Variation in pathogenicity and virulence of Phytophthora clandestina on four cultivars of subterranean clover

1995 ◽  
Vol 35 (6) ◽  
pp. 717 ◽  
Author(s):  
A Purwantara ◽  
SP Flett ◽  
PJ Keane
Keyword(s):  
Growth Rate ◽  
Agar Medium ◽  
Sandy Loam ◽  
Severe Disease ◽  
Subterranean Clover ◽  
Race 1 ◽  
Pathogenicity Tests ◽  
Loam Soil ◽  
Race 2 ◽  
Cultivar Specificity

The pathogenicity of 6 isolates of Phytophthora clandestina on seedlings of 4 cultivars of subterranean clover was studied. There was a highly significant isolate x cultivar interaction in pathogenicity tests on axenic seedlings and seedlings grown in pasteurised potting mix or untreated sandy loam soil, indicating the existence of race-cultivar specificity. The isolates showed differences in virulence against the cultivars. Three isolates (race 0) caused severe disease only on Woogenellup; 2 isolates (race 1) caused severe disease on Larisa, Trikkala, and Woogenellup, but not on Meteora; one isolate (race 2) caused severe disease on Meteora and Woogenellup, but not on Larisa and Trikkala. As well as differing in virulence (the ability of a race to attack a range of cultivars), the races also differed in their aggressiveness on Woogenellup, with race 2 being the most, and race 0 the least, pathogenic. The isolates varied in their growth rate on agar medium, but this was not related to virulence or aggressiveness.

Resistance to race 1 of Kabatiella caulivora in subterranean clover (Trifolium subterraneum L.) cultivars and breeding lines

2008 ◽  
Vol 59 (6) ◽  
pp. 561 ◽  
Author(s):  
P. G. H. Nichols ◽  
M. P. You ◽  
M. J. Barbetti
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Breeding Lines ◽  
Race 1 ◽  
Kabatiella Caulivora ◽  
Selection For ◽  
Race 2 ◽  
Resistant Progeny ◽  
Clover Scorch

Twenty-eight cultivars and 106 F6-derived breeding lines of subterranean clover (Trifolium subterraneum) were screened in the field for their response to clover scorch disease caused by race 1 of Kabatiella caulivora. Eleven of the cultivars, including Denmark and Goulburn, were classified as resistant. Breeding lines with Denmark parentage had 55% of progeny with resistance, while those of Goulburn had only 19% of resistant progeny, suggesting different modes of inheritance. Selection for resistance to race 2 of K. caulivora in the F4 generation markedly increased the probability of selecting F6-derived lines with resistance to race 1, suggesting linkage between genes for resistance to both races.

scholarly journals Genetic Diversity of Fusarium oxysporum f. sp. dianthi in Southern Spain

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Raúl Castaño ◽  
Barbara Scherm ◽  
Manuel Avilés
Keyword(s):  
Fusarium Oxysporum ◽  
Phylogenetic Analyses ◽  
Gene Sequencing ◽  
Southern Spain ◽  
Specific Pcr ◽  
Rapd Pcr ◽  
Race 1 ◽  
Pathogenicity Tests ◽  
Specific Band ◽  
Race 2

The diversity of races and prevalence of pathogenic populations of Fusarium oxysporum f. sp. dianthi (Fod) were surveyed in an area in southern Spain. From 54 farms, 132 isolates were collected from wilted carnation plants. Isolates were characterized by RAPD-PCR, DNA sequence analysis of the TEF1-α gene, and race-specific molecular markers. Selected isolates from RAPD groups were phenotypically evaluated by pathogenicity tests. Data analysis showed that Fod race 2 was the most frequent and prevalent race in the study area, followed by race 1/8. Moreover, phylogenetic analyses showed similar results, which were different to those of the race-specific PCR assays. It was concluded that (i) seven isolates were not classified in groups where Fod testers were clustered; even they showed different results when race-specific markers were used, (ii) ten isolates with retarded race 1 or race 8 specific band were characterized as F. proliferatum by TEF1-α gene sequencing and clustered into an outgroup, and (iii) six isolates failed to generate an amplification signal using race-specific markers. Furthermore, three of them were grouped close to race 2 tester according to the phylogenetic analyses, showing the same differential pathogenicity as race 2. This may indicate a Fod race 2 subgroup in this region.

