scholarly journals Karakteristik morfologi dan sebaran tipe kawin Phytophthora capsici asal lada di Pulau Jawa

2019 ◽  
Vol 14 (5) ◽  
pp. 166
Author(s):  
Bahru Rohmah ◽  
Bambang Hadisutrisno ◽  
Dyah Manohara ◽  
Achmadi Priyatmojo
Keyword(s):  
Mating Type ◽  
Phytophthora Capsici ◽  
Morphological Characteristics ◽  
Black Pepper ◽  
Piper Nigrum ◽  
Mating Types ◽  
Foot Rot ◽  
Distribution Map ◽  
Rot Disease ◽  
Special Region

Morphology characters and mating types distribution of Phytophthora capsici from black pepper in Java IslandPepper (Piper nigrum) is one of the most important spice crops in Indonesia.  Recently its production declining due to infection of foot rot disease caused by Phytophthora capsici. This pathogen has two different mating types, namely A1 and A2, in which the presence of opposite two mating types is important for sexual reproduction and formation of oospores. The movement of pepper seedling from one area to another is highly facilitated alteration of  mating type distribution map of P. capsici. The objectives of this research were to determine the morphological characteristics and the spread of mating types of P. capsici in Java. Morphology characters of P. capsici isolates were indicated by variation in sporangial size and shape, as well as types of colony appearance. The length (l) and width (w) of sporangium were in the range of 15.1–76.2 µm and 9.8–44.8 µm, respectively; while the l/w ratio was 1.12–2.27. Mating type assay showed that A2 type was more dominantly found than A1 type. This study found two different mating types present in the same area, i.e. Regency of Pacitan (East Java) and Regency of Sleman (Special Region of Yogyakarta). The findings of this research suggested that it is required more strict control strategy on the mobilization of black pepper seedling particularly in the area where the certain mating type is not found yet so that the emergence of new more virulent genotype of pathogen can be prevented.

Virulence of Phytophthora isolates from Piper nigrum L. and their sensitivity to metalaxyl-mancozeb

2016 ◽  
Vol 44 (2) ◽  
Author(s):  
K.B. Vinitha, M. Anandaraj and R. Suseela Bhai
Keyword(s):  
Phytophthora Capsici ◽  
Geographical Location ◽  
Black Pepper ◽  
Indian Institute ◽  
Piper Nigrum ◽  
Foot Rot ◽  
Highly Sensitive ◽  
Rot Disease ◽  
Highly Virulent

<p>Foot rot disease caused by <em>Phytophthora capsici</em> in black pepper is the most destructive disease. A total of 82 isolates from the National Repository of <em>Phytophthora</em> at ICAR-Indian Institute of Spices Research were evaluated for their sensitivity to metalaxylmancozeb and also tested for their virulence. Of the 82 isolates studied, 19 (23.2%) were highly sensitive to metalaxyl-mancozeb and six (7.3%) were comparatively insensitive (EC<sub>90</sub> value &gt;40 ppm; range 41.3 to 68.5 ppm). The isolates also varied in the degree of virulence, viz., 34 (41.5%) were highly virulent, 39 (47.6%) moderately virulent, 4 (3.7%) mildly virulent, and 5 (6.1%) non-virulent. There was neither any significant correlation between sensitivity to metalaxyl-mancozeb and virulence nor with the geographical location<strong>. </strong></p>

scholarly journals KORELASI ANTARA AGRESIVITAS INOKULUM SPORANGIA DENGAN TOKSISITAS FILTRAT Phytophthora capsici ASAL TANAMAN LADA (Piper nigrum L.)

