scholarly journals Fitness Evaluation of Phytophthora infestans Isolates Collected from Punjab, Pakistan During 2017-18

2019 ◽  
Vol 39 (04) ◽  
Author(s):  
Waqas Raza ◽  
Muhammad Usman Ghazanfar ◽  
Muhammad Imran Hamid
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Potato Crop ◽  
Lesion Size ◽  
Management Approach ◽  
Fitness Evaluation ◽  
Pathogen Fitness ◽  
Detached Leaves ◽  
Fitness Parameters ◽  
Experimental Findings

Potato late blight (Phytophthora infestans) is an important disease causing severe damage in potato crop worldwide. Seventy seven isolates of P. infestans selected on the basis of aggressiveness were characterized for pathogen fitness test based on their lesion size, latent incubation period and sporulation capacity after their inoculation onto detached leaves of potato. The results showed that large variations in pathogen fitness were present among isolates for each regional P. infestans population studied. Those isolates selected during 2017-18 exhibited 85% and 74% successful pathogen fitness behavior respectively. Those isolates which had higher composite fitness index values were observed higher lesion size and spore count and same trend of pathogen fitness parameters was observed with respect to their districts during both the years.This is the first inclusive study to determine pathogen fitness of isolates in Pakistan. The experimental findings indicated that population of P. infestans in the Punjab province comprises diverse isolates with low to high fitness potential. A future challenge planned to combine our accumulated knowledge with that from other scientific fields to develop a disease management approach for late blight.

scholarly journals Virulence of Phytophthora infestans isolates from potato in Spain

2021 ◽  
Vol 57 (No. 4) ◽  
pp. 279-288
Author(s):  
Jose Ignacio Ruiz de Galarreta ◽  
Alba Alvarez-Morezuelas ◽  
Nestor Alor ◽  
Leire Barandalla ◽  
Enrique Ritter
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Late Blight Resistance ◽  
Blight Resistance ◽  
Genetic Changes ◽  
Detached Leaves ◽  
Severity Of The Disease ◽  
Pathogen Populations ◽  
Incompatibility Reactions

The oomycete Phytophthora infestans is responsible for the disease known as late blight in potato and tomato. It is the plant pathogen that has caused the greatest impact on humankind so far and, despite all the studies that have been made, it remains the most important in this crop. In Spain during the last years a greater severity of the disease has been observed in both, potato and tomato, probably due to genetic changes in pathogen populations described recently. The aim of this study was the characterization of the physiological strains of 52 isolates of P. infestans obtained in different potato-growing areas in Spain. For this purpose, inoculations on detached leaves were performed in order to determine compatibility or incompatibility reactions. A total of 17 physiological races were found. The less frequent virulence factors were Avr5 and Avr8. By studying the epidemiology of the pathogen, a specific breeding program for late blight resistance can be implemented.

scholarly journals Sprinkling Irrigation Enhances Production of Oospores of Phytophthora Infestans in Field-Grown Crops of Potato

2000 ◽  
Vol 90 (10) ◽  
pp. 1105-1111 ◽  
Author(s):  
Yigal Cohen ◽  
Sonja Farkash ◽  
Alexander Baider ◽  
David S. Shaw
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Field Experiments ◽  
Soil Surface ◽  
Field Trials ◽  
Detached Leaves ◽  
Oospore Formation ◽  
Potato Crops ◽  
Host Tissues

