New resistances offer opportunity for effective management of the downy mildew (Hyaloperonospora parasitica) threat to canola

2017 ◽  
Vol 68 (3) ◽  
pp. 234 ◽  
Author(s):  
A. E. Mohammed ◽  
M. P. You ◽  
M. J. Barbetti
Keyword(s):  
Downy Mildew ◽  
Breeding Programs ◽  
Crambe Abyssinica ◽  
Hyaloperonospora Parasitica ◽  
Resistant Varieties ◽  
Effective Option ◽  
Hybrid Variety ◽  
Cent Disease ◽  
Moderately Resistant ◽  
Important Disease

Downy mildew (Hyaloperonospora parasitica) is a problem for canola production worldwide, including in Australia where it has remained a persistent threat since 1998. Testing of 131 Brassicaceae varieties, including 109 Australian canola varieties (Brassica napus and B. juncea) and 22 diverse Brassicaceae (including B. napus, B. carinata, B. juncea, B. nigra, B. rapa, Crambe abyssinica and Raphanus sativus) highlighted excellent resistance to downy mildew. Using a mixture of 10 H. parasitica isolates, R. sativus Colonel and Boss showed highest resistance to H. parasitica, with per cent disease index (%DI) values of 3.7% and 10.2%, respectively. These were followed by (%DI values): B. carinata ATC 94011 (11.1%), B. napus CB™ Tanami (14.1%) and Komet-741 A (14.3%), B. juncea 397.23.2.3.3 (14.8%), B. napus ATR-Banjo (16.9%), Hyola 575 CL (16.9%), Komet-744 A (18.1%), Cresor-770 B (18.5%), Wamus (18.5%), Surpass 400 (19.2%), Hyola 432 (19.4%) and Hyola 76 (19.4%), and C. abyssinica (19.9%). These varieties were also considered highly resistant. Another five B. juncea genotypes and B. nigra P.23845 were considered highly resistant with %DI of 22.2%. Those considered resistant (but not highly resistant) included hybrid B. napus Hyola 444 TT, Hyola 500 RR, Hyola 504 RR, Pioneer 46Y78, Pioneer 45Y77 and Hyola 650 TT, and the non-hybrid variety ATR-Eyre, all with %DI values 23.1–28.2%. By contrast, B. napus Thunder TT, Hyola 450 TT and ATR-Grace were highly susceptible with %DI values of 90.3%, 88.2% and 81.7%, respectively. Cluster analysis revealed six distinct clusters (highly resistant, resistant, moderately resistant, moderately susceptible, susceptible, very susceptible) for the tested Brassicaceae genotypes that, on average, showed similar responses within each cluster against H. parasitica based on their %DI values. From 2000 onwards (with the exception of Surpass 400), 10 B. napus varieties and one B. juncea released were classified as highly resistant; however, there was no overall correlation between year of variety release and level of resistance expressed against H. parasitica. This is the first study to demonstrate the existence of very high levels of pathotype-independent resistance in Australian canola varieties to H. parasitica. The most resistant varieties identified can be used in canola breeding programs and also directly deployed into regions where downy mildew is prevalent, providing the canola industry with an immediate and effective option for management of this important disease.

scholarly journals Assessment of chilli genotypes for anthracnose resistance under field conditions

2020 ◽  
Vol 15 (2) ◽  
pp. 67-72
Author(s):  
K. Arjun ◽  
T. Arumugam ◽  
M. Karthikeyan ◽  
H. Usha Nandhini Devi ◽  
S. Mohankumar
Keyword(s):  
Disease Index ◽  
Field Conditions ◽  
High Yield ◽  
Anthracnose Resistance ◽  
Colletotrichum Species ◽  
Cent Disease ◽  
Moderately Resistant ◽  
Resistant Genotypes ◽  
Important Disease

