Methods of Screening Raspberries for Resistance to Phytophthora Root Rot

Laun, N.; Zinkernagel, V.

doi:10.17660/actahortic.1993.352.83

Cited by 4 publications

(10 citation statements)

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“…'Cascade Nectar', 'Kitsilano', and WSU 1226 also had very high susceptibility in this study. 'Meeker', 'Tulameen', and 'Willamette' were found to be susceptible to root rot, consistent with earlier reports (Barritt et al, 1981;Laun and Zinkernagel, 1993;Lévesque and Daubeny, 1999).…”

Section: Discussionsupporting

confidence: 90%

“…However, field evaluations are time-consuming, as symptoms may take several years to develop, and soil conditions and disease pressure may not be uniform. Greenhouse pot tests (Bristow et al, 1988;Kennedy and Duncan, 1991;Laun and Zinkernagel, 1993;Wilcox et al, 1999a) and hydroponic culture systems (Pattison et al, 2004) can provide greater control of environment and disease pressure, but typically use small plants that may not respond in the same manner as mature, well-established plants under field conditions. 'Cowichan' was moderately resistant to root rot in a greenhouse pot test but was shown to be susceptible in subsequent field plantings (Kempler et al, 2005).…”

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Field and Greenhouse Response of Red Raspberry Genotypes to Root Rot

Hoashi-Erhardt¹,

Moore²,

Windom³

et al. 2008

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Red raspberry genotypes (Rubus idaeus L.) were evaluated for resistance to root rot at two field sites in Washington state and in a greenhouse study. Thirteen raspberry genotypes were planted in two field sites naturally infested with Phytophthora fragariae var. rubi Wilcox and Duncan and evaluated over 3 years for growth and symptom expression. In greenhouse pot tests, 14 genotypes were inoculated with an isolate of P. fragariae var. rubi at three inoculum levels and evaluated for growth, root color, and symptom expression using a 1 to 4 rating scale. Eleven of the 14 cultivars were found to be susceptible or very susceptible to root rot in the field and greenhouse. ‘Summit’ and ‘Newburgh’ possessed high levels of resistance to the pathogen. ‘Cascade Bounty’ also showed high resistance to root rot in the greenhouse, but confirmation from a field study is needed. Subjective root ratings of greenhouse-grown plants correlated well with measurements of cane numbers and cane infection in the field. The greenhouse tests were useful in identifying resistant genotypes and very susceptible genotypes but did not always match field results. Observation of at least 3 years in the field was necessary to compare relative reaction with root rot among genotypes.

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Section: Discussionsupporting

confidence: 90%

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confidence: 99%

Field and Greenhouse Response of Red Raspberry Genotypes to Root Rot

Hoashi-Erhardt¹,

Moore²,

Windom³

et al. 2008

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“…The three genotypes used in this study represent extremes in symptom expression against Phytophthora root rot. Other raspberry cultivars than 'Schonemann' and 'Win-klers Samling' can be ranked between these two (Laun and Zinkernagel, 1993). Diiferences in resistance among the tested genotypes were strictly post-infectional.…”

Section: Discussionmentioning

confidence: 92%

“…The differences recorded here fit to greenhouse and field observations. 'Winklers Samling' was largely unaffected by infection and 'Schonemann' was severely infected and died (Lutz and Lauber, 1981;Laun and Zinkernagel, 1993). The invasion of the stem bases represents the final stages of pathogenesis after leaf wilt- Table 4 Frequencies of isolation of Phytophthora fragariae var.…”

Section: Discussionmentioning

confidence: 99%

“…Affected plants have rotted root systems and lesions on their stem bases that result in wilting and dieback of yoting and fruiting canes. All commercially useful summer-fruiting cultivars are more or less susceptible but quantitative resistance has been found in small-fruited cultivars from America and Europe (Baritt et al, 1979, Duncan et ai., 1987Laun and Zinkernagel, 1993). Tayberry, a blackberry x raspberry hybrid, was highly resistant in pot inoculations (Duncan et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

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A Comparison of the Resistance Against Phytophthora fragariae var. rubi, the Causal Agent of a Raspberry Root Rot

Laun¹,

Zinkernagel²

1997

Journal of Phytopathology

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Zoospore encystment, sporulatioti, oospore formation and detection of Phyiophthora fragariae var. rubi, the causal agent of raspberry root rot, on three Rubus genotypes with different levels of resistance were investigated. There were no qualitative or quantitative diiferences in encystment as determined by scanning electron and fluorescence microscopy. Susceptibility was associated with an extended period of sporulation on roots with a proportion of roots containing oospores increasing continuously until the whole root system was colonised and the fungus could be isolated from the stem bases. Quantitative resistance as found in some raspberry (Rubus idaeus) cultivars was associated with a shorter sporulation period and decreasing proportion of the roots containing oospores due to the strong regeneration of healthy roots and limited spread ofthe fungus in the root system. Stem bases were consequently not affected. Sporulation was very limited on a blackberry x raspberry hybrid that was almost totally resistant to root rot and sustained infections could not be found. Zusammenfassung Vergleichende Untersuchungen zur Resistenz gegen Phytophthora fragariae var. rttbi, dem Erreger der HimbeerwurzelfiiuleAn drei Rubus-Gsnoiypsn mit unterschiedlichem Resistenzniveau gegenuber der Himbeerwurzelfaule, wurden die Enzystierung der Zoosporen, die Sporulation, die Oosporenbildung und die Nachweisbarkeit von Phytophthora fragariae var. rubi untersucht.In der Enzystierung zeigten sich weder qualitative noch quantitative Unterschiede mit den verwendeten fluoreszenz-und rasterelektronenmikroskopischen Verfahren. Die beobachteten Unterschiede lagen alle im postinfektionellen Bereich. Die Anfalligkeit der Wirtspflanze zeigte sich in einer verlangerten Sporulationsphase auf der Wurzeloberflache, einer im Zeitverlauf kontinuierlich zunehmenden Oosporenbildung in den Wurzeln und einer vollstandigen Besiedlung des Wurzelsystems und der SproSbasis, aus der Erreger isoliert werden konnte. Eine quantitative Resistenz, wie sie in einigen Sorten der Himbeere {Rubus idaeus) vorliegt, fuhrte zu einer verkilrzten Sporulationsphase und einem im spateren Zeitverlauf abnehmenden Anteil von Wurzeln mit Oosporen. Verursacht wurde dieser Rtickgang der Besiedlung durch eine starke Regeneration gesunder Wurzeln und eine nur begrenzte Ausbreitung des Erregers im Wurzelsystem. 'Die SproBbasis war demzufolge nicht befallen. Auf Tayberry war Sporulation nur sehr spadich. Die Hybride ist nahezu voUstandig wurzelfauleresistent, ernsthafte Infektionen konnten nicht festgestellt werden.'

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