Two field experiments were conducted to study the effect of overhead sprinkling irrigation on oospore formation by the late blight fungus Phytophthora infestans in potato. Total rain (natural + sprinkling) accumulated in treatments of experiment 1 (winter 1997 to 1998) were 765, 287, and 219 mm and treatments of experiment 2 (winter 1999 to 2000) were 641, 193, and 129 mm. Sporangia from 11 isolates of P. infestans were combined in eight pairs, seven of A1 and A2 and one of A2 and A2 mating type, and were sprayed on field-grown potato crops (42 plants per plot at 7 m2 each) and examined for their ability to form oospores in the host tissues. In experiment 1, oospores were recorded in a total of 132 of 1,680 leaflets (7.9%), 24 of 105 stems, and 2 of 90 tubers. In experiment 2, oospores were recorded in 40 of 519 leaflets (7.7%), but not in any of the 90 stems or the 45 tubers examined. Both the proportion of leaflets containing oospores and the number of oospores per leaflet increased with time after inoculation and were dependent on the rain regime, the position of leaves on the plant, and the isolate pair combination. In both field trials, increasing the rainfall significantly enhanced oospore production in leaves. Leaf samples collected from the soil surface had significantly more oospores than those collected from the midcanopy. Two pairs in experiment 1 were more fertile than the others, whereas the pair used in experiment 2 was the least fertile. The total number of oospores per leaflet usually ranged from 10 to 100 in experiment 1, but only from 2 to 10 in experiment 2. Maximal oospore counts in the field were 200 and 50 in experiments 1 and 2, respectively, but ranged from ≈2,000 to 12,000 oospores per leaflet in detached leaves in the laboratory. We concluded that P. infestans can produce oospores in the foliage of field-grown potato crops, especially when kept wet by regular overhead sprinkling irrigation, but production was far below that in the laboratory.

Identification and Screening of Introduced Tomato Varieties Resistant to late Blight

2012 ◽  
Vol 610-613 ◽  
pp. 3472-3477
Author(s):  
Dan Luo ◽  
Xi Chun Zhang ◽  
Xiao Han Wen
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
New Disease ◽  
Tomato Production ◽  
Disease Resistant ◽  
Resistant Varieties ◽  
Detached Leaves ◽  
Late Blight Disease ◽  
Blight Disease ◽  
Selection Of

Tomato late blight disease that infected by Phytophthora infestans (Mont.) de Bary has already become one of the main obstacles that influence the tomato production. To resolve tomato late blight disease, cultivating the disease-resistant breed is importance. Based on the previous study, different introduced varieties were used as materials in this test for the identification and varieties selection of tomato resistant to late blight, by measuring the DIS of inoculated seedlings and detached leaves. It indicated that Jingle 502 and O-33-1 are possible to become resistant varieties to late blight or the parents for cultivating new disease resistant varieties.

scholarly journals Infection of Potatoes by Oospores of Phytophthora infestans in Soil

Plant Disease ◽  
1999 ◽  
Vol 83 (9) ◽  
pp. 876-876 ◽  
Author(s):  
A. Strömberg ◽  
L. Persson ◽  
M. Wikström
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Potato Crop ◽  
Selective Medium ◽  
Day Length ◽  
Talcum Powder ◽  
Soil P ◽  
Nodal Cuttings

Phytophthora infestans (Mont.) de Bary, causing late blight on potatoes and considered to be a typical airborne disease, was found to be infective also by oospores in the soil. P. infestans is heterothallic, and is known to reproduce asexually in Sweden since only one mating type, A1, was present until 1986. Since the 1970s, the other mating type, A2, of P. infestans has migrated to most parts of the world from its original location in central Mexico (2). When A1 and A2 meet, they may form oospores, which are thick-walled, resting structures, giving the pathogen a possibility to recombine as well as survive without its host, for instance in the soil. The soil stages of the pathogen are now therefore under intense investigation. Oospores of P. infestans were produced from two Scandinavian A1 and A2 isolates in Rye A broth mixed with talcum powder and dried for 7 weeks. The inoculum was mixed with sterile, standardized soil in concentrations of 10, 150, 250, and 400 oospores per ml of soil. Cv. Bintje plants cultivated in vitro from nodal cuttings on Murashige and Skoog medium were transplanted to the soil after rooting. Brown discolorations were obtained on the underground stems and tubers on potato plants grown in the two highest concentrations of oospores for 1 month at 15°C and 16-h day length. After 3 days of incubation on P. infestans-selective medium (3), sporangia covered the tissue from plants grown in 250 and 400 oospores per ml of soil and the pathogen was reisolated. This shows that germinating oospores of P. infestans can infect underground stems and tubers of potatoes in soil and further explains the early attack of late blight as observed in a potato crop in Sweden 1996 and 1997 (1). References: (1) B. Andersson et al. Potato Res. 41:305, 1998. (2) D. Andrivon. Phytopathology 85:1053, 1995. (3) G. W. Griffith et al. Mycologist 9:87, 1995.

