scholarly journals Genetic Interactions Between Glycine max and Sclerotinia sclerotiorumUsing a Straw Inoculation Method

Plant Disease ◽  
2004 ◽  
Vol 88 (8) ◽  
pp. 891-895 ◽  
Author(s):  
J. Auclair ◽  
G. J. Boland ◽  
L. M. Kohn ◽  
I. Rajcan

Genetic interactions for disease response between cultivars of Glycine max and isolates of Scle-rotinia sclerotiorum were evaluated in controlled-environment inoculations of five soybean cultivars with four genetically unique isolates of S. sclerotiorum. The objective of this study was to identify host-pathogen interactions using isolates of the pathogen which had different geographical and crop-wise distribution as well as a different DNA-based fingerprint. To do so, 4-week-old soybean plants were inoculated with individual isolates of S. sclerotiorum using a straw inoculation method. Inoculated plants were incubated for 48 h in continuous leaf wetness and rated for disease severity 1 and 2 weeks after inoculation. Significant differences in disease severity were detected among the soybean cultivars, and NK S08-80 consistently had the lowest disease severity among the five cultivars tested. No significant differences in disease severity were observed among pathogen isolates and no significant interactions were detected between soybean cultivars and pathogen isolates. These results suggest the following interpretations: (i) either the clonal genotype of the four pathogen isolates as determined by mycelial compatibility and DNA fingerprint was not associated with level of virulence on the five soybean cultivars or (ii) the soybean cultivars themselves were not capable of revealing any differences in virulence among isolates that would be related to their genetic fingerprint or regional distribution. The results of this study are consistent with the practice of considering different isolates of S. scle-rotiorum sampled from soybean in the same geographical region as equivalent for the evaluation of soybean cultivars for resistance to Sclerotinia stem rot.

Plant Disease ◽  
2019 ◽  
Vol 103 (4) ◽  
pp. 677-684 ◽  
Author(s):  
Krishna Ghimire ◽  
Kristina Petrović ◽  
Brian J. Kontz ◽  
Carl A. Bradley ◽  
Martin I. Chilvers ◽  
...  

One hundred fifty-two Diaporthe isolates were recovered from symptomatic soybean (Glycine max) stems sampled from the U.S. states of Iowa, Indiana, Kentucky, Michigan, and South Dakota. Using morphology and DNA sequencing, isolates were identified as D. aspalathi (8.6%), D. caulivora (24.3%), and D. longicolla (67.1%). Aggressiveness of five isolates each of the three pathogens was studied on cultivars Hawkeye (D. caulivora and D. longicolla) and Bragg (D. aspalathi) using toothpick, stem-wound, mycelium contact, and spore injection inoculation methods in the greenhouse. For D. aspalathi, methods significantly affected disease severity (P < 0.001) and pathogen recovery (P < 0.001). The relative treatment effects (RTE) of stem-wound and toothpick methods were significantly greater than for the other methods. For D. caulivora and D. longicolla, a significant isolate × method interaction affected disease severity (P < 0.05) and pathogen recovery (P < 0.001). Significant differences in RTEs were observed among D. caulivora and D. longicolla isolates only when the stem-wound and toothpick methods were used. Our study has determined that the stem-wound and toothpick methods are reliable to evaluate the three pathogens; however, the significant isolate × method interactions for D. caulivora and D. longicolla indicate that multiple isolates should also be considered for future pathogenicity studies.


Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 887 ◽  
Author(s):  
Chang-Jie Jiang ◽  
Shoji Sugano ◽  
Sunao Ochi ◽  
Akito Kaga ◽  
Masao Ishimoto

Breeding for resistance to soybean red crown rot (Calonectria ilicicola) has long been hampered by the lack of genetic sources of adequate levels of resistance to use as parents. Mini core collections of soybean (Glycine max) originating from Japan (79 accessions), from around the world (80 accessions), and a collection of wild soybeans (Glycine soja) consisting 54 accessions were evaluated for resistance to C. ilicicola (isolate UH2-1). In the first two sets, average disease severity scores of 4.2 ± 0.28 and 4.6 ± 0.31 on a rating scale from zero for no symptom to 5.0 for seedling death were recorded from the set from Japan and the world. No high levels of resistance were observed in these two sets. On the other hand, disease severity score of 3.8 ± 0.35 for the wild soybean accessions was somewhat lower and exhibited higher levels of resistance compared to the soybean cultivars. Three accessions in the wild soybean collection (Gs-7, Gs-9, and Gs-27) had disease severity score ≤2.5 and showed >70% reduction in fungal growth in the roots compared to soybean control cv. “Enrei”. Further analysis using 10 C. ilicicola isolates revealed that accession Gs-9 overall had a wide range of resistance to all isolates tested, with 37% to 93% reduction in fungal growth relative to the cv. Enrei. These highly resistant wild soybean lines may serve as valuable genetic resources for developing C. ilicicola-resistant soybean cultivars.