Anthracnose caused by complex of Colletotrichum species is an economically important disease of chilli. The study involved 132 genotypes grown under field conditions. Among the genotypes evaluated, fifteen genotypes were moderately resistant to anthracnose with fairly high yield. In the order of merit, the genotypes were CA 177 (10.74%), Paramakudi 1 (16.64%), F 507 (17.17%), Bird’s eye chilli (17.85%), Kadaladi 1 (19.70%), Ramnad local (20.64%), CO 1 (20.82%), TA/CA/ 10 (21.56%), CA 166 (21.94%), CA 188 (22.29%), Paramakudi 2 (22.45%), CA 13/6 (23.42%), Chilli CO hybrid 1 (24.36%), IC 342465 (24.68%) and CA 165 (25.70%). whereas, 40 genotypes were susceptible with PDI ranging from 26.30 to 50.69 per cent and majority of the genotypes (77nos) were found to be highly susceptible to anthracnose with per cent disease index ranging from 51.81 to 96.42 per cent. The moderately resistant genotypes identified in the present investigation will serve as donors or source of resistance for anthracnose.

scholarly journals THE EFFECTIVENESS COMBINATION OF RESISTANT VARIETIES AND METALAXIL FUNGICIDE IN CONTROLLING DOWNY MILDEW DISEASE (Peronosclerospora maydis) IN MAIZE PLANT

2019 ◽  
Vol 19 (1) ◽  
pp. 42
Author(s):  
Syahrir Pakki ◽  
Nurasiah Djaenuddin
Keyword(s):  
Downy Mildew ◽  
Seed Treatment ◽  
Disease Incidence ◽  
Susceptible Variety ◽  
Treatment Conditions ◽  
Resistant Varieties ◽  
Treatment Dose ◽  
Important Disease ◽  
Downy Mildew Disease ◽  
Plot Design

Downy mildew caused by Peronosclerospora maydis is an important disease in the centers of corn cultivation in Java. The aim of this study was to determine the effectiveness of a combination of metalaxyl fungicide and varieties that have a high sustainability of downy mildew caused by P. maydis. The study was conducted in Kediri, East Java, which is an endemic area of downy mildew caused by P. maydis. The Split Plot Design with 3 replications was used in this study. The main plots were 5 corn varieties (1) Bima-3 Bantimurung, (2) Bima-20 URI, (3) Lagaligo, (4) Bima-15 Sayang, and (5) Anoman as a susceptible check. The subplots were 5 levels of seed treatment dose with metalaxyl fungicide (0 g/kg, 2 g/kg, 3 g/kg, 5 g/kg, and 7 g/kg seeds). The combination of resistant varieties with metalaxyl at a dose level of 5 g and 7 g/kg of corn seeds was effective in controlling downy mildew caused by P. maydis. In Bima-3 varieties Bantimurung and Lagaligo showed low infection reactions of 7.7-8.1%, and 10.4–11.2% respectively. In a combination of treatment conditions of susceptible varieties (Anoman) with 2, 3, 5 and 7 g/kg seeds, disease incidence reach 100% or most of the plants die. The lower incidence was also followed by yield, ear length and weight of a 1000 seeds that higher than other treatments. The combination of the use of susceptible variety with 2 g to 7 g/kg of metallaxyl doses was not effective in controlling downy mildew caused by P. maydis.

scholarly journals Evaluation of resistance and morphological parameters of different sunflower cultivars against charcoal rot

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Muhammad Ahmad Zeshan ◽  
Safdar Ali ◽  
Nadeem Ahmed ◽  
Maryam Yousaf ◽  
Atta-ur-Rehman Khan ◽  
...  
Keyword(s):  
Agricultural Research ◽  
Genetic Resistance ◽  
Macrophomina Phaseolina ◽  
Morphological Parameters ◽  
Breeding Programs ◽  
Charcoal Rot ◽  
Resistant Varieties ◽  
Moderately Resistant ◽  
Resistant Genotypes ◽  
Better Than

Charcoal rot is one of the major threats to sunflower which causes complete crop loss in epidemic conditions. The genetic resistance of sunflower germplasm could be more economical and durable approach for the management of charcoal rot. In the current experiment, six genotypes obtained from Ayub Agricultural Research Institute, Faisalabad were evaluated for their resistance and morphological parameters against Macrophomina phaseolina. Under field conditions, none of the cultivars gave immune or resistant response against the disease. FH-337 was found to be susceptible with 54.87% infection while FH-331, FH-106 and Hycanth-33 appeared moderately susceptible with 25-49% infections. The least affected varieties were FH-259 and DK-40 with moderately resistant status in the range of 10-24%. Yield parameters of resistant varieties were better than susceptible ones when compared under inoculated conditions. Moderately resistant genotypes might have the better genetic makeup and could be selected in breeding programs to find out resistant sunflower germplasm to fulfill the needs of growing population. Moreover, these cultivars could be used for better yield of sunflower.

