scholarly journals Screening Brassica Cultivars for Resistance to Western Oregon Clubroot Pathotypes

2017 ◽  
Vol 27 (4) ◽  
pp. 510-516
Author(s):  
Aaron Heinrich ◽  
Shinji Kawai ◽  
Jim Myers
Keyword(s):  
Plasmodiophora Brassicae ◽  
Disease Incidence ◽  
Genetic Resistance ◽  
Crop Loss ◽  
Soilborne Pathogen ◽  
Host Reaction ◽  
Brussels Sprouts ◽  
Pak Choi ◽  
Susceptible Control ◽  
Brassicaceae Family

Growing resistant cultivars from the Brassicaceae family (brassicas) is an effective strategy to minimize crop loss caused by the soilborne pathogen Plasmodiophora brassicae (clubroot). However, there are many clubroot pathotypes, and genetic resistance to clubroot may be pathotype-specific. To determine which pathotypes are present in western Oregon, diseased roots were collected from five farms and identified by the European clubroot differential (ECD) set. To assess resistance to the identified pathotypes, 21 vegetable cultivars from nine crops with purported resistance to clubroot were evaluated for disease incidence and severity in field and greenhouse studies. The crops evaluated included broccoli (Brassica oleracea var. italica), cauliflower (B. oleracea var. botrytis), brussels sprouts (B. oleracea var. gemmifera), cabbage (B. oleracea var. capitata), napa cabbage (Brassica rapa var. pekinensis), pak choi (B. rapa var. chinensis), kohlrabi (B. oleracea var. gongylodes), turnip (B. rapa var. rapa), and rutabaga (Brassica napus var. napobrassica). ECD host reaction showed similar virulence among clubroot collections, and all field isolates had the same ECD pathotype designation, 16/02/30. Compared with a crop-specific susceptible control, 17 of 21 cultivars had some resistance to clubroot, and of those, 15 were highly resistant (≤15% incidence with low disease severity). This research demonstrated that western Oregon farmers have several commercially available cultivars with resistance to the dominant pathotyope in the region. However, each farmer must evaluate the suitability of these cultivars to meet consumer and industry requirements.

scholarly journals Preservação do inóculo de Plasmodiophora brassicae utilizando o método de congelamento

2009 ◽  
Vol 35 (1) ◽  
pp. 57-59 ◽  
Author(s):  
Juliana Cristina Sodário Cruz ◽  
Nilton Luiz de Souza ◽  
Carlos Roberto Padovani ◽  
Edson Luiz Furtado
Keyword(s):  
Plasmodiophora Brassicae ◽  
Sao Paulo ◽  
São Paulo ◽  
Pak Choi ◽  
De Se

A preservação das estruturas de resistência de Plasmodiophora brassicae, em condições laboratoriais, é dificultada pelo fato de se tratar de um parasita obrigatório. O método de congelamento, utilizando freezer, comum foi testado com o objetivo de viabilizar a sobrevivência e a preservação de suas características infectivas. Raízes de diferentes brássicas, naturalmente infectadas por P. brassicae, contendo sintomas típicos de hérnia, de uma mesma propriedade localizada no município de Pardinho, Estado de São Paulo, foram coletadas em diferentes épocas e imediatamente congeladas, em freezer, a aproximadamente -20ºC. Os tratamentos foram divididos da seguinte maneira: T1: hérnias congeladas por 389 dias (rúcula); T2: hérnias congeladas por 242 dias (brócolis); T3: hérnias congeladas por 21 dias (couve chinesa) e T4: testemunha (sem inóculo). Os testes de patogenicidade, após diferentes períodos de armazenamento, foram realizados em condições de casa de vegetação (25±2ºC). Cada planta de uma variedade suscetível de couve-chinesa (Pak choi) foi inoculada com 2mL da suspensão de esporos de cada tratamento, na concentração de 10(7) esporos.mL-1. Cada tratamento contou com seis repetições distribuídas em blocos ao acaso. Passadas cinco semanas após a inoculação, as raízes das plantas foram lavadas e avaliadas. Houve diferença significativa entre os tratamentos. Os materiais congelados, entre 21 a 242 dias preservaram suas características infectivas, mostrando que o método de congelamento em freezer, nesse período, pode ser uma boa opção para a preservação das estruturas de resistência deste patógeno.