Accumulation of hypoxanthine in potato leaves and its effect on spore germination in Phytophthora infestans

1968 ◽  
Vol 46 (3) ◽  
pp. 267-270 ◽  
Author(s):  
M. C. Clark ◽  
O. T. Page
Keyword(s):  
Aqueous Solution ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
Spore Germination ◽  
Detached Leaves ◽  
Whole Plants

The accumulation of hypoxanthine (6-hydroxypurine) in blighted potato leaves and its effect on spore germination in the late blight organism, Phytophthora infestans, were investigated. Preliminary experiments on the translocation of this compound in whole plants and detached leaves were also conducted.Under in vitro and in vivo conditions, hypoxanthine had a pronounced stimulatory effect on the indirect germination of sporangia. Studies on the movement of this base indicate that it is freely translocated, but fails to be exported from detached leaves into aqueous solution. These observations, coupled with the finding that hypoxanthine readily accumulated in blighted leaves, suggest that this compound could be of importance in predisposing uninfected portions of the host to invasion by the pathogen.

scholarly journals Evaluasi Resistensi dan Daya Hasil Enam Klon Harapan Kentang Transgenik Terhadap Serangan Penyakit Hawar Daun (Evaluation of Resistance to Late Blight and Tuber Yield of Six Potential Potato Transgenic Clones)

2019 ◽  
Vol 28 (1) ◽  
pp. 41
Author(s):  
NFN Kusmana ◽  
Alberta Dinar Ambarwati
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Tuber Yield ◽  
Potato Crop ◽  
Transgenic Potato ◽  
Yield Component ◽  
Experimental Unit ◽  
Plant Vigor ◽  
Main Plot ◽  
Rb Gene

<p>Penyakit hawar daun (Phytophthora infestans) merupakan salah satu penyakit utama pada tanaman kentang. Kerusakan yang berat akibat penyakit hawar daun dapat menyebabkan kehilangan hasil panen sampai 80%. Gen pembawa ketahanan terhadap penyakit hawar daun dikenal dengan nama gen RB dan telah berhasil dimasukkan ke dalam genom kentang dan menghasilkan kentang transgenik. Tujuan penelitian untuk menguji ketahanan enam klon kentang transgenik terhadap serangan penyakit hawar daun (P. infestans) dan daya hasil. Penelitian dilakukan di Lapangan Uji Terbatas Desa Citere, Kecamatan Pangalengan, Kabupaten Bandung, 1.400 m di atas permukaan laut. Rancangan percobaan menggunakan rancangan petak terpisah, dengan petak utama perlakuan tidak disemprot fungisida dan disemprot fungisida dua kali seminggu dan anak petak 10 genotipe kentang yang terdiri atas enam hibrida kentang transgenik, satu genotipe kentang transgenik Katahdin SP951 sebagai pembanding resisten dan tiga varietas pembanding rentan kentang nontransgenik Granola, Atlantic, dan Katahdin. Jumlah ulangan tiga kali dengan populasi tanaman terdiri atas 50 tanaman/plot. Pengamatan dilakukan terhadap vigor tanaman, insiden serangan hawar daun, dan komponen hasil. Hasil pengamatan menunjukkan bahwa untuk vigor tanaman tidak terjadi interaksi serta antarperlakuan tidak berbeda nyata. Genotipe yang resisten terhadap hawar daun adalah klon 20, 27, 65, dan 66 setara dengan kontrol positif Katahdin SP951 dan nyata lebih resisten dari varietas pembanding Granola, Atlantic, dan Katahdin. Klon yang resisten terhadap hawar daun menampilkan hasil yang tinggi pada plot tidak disemprot fungisida, sementara pada plot disemprot fungisida 20 kali semua genotipe menampilkan hasil optimalnya. Tingkat kehilangan hasil mencapai 18,8–84,4%. Genotipe dengan intensitas serangan hawar daun tinggi memiliki tingkat kehilangan hasil yang juga tinggi. Klon 20 dan 27 menampilkan daya hasil yang relatif tinggi dengan penundaan penggunaan fungisida 7 minggu setelah tanam.</p><p><strong>Keywords</strong></p><p>Genotipe; <em>P. infestans; Solanum tuberosum</em> L</p><p><strong>Abstract</strong></p><p>Late blight (Phytophthora infestans) is one of main potato diseases. Due to severe damage to late blight potato, crop will be cause lost of harvest up to 80%. Gene carriers of resistance to late blight known as the RB gene and have been incorporate into the genom of potato and produce transgenic potato. The objective of the research was to test six advanced transgenic potato clones for resistance to late blight (Phytophthora infestans). The research was conducted at Confined Field Trial at Citere Village, Pangalengan District Bandung (1,400 m above sea level). The experimental design was split plot. The main plot was spray with fungicides twice/week and was replicated three times. Subplot were 10 potato genotypes, consists of six transgenic potato hybrids, transgenic Katahdin SP951 as resistant check and three varieties of nontransgenic as susceptible check, i.e. Granola, Atlantic, and Katahdin.  An experimental unit consists of 50 plants/plot, every treatment with three replicates. Plant observed were plant vigor, intensity of late blight damage, tuber yield component, and lost of yield. The result showed that there were no interaction of plant vigor and also all the treatmens were not significantly different. Transgenic potato clones of 20, 27, 65, 66, and Katahdin SP951 were resistant to late blight compare to check varieties of Granola, Atlantic, and Katahdin. The highest yielding at none spraying of fungicides were obtained from the resistance clones. Whereas,  on the 20 sprayed fungicides all of  the clones were high yielding. Tuber yield lossed ranged from 18,8–84,4%, the susceptible genotypes were also showed high losses. Clones 20 and 27 showed reletive high yielding and can be delayed application fungicides for period of 7 weeks after planting. </p>