INHERITANCE OF RESISTANCE TO NET BLOTCH IN BARLEY. I. FACTORS AFFECTING THE PENETRANCE AND EXPRESSIVITY OF GENE(S) CONDITIONING HOST RESISTANCE

1969 ◽  
Vol 11 (3) ◽  
pp. 587-591 ◽  
Author(s):  
T. N. Khan
Keyword(s):  
Environmental Conditions ◽  
Net Blotch ◽  
Host Reaction ◽  
Susceptible Parent ◽  
Breeding Programs ◽  
Genetic Studies ◽  
Factors Affecting ◽  
Drechslera Teres ◽  
Resistant Varieties ◽  
High Level

Variability in the host-reaction of barley to infection by Drechslera teres was examined in the parents and progeny of selected crosses under different environmental conditions of testing.The Ethiopian variety C.I. 5791 exhibits a consistently high level of resistance under a range of environmental conditions, which is in contrast to the Manchurian variety C.I. 2330. The sensitivity of the genes for resistance possessed by these varieties to environmental modifications is considered to depend upon their respective genetic backgrounds. Furthermore, variability of host reaction in the progeny of these resistant varieties was shown to be influenced by the genetic background of the susceptible parent used.The implications of these findings in the conduct and interpretation of genetic studies and in backcross breeding programs is discussed.

scholarly journals Resistance to nematode Meloidogyne paranaensis in Arabica coffee genotypes introgressed with Coffea liberica

2020 ◽  
pp. 1236-1241
Author(s):  
Gustavo H. Sera ◽  
Filipe G. Carvalho ◽  
Inês C. de B. Fonseca ◽  
Luciana H. Shigueoka ◽  
Santino A. da Silva ◽  
...  
Keyword(s):  
Germplasm Bank ◽  
Breeding Programs ◽  
Arabica Coffee ◽  
Randomized Design ◽  
Mother Plants ◽  
Completely Randomized Design ◽  
Set Up ◽  
Moderately Resistant ◽  
Reproduction Factor ◽  
Coffea Liberica

The aim of this study was to prove that Arabica coffee introgressed with C. liberica, have resistance to Meloidogyne paranaensis (Mp). Open pollinated fruits were harvested from mother plants of 29 Arabica coffee genotypes from the IAPAR germplasm bank. Seeds were collected from the fruits and were sown to obtain seedlings to test the resistance to Mp. The experiment was set up in a completely randomized design with 29 coffee genotypes, 8 replications, and one plant per plot. Cultivars Catuaí Vermelho IAC 99 and IPR 100 were used as susceptible and resistant checks, respectively. Seedlings with three to four pairs of leaves were inoculated with 1,400 eggs and juveniles J2 of Mp (IP). At 120 days after inoculation, seedlings were evaluated by counting the nematodes per gram of roots, and the final nematodes population was obtained (FP). The reproduction factor (RF) was calculated using the formula: RF = FP/IP. The reproduction factor reduction was used to classify the resistance levels of genotypes, which were classified as highly resistant (HR), resistant (R), moderately resistant (MR), moderately susceptible (MS), susceptible (S) an highly susceptible (HS). All genotypes differed from Catuaí in resistance factor (RF), five of which did not differ from IPR 100 for RF, and only the line IAPAR 15242 had RF < 1.0. Out of 28 Arabica genotypes introgressed with C. liberica, five HR, 11 R, 11 MR and one MS were identified. However, only IAPAR 15242 and IPR 100 were classified as HR and presented 100% of HR plants, but only the first showed an RF < 1.0. Results revealed that these Arabica coffee genotypes with introgression of C. liberica genes have great potential to be used in breeding programs and they are a new alternative as a source of resistance.