2020 ◽  
Vol 18 (4) ◽  
pp. 173
Author(s):  
CHAERANI CHAERANI ◽  
DYAH MANOHARA
Keyword(s):  
Culture Filtrate ◽  
Block Design ◽  
Phytophthora Capsici ◽  
Effective Means ◽  
Black Pepper ◽  
Early Selection ◽  
Piper Nigrum ◽  
Foot Rot ◽  
Rot Disease ◽  
Moderately Resistant

<p>ABSTRAK<br />Penggunaan varietas lada tahan penyakit paling praktis dan efektif<br />untuk menekan serangan Phytophthora capsici, penyebab penyakit busuk<br />pangkal batang (BPB) lada, tetapi varietas lada tersebut belum tersedia.<br />Seleksi dini ketahanan lada dapat dilakukan di laboratorium menggunakan<br />inokulum sporangia atau filtrat biakan P. capsici. Tujuan penelitian ini<br />ialah membandingkan agresivitas inokulum sporangia dengan toksisitas<br />filtrat biakan (FB) P. capsici. Penelitian dilakukan dari bulan Juni sampai<br />September 2009 di laboratorium Biokimia BB Biogen dan Hama dan<br />Penyakit Balittro. Penelitian menggunakan 50 isolat P. capsici dari<br />berbagai daerah pertanaman lada yang diisolasi tahun 1982 sampai 2009.<br />Daun-daun lada yang diambil dari varietas Natar-1 (agak tahan terhadap P.<br />capsici) dan Petaling-1 (rentan terhadap P. capsici) diinokulasi dengan<br />potongan agar mengandung sporangia atau 20 µl FB P. capsici. Percobaan<br />dilakukan secara faktorial (2 varietas × 50 isolat) dengan rancangan acak<br />kelompok dan tiga ulangan. Derajat agresivitas isolat dan toksisitas FB<br />diukur berdasarkan luas bercak nekrotik. Hasil penelitian menunjukkan<br />bahwa agresivitas inokulum sporangia dan toksisitas FB bervariasi antar<br />isolat P. capsici. Bercak nekrotik yang disebabkan oleh inokulum<br />sporangia lebih luas (0,0–2.535,2 mm 2 ) dibandingkan dengan FB (0,7–<br />233,0 mm 2 ). Derajat agresivitas isolat dan toksisitas FB sangat dipengaruhi<br />oleh asal isolat (P&lt;0,0001), tetapi tidak dipengaruhi oleh varietas dan<br />interaksi isolat×varietas (P&gt;0,05). Derajat ketahanan pada varietas tahan<br />Natar-1 diduga tidak berbasis genetik dan tidak berbeda nyata dari varietas<br />rentan Petaling-1 sehingga kedua metode seleksi ketahanan tidak dapat<br />dibedakan keefektifannya. Luas bercak nekrotik yang diinduksi oleh FB<br />tidak berkorelasi nyata dengan yang ditimbulkan oleh inokulum sporangia<br />(R 2 =0,002; P&gt;0,05), sehingga secara umum FB P. capsici tidak dapat<br />digunakan sebagai standar pengujian ketahanan lada. Oleh karena itu<br />masih perlu dikembangkan metode inokulasi yang konsisten untuk seleksi<br />dini ketahanan lada.<br />Kata kunci: lada, penyakit busuk pangkal batang, Phytophthora capsici,<br />agresivitas, filtrat biakan, seleksi dini</p><p>ABSTRACT<br />Resistant varieties are the most practical and effective means to<br />control Phytophthora capsici, the pathogen of foot rot disease of black<br />pepper. However, no resistant cultivars are available. Early selection of<br />black pepper resistance can be performed in laboratory using P. capsici<br />inocula or culture filtrate. The objective of this study was to compare P.<br />capsici isolate aggressiveness with culture filtrate (CF) toxicity. The study<br />was conducted from June until September 2009 at the Biochemistry<br />Laboratory of the Indonesian Center for Agriculutral Biotechnology and<br />Genetic Resources Research and Development and the Plant Pest and<br />Disease Laboratory of the Indonesian Research Institute of Spice and<br />Medicinal Crops. The study used 50 P. capsici isolates collected from<br />various black pepper plantations during 1982 until 2009. Detached leaves<br />of two black pepper cultivars, i.e. moderately resistant cv. Natar-1 and<br />susceptible cv. Petaling-1, were inoculated with agar blocks containing<br />sporangia or 20 µl CF of P. capsici. The experiments were designed as<br />factorial experiments (2 cultivars × 50 isolates) under a randomized<br />completely block design. Isolate aggressiveness and CF toxicity were<br />measured based on the necrotic area of the inoculated leaves. The results<br />from the two inoculation methods showed varying levels of aggressiveness<br />and CF toxicity among isolates. Necrotic lesions incited by sporangial<br />inoculum were more extensive (0.0-2,535.2 mm 2 ) than those induced by<br />CF (0.7-233.0 mm 2 ). Degree of isolate aggressiveness and CF toxicity<br />were significantly affected by origins of isolate (P&lt;0.0001), but not by<br />cultivar and isolate×cultivar interaction (P&gt;0.05). Resistance degree in the<br />moderately resistant cv. Natar-1 was presumably not genetically based and<br />was not different to that in the susceptible cv. Petaling-1, and hence both<br />selecting agents were unable to discriminate resistance level between the<br />two cultivars. Necrotic sizes induced by CF did not well correlate with<br />those incited by sporangial inocula (R 2 =0.002; P&gt;0.05), indicating that CF<br />is generally not suitable to be used as early selection agent of resistant<br />plants. Therefore, further study is justified to find more reliable inoculation<br />method for early detection of resistant black pepper.<br />Key words: black pepper, foot rot disease, Phytophthora capsici,<br />aggressiveness, culture filtrate, early selection in laboratory</p>