scholarly journals Genetic Diversity and Identification of Wilt and Root Rot Pathogens of Tomato in China

Plant Disease ◽  
2020 ◽  
Vol 104 (6) ◽  
pp. 1715-1724
Author(s):  
Qingjing Ye ◽  
Rongqing Wang ◽  
Meiying Ruan ◽  
Zhuping Yao ◽  
Yuan Cheng ◽  
...  
Keyword(s):  
Root Rot ◽  
Management Strategies ◽  
Resistance Breeding ◽  
Its Region ◽  
Fusarium Equiseti ◽  
Resistant Varieties ◽  
Causative Agents ◽  
Race 1 ◽  
Pathogenicity Tests ◽  
Race 2

Fungal wilt and root rot diseases affecting tomato have become prevalent in China in recent years and have caused considerable damage. In 2016 to 2018, symptoms of putative wilt and root rot diseases were observed in several locations in tomato cultivars with resistance to Fusarium oxysporum f. sp. lycopersici races 1 and 2. The objective of this study was to identify the causative agents of wilt and root rot of tomato in China and provide a basis for disease prevention and resistance breeding programs. Based on DNA sequence analyses of the internal transcribed spacer (ITS) region, 91 isolates from the roots of tomato plants showing symptoms of wilt and root rot were identified, including F. oxysporum (64 isolates), Fusarium solani (11 isolates), Fusarium proliferatum (2 isolates), Fusarium graminearum (2 isolates), Fusarium equiseti (1 isolate), Pythium aphanidermatum (6 isolates), Ascomycota sp. (2 isolates), and Plectosphaerella cucumerina (3 isolates). F. oxysporum accounted for 70.33% of the isolates obtained. In this case, using PCR-based methods for differentiation of F. oxysporum, we identified several formae speciales and races of F. oxysporum: 7 isolates were identified as F. oxysporum f. sp. lycopersici race 1, 2 isolates as F. oxysporum f. sp. lycopersici race 2, 35 isolates as F. oxysporum f. sp. lycopersici race 3, and 13 isolates as F. oxysporum f. sp. radicis-lycopersici. Pathogenicity tests revealed 55 isolates of tomato wilt and root rot pathogens to be virulent. This study demonstrated that F. oxysporum f. sp. lycopersici race 3 was the most widespread and highly virulent race among these tomato pathogens in China, followed by F. oxysporum f. sp. radicis-lycopersici. Therefore, the development of resistant varieties of tomato against F. oxysporum f. sp. lycopersici race 3 and F. oxysporum f. sp. radicis-lycopersici would aid efforts to develop effective disease management strategies.

scholarly journals Characterisation of the pathogenicity of strains of Pseudomonas syringae towards cherry and plum

2017 ◽  
Author(s):  
M.T. Hulin ◽  
J.W. Mansfield ◽  
P. Brain ◽  
X. Xiangming ◽  
R.W. Jackson ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Host Resistance ◽  
Resistance Mechanisms ◽  
Genetic Dissection ◽  
Depth Study ◽  
Detached Leaves ◽  
Race 1 ◽  
Pathogenicity Tests ◽  
Race 2 ◽  
Cultivar Susceptibility

