scholarly journals Screening coffee genotypes for Cercospora coffeicola resistance in Brazil

2021 ◽  
Author(s):  
Juliana Barros Ramos ◽  
Mario Lucio Vilela de Resende ◽  
Deila Magna dos Santos Botelho ◽  
Renata Cristina Martins Pereira ◽  
Tharyn Reichel ◽  
...  

Several efforts have been made by many researchers worldwide to develop coffee plants resistant to different Cercospora species; however, studies concerning C. coffeicola , specifically, are still incipient. In the present study, a blend of strains from this pathogen was inoculated into 18 Brazilian commercial cultivars, a coffee clone of Arabica, as well as into 41 accessions from the Germplasm Collection of Minas Gerais, to evaluate the genetic resistance ability within the population and select superior genotypes for the breeding program. After predicting genotypic values of the evaluated material, the most efficient way to select genotypes based on the data of severity to brown eye spot (BES) was also examined. Moreover, the action of defense mechanisms against C. coffeicola attacks was investigated by assessing the levels of total soluble phenolic compounds and soluble lignin in contrasting genotypes regarding disease susceptibility. Based on the results, the accession MG 1207 Sumatra demonstrated an intrinsic genetic capacity to maintain low levels of severity to brown eye spot. This genotype can thus substantially contribute to the development of new cultivars, which may lead to reduced use of pesticides. This study also evidenced that four evaluations of severity is enough to reach accuracy and efficiency for the severity of BES, thus providing expressive genetic gains. Finally, it is suggested that the levels of lignin and phenolic compounds are not associated with the resistance of coffee genotypes to brown eye spot.

2016 ◽  
Vol 1 (2) ◽  
pp. 78 ◽  
Author(s):  
Yuza Defitri

AbstractThe research about the observation of diseases that attack Coffee plants (Coffea sp.) in Mekar Jaya village Betara subdistrict Tanjung Jabung Barat Regency,  and Agriculture Quarantine Laboratory Jambi had been done for six months. The aim of this research is to identification the disease that attack coffee plants. The research was conducted by observing the disease which in coffea plants area, and  identificaton pathogenic fungi in laboratory by moist chamber method using microscop and also fungi identifications book. The result of this research showed that there were three pathogenic fungies which attack Coffee plants namely: 1) Hemileia sp wich caused coffee leaft rust disease, 2) Cercospora coffeicola wich caused Brown eye-spot disease, and 3) Upasia salmanicolor wich caused  Upas fungi disease.  Keywords : Pathogenic fungi, Cooffee Plants Disease, Coffee Plants. AbstrakPenelitian tentang pengamatan beberapa penyakit yang menyerang tanaman Kopi (Coffea sp) di desa Mekar Jaya kecamatan Betara kabupaten Tanjung Jabung Barat dan di Laboratorium Karantina Pertanian Jambi telah dilakukan selama 6 bulan.  Tujuan penelitian adalah untuk mengetahui penyakit yang menyerang tanaman kopi.  Penelitian dilakukan dengan mengamati gejala penyakit di lapangan dan mengidentifikasi jamur patogen di laboratorium secara moist chamber dengan menggunakan mikroskop dan buku identifikasi jamur. Hasil penelitian menunjukkan bahwa ditemukan tiga jamur patogen yang menyerang tanaman kopi yaitu: 1) . Hemileia sp penyebab penyakit Karat Daun 2) Cercospora coffeicola penyebab penyakit Bercak Daun, 3) Upasia salmanicolor penyebab penyakit Jamur upas. Kata Kunci : Jamur Patogen, Penyakit tanaman kopi, Tanaman kopi


2012 ◽  
Vol 36 (4) ◽  
pp. 383-390 ◽  
Author(s):  
Ricardo Borges Pereira ◽  
Gilvaine Ciavareli Lucas ◽  
Fabiano José Perina ◽  
Pedro Martins Ribeiro Júnior ◽  
Eduardo Alves

The rust and brown eye spot are the main coffee diseases. The losses are due to intense defoliation of plants, which has reduced its production and longevity. The brown eye spot also occurs in fruits, with negative effects on the beverage quality. Some essential oils have presented promising results in the control of plant diseases, as an alternative to the use of fungicides. The objective of this study was to evaluate citronella essential oil in the control of rust and brown eye spot and in the activation of coffee plants defense responses. Twelve-month-old plants were sprayed with citronella oil 1000 µL L-1, acibenzolar-S-methyl 200 mg L-1 and tebuconazole fungicide 200 mg L-1. Plants were inoculated with Hemileia vastatrix and Cercospora coffeicola seven days later. The application was repeated after 30 days. Plants with five months were sprayed with the same treatments to assess the induced defense responses. Citronella oil controlled rust and brown eye spot with efficiencies of 47.2% and 29.7%, respectively, while tebuconazole presented control of 96.5% and 90.5%, respectively. Acibenzolar-S-methyl reduced brown eye spot by 55.9% and showed no significant control of rust. Citronella oil increased peroxidase and chitinase activities in five months coffee plants 336, and 24 and 336 hours after spraying, respectively. Acibenzolar-S-methyl increased peroxidase, chitinase and ββ-1,3-glucanase activities 192, 288 and 336; 24 and; 240 hours after spraying, respectively. The treatments did not increase accumulation of phenols, but a significant increase in lignin was observed in plants sprayed with citronella oil.