scholarly journals Variasi Morfologi dan Virulensi Phytophthora capsici Asal Lada

2016 ◽  
Vol 13 (2) ◽  
pp. 70
Author(s):  
Dono Wahyuno ◽  
Dyah Manohara ◽  
Dwi N. Susilowati
Keyword(s):  
Leaf Area ◽  
Geographic Distribution ◽  
Mating Type ◽  
Phytophthora Capsici ◽  
Morphological Characteristics ◽  
Black Pepper ◽  
Parasitic Fungus ◽  
Plant Parts ◽  
Detached Leaves ◽  
Rot Disease

<p>Phytophthora capsici is the most important plant parasitic fungus causes stem rot disease in black pepper cultivation in Indonesia. The objective of the present study was to observe morphological variation and virulence of Phytophthora isolated on black pepper from various areas in Indonesia. Fifty isolates of Phytophthora were observed under light microscope. The observed morphological characteristics of each isolate, i.e. sporangiophore branching type, colony type, mating type and shape of sporangium after they were grown in growth medium of V8 juice agar, while length and width of sporangium, length of sporangiophore, and papilla were measured by micrometer. The variation of their virulence was observed by inoculating the hypha of each isolate on detached leaves of black pepper that incubated in damped boxes in room conditions. The width of necrotics were measured with leaf area meter after incubated for four days. The results indicated, those morphological characteristics of the isolates were vary in size, shape, colony pattern, mating type and sporangiophore branching pattern, which those characteristics were belong to P. capsici. Those morphological characteristics were not related with the mating type, isolated plant parts and its geographic distribution. The virulence of the tested isolates were also vary from low to high, and their virulence were also not related with the mating type, isolated plant parts and its geographic distribution.</p><p> </p><p><strong>Abstrak</strong></p><p>Phytophthora capsici merupakan cendawan penyebab penyakit busuk pangkal batang yang paling banyak menimbulkan kerusakan pada tanaman lada di Indonesia. Penelitian ini bertujuan untuk mengamati variasi morfologi dan virulensi Phytophthora yang diperoleh dari berbagai lokasi pertanaman lada di Indonesia. Setelah ditumbuhkan pada media V8 jus agar, sebanyak 50 isolat Phytophthora diamati karakteristik morfologinya di bawah mikroskop cahaya, yang meliputi tipe percabangan tangkai sporangium, tipe koloni, tipe kawin, dan bentuk sporangium. Pengukuran panjang dan lebar sporangium, tangkai sporangium, dan papilla dilakukan menggunakan micrometer. Variasi virulensi yang ada diamati dengan cara menginokulasikan potongan hifa dari setiap isolat pada helaian daun lada, kemudian diinkubasi di dalam kotak yang lembab dan diletakkan di suhu ruang. Setelah diinkubasi selama empat hari, luas nekrose yang terjadi diukur menggunakan leaf area meter. Hasil pengamatan menunjukkan adanya variasi karakterisitik morfologi dari setiap isolat pada tipe koloni, tipe kawin, percabangan sporangium, ukuran, dan bentuk sporangium. Semua isolat menunjukkan karakteristik P. capsici. Variasi morfologi yang ada tidak berkaitan dengan tipe kawin, asal bagian tanaman yang diisolasi, dan geografi asal isolat. Lima puluh isolat P. capsici juga bervariasi virulensinya, dari rendah sampai tinggi. Variasi virulensi tersebut juga tidak berkaitan dengan tipe kawin, asal bagian tanaman yang diisolasi maupun geografi asal isolat.</p>