scholarly journals Resistance Response of Maize Germplasm to Downy Mildew [Peronosclerospora philipinensis]

2018 ◽  
Vol 24 (1) ◽  
pp. 43
Author(s):  
Syahrir Pakki ◽  
Mappaganggang Mappaganggang
Keyword(s):  
Downy Mildew ◽  
Block Design ◽  
Susceptible Variety ◽  
Resistant Variety ◽  
Average Intensity ◽  
Standard Score ◽  
Resistance Response ◽  
Maize Germplasm ◽  
Randomized Block Design ◽  
Moderately Resistant

<p>Two experiments to study responses of resistance of maize germplasm to downy mildew (Peronosclerospora philipinensis) have been conducted. Both experiments were arranged in randomized block design with two replication. The treatments in each experiment (2014 and 2016) were 70 maize accessions. The accessions were planted in planting distant of 75 cm × 20 cm, in 5 m rows, resulting in 20 plants per row. In every 10 rows, two check varieties were planted, i.e. one susceptible and one resistant variety. Ten days prior to planting, the soil was fertilized with mixed fertilizers consisted of urea, ZA, SP36, and KCl at a dose of 100, 100, 100, and 100 kg/ha, respectively. Fertilization II and III was given at 30 days after planting, and 45 days after planting with a dose of 100 kg urea/ha. As a source of inoculum downy mildew, around the repeated plot was planted with varieties Anoman variety (susceptible variety) that was inoculated with a suspension of downy mildew pathogen. Observation was conducted at 25, 35, and 55 days after planting, with the standard score of resistant to downy mildew, followed: 0–10% = resistant, 11–25% = moderately resistant, 26–50% = moderately susceptible, &gt;50% = susceptible. The result of the experiments showed that there were 5 accessions resistant to downy mildew (P. philipinensis), i.e. CML 440×MR4-9-30-3, 664, 60, 572, and 554 with the intensity of downy mildew infection ranged from 5 to 10%. Twelve other accessions were classified as moderately resistant, i.e. CML 440×MR4-9-98-2, 440×MR4-9-98-4 CML, CML 440×MR4-9-124-1, 66, 71, 319, 108, 73, 48, 105, 554, and 682 with intensity of infection ranged from 13 to 25%. At the same experiments, the average intensity of downy mildew infection on susceptible check varieties reached 100 percent.</p>

scholarly journals Identification of new resistant sources against downy mildew disease from a selected set of cucumber germplasm and its wild relatives

2020 ◽  
Vol 80 (04) ◽  
Author(s):  
Jameel Akhtar ◽  
Dikshant Gautam ◽  
Ranjan Nath ◽  
A. B. Gaikwad ◽  
K. V. Bhat ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Plant Disease ◽  
Mapping Population ◽  
Disease Index ◽  
Sources Of Resistance ◽  
Resistant Accession ◽  
Genomic Regions ◽  
Moderately Resistant ◽  
Agroclimatic Zones ◽  
Downy Mildew Disease

This study was undertaken to identify new sources of resistance against downy mildew of cucumber caused by Pseudoperonospora cubensis [(Berk. and Cart.) Rostow]. Pot experiments were conducted with 16 accessions each of Cucumis sativus and C. hardwickii during the years 2017 and 2018 using 12 isolates of P. cubensis representing different agroclimatic zones of India. The accession, IC331627 from Dehradun, Uttarakhand showed plant disease index (PDI) ranging from 5.55-20.35 per cent with an average PDI of 11.56 and 11.87 per cent during the years, 2017 and 2018, respectively. Hence, IC331627 was identified to be resistant against the five isolates of P. cubesis (Pc12, Pc17, Pc19, Pc21 and Pc24) and moderately resistant against one isolate (Pc22). This resistant accession C. hardwickii (IC331627) could be utilized to develop mapping population to map genomic regions conferring the resistance to downy mildew in cucumber.