2019 ◽  
Vol 14 (1) ◽  
pp. 1
Author(s):  
Marie Caroline Ferreira Laborde ◽  
Deila Magna dos Santos Botelho ◽  
Gabriel Alfonso Alvarez Rodriguez ◽  
Mário Lúcio Vilela de Resende ◽  
Marisa Vieira de Queiroz ◽  
...  

<p>Saprobe fungi and necrotrophic pathogens share the same niche within crop stubble and the search for fungi non-pathogenic to plants that are able to displace the plant pathogens from its overwintering substrate contributes to the disease management. Brown eye spot (<em>Cercospora coffeicola</em>) is among the most important coffee diseases, it is caused by a necrotrophic pathogen that has decaying leaves as its major source of inoculum. We have screened saprobe fungi for the ability to reduce <em>C. coffeicola</em> sporulation and viability and determined the possible mechanisms involved in the observed biocontrol. A selected saprobe fungus, <em>Phialomyces macrosporus</em>, reduced the pathogen’s viability by 40% both <em>in vitro</em> and <em>in vivo</em>. The fungus acts through antibiosis and competition for nutrients. It produced both volatile and non-volatile compounds that inhibited <em>C. coffeicola</em> growth, sporulation, and viability. It also produced the tissue maceration enzyme (polygalacturonase), which reduces the pathogen both in detached leaves or in planta. The reduction in the fungal viability either by the saprobe fungus or its polygalacturonase-fraction supernatant resulted in the reduction of the disease rate. Therefore, <em>P. macrosporus </em>is a potential microbial agent that can be used in an integrated management of brown eye spot through the reduction of the initial inoculum of the pathogen that survives and builds up in infected leaves.</p><p> </p>


2014 ◽  
Vol 45 (2) ◽  
pp. 335-341 ◽  
Author(s):  
Tânia da Silveira Agostini-Costa ◽  
Ana Flávia Pádua Teodoro ◽  
Rosa de Belem das Neves Alves ◽  
Leandro Ribeiro Braga ◽  
Ieler Ferreira Ribeiro ◽  
...  

The objective of this study was to characterize for the first time polyphenols and DPPH (2-diphenyl-1-picryhydrazyl radical) antioxidant activity in commonly cultivated accessions of Phaseolus lunatus from an ex situ germplasm collection maintained by Embrapa, in Brazil. Furthermore, the study aimed to detect changes in total polyphenols, total flavonoids and condensed tannin for the same accessions after regeneration in a greenhouse. The results showed the diversity of the lima bean collection for phenolic compounds, which were strongly correlated with antioxidant activity. Lima beans accessions with the highest polyphenols and antioxidant activity were those with colored seeds. Conservation through cold storage of P. lunatus seeds in a cold chamber in the germplasm collection did not necessarily affect phenolic compounds. Variations observed in values after regeneration seeds may be mainly results of biotic and abiotic factors, including not only cultivar, but also environmental conditions. This study suggests that polyphenols in the lima beans present antioxidant activity, with possible beneficial effects for human health. It was expected that the potential of this tasty legume can be also used as a functional food crop and/or as a new ingredient in gastronomy.


Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1799
Author(s):  
Eleonora Barilli ◽  
Juan Moral ◽  
Thaïs Aznar-Fernández ◽  
Diego Rubiales

Anthracnose, caused by the fungal pathogen Colletotrichum lentis, is a severe disease of lentil (Lens culinaris) causing premature defoliation, necrotic stem lesions that lead to plant wilting and death in susceptible varieties. Two races of C. lentis (0 and 1) have been described so far. Race 0 is the most virulent one and limited genetic resistance is available to date. To address this scarcity of resistance, we screened a germplasm collection covering different Lens spp. originating from different countries for C. lentis race 0 resistance. Leaf and stem damage and plant mortality were assessed on seedlings inoculated under controlled conditions. A significant variability was observed among accession. Most of the collection studied was highly susceptible, but some levels of resistance were identified in about 15% of the accessions. The highest levels of resistance were identified in L. ervoides accessions PI572330, PI572334 and PI572338. Moderate resistance was also identified in 10 L. culinaris ssp. culinaris accessions but not in the remaining species studied. Selected accessions showed potential to integrate several breeding programs.