Author(s):  
Denise Pauletto Spanhol ◽  
José Rogerio De Oliveira ◽  
Bianca Obes Corrêa ◽  
Ismail Teodoro de Souza Junior ◽  
Marcelo Vedovatto ◽  
...  

O presente estudo teve como objetivo avaliar o potencial de bactérias, na promoção de crescimento, produção de compostos de defesa e no biocontrole do mofo branco em folhas destacadas de duas cultivares de soja. Os ensaios foram realizados com as bactérias antagonistas FIT09 (Bacillus cereus) e FIT62 (B. thuringensis), do fungo Sclerotinia sclerotiorum e com as cultivares de soja M6210 IPRO e Brasmax Garra IPRO. Nos ensaios in vivo foram avaliados a capacidade das bactérias na promoção do crescimento de plantas de soja e na constituição dos compostos secundários produzidos pelas plantas oriundas de sementes microbiolizadas com suspensões bacterianas. Além disso, os ensaios de biocontrole do mofo branco, foram realizados com folhas destacadas em estádio V3, as quais foram pulverizadas com as suspensões das bactérias FIT09 e FIT62. As bactérias FIT09 e FIT62 apresentaram compatibilidade com B. japonicum e no ensaio de biocontrole com folhas destacadas, verificou-se que a FIT 09 reduziu o diâmetro das lesões necróticas causadas por S. sclerotiorum em ambas cultivares de soja avaliadas em teste de folhas destacadas. No ensaio de promoção de crescimento, as bactérias aumentaram o poder germinativo na cultivar M6210 IPRO. Para a avaliação da análise fitoquímica, as bactérias auxiliaram positivamente na produção dos compostos relacionados ao sistema de defesa. Palavras-chave: Metabólitos Secundários. Fitoquímica. Sclerotinia sclerotiorum. Bacillus, Glycine max   Abstract The present study aimed to evaluate the potential of bacteria, in the promotion of growth, production of compounds of defens, and in the biocontrol of white mold in detached leaves of two soybean cultivars. The tests were performed with the antagonist bacteria FIT09 (Bacillus cereus) and FIT62 (B. thuringensis), with the fungus Sclerotinia sclerotiorum and with the soybean cultivars M6210 IPRO and Brasmax Garra IPRO. In vivo tests evaluated the capacity of bacteria to promote the growth of soybean plants and the constitution of secondary compounds produced by plants from microbiolized seeds with bacterial suspensions. In addition,  white mold biocontrol bioassays were carried out with detached leaves in stage V3 and they were sprayed with suspensions of the bacteria FIT09 and FIT62.The bacteria FIT09 and FIT62 were compatible with B. japonicum and in the biocontrol assay with detached leaves, it was found that FIT09 promoted superior control of 70% against the disease in both cultivars, however the disease did not manifest in the assay in plants. In the growth promotion test, the bacteria increased the germinative power in cultivar M6210 IPRO, for the assessment of fresh and dry mass there were no differences and for phytochemical analysis, the bacteria positively helped in the production of compounds related to the defense system.   Keywords: Secondary Metabolites. Phytochemistry, Sclerotinia sclerotiorum. Bacillus, Glycine max


Plant Disease ◽  
2021 ◽  
Author(s):  
Richard Wade Webster ◽  
Mitchell Roth ◽  
Brian Mueller ◽  
Daren S. Mueller ◽  
Martin I Chilvers ◽  
...  

Soybean (Glycine max) farmers in the Upper Midwest region of the United States frequently experience severe yield losses due to Sclerotinia stem rot (SSR). Previous studies have revealed benefits of individual management practices on SSR. This study examined the integration of multiple control practices on the development of SSR, yield, and the economic implications of these practices. Combinations of row spacings, seeding rates, and fungicide applications were examined in multi-site field trials across the Upper Midwest from 2017-2019. These trials revealed that wide row spacing and low seeding rates individually reduced SSR levels but also reduced yields. Yields were similar across the three higher seeding rates examined. However, site-years where SSR developed showed the highest partial profits in the intermediate seeding rates. This indicates that partial profits in diseased fields were negatively impacted by high seeding rates, but this trend was not observed when SSR did not develop. Fungicides strongly reduced the development of SSR, while also increasing yields. However, there was a reduction in partial profits due to their use at a low soybean sale price, but at higher sale prices fungicide use was similar to not treating. Additionally, the production of new inoculum was predicted from disease incidence, serving as an indicator of increased risk for SSR development in future years. Overall, this study suggests the use of wide rows and low seeding rates could be useful in fields with a history of SSR, while reserving narrow rows and higher seeding rates for fields without a history of SSR.