scholarly journals Genotype reaction of Solanum tuberosum, andigena and phureja groups to late blight (Phytophthora infestans Mont. De Bary)

2019 ◽  
Vol 36 (E) ◽  
pp. 138-157
Author(s):  
Jennyfer Moncayo ◽  
Roberth Delgado ◽  
Carlos Marcillo ◽  
Claudia Salazar ◽  
Carlos Betancourth
Keyword(s):  
Solanum Tuberosum ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
Potato Crop ◽  
Block Design ◽  
Food Product ◽  
Randomized Complete Block Design ◽  
Late Blight Disease ◽  
Disease Effect ◽  
Blight Disease

Potato crop is the fourth main food product in the world, but is affected by Phytophthora infestans, the late blight disease causal agent. This research was carried out in a town of Pasto high plateau, South of Colombia. In order to evaluate the reaction of different genotypes of creole potato (Solanum tuberosum groups Phureja and Andigena) with regard the disease. A Randomized Complete Block design was established with three repetitions, where 30 genotypes were distributed and three plants were evaluated per repetition during two crop cycles in natural exposure to the pathogen. To assess the disease effect on production, the same genotypes were maintained with chemical control in an adjacent batch. Genotypes classified as tolerant are Chaucha Manzana, Cachuda, Criolla Colombia, Malvaseña, Andina and Criolla, during the first cycle with performance values ​​between 23 to 26t.ha-1 and during the second to Calavera Negra, Chaucha Paisa, Ratona, Criolla Galeras, Ratona Roja, Tornilla Roja and Aguacata with performance values ​​between 23 to 28t.ha-1. The graphic severity scale allowed genotypes to be categorized as susceptible and highly susceptible. The results indicate that for the prevalent pathogen race in this study area, there are no resistance sources within the studied collection. However, genotypes such as Criolla Colombia and Andina showed a better performance in terms of yield.

scholarly journals Practical experience with antiresistance strategies in the fungicides control of potato late blight

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 684-687
Author(s):  
P. Doležal ◽  
E. Hausvater ◽  
V. Táborský
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Fungicide Resistance ◽  
Potato Crop ◽  
Potato Late Blight ◽  
Practical Experience ◽  
Reproductive Cycles ◽  
Seed Crops ◽  
Disease Pressure ◽  
Potato Crops

Pathogens with rapid reproductive cycles, producing large number wind-spread dispersed infection propagules like sporangiospores, are more likely to pose problems of resistance than slowly reproducing pathogens, which are dispersed over only short distances. Phytophthora infestans, is highly adaptable pathogen capable of exerting high disease pressure on crop, and develop resistance to phenylamid fungicide methalaxyl in the potato crop in Europe (1981–1984). Metalaxyl was then reintroduced for use in mixtures coformulated with multisite compounds, and the proportion of resistance strains “subpopulations” rose again, and albeit to a level lower than at the outset. The use of metalaxyl on seed crops, with the possibility of resistance being carried over the next season. Current recommendations are to use alternative multiside fungicides on potato crops. Our results illustrate the importance of understanding pathogen epidemiology in the management of fungicide resistance.