2016 ◽  
Vol 164 (10) ◽  
pp. 791-800 ◽  
Author(s):  
Paulo V. A. Azevedo de Paula ◽  
Edson A. Pozza ◽  
Leandro A. Santos ◽  
Eugênio Chaves ◽  
Matheus P. Maciel ◽  
...  

2009 ◽  
pp. 835-840 ◽  
Author(s):  
M. Neamtu ◽  
A. Barbulescu ◽  
A. Petcu ◽  
A. Ilie ◽  
M.-M. Vlad ◽  
...  

2020 ◽  
Vol 20 (2) ◽  
pp. 43
Author(s):  
Nafisah Nafisah ◽  
Celvia Roza ◽  
Nani Yunani ◽  
Aris Hairmansis ◽  
Tita Rostiati ◽  
...  

<p class="abstrakinggris">Hundred of high yielding and bacterial leaf blight (<em>Xanthomonas oryzae</em> pv. <em>oryzae, Xoo</em>) resistant rice varieties released since the 1960s are important sources of genetic materials for exploring superior genotypes. The study aimed to evaluate the genetic resistance of 177 rice varieties to <em>Xoo</em> and their agronomic traits. The evaluations were conducted at the Indonesian Center for Rice Research Experimental Station during the wet season (December 2015-March 2016). The bacterial leaf blight resistance was evaluated for <em>Xoo</em> pathotypes III, IV, and VIII using the clipping method. The genetic variation among genotypes was categorized as low (0–10%), medium (10–20%), and high (&gt;20%), whereas the heritability was categorized as low (0-30%), medium (30-60%), and high (&gt;60%). The variability of resistance to <em>Xoo</em> pathotypes, grain yield, and spikelet fertility was low, while the variability of plant height, productive tiller number, filled grain, and total spikelet was medium, and the variability of unfilled grain number was high. The 29 varieties  were categorized as superior based on their agronomic traits or resistance to <em>Xoo</em> pathotypes. In conclusion, Batutegi and Fatmawati were superior in the total spikelet number, while Rojolele and Inpari 2 were supreme in the thousand-grain weight. Dodokan had a very short maturity, and Inpari 24, Conde, Kalimas, Angke, Inpari 17, and Inpara 8 had the highest resistance to <em>Xoo</em> pathotypes. The study implies that the identified rice superior genotypes could be used as genetic materials to design cross combinations for higher yield potential and BLB resistance varietal improvement.</p>


HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 446D-446
Author(s):  
E. Bruton Strange ◽  
Todd C. Wehner ◽  
Zvezdana Pesic-Van Esbroeck

Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] is a major crop in the southern U.S., where the most important virus diseases are papaya ringspot virus (PRSV), watermelon mosaic virus-2, and zucchini yellow mosaic. The most economical control of virus diseases of watermelon is probably through genetic resistance. Watermelon has not been screened extensively for resistance to PRSV. The objective of this research was to develop a suitable method for screening watermelons for resistance to PRSV and then to screen the USDA germplasm collection. To date, we have developed an effective method and have nearly completed the screening. Several of the 1283 accessions have shown resistance to the virus. Methods tests involved 10 isolates of PRSV, several watermelon accessions and multiple inoculation procedures. Seedlings were screened in greenhouse flats with six replications per test. Tests were rated visually on a 0 to 9 scale (0 = no damage, 9 = plant dead), as well as with ELISA to detect the presence of virus. The watermelon germplasm collection was screened in four separate runs of 1283 accessions with `Charleston Gray' as the susceptible check. This research will be useful for those interested in effective screening methods, and sources of resistance for development of improved watermelon cultivars.


Author(s):  
İlkay Yavaş ◽  
Aydın Ünay ◽  
Shafaqat Ali ◽  
Zohaib Abbas

Ultraviolet-B (UV-B: 280 to 320 nm) radiations have appeared to be detrimental to plants, due to their damaging effects on proteins, lipids, membranes and DNA. UV-B radiations are a significant regulator of plants’ secondary metabolites. High intensity of ultraviolet radiations may interfere with growth and productivity of crops. But low levels of UV-B radiations give rise to changes in the plants’ secondary metabolites such as phenolic compounds, carotenoids and glucoseinolates. Therefore, low intensity of UV-B radiations may be used to generate plants, enriched with secondary metabolites, having improved reproductive ability, early ripening and tolerance against fungi, bacteria and herbivores.


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