Variation in pathogenicity among and within Mycosphaerella pinodes populations collected from field pea in Australia

1998 ◽  
Vol 76 (11) ◽  
pp. 1955-1966 ◽  
Author(s):  
J M Wroth
Keyword(s):  
Cluster Analysis ◽  
Pisum Sativum ◽  
Host Resistance ◽  
Ascochyta Blight ◽  
Mycosphaerella Pinodes ◽  
Environment Interaction ◽  
Pathogen Population ◽  
Host Genotype ◽  
Host Pathogen Interaction ◽  
The Relationship

Ninety-nine single ascospore isolates of Mycosphaerella pinodes (Berk. & Blox.) Vestergr. from widely separated locations in southern Australia varied greatly in their ability to cause disease in leaves and stems of 10 host genotypes when assayed at two inoculum pressures. There were highly significant differences between the infection pressures, isolates, and host genotypes that accounted for most of the variance. A small proportion of the variance included a highly significant host genotype beta isolate interactions in leaves and stems and a highly significant host genotype beta isolate beta environment interaction in leaves. The continuous variation in disease responses among isolates precluded classification into distinct pathotypes. A cluster analysis of the data revealed that many isolates were closely related irrespective of the host cultivar or location from which they were collected. The relationship between mean host resistance and the variation among isolates was assessed, and it was concluded that increasing host resistance was unlikely to increase variation in the pathogen population; therefore, resistance should be relatively stable.Key words: Ascochyta blight, Pisum sativum, host-pathogen interaction, cluster analysis.

Importance of seed-borne inoculum in the etiology of the Ascochyta blight complex of field peas (Pisum sativum L.) grown in Victoria

1995 ◽  
Vol 35 (4) ◽  
pp. 525 ◽  
Author(s):  
TW Bretag ◽  
TV Price ◽  
PJ Keane
Keyword(s):  
Pisum Sativum ◽  
Ascochyta Blight ◽  
Mycosphaerella Pinodes ◽  
Seed Infection ◽  
Seeding Rate ◽  
Pisum Sativum L ◽  
Field Peas ◽  
Ascochyta Pisi ◽  
Growing Region ◽  
Seed Infestation

Fungi associated with the ascochyta blight complex of field peas were isolated from 436 of 691 seedlots tested. Of the fungi detected, 94.8% of isolates were Mycosphaerella pinodes, 4.2% Phoma medicaginis, and 1.0% Ascochyta pisi. The levels of infestation of seed varied considerably from year to year and between seedlots, depending on the amount of rainfall between flowering and maturity. Within a particular pea-growing region, the level of seed-borne infection was often highest in seed from crops harvested latest. In addition, crops sown early were usually more severely affected by disease than late-sown crops, and this resulted in higher levels of seed infection. There was no correlation between the level of seed infestation by M. pinodes and the severity of ascochyta blight; however, where the level of seed infection was high (>11%) there was a significant reduction in emergence, which caused a reduction in grain yield. It may therefore be possible to use seed with high levels of seed-borne ascochyta blight fungi, provided the seeding rate is increased to compensate for poor emergence.

Fungicidal control of ascochyta blight of field pea

1996 ◽  
Vol 76 (1) ◽  
pp. 67-71 ◽  
Author(s):  
T. D. Warkentin ◽  
K. Y. Rashid ◽  
A. G. Xue
Keyword(s):  
Pisum Sativum ◽  
Key Words ◽  
Untreated Control ◽  
Seed Weight ◽  
Ascochyta Blight ◽  
Field Pea ◽  
Mycosphaerella Pinodes ◽  
Yield Increase ◽  
Pisum Sativum L

The use of fungicides for the control of ascochyta blight in field pea was investigated. Four fungicides were applied to the cultivars AC Tamor and Radley at two locations in Manitoba in 1993 and 1994. Fungicides were applied either once, twice, or three times at 10-d intervals, beginning at the initiation of flowering. Chlorothalonil and benomyl were effective m reducing the severity of ascochyta blight and increasing the yield and seed weight of field pea. The triple application of chlorothalonil resulted in a mean yield increase of 33% over that of the untreated control. Iprodione and propiconazole were relatively ineffective in controlling ascochyta blight. The percentage of seedborne ascochyta was not significantly affected by fungicide treatments. The severity of ascochyta blight was greater in 1993 that in 1994, resulting in greater benefits of chlorothalonil and benomyl applications in 1993. Key words: Field pea, Pisum sativum L., ascochyta blight, Mycosphaerella pinodes, fungicide

scholarly journals Relative Host Resistance to Black Spot Disease in Field Pea (Pisum sativum) is Determined by Individual Pathogens