scholarly journals Virulensi Phytophthora capsici Asal Lada terhadap Piper spp.

2016 ◽  
Vol 16 (2) ◽  
pp. 140 ◽  
Author(s):  
Dono Wahyuno ◽  
Dyah Manohara ◽  
Dwi N. Susilowati
Keyword(s):  
Phytophthora Capsici ◽  
Effective Means ◽  
Black Pepper ◽  
Piper Nigrum ◽  
Resistant Variety ◽  
Piper Betle ◽  
Foot Rot ◽  
Dominant Group ◽  
Abaxial Leaf Surface ◽  
Rot Disease

<p>Black Pepper (Piper nigrum) is Widely Cultivated in Indonesia by Smallholder. Foot rot disease caused by Phytophthora capsici is the main constraint in pepper cultivation in Indonesia. Developing a resistant variety is considered the most effective means to reduce the foot rot disease impact. However, the genetic variability of cultivated pepper in Indonesia is narrow. Therefore, attempt to find new gene source from other Piper spp. is an alternative method to get resistant genes against foot rot disease. Six Piper spp. i.e. Piper betle, P. colubrinum, P. cubeba, P. hispidum, and P. retrofractum were tested, while P. nigrum used as control. To find the resistance of those Piper spp. against P. capsici, artificial inoculation experiment was conducted in laboratory. Third and fourth leaves of Piper spp. were inoculated by placing a piece mycelial colony of tested Phytophthora isolates, 5 mm in diameter on abaxial leaf surface. Fifty isolates of P. capsici obtained from various pepper areas in Indonesia were used in the experiment. Width of necrotic area on each inoculated leaves were measured after incubated for 72 hours. Results of statistical analyses showed that P. betle, P. cubeba, P. retrofractum existed in the same group with P. nigrum; while P. colubrinum and P. hispidum presented in another group. Those 50 isolates P. capsici were grouped into 3 groups, the first was a big dominant group that infected all Piper spp., second group consisted of isolates infected P. betle, P. cubeba, P. retrofractum and P. nigrum; and the last one was isolates that infected P. colubrinum and P. hispidum. Hence, virulence of P. capsici was wide and not all Piper spp. were resistant against P. capsici.</p><p> </p><p><strong>Abstrak</strong></p><p>Lada telah dibudidayakan secara luas di Indonesia dan sebagian besar diusahakan oleh petani bermodal kecil. Salah satu kendala dalam budi daya lada di Indonesia ialah penyakit busuk pangkal batang lada yang disebabkan oleh Phytophthora capsici. Salah satu usaha pengendalian yang dianggap efektif ialah menggunakan varietas tahan, tetapi keragaman genetik lada budi daya sempit. Hal ini merupakan kendala dalam program perbaikan varietas. Untuk itu perlu dicari sumber gen ketahanan dari spesies lainnya, yaitu Piper betle, P. colubrinum, P. cubeba, P. hispidum, dan P. retrofractum; sedang P. nigrum digunakan sebagai pembanding. Inokulasi dilakukan dengan cara meletakkan potongan hifa P. capsici pada permukaan bawah daun ketiga dan keempat dari masing-masing Piper spp. Sebanyak 50 isolat P. capsici asal lada yang diperoleh dari berbagai lokasi digunakan dalam penelitian. Daun yang telah diinokulasi diinkubasi pada kotak yang dijaga kelembabannya pada suhu kamar. Luas nekrosa yang terbentuk diukur 72 jam setelah inokulasi. Data luas nekrosa dianalisis secara statitistik untuk melihat ketahanan masing-masing Piper spp. terhadap isolat P. capsici yang digunakan. Hasil analisis menunjukkan bahwa P. betle, P. cubeba, dan P. retrofractum terdapat dalam kelompok yang sama dengan P. nigrum, sedangkan P. colubrinum dan P. hispidum terdapat pada kelompok yang lain. Hasil analisis menunjukkan, 50 isolat P. capsici yang digunakan terbagi ke dalam tiga kelompok, yaitu kelompok yang dapat menyerang semua Piper spp., kelompok yang efektif menyerang P. betle, P. cubeba, P. retrofractum, dan P. nigrum; serta kelompok yang efektif menyerang P. colubrinum dan P. hispidum. Data pengujian menunjukkan adanya variasi virulensi yang luas pada P. capsici dan tidak semua Piper spp. berpotensi digunakan sebagai sumber ketahanan.</p>