scholarly journals First Report of Downy Mildew Caused by Hyaloperonospora parasitica on Siberian Kale in Kentucky

Plant Disease ◽  
2017 ◽  
Vol 101 (6) ◽  
pp. 1057-1057
Author(s):  
B. Amsden ◽  
K. Kwiatkowski ◽  
E. Dixon ◽  
T. Thompson ◽  
M. Williams ◽  
...  
Keyword(s):  
Downy Mildew ◽  
First Report ◽  
Hyaloperonospora Parasitica

scholarly journals A diagnostic marker kit for Fusarium wilt and sterility mosaic diseases resistance in pigeonpea

2020 ◽  
Author(s):  
Rachit K. Saxena ◽  
Anil Hake ◽  
Abhishek Bohra ◽  
Aamir W. Khan ◽  
Anupama Hingane ◽  
...  
Keyword(s):  
Fusarium Wilt ◽  
Diagnostic Marker ◽  
Development Program ◽  
Cost Effective ◽  
Phenotypic Variance ◽  
Breeding Programs ◽  
Specific Pcr ◽  
Novel Approach ◽  
Resistant Varieties ◽  
Pathogen Variability

Abstract Fusarium wilt (FW) and sterility mosaic diseases (SMD) are key biotic constraints to pigeonpea production. Occurrence of these two diseases in congenial conditions is reported to cause complete yield loss in susceptible pigeonpea cultivars. Various studies to elucidate genomic architecture of the two traits have revealed significant marker–trait associations for use in breeding programs. However, these DNA markers could not be used effectively in genomics-assisted breeding for developing FW and SMD resistant varieties primarily due to pathogen variability, location or background specificity, lesser phenotypic variance explained by the reported QTL and cost-inefficiency of the genotyping assays. Therefore, in the present study, a novel approach has been used to develop a diagnostic kit for identification of suitable FW and SMD resistant lines. This kit was developed with 10 markers each for FW and SMD resistance. Investigation of the diversity of these loci has shown the role of different alleles in different resistant genotypes. Two genes (C.cajan_03691 and C.cajan_18888) for FW resistance and four genes (C.cajan_07858, C.cajan_20995, C.cajan_21801 and C.cajan_17341) for SMD resistance have been identified. More importantly, we developed a customized and cost-effective Kompetitive allele-specific PCR genotyping assay for the identified genes in order to encourage their downstream applications in pigeonpea breeding programs. The diagnostic marker kit developed here will offer great strength to pigeonpea varietal development program, since the resistance against these two diseases is essentially required for nominating an improved line in varietal release pipeline.

scholarly journals Common bean landraces as potential sources of resistance to anthracnose

2018 ◽  
Vol 48 (2) ◽  
pp. 126-133
Author(s):  
Ana Carolina da Costa Lara Fioreze ◽  
Sibila Grigolo ◽  
Claudia Aparecida Guginski Piva ◽  
Lays Sartori
Keyword(s):  
Environmental Conditions ◽  
Colletotrichum Lindemuthianum ◽  
Grain Production ◽  
Sources Of Resistance ◽  
Local Varieties ◽  
Commercial Cultivars ◽  
Potential Sources ◽  
Cropping Seasons ◽  
Moderately Resistant ◽  
Important Disease

ABSTRACT Anthracnose is an important disease caused by the Colletotrichum lindemuthianum (Sacc. & Magnus) fungus in bean crops. It occurs throughout Brazil and may cause losses of up to 100 % in grain production. About 20 genes that confer resistance to specific races of the pathogen have already been described in the literature. This study aimed to evaluate bean varieties from the Brazilian states of Santa Catarina and Paraná, regarding the resistance to anthracnose, in two cropping seasons. In addition, two commercial cultivars were used as controls: IPR Tangará, as susceptible; and BRS Campeiro, as moderately resistant. The majority of the local varieties was considered resistant or moderately resistant, being more pronounced the Amendoim cultivar, with large grains and red tegument, evincing resistance in both evaluations. Regarding this, the possibility of using them as resistance sources to anthracnose may be considered, since they also show adaptability to the environmental conditions.

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