scholarly journals History of Oilseed Rape Cropping and Geographic Origin Affect the Genetic Structure of Plasmodiophora brassicae Populations

2014 ◽  
Vol 104 (5) ◽  
pp. 532-538 ◽  
Author(s):  
Becke Strehlow ◽  
Friederike de Mol ◽  
Christine Struck
Keyword(s):  
Oilseed Rape ◽  
Plasmodiophora Brassicae ◽  
Gene Diversity ◽  
Spatial Scales ◽  
Field Isolate ◽  
Geographic Origin ◽  
Fixation Index ◽  
Common Disease ◽  
Geographic Differentiation ◽  
Soilborne Pathogen

The soilborne pathogen Plasmodiophora brassicae causes clubroot on Brassica crops, a common disease in many oilseed rape growing regions. Here, we investigate genetic diversity and geographic differentiation of P. brassicae populations from different regions in Germany. We compared three regions that differ in oilseed rape cropping history, oilseed rape acreage, and incidence of clubroot. These regions were either spatially separated or separated by the former inner German border. Plasmodiophora isolates were collected from 59 fields (29, 17, and 13 fields per region, respectively) and 174 amplified fragment length polymorphism (AFLP) markers were analyzed. Every field isolate showed a unique genotype pattern; that is, no genotype was shared among the regions and different fields. The mean gene diversity was 0.27, suggesting that P. brassicae is a genetically diverse species. The comparison of indexes (gene diversity, genotypic diversity, and linkage disequilibrium) between the regions does not support our hypotheses that cropping history, oilseed rape acreage, and incidence of clubroot affect these estimates. Principal component analysis (PCA), fixation index (FST), and generalized linear model (GLM) were suitable to specify regional differences. PCA revealed two clusters of isolates based on the geographic origin of the isolates and FST showed that these clusters were highly differentiated. Hypotheses about association of genotypes with different spatial scales were tested with GLM: the region, reflecting the cropping history, and the individual field had a significant effect on the AFLP pattern. We propose that individual field isolates represent a discrete population and that geographic differentiation results from low levels of gene flow due to the limited dispersal of this soilborne pathogen and from localized selection pressure as unifying force on the genotypes.

Clubroot in Brassica: Recent advances in genomics, breeding and disease management

Genome ◽  
2021 ◽  
Author(s):  
Muhammad Jakir Hasan ◽  
Swati Megha ◽  
Habibur Rahman
Keyword(s):  
Host Resistance ◽  
Molecular Basis ◽  
Host Plants ◽  
Cultural Practices ◽  
Plasmodiophora Brassicae ◽  
Genetic Resistance ◽  
Vegetable Production ◽  
Comprehensive Understanding ◽  
Clubroot Disease

Clubroot disease, caused by Plasmodiophora brassicae, affects Brassica oilseed and vegetable production worldwide. This review is focused on various aspects of clubroot disease and its management, including understanding the pathogen and resistance in the host plants. Advances in genetics, molecular biology techniques and ‘omics’ research have helped to identify several major loci, QTL and genes from the Brassica genomes involved in the control of clubroot resistance. Transcriptomic studies have helped to extend our understanding of the mechanism of infection by the pathogen and the molecular basis of resistance/susceptibility in the host plants. A comprehensive understanding of the clubroot disease and host resistance would allow developing a better strategy by integrating the genetic resistance with cultural practices to manage this disease from a long-term perspective.

scholarly journals GROWTH AND YIELD RESPONSE OF PAK CHOI (BRASICCA RAPA) TO DIFFERENT FOLIAR FERTILIZERS UNDER PROTECTED CULTIVATION

2021 ◽  
Vol 9 (09) ◽  
pp. 430-431
Author(s):  
May Ann G. Cantillo ◽  
◽  
Cornelio R. Molon SR. ◽  
Keyword(s):  
Disease Incidence ◽  
Growth And Yield ◽  
Yield Response ◽  
Net Income ◽  
Effective Microorganisms ◽  
Pak Choi ◽  
Foliar Fertilizer ◽  
Remarkable Effect ◽  
Protected Cultivation ◽  
The Cost