scholarly journals EFIKASI SERBUK TUMBUHAN DALAM MENGENDALIKAN PENYAKIT BUSUK PANGKAL BATANG LADA DI LAPANGAN

2011 ◽  
Vol 2 (1) ◽  
pp. 15-19
Author(s):  
Cipta Ginting ◽  
Dad R.J. Sembodo ◽  
Herry Susanto
Keyword(s):  
Field Condition ◽  
Block Design ◽  
Phytophthora Capsici ◽  
Zingiber Officinale ◽  
Black Pepper ◽  
Piper Nigrum ◽  
Foot Rot ◽  
Field Soil ◽  
Fungal Propagules ◽  
Whole Plants

The efficacy of plant powder to control foot rot on black pepper in field condition. One of the problems in cultivating black pepper (Piper nigrum L.) is foot rot caused by Phytophthora capsici Leonian (P. palmivora MF4), that could kill the plants in only few days especially during rainy season.  The objective of this experiment was to evaluate the efficacy of several plant powder to control the disease in semi-field condition.  The experiment was conducted at the experiment station located at the campus of the University of Lampung from May to October of 2000.  The semi-field condition was made by pushing a barrel into the soil to isolate the field soil as testing medium from the rest of the field soil.  The treatments were arranged in a randomized complete block design with five replications and consisted of the rhizomes of Zingiber officinale, Alpinia galanga, and Kaempferia galanga, whole plant of Cymbopogon citratus and Elephantopus scaber, metalaxyl, and untreated control.  To prepare the plant powder, each material was cut into small pieces then dried in oven at 50o C for 4 days and then ground in a blender.  The powder was applied 3 days after inoculum infestation.  The powder and inoculum was mixed with soil to the depth of 12 cm so that the soil contained 2% each.  After one week, four plants were planted.  As additional bioindicator to detect infective inoculum, eight leaf portions were pressed into the soil so that half of the leaf was bellowed the soil line.  The plants were watered and observed daily.  To determine viable fungal propagules, soil sample was taken weekly for five weeks.  Soil assay was done with dilution technique using PDA supplemented with rosebengal.  The results of the observation show that the treatments did not influence significantly the disease intensity on leaf portions or the whole plants.  There were no significant differences on viable fungal propagules in soils received different treatments.

scholarly journals EPIDEMI PENYAKIT BUSUK PANGKAL BATANG LADA PADA KONDISI LINGKUNGAN YANG BERVARIASI

2015 ◽  
Vol 15 (1) ◽  
pp. 95
Author(s):  
La Ode Santiaji Bande ◽  
Bambang Hadisutrisno ◽  
Susamto Somowiyarjo ◽  
Bambang Hendro Sunarminto
Keyword(s):  
Infection Rate ◽  
Logistic Model ◽  
Disease Incidence ◽  
Phytophthora Capsici ◽  
Gompertz Model ◽  
Black Pepper ◽  
Pepper Plant ◽  
Disease Development ◽  
Foot Rot ◽  
Rot Disease