Plant Disease ◽  
2015 ◽  
Vol 99 (5) ◽  
pp. 580-587 ◽  
Author(s):  
Hieu Sy Tran ◽  
Ming Pei You ◽  
Tanveer N. Khan ◽  
Martin J. Barbetti
Keyword(s):  
Pisum Sativum ◽  
Host Resistance ◽  
Ascochyta Blight ◽  
Black Spot ◽  
Field Pea ◽  
Breeding Programs ◽  
Didymella Pinodes ◽  
Progress Curve ◽  
The Individual ◽  
Important Disease

Black spot, also known as Ascochyta blight, is the most important disease on field pea (Pisum sativum). It is caused by a complex of pathogens, the most important of which in Australia include Didymella pinodes, Phoma pinodella, and P. koolunga. The relative proportions of these and other component pathogens of the complex fluctuate widely across time and geographic locations in Australia, limiting the ability of breeders to develop varieties with effective resistance to black spot. To address this, 40 field pea genotypes were tested under controlled environment conditions for their individual stem and leaf responses against these three pathogens. Disease severity was calculated as area under disease progress curve (AUDPC), and subsequently converted to mean rank (MR). The overall rank (OR) for each pathogen was used to compare response of genotypes under inoculation with each pathogen. The expressions of host resistance across the field pea genotypes were largely dependent upon the individual test pathogen and whether the test was on stem or leaf. Overall, P. koolunga caused most severe stem disease; significantly more severe than either D. pinodes or P. pinodella. This is the first report of the host resistance identified in field pea to P. koolunga; the five genotypes showing highest resistance on stem, viz. 05P778-BSR-701, ATC 5338, ATC 5345, Dundale, and ATC 866, had AUDPC MR values <250.4, while the AUDPC MR values of the 19 genotypes showing the best resistance on leaf was less than 296.8. Two genotypes, ATC 866 and Dundale, showed resistance against P. koolunga on both stem and leaf. Against D. pinodes, the four and 16 most resistant genotypes on stem and leaf had AUDPC MR values <111.2 and <136.6, respectively, with four genotypes showing resistance on both stem and leaf including 05P770-BSR-705, Austrian Winter Pea, 06P822-(F5)-BSR-6, and 98107-62E. Against P. pinodella, four and eight genotypes showing the best resistance on stem and leaf had AUDPC MR values <81.3 and <221.9, respectively; three genotypes, viz. 98107-62E, Dundale, and Austrian Winter Pea showed combined resistance on stem and leaf. A few genotypes identified with resistance against two major pathogens of the complex will be of particular significance to breeding programs. These findings explain why field pea varieties arising from breeding programs in Australia fail to display the level or consistency of resistance required against black spot and why there needs to be a wider focus than D. pinodes in breeding programs.

scholarly journals Aromatic Profile Variation of Essential Oil from Dried Makwhaen Fruit and Related Species

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 803
Author(s):  
Trid Sriwichai ◽  
Jiratchaya Wisetkomolmat ◽  
Tonapha Pusadee ◽  
Korawan Sringarm ◽  
Kiattisak Duangmal ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Essential Oil ◽  
Related Species ◽  
Phenotypic Characteristic ◽  
Genetic Sequencing ◽  
Dried Fruits ◽  
Profile Variation ◽  
Chemical Profiles ◽  
The Relationship ◽  
Different Sources

The aim of this research is to evaluate the relationship between genotype, phenotype, and chemical profiles of essential oil obtained from available Zanthoxylum spp. Three specimens of makhwaen (MK) distributed in Northern Thailand were genetically and morphologically compared with other Zanthoxylum spices, known locally as huajiao (HJ) and makwoung (MKO), respectively. HJ was taxonomically confirmed as Z. armatum while MKO and MK were identified as Z. rhetsa and Z. myriacanthum. Genetic sequencing distributed these species into three groups accordingly to their confirmed species. Essential oil of the dried fruits from these samples was extracted and analyzed for their chemical and physical properties. Cluster analysis of their volatile compositions separated MKO and MK apart from HJ with L-limonene, terpinen-4-ol, β-phellandrene, and β-philandrene. By using odor attributes, the essential oil of MKO and MK were closely related possessing fruity, woody, and citrus aromas, while the HJ was distinctive. Overall, the phenotypic characteristic can be used to elucidate the species among makhwaen fruits of different sources. The volatile profiling was nonetheless dependent on the genotypes but makwoung and makhwaen showed similar profiles.

