A potyvirus of Polianthes tuberosa in New Zealand

Tuberose (Polianthes tuberosa L.). a member of the Amaryllidaceae, is a cutflower crop currently being evaluated for export potential by the New Zealand Ministry of Agriculture and Fisheries (MAF). Tuberose, a native of Mexico. is grown commercially in several countries including Japan. Taiwan, Italy and India. Production is primarily for cut flowers. but essential oil may also be extracted (5). Observations by MAF staff suggest that the vast majority. possibly all. tuberose plants in New Zealand exhibit a leaf mottling symptom characteristic of virus infection (D.J. Brundell. personal communication, 1985). In late 1983 leaf samples from plants of the double tepalled cultivar 'The Pearl' at the MAF Research Station, Pukekoe was macerated in 2% potassium phosphotungstate (pH 7.0) and examined in an electron microscope. All preparations contained flexuous rods with a mean length of 732.6 +/11.6 nrn, a size typical of members of the potyvirus group (3). Similar particles were also observed in samples of 'The Pearl' from elsewhere in New Zealand and from samples of the single tepalled cultivar 'Single'. Potyvirus-Iike particles have also been found in tuberose in Tasmania. Australia (D. Munro, personal communication. 1985). Like many potyviruses, the virus found in tuberose appears to have a limited host range. Mechanical inoculations were made using infected tuberose leaf material ground up in 0.1 M phosphate buffer, pH 7.0 both with and without the addition of either sodium diethyldithiocarbamate, ethylenediaminetetraacetic acid or mercaptoethanol. The following species were inoculated: Beta vulgaris L., Brassica pekinensis (Lour.) Rupr., Callistephus chinensis (L.) Nees cv. Princess, Chenopodium amaranticolor Coste and Reyn.. C. murale L.. C. quinoa Willd .• Cucumis sativus L. cv. Short Green Prickly. Datura stramonium L., Gomphrena globosa L.. Latuca sativa L. cv. Great Lakes, Nicotiana clevelandii Gray. N. glutinosa L.. N. tabacum L. cvs. Burley