Foot rot disease epidemic on black pepper in variety of environmental conditions. The foot rot disease on black pepper caused by Phytophthora capsici Leonian, is often destructive to farmers of black pepper. This research aims to study the infection rate and the pattern of development of the black pepper foot rot disease in various condition of the environment. The research was conducted in the areas of black pepper cultivation in the Ultisol and Entisol soils. In each location plots were set with few (<25%) and abundant (>75%) weeds. Variable observed was disease incidence. The data were used to analyze model of development of the black pepper foot rot disease and infection rate. Results of the research showed that the model of development of the black pepper foot rot disease was not affected by soil type, but the type of soil affected the infection rate. At the pepper plantation with abundance of weeds, the disease development followes Gompertz model. At the plantation with few weeds, however the disease developed in a logistic model. The rate of disease infection on the black pepper plant with abundant weeds lower compared with those with few weeds.

scholarly journals KETAHANAN BEBERAPA LADA HASIL PERSILANGAN TERHADAP Phytophthora capsici ASAL LADA

2020 ◽  
Vol 15 (2) ◽  
pp. 77
Author(s):  
DONO WAHYUNO ◽  
DYAH MANOHARA ◽  
RUDI T. SETIYONO
Keyword(s):  
Leaf Area ◽  
Phytophthora Capsici ◽  
Economic Loss ◽  
Black Pepper ◽  
Piper Nigrum ◽  
Two Factors ◽  
Phytophthora Resistance ◽  
Rot Disease ◽  
Zoospore Suspension

<p>ABSTRAK</p><p>Busuk pangkal batang (BPB) lada yang disebabkan oleh cendawanPhytophthora capsici merupakan masalah utama pada budidaya lada diIndonesia. Penyakit ini telah ditemukan di semua areal produksi lada diIndonesia. Sampai saat ini, saran pengendalian yang dianjurkan adalahpengendalian secara terpadu untuk mengurangi kerugian ekonomi akibatpenyakit ini. Akhir-akhir ini usaha untuk mendapatkan jenis lada yangtahan dilakukan melalui persilangan. Tujuan penelitian ini adalahmengevaluasi ketahanan F1 yang diperoleh dari persilangan beberapatetua. Penelitian dilakukan di laboratorium dan rumah kaca, BalaiPenelitian Tanaman Rempah dan Obat, Bogor, dari Januari sampaiDesember 2005. Dari 400 aksesi hasil persilangan yang ada, dipilih 15aksesi yang menunjukkan hasil yang menjanjikan pada uji pendahuluan.Tiga isolat Phytophthora yang menunjukkan virulensi yang berbedadigunakan sebagai isolat uji. Di laboratorium, helaian daun ke-3 dan 4diambil dari tiap aksesi dan diletakkan dalam kotak yang telah diberi tissuebasah untuk menjaga kelembapannya. Inokulasi secara buatan dilakukandengan meletakkan potongan koloni masing-masing isolat Phytophthorapada permukaan bawah daun. Luas nekrosa yang terbentuk pada masing-masing aksesi diukur dengan leaf area meter setelah diinkubasi selama 72jam. Percobaan di rumah kaca dilakukan dengan cara menyiramkansuspensi zoospora sebanyak 50 ml pada bibit lada dari masing-masingaksesi yang telah berumur 4 bulan. Jumlah tanaman yang mati dihitungsetelah diinkubasi selama 1 bulan. Data hasil pengukuran luas serangandianalisis dengan rancangan faktorial dengan dua faktor untuk duakegiatan di atas. Hasil penelitian menunjukkan bahwa tidak ada interaksiyang nyata antara aksesi dengan isolat Phytophthora yang digunakan, baikpengujian in vitro maupun rumah kaca. Sembilan aksesi menunjukkankerusakan kurang dari 20% saat di laboratorium maupun di rumah kaca,dan aksesi 27-1, 36-31, dan 4-5L menunjukkan kerusakan kurang dari10%. Persilangan lebih lanjut perlu dilakukan pada aksesi-aksesi tersebutuntuk mendapatkan keturunan yang mempunyai ketahanan lebih baik danstabil.</p><p>Kata kunci : Piper nigrum L., Phytophthora, ketahanan, persilangan</p><p>ABSTRACT</p><p>Resistance of Black Pepper Accessions to Phytophthora capsiciFoot rot disease of black pepper caused by Phytophthora capsici ismain constraint in black pepper cultivation in Indonesia. The diseasespread widely over all pepper producing areas in Indonesia. Integratedpest managements are suggested to reduce the economic loss due to thedisease. Recently, breeding program has been developed in Indonesiathrough hybridization to find out promising accessions resistant to foot rotdisease. The objective of the present study was to evaluate the resistanceof F1 progenies obtained from polination of various parents to foot rotdisease. Among 400 accessions of black pepper obtained from breedingprogram, 15 accessions were selected based on previous evaluation. ThreePhytophthora isolates were used as tester in the study. The research wascarried out in laboratory and glass house of Indonesian Spice andMedicinal Crops Research Institute, from January to December 2005. Invitro screening was carried out by inoculating detached third and fourthleaves of each accession. The leaves were set in boxes abaxial surfacefacing up, while wet tissue papers were used to retain air humidity in thebox. The lower leaf surface of each pepper accession was inoculated witha piece of Phytophthora colony then incubated in room temperature. Thewidth of necrotic areas was measured with leaf area meter after the leaveswere incubated for 72 hours. Each treatment was replicated 5 times. Ingreen house experiment, 4 month seedlings of each accession wereinoculated with 50 ml of zoospore suspension (10 5  zoospore/ml), replicated3 times, and each replication consisted of 5 seedlings. The number ofinoculated seedlings was counted after one month of incubation. Bothexperiments were arranged using factorial design with two factors: pepperaccession and Phytophthora isolate. There was no significant interactionbetween black pepper accession and the Phytophthora isolates, neither invitro nor green house. Nine accessions showed disease severity less than20%, and accession number 27-1, 36-31, and 4-5L showed disease severitybelow 10% in both experiments. To obtain better progeny resistant to stemrot disease and more stable, it is suggested to continue this pollinationprogram by using those promising accessions.</p><p>Key words: Piper nigrum L., Phytophthora, resistance, pollination</p>