AbstractBacterial canker is a major disease of cherry and other stone fruits caused by several pathovars of Pseudomonas syringae. These are P.s pv. morsprunorum race 1 (Psm R1), P.s pv. morsprunorum race 2 (Psm R2) and P.s pv. syringae (Pss). Psm R1 and R2 were originally designated as races of the same pathovar, however phylogenetic analysis has revealed them to be distantly related. This study characterised the pathogenicity of P. syringae on cherry and plum, in the field and the laboratory. The field experiment identified variation in host cultivar susceptibility to the different pathogen clades. The cherry cultivar Merton Glory exhibited a broad resistance to all clades, whilst cultivar Van showed race-specific resistance. Psm R1 may be divided into a race structure with some strains pathogenic to both cherry and plum and others only pathogenic to plum. The results of laboratory-based pathogenicity tests were compared to results obtained on whole-trees. Only cut shoot inoculations were found to be sensitive enough to detect cultivar variation in susceptibility. Measuring population growth of bacteria in detached leaves reliably discriminated pathogens from non-pathogens. In addition, symptom appearance discriminated Psm races from non-pathogens which triggered a rapid hypersensitive response (HR). The pathogen Pss rapidly induced disease lesions and therefore may exhibit a more necrotrophic lifestyle than hemi-biotrophic Psm races. This in-depth study of pathogenic interactions, identification of host resistance and optimisation of laboratory assays, will provide a framework for future genetic dissection of virulence and host resistance mechanisms.

Comparing vegetative compatibility and protein banding patterns for identification of Fusarium oxysporum f.sp. apii race 2

1991 ◽  
Vol 37 (9) ◽  
pp. 669-674 ◽  
Author(s):  
K. F. Toth ◽  
M. L. Lacy
Keyword(s):  
Fusarium Oxysporum ◽  
Polyacrylamide Gel Electrophoresis ◽  
Vegetative Compatibility ◽  
Wild Type ◽  
Banding Patterns ◽  
Formae Speciales ◽  
Compatibility Group ◽  
Race 1 ◽  
Pathogenicity Tests ◽  
Race 2

Vegetative compatibility grouping and electrophoretic separation of total proteins were compared as possible techniques for identifying isolates of Fusarium oxysporum f.sp. apii race 2, the cause of fusarium yellows of celery. Vegetative compatibility grouping was determined by pairing chlorate-tolerant, nitrate-nonutilizing mutants on a minimal medium containing nitrate as the sole nitrogen source. Heterokaryon formation, which resulted in wild-type growth, occurred only between mutants from vegetatively compatible isolates. All isolates of F. oxysporum f.sp. apii race 2 examined were placed within a unique vegetative compatibility group that excluded F. oxysporum f.sp. apii race 1 and the 11 other formae speciales of F. oxysporum tested. Few differences were observed in protein banding patterns among isolates of F. oxysporum f.sp. apii race 2, F. oxysporum f.sp. apii race 1, 11 other formae speciales of F. oxysporum, and 2 formae speciales of F. solani on 12% polyacrylamide gels. No banding pattern unique to F. oxysporum f.sp. apii race 2 was observed. Vegetative compatibility grouping could be accomplished more rapidly than greenhouse pathogenicity tests and more accurately identified race 2 isolates in a population of isolates of F. oxysporum from muck soils than did greenhouse pathogenicity tests or electrophoretic protein banding patterns. Key words: celery, fusarium yellows, nitrate-nonutilizing mutants, polyacrylamide gel electrophoresis.

Differences in symptom development in subterranean clover infected with Kabatiella caulivora Race 1 and Race 2 are related to host resistance

2002 ◽  
Vol 53 (3) ◽  
pp. 305 ◽  
Author(s):  
K. L. Bayliss ◽  
J. Kuo ◽  
K. Sivasithamparam ◽  
M. J. Barbetti ◽  
E. S. Lagudah
Keyword(s):  
Subterranean Clover ◽  
Post Inoculation ◽  
Vascular Bundles ◽  
Incompatible Interaction ◽  
Mesophyll Cells ◽  
Starch Grains ◽  
Race 1 ◽  
Kabatiella Caulivora ◽  
Race 2 ◽  
Clover Scorch

