5, 6, 9, 10, 12, 13, 15, 16, 17, 19, and 20. Approximately 113 putative genes associated with significant markers for resistance to red leaf blotch disease were identified across soybean genome. Positional candidate genes associated with significant SNP loci-encoding proteins involved in plant defense responses and that could be associated with soybean defenses against CG infection were identified. The results of this study provide valuable insight for further dissection of the genetic architecture of resistance to CG in soybean. They also highlight SNP variants and genes useful for genomics-informed selection decisions in the breeding process for improving resistance traits in soybean.

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Method of assessment of red leaf blotch on soybeans used to evaluate cultivar susceptibility and chemical control

Cited by 7 publications

References 5 publications

Breeding for disease resistance in soybean: a global perspective

Breeding for disease resistance in soybean: a global perspective

Red leaf blotch (Dactuliochaeta glycines) of soybeans (Glycine max) and its relationship to yield

Genome-Wide Association Analysis for Resistance to Coniothyrium glycines Causing Red Leaf Blotch Disease in Soybean

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