Proceedings ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 195
Author(s):  
Rashmi Yadav ◽  
J. Nanjundan ◽  
Ashish K. Gupta ◽  
Mahesh Rao ◽  
Jameel Akhtar ◽  
...  

In rapeseed and mustard, the major diseases (downy mildew, white rust, Alternaria blight and Sclerotinia stem rot) cause 37–47%loss in pod formation and 17–54% reduction in grain yield. The identification of new sources of resistance is a high priority in breeding programs. About 3000 germplasm accessions of Indian mustard were evaluated under multiple environments (3 seasons) at hot spots (4 locations) and under artificial epiphytophic conditions against insect pests and diseases (aphids, white rust, powdery mildew and Alternaria blight). Accessions IC265495, IC313380, EC766091, EC766133, EC766134, EC766192, EC766230, EC766272 were identified as highly resistant to white rust (A. candida) with disease severity reaction (Percent disease severity Index, PDI = 0) under artificial inoculation. Accession RDV 29 showed the inheritance of resistant source for powdery mildew in Indian mustard. Screening of brassica wild relatives (about 25 species) for white rust found that Brassica fruticulosa, Brassica tournefortii, Camelina sativa, Diplotaxis assurgens, D. catholica, D. cretacia, D. Erucoides, D. Muralis, Lepidium sativum had highly resistance (PDI = 0) to Delhi isolates of white rust. Several traits identified from cultivated and related species will be useful for genetic improvement of rapeseed and mustard.


1989 ◽  
Vol 3 (4) ◽  
pp. 566-572 ◽  
Author(s):  
W. W. De Weese ◽  
L. M. Wax ◽  
W. C. Carlson ◽  
J. A. Ciarletta

Experimental objectives were to assess metribuzin tolerance of predominately privately developed soybean cultivars and to evaluate a greenhouse screening procedure. In field results in 1982, ‘Vinton 81’, ‘Northrup King 1884’ and ‘L77-1863’ soybean cultivars were extremely sensitive to metribuzin at 0.56 kg/ha, averaging 34% injury. The other 45 cultivars showed no significant injury at the 0.56 kg/ha rate, from 9 to 46% injury at 1.4 kg/ha, and 18 to 72% injury at 2.2 kg/ha. In greenhouse hydroponic studies, these same three soybean cultivars were killed, while the other 45 cultivars were injured from 15 to 82%. A good agreement of greenhouse and field data was determined, with a correlation coefficient of r = 0.82.


1993 ◽  
Vol 7 (2) ◽  
pp. 343-348 ◽  
Author(s):  
Carroll Moseley ◽  
Kriton K. Hatzios ◽  
Edward S. Hagood

The uptake, translocation, and metabolism of the ethyl ester of chlorimuron in three soybean cultivars and two morningglory species was investigated. Soybean used included the normal cultivars ‘Vance’ and ‘Essex,’ and the sulfonylurea-resistant cultivar ‘W-20.’ Entireleaf morningglory and pitted morningglory, both moderately tolerant to chlorimuron, were used. Twenty-day-old seedlings of all plant species were exposed to root-applied14C-labeled chlorimuron for 6, 24, and 72 h. After 24 and 72 h, chlorimuron uptake was lowest in W-20 soybean and the two morningglory species. Translocation of root-absorbed chlorimuron to shoots and leaves of all species was limited and it did not differ among species. The moderate tolerance of pitted and entireleaf morningglories to chlorimuron may be due to reduced herbicide uptake. The response of Essex and Vance soybean to chlorimuron was related to herbicide metabolism. At 6 h after treatment with radiolabeled chlorimuron, Essex soybean metabolized the herbicide more rapidly than either W-20 or Vance soybean. At 24 h and 72 h, Essex and Vance soybean metabolized chlorimuron to the same extent. W-20 was not very efficient in metabolizing chlorimuron at any time after treatment and its resistance to chlorimuron is due to an altered target site.


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