Event quality and loyalty among runners with different running involvement levels

2017 ◽  
Vol 8 (3) ◽  
pp. 292-307 ◽  
Author(s):  
Kostantinos Alexandris ◽  
Nicholas Theodorakis ◽  
Kiki Kaplanidou ◽  
Dimitra Papadimitriou
Keyword(s):  
Service Quality ◽  
Environment Interaction ◽  
Sport Event ◽  
Content Type ◽  
Service Environment ◽  
Event Marketing ◽  
Quality Dimensions ◽  
The Relationship ◽  
Moderating Role

Purpose The purpose of this paper is twofold: to investigate if the three service quality dimensions (service environment, interaction and outcome quality), proposed by Brady and Cronin (2001), influence the development of event loyalty, among runners of the “‘Alexander the Great’ International Marathon”, and to test if running loyalty moderates the relationship between event quality and event loyalty. Design/methodology/approach In all, 368 runners participated in the study and filled the Sport Event Quality Questionnaire (Theodorakis et al., 2015) and an adjusted version of the Leisure Involvement Questionnaire (Kyle et al., 2010). Findings The results indicated that only the service environment and outcome dimensions contributed significantly to the prediction of event loyalty, while, and in contrast to other sport services, interaction quality was not shown to be an important determinant for the development of event loyalty. Furthermore, running involvement was shown to play a moderating role in the relationship between event quality and event loyalty. Service quality is more important for the development of event loyalty among low- than high-involved runners. The theoretical and applied implications of these results are discussed. Research limitations/implications The study provided results on how high- and low-involved runners perceive event quality, and for which of these groups the event quality is an important antecedent for the development of event loyalty. Practical implications Investigating the moderating role of involvement on the relationship between service quality and loyalty has also applied value. While committed runners have been traditionally seen as a key target group for event marketing professionals, the majority of runners in city marathons today are more leisure oriented. The increase in the number of leisure runners is actually the reason for the rapid growth of city marathons in the last few years. Meeting the needs of these leisure runners and increasing their loyalty levels is therefore a key task for marathon marketers today. Originality/value This study contributes to the literature, as for the first time it explores the moderating role of involvement on the relationship between service quality and loyalty in the context of a sport event.

The relationship between protein nutrition, reproductive effort and breakdown in immunity toTeladorsagia circumcinctain periparturient ewes

2001 ◽  
Vol 72 (3) ◽  
pp. 595-606 ◽  
Author(s):  
J.G. M. Houdijk ◽  
I. Kyriazakis ◽  
F. Jackson ◽  
R. L. Coop
Keyword(s):  
Host Resistance ◽  
Dry Matter ◽  
Reproductive Effort ◽  
Late Pregnancy ◽  
Gastrointestinal Nematodes ◽  
Dry Matter Intake ◽  
Teladorsagia Circumcincta ◽  
Nutrient Partitioning ◽  
Ad Libitum ◽  
The Relationship

AbstractA nutritional hypothesis for the occurrence of the periparturient relaxation of immunity (PPRI) to gastrointestinal nematodes was tested within the bounds of a nutrient partitioning framework. It was hypothesized that at times of a scarce supply of metabolizable protein (MP), an increase in MP supply or a reduction in MP demand (having singles instead of twins) should lower the extent of PPRI in sheep. Twenty-one single- and 21 twin-bearing and -rearing Finn-Dorset ewes, 2 to 7 years old, and repeatedly infected withTeladorsagia circumcincta, were given one of three pelleted foods (no. = 7). The foods were formulated to supply 0·8 (L), 1·0 (M) and 1·2 (H) times the MP requirements during lactation, and were offeredad libitumfrom d–21to d35(d0 is day of parturition). Faecal egg counts (FEC) were assessed twice weekly as an indicator for host resistance. Dry-matter intake (DMI) during late pregnancy was higher than expected, and MP supply did not limit performance at this stage. In accordance with the hypothesis, there were no indications of a breakdown of immunity toT. circumcinctaduring late pregnancy. DMI during lactation did not differ between the single- and twin-rearing ewes. Calculated milk production was lower for the L than for the M and H ewes, especially for the twin-rearing ewes. A temporarily elevated FEC was observed during the first few days in lactation, which was probably mainly due to changes in faecal output rather than to PPRI. The FEC returned to low, late pregnancy levels at d12and remained low for the single- but not for the twin-rearing ewes (P< 0·001). Overall, the L ewes had higher FEC than the M and H ewes from d19onwards; this effect was more pronounced for the twin- than for the single-rearing ewes. It was postulated that DMI achieved overcame MP scarcity and thus prevented breakdown in immunity in the single-rearing ewes. The data support the view that, at times of MP scarcity, an increase in MP supply and reduction in MP demand can lower the extent of the breakdown in immunity towardsT. circumcincta.

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