The experiment was conducted to determine the growth and yield response of pak choi (Brasiccarapa var. Chinkang Genghis Khan) to different foliar fertilizers (viz. vermitea, commercial foliar fertilizer, effective microorganisms [EM-1] and natural farming inputs [NFI]) under protected cultivation. It aimed to evaluate the influence of the different foliar fertilizers on pak choi in terms of growth characteristics, yield components, and pests and disease incidence. Similarly, to conclude which among the foliar fertilizers evaluated will be most the economical for pak choi production. The study was done in the DA-ATI IV-A and LSPU Organic Agriculture Learning Site in the Laguna State Polytechnic University, Siniloan, Laguna in December 2015 to February 2016. A total of 300 plants were used as experimental units in the study. Every treatment was replicated three times and each replication has 10 polyethylene bags planted with two plants each. Data was collected and analysed with the use of the Duncans Multiple Range Test (DMRT). Results revealed that the foliar fertilizers used have no remarkable effect on the weekly height, weekly growth rate, length of leaves, and shoot root ratio of pak choi. Nevertheless, commercial fertilizer significantly increased the mean number of leaves (7.53cm), width of leaves (15.10cm), economic and biological yields (105.10 grams and 106.88 grams, respectively) of pak choi compared with the rest of the treatments, except for vermitea which produced a comparable width of leaves (15.04cm). Also, a significantly lower number of the damaged leaves caused by looper (TrichoplusianiHübner) was noted on plants treated with commercial foliar fertilizer (0.51 leaf per plant). The highest net income was obtained by commercial foliar fertilizer-treated plants, but plants treated with vermitea earned the highest return of investment (ROI). Therefore, the utilization of vermitea in pak choi production can reduce the cost of fertilizer and contribute to an economical production system under protected cultivation.

scholarly journals Assessing Genetic Resistance in Wheat to Black Point Caused by Six Fungal Species in the Yellow and Huai Wheat Area of China

Plant Disease ◽  
2020 ◽  
Vol 104 (12) ◽  
pp. 3131-3134
Author(s):  
Qiaoyun Li ◽  
Mengyu Li ◽  
Yumei Jiang ◽  
Siyu Wang ◽  
Kaige Xu ◽  
...  
Keyword(s):  
Disease Incidence ◽  
Genetic Resistance ◽  
Bipolaris Sorokiniana ◽  
Triticum Aestivum L ◽  
Fungal Species ◽  
Field Conditions ◽  
Sources Of Resistance ◽  
Black Point ◽  
Environmentally Sustainable ◽  
Resistant Cultivars

The most effective and environmentally sustainable method for controlling black point disease of wheat (Triticum aestivum L.) is to plant resistant cultivars. To identify sources of resistance to black point, 165 selected cultivars/lines were inoculated with isolates of six fungal species (Bipolaris sorokiniana, Alternaria alternata, Fusarium equiseti, Exserohilum rostratum, Epicoccum sorghinum, and Curvularia spicifera) known to cause black point in wheat using spore suspensions under controlled field conditions in 2016 and 2017. Inoculation of the isolates significantly increased the incidence of black point in the cultivars/lines compared with those grown under natural field conditions (NFC). The disease incidence of plants inoculated with B. sorokiniana and E. rostratum was 15.5% and 18.8% in 2016, and 20.4% and 23.0% in 2017, whereas those under NFC were 5.7% (2016) and 1.5% (2017), respectively. Furthermore, disease symptoms varied with pathogen. Among the 165 cultivars/lines tested, 3.6%, 50.9%, 60.0%, 1.8%, 47.3%, and 58.8% were resistant to B. sorokiniana, A. alternata, F. equiseti, E. rostratum, E. sorghinum, and C. spicifera, respectively. In addition, we identified one line (‘SN530070’) resistant to black point caused by all six pathogens. This is the first study to assess resistance to wheat black point caused by six fungal species under controlled conditions. The black point-resistant cultivars/lines could be useful in breeding and also in research on the mechanisms of resistance to black point.

scholarly journals Differences in Thermal Stability of Glucosinolates in Five Brassica Vegetables

2009 ◽  
Vol 27 (Special Issue 1) ◽  
pp. S85-S88 ◽  
Author(s):  
M. Dekker ◽  
K. Hennig ◽  
R. Verkerk
Keyword(s):  
Thermal Stability ◽  
Brussels Sprouts ◽  
Pak Choi ◽  
Red Cabbage ◽  
Indole Glucosinolates ◽  
First Order Kinetics ◽  
Degradation Rates ◽  
Brassica Vegetables ◽  
The Stability ◽  
Thermal Stability Of