Clover scorch (Kabatiella caulivora) is a severe fungal disease of Trifolium spp. contributing to the collapse of pasture swards across southern Australia during warm, humid spring weather. Host plant responses associated with resistance to the disease were determined in 2 cultivars of subterranean clover (T. subterraneum) separately inoculated with K. caulivora Race 1 or Race 2. Germination of conidia of both races reached a maximum 5 days post-inoculation on cv. Woogenellup (susceptible to both races) and 4 days post-inoculation on cv. Daliak (resistant to Race 1 but susceptible to Race 2). Germ tube growth of Race 1 was inhibited on cv. Daliak and the percentage of conidia penetrating leaf surfaces was lowest on this race–cultivar combination. Susceptibility was characterised by large petiole lesions, with invasive hyphae extending through the mesophyll tissue into the pith and then through the phloem tissue of vascular bundles, eventually causing the petioles to collapse. Resistance was characterised by small, black lesions with invasive hyphae extending no further than the fourth layer of mesophyll cells. A suberin-based material was observed beneath infected mesophyll cells in the incompatible interaction, beyond which no further growth of hyphae occurred. Race 2 caused a faster rate of host tissue necrosis than Race 1 and also the breakdown of starch grains in uninvaded petiole tissues. Starch grains in plants infected with Race 1 were evenly distributed in uninvaded tissue. Sporulation was rarely observed in the incompatible interaction but was common in compatible interactions within 15 days post-inoculation. These responses to K. caulivora can now be used as a breeding tool in evaluating and selecting improved resistance to clover scorch disease among breeding lines of subterranean clover.

Soil management for irrigated vegetable production. II. Possible causes for slow vegetative growth of lettuce associated with zero tillage

1993 ◽  
Vol 44 (4) ◽  
pp. 831 ◽  
Author(s):  
RJ Stirzaker ◽  
JB Passioura ◽  
BG Sutton ◽  
N Collis-George
Keyword(s):  
Vegetative Growth ◽  
Sandy Loam ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Vegetable Production ◽  
Zero Tillage ◽  
Evaporative Demand ◽  
Loam Soil ◽  
Hard Soil ◽  
Tillage Treatment

This work explores the consequences of using zero-tillage for irrigated vegetable production. The research is based on the hypothesis that, under the well-watered and adequately fertilized conditions prevailing in commercial vegetable growing, the reduced root density expected under zero-tillage should not limit vegetative growth. To test this hypothesis, irrigated lettuce crops were grown under a range of soil physical conditions on a hardsetting sandy loam soil. Crops were grown during the spring, autumn and summer, in order to compare zero-tillage and cultivation treatments under conditions of low, medium and high evaporative demand. Lettuce yields under zero-tillage were reduced relative to those under cultivation for each of these crops. However, calculations based on a model which describes the movement of water to roots show that the root length measured in the zero-tillage treatment greatly exceeded that required to meet the potential evaporative demand in the field. A possible explanation for the reduced growth is given, based on an inhibitory root signal which has been shown under controlled conditions to reduce shoot growth in hard soil even when the leaves are well supplied with water and nutrients. When lettuce was grown under zero-tillage, but following a crop of subterranean clover (Trifolium subterraneum L.) which senesced in summer to form an in-situ mulch, yield was as high as in cultivated soil. The soil near the surface in this treatment was not only moister and physically weaker than that from the conventional zero-tillage treatment, but also likely to contain biopores which would provide zones of low root impedance in an otherwise hard soil.

scholarly journals Organic Fertilizers Effect on Potato (Solanum tuberosum L.) Tuber Production in Sandy Loam Soil

2019 ◽  
pp. 1-11
Author(s):  
Farid Ahmed ◽  
M. Monjurul Alam Mondal ◽  
Md. Babul Akter
Keyword(s):  
Growth Rate ◽  
Tuber Yield ◽  
Sandy Loam ◽  
Organic Fertilizer ◽  
Potato Cultivar ◽  
Organic Fertilizers ◽  
Chicken Manure ◽  
Fresh Weight ◽  
Tuber Production ◽  
Loam Soil