scholarly journals Evaluation of tolerance to Phytophthora capsici-the causal agent of foot rot disease in black pepper

2019 ◽  
Vol 18 (01) ◽  
pp. 26-34
Author(s):  
Anh T. Ton
Keyword(s):  
Phytophthora Capsici ◽  
Black Pepper ◽  
Disease Index ◽  
Significant Decline ◽  
Foot Rot ◽  
Greenhouse Condition ◽  
Resistance Level ◽  
Pepper Leaves ◽  
Rot Disease

Vietnam is the leading black pepper export country in the world. However, the production of pepper may be affected by natural disasters, pests such as Phytophthora capsici. The Phytophthora capsica disease has caused a significant decline in pepper yields. The disease is characterized with a high mortality rate (up to 100%) and rapid outbreak and thus is very challenging to control. In the present study, eight strains of P. capsici were isolated from 100 samples of leaf, stem, root and soil that were collected from pepper-growing areas of Dong Nai, Binh Duong and Ba Ria - Vung Tau provinces. These isolates' straits had capacity to cause foot rot on pepper leaf after two days of inoculation. Among them, the isolates with the highest pathogenicity are BR-L1, DN-D1 and DN-D2. In order to determine the resistance level to P. capsici of commonly grown pepper varieties (Vinh Linh, Se, Xanh, Trau and Kuching), the pepper leaves were in vitro infected with P. capsici BR-L1 spores in laboratory and greenhouse conditions. Trau variety showed the highest resistance level to P. capsici with the as indicated by (P < 0.01) disease ratio (74.1%) and disease index (73.7%) after 6 days in laboratory condition and the corresponding numbers of 17.3% and 15.8% after 12 days in greenhouse condition.

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