The thermal stability of individual glucosinolates within five different Brassica vegetables was studied at 100°C for different incubation times up to 120 minutes. Three vegetables that were used in this study were <I>Brassica oleracea</I> (red cabbage, broccoli and Brussels sprouts) and two were <I>Brassica rapa</I> (pak choi and Chinese cabbage). To rule out the influence of enzymatic breakdown, myrosinase was inactivated prior to the thermal treatments. The stability of three glucosinolates that occurred in all five vegetables (gluconapin, glucobrassicin and 4-methoxyglucobrassicin) varied considerably between the different vegetables. The degradation could be modeled by first order kinetics. The rate constants obtained varied between four to twenty fold between the five vegetables. Brussels sprouts showed the highest degradation rates for all three glucosinolates. The two indole glucosinolates were most stable in red cabbage, while gluconapin was most stable in broccoli. These results indicate the possibilities for plant breeding to select for cultivars in which glucosinolates are more stable during processing.

scholarly journals First Report of Clubroot on Capsella bursa-pastoris Caused by Plasmodiophora brassicae in Sichuan Province of China

Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 687-687 ◽  
Author(s):  
L. Ren ◽  
X. P. Fang ◽  
C. C. Sun ◽  
K. R. Chen ◽  
F. Liu ◽  
...  
Keyword(s):  
Plasmodiophora Brassicae ◽  
Tap Water ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Pcr Amplification ◽  
Sichuan Province ◽  
Clubroot Disease ◽  
Cruciferous Vegetable ◽  
First Report ◽  
Resting Spores

Shepherd's purse (Capsella bursa-pastoris (L.) Medicus) is an edible and wild medicinal plant widely distributed in China. This plant has been cultivated in Shanghai, China, since the end of the 19th century. Infection of C. bursa-pastoris by Plasmodiophora brassicae, the causal agent of clubroot disease on Brassica spp. has been reported in Korea (2), but is not known to occur in China. In February of 2011, stunted and wilted shepherd's purse (SP) plants were observed in a field planted to oilseed rapes (B. napus) in Sichuan Province of China. Symptomatic SP plants also exhibited root galls. Disease incidence was 6.2% and 100% for SP and B. napus, respectively. Root galls on diseased SP plants were collected for pathogen identification. Many resting spores were observed when the root galls were examined under a light microscope. The resting spores were circular in shape, measuring 2.0 to 3.1 μm in diameter (average 2.6 μm). PCR amplification was conducted to confirm the pathogen. DNA was extracted from root galls and healthy roots (control) of SP. Two primers, TC2F (5′-AAACAACGAGTCAGCTTGAATGCTAGTGTG-3′) and TC2R (5′-CTTTAGTTGTGTTTCGGCTAGGATGGTTCG-3′) were used to detect P. brassicae (1). No PCR amplifications were observed with the control DNA as template. A fragment of the expected size (approximately 520 bp) was obtained when DNA was amplified from diseased roots of SP. These results suggest that the pathogen in the galled roots of SP is P. brassicae. Pathogenicity of P. brassicae in SP was tested on plants of both SP and Chinese cabbage (CC) (B. campestris ssp. pekinensis). A resting spore suspension prepared from naturally infected SP roots was mixed with a sterilized soil in two plastic pots, resulting in a final concentration of 5 × 106 spores/g soil. Soil treated with the same volume of sterile water was used as a control. Seeds of SP and CC were pre-germinated on moist filter paper for 2 days (20°C) and seeded into the infested and control pots, one seed per pot for planted for CC and four seeds per pot for SP. The pots were placed in a chamber at 15 to 25°C under 12 h light and 12 h dark. Plants in each pot were uprooted after 4 weeks and the roots of each plant were washed under tap water and rated for clubroot disease. No disease symptoms were observed in the control treatments of SP or CC. Plants of both species showed symptoms of clubroot, with the disease incidence of 62.5% and 100% on SP and CC, respectively. The pathogen was isolated from diseased roots of each plant and confirmed as P. brassicae based on morphological characteristics and PCR detection. To our knowledge, this is the first report of clubroot disease on C. bursa-pastoris in Sichuan Province of China. This finding suggests that it may be necessary to manage C. bursa-pastoris in cruciferous vegetable (cabbage, turnip) and oilseed rape production fields. References: (1) T. Cao et al. Plant Dis. 91:80, 2007. (2) W. G. Kim et al. Microbiology 39:233, 2011.