Potatoes are one of the most common and important vegetable crops in the world and carrying different health benefits that make them all the more essential as a staple dietary item for much of the world’s population. The high nutrient content, ability to adapt to marginal environments, relative ease of cultivation and low cost and high productivity are attributes that make potatoes one of the principal and most important sources of food and income for developing countries. Considering the importance of organic manure for potato cultivation, the experiment was conducted to evaluate the effect of four organic fertilizers on potato tuber production in sandy loam soil. The most popular and easily available two potato cultivars namely Cardinal and Diamant and four organic fertilizers viz., cowdung at the rate of 8 t ha-1, chicken manure at the rate of 8 t ha-1, Rangpur Dinajpur Rural Service (RDRS) developed organic fertilizer at the rate of 740 kg ha-1 and Northern organic fertilizer at the rate of 500 kg ha-1 along with a control. The results revealed that the plant height, number of leaves, leaves fresh weight, yield contributing characters and yield were significantly different and higher in organic fertilizers over control. The highest plant height, leaf number, leaf fresh weight, total dry matter, absolute growth rate, tuber growth rate, tubers plant-1 and larger tuber size were observed in chicken manure which resulted the highest tuber yield (29.71 t ha-1) followed by cowdung (28.67 t ha-1) with same statistical rank. The third highest tuber yield was recorded in RDRS organic fertilizer (26.42 t ha-1) and Northern organic fertilizer (26.00 t ha-1). Besides, the potato cultivar, cardinal gave the highest tuber yield (26.39 t ha-1) compare to diamont (24.57 t ha-1). Finally, the potato cultivar cardinal and organic fertilizers, chicken manure followed by cowdung are recommended for potato cultivation in Rangpur region due to the highest yield production as well as maximum benefit-cost ratio.

Emissions of nitrous oxide and nitric oxide associated with the decomposition of arable crop residues on a sandy loam soil in Eastern England

Agronomie ◽  
2002 ◽  
Vol 22 (7-8) ◽  
pp. 731-738 ◽  
Author(s):  
Roland Harrison ◽  
Sharon Ellis ◽  
Roy Cross ◽  
James Harrison Hodgson
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Crop Residues ◽  
Sandy Loam ◽  
Sandy Loam Soil ◽  
Arable Crop ◽  
Loam Soil

Effect of Bio and Organic Fertilizers on Pumpkin's (Cucurbita pepo L.) Leave Content of N, P, and K

2020 ◽  
Vol 10 (1) ◽  
pp. 241-245
Author(s):  
Ammar Hameed Madi ◽  
Jawad A. Kamal Al-Shibani
Keyword(s):  
Cucurbita Pepo ◽  
Sandy Loam ◽  
Block Design ◽  
Organic Fertilizers ◽  
Flowering Stage ◽  
College Of Agriculture ◽  
Significant Difference ◽  
Randomized Complete Block Design ◽  
Loam Soil ◽  
Four Levels

This study was conducted to investigate the effect of bacterial bio-fertilization A. chroococcum and P. putide and four levels of compost (0, 1, 2, 3) tons.h-1 on the leaves content of N.P.K elements. The experiment was carried out in one of the greenhouses of the College of Agriculture - University of Al-Qadisiyah during fall season 2018-2019. It designed in accordance with the Randomized Complete Block Design (RCBD) with three replicates in sandy loam soil. The means of treatments were compared with the least significant difference (LSD) at (5)% probability level. The results present that the treatments of A. chroococcum, P. putide and compost at (3) tons.kg-1 significantly increases the leaves content of K.P.K compared to all other treatments in the flowering stage (4.970, 0.5000, and 4.930) mg.kg-1, respectively. This treatment was followed by the effect of the treatment of A. chroococcum and compost at (3) tons.kg-1, which increases the values of all traits except the leaf content of (P). Bio-fertilizer with P. putide + A. chroococcum significantly increases the leaves' content of P.

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