scholarly journals Pengaruh Asam Salisilat dan K2HPO4 Pada Ketahanan Tanaman Kentang Terhadap Penyakit Busuk Daun di Musim Penghujan (The Effect of Salicylic Acid and K2HPO4 on the Resistance of Potato Plant to Late Blight in Rainy Season)

2019 ◽  
Vol 28 (2) ◽  
pp. 209
Author(s):  
Rasiska Tarigan ◽  
Susilawati Barus ◽  
NFN Kuswandi
Keyword(s):  
Salicylic Acid ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
Rainy Season ◽  
Potato Crop ◽  
Block Design ◽  
Economic Value ◽  
Combination Treatments ◽  
Randomized Complete Block Design ◽  
Synthetic Pesticides

<p>Kentang merupakan tanaman pangan bernilai ekonomi tinggi yang rentan terhadap serangan busuk daun (Phytophthora infestans) pada musim penghujan. Penggunaan pestisida sintetik hasilnya belum memuaskan sehingga perlu dilakukan induksi ketahanan terhadap serangan penyakit. Tujuan penelitian untuk mengetahui pengaruh  pemberian asam salisilat dan K2HPO4 dalam meningkatkan ketahanan tanaman kentang pada musim penghujan terhadap penyakit busuk daun. Penelitian dilakukan di Kebun Percobaan Berastagi pada ketinggian tempat 1.340 m dpl. pada bulan September sampai dengan Desember 2015. Tata letak percobaan disusun berdasarkan rancangan acak kelompok dua faktor dengan tiga ulangan dan 18 kombinasi perlakuan. Faktor pertama adalah dosis asam salisilat  (a0 = 0, a1 = 0,1g/L, a2 = 0,2 g/L, a3 = 0,3 g/L, a4 = 0,4 g/L, dan a5 = 0,2 g/L propineb). Faktor kedua adalah dosis K­2HPO4 (k0  =  kontrol, k1 = 0,1 g/L, k2 = 0,2 g/L). Hasil penelitian menunjukkan bahwa kombinasi perlakuan 0,1 g/L asam salisilat dan  0,1 g/L K2HPO4 merupakan perlakuan terbaik menurunkan intensitas penyakit P. infestans dan kerusakan umbi kentang. Intensitas penyakit sampai 9 minggu setelah aplikasi hanya 7,46%, sedangkan kerusakan umbi hanya sebesar 0,35%. Jumlah umbi dan persentase kelas umbi per tanaman hanya dipengaruhi oleh K2HPO4, sedangkan bobot umbi tidak dipengaruhi kedua perlakuan. </p><p><strong>Keywords</strong></p><p>Kentang; Asam salisilat; K­2HPO4; Ketahanan; Musim penghujan</p><p><strong>Abstract</strong></p><p>Potatoes are high economic value crops that are vulnerable to the attack of late blight (Phytophthora infestans) in the rainy season. The use of synthetic pesticides has not been satisfactory, so that should be induced for the disease resistance. The objective of the research was to determine the giving effect of salicylic acid and K2HPO4 in improving the resilience of the potato crop in the rainy season to late blight. The study was conducted at Berastagi Experimental Garden in altitude 1,340 meters above sea level, from September to December 2015. The layout of the trial is based on two factor randomized complete block design with three replications and 18 combination treatments. The first factor is the dose of salicylic acid (A0 = 0, A1 = 0,1g/L, A2 = 0,2 g/L, A3 = 0,3 g/L, A4 = 0,4 g/L and A5 = 0,2 g/L propineb), the second factor is the dose K 2HPO4 (K0 = control, K1 = 0.1 g/L, K2 = 0.2 g / L). The results showed that the combination treatment of 0.1 g/L of salicylic acid and 0,1 g/L K2HPO4 is the best treatment because it can reduce the intensity of the Phytophthora infestans disease and potato tuber damage. The disease intensity up to 9 weeks after application only 7.46%, while the tuber damage only 0.35%. The number and percentage of class tubers per plant only affected by K2HPO4, while the tuber weight was not influenced both treatments.</p>

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