scholarly journals Suppression of Fusarium Wilt Caused by Fusarium oxysporum f. sp. niveum Race 2 on Grafted Triploid Watermelon

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1326-1332 ◽  
Author(s):  
Anthony P. Keinath ◽  
Richard L. Hassell
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Disease Incidence ◽  
The United States ◽  
Infested Soil ◽  
Marketable Yield ◽  
Race 1 ◽  
Susceptible Control ◽  
Triploid Watermelon ◽  
Race 2

Fusarium wilt of watermelon, caused by the soilborne fungal pathogen Fusarium oxysporum f. sp. niveum race 2, is a serious, widespread disease present in major watermelon-growing regions of the United States and other countries. ‘Fascination,’ a high yielding triploid resistant to race 1, is grown in southeastern states in fields that contain a mixture of races 1 and 2. There is some benefit to using cultivars with race 1 resistance in such fields, even though Fascination is susceptible to Fusarium wilt caused by race 2. Experiments in 2012 and 2013 were done in fields infested primarily with race 2 and a mixture of races 1 and 2, respectively. Fascination was grafted onto four rootstock cultivars: bottle gourd (Lagenaria siceraria) ‘Macis’ and ‘Emphasis’ and interspecific hybrid squash (Cucurbita maxima× C. moschata) ‘Strong Tosa’ and ‘Carnivor.’ Nongrafted and self-grafted Fascination were used as susceptible control treatments. In both experiments, mean incidence of plants with symptoms of Fusarium wilt was ≥52% in the susceptible control treatments and ≤6% on the grafted rootstocks. Disease incidence did not differ between rootstock species or cultivars. In both years, Fascination grafted onto Strong Tosa and Macis produced more marketable-sized fruit than the susceptible control treatments. Grafted Emphasis and Carnivor also produced more fruit than the control treatments in 2012. The cucurbit rootstocks suppressed Fusarium wilt caused by race 2 and increased marketable yield of triploid watermelon grown in infested soil.

scholarly journals Evaluation of Winter Squash and Pumpkin Cultivars for Age-related Resistance to Phytophthora capsici Fruit Rot

HortScience ◽  
2016 ◽  
Vol 51 (10) ◽  
pp. 1251-1255 ◽  
Author(s):  
Charles S. Krasnow ◽  
Mary K. Hausbeck
Keyword(s):  
Cucurbita Pepo ◽  
Disease Incidence ◽  
Phytophthora Capsici ◽  
Genetic Resistance ◽  
Fruit Rot ◽  
Infested Soil ◽  
Cucurbita Moschata ◽  
Cucurbita Maxima ◽  
Age Related ◽  
Winter Squash

Phytophthora capsici annually threatens production of cucurbit and solanaceous crops. Long-lived oospores produced by the pathogen incite primary infection of susceptible plants when conditions are wet. Limiting the rot of winter squash and pumpkin (Cucurbita sp.) fruits is difficult due to the long maturation period when fruits are often in direct contact with infested soil. Genetic resistance to fruit rot is not widely available within Cucurbita sp.; however, age-related resistance (ARR) to P. capsici fruit rot develops in specific cultivars during maturation. The objective of this study was to evaluate the fruits of 12 cultivars of Cucurbita pepo, Cucurbita moschata, and Cucurbita maxima for ARR to P. capsici using a mycelial-plug inoculation method. All Cucurbita pepo and Cucurbita moschata cultivars displayed ARR; 7 days postpollination (dpp) fruits were susceptible, limited lesion development occurred on fruits 22 dpp, and lesions did not develop at 56 dpp. Disease developed on both Cucurbita maxima cultivars tested at 7, 14, 22, and 56 dpp. Firmness of fruit exocarps was measured with a manual penetrometer. Exocarp firmness of all cultivars increased during maturation; however, there was no correlation between firmness and disease incidence among cultivars at 22 dpp (R2 = −0.01, P = 0.85). When fruits of cultivars expressing ARR at 22 dpp were wounded before inoculation, fruit rot developed.

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