Infection of Cullen australasicum (syn. Psoralea australasica) with Alfalfa mosaic virus
R. M. Nair A C , N. Habili B and J. W. Randles BA South Australian Research & Development Institute (SARDI), GPO Box 397, Adelaide, SA 5001, Australia.
B School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, PMB 1, Glen Osmond, SA 5064, Australia.
C Corresponding author. Email: madhavannair.ram@saugov.sa.gov.au
Australasian Plant Disease Notes 4(1) 46-48 https://doi.org/10.1071/DN09019
Submitted: 31 July 2008 Accepted: 20 April 2009 Published: 25 May 2009
Abstract
Severe yellow mosaic and leaf distortion symptoms have been observed on Cullen australasicum (cullen) plants growing in experimental plots at Urrbrae, South Australia. The incidence of the affected plants in a 2-year-old stand was ~80%. Symptom distribution on plants was uneven and symptom intensity appeared to vary between seasons. Alfalfa mosaic virus (AMV) was identified in 6/10 symptomatic and 1/10 asymptomatic field plants by reverse transcription-polymerase chain reaction (RT–PCR). Transmission of mosaic symptoms from cullen to cullen by mechanical inoculation was unsuccessful, but a cullen AMV isolate passaged through herbaceous indicators induced systemic mosaic in 1/4 of inoculated cullen seedlings. No seed transmission of AMV was observed in 50 seedlings raised from symptomatic parents. These results show that cullen is a host of AMV, but further studies are needed to determine whether AMV is the sole cause of the mosaic disease.
Acknowledgements
We thank E. Kobelt, SARDI, for allowing access to his seed production trial and A. Humphries, SARDI, for recognising the disease.
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