Heuer, B., Institute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Markovitz, T., Institute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel

Israel is facing severe water restrictions, which led its cut-flower growers to seek alternative water sources for irrigation. These sources include recycled water, treated effluent, and saline water, which all contain relatively high levels of soluble salts. Cut flowers are traditionally considered sensitive to poor quality water, but recent research indicated that they may be more salt-tolerant then was originally considered. Grevillea is used as a cut flower in Israeli agriculture. The response of Grevillea cultivars to irrigation with treated effluent is not known and was evaluated in a field study. Four commercial varieties of Grevillea were studied: 'Misty Red', 'Calundra Gem', 'Misty Red' x 'Calundra Gem' ('Calgem'), and 'Spiderman' x 'Calundra Gem'. The plants were planted in soil or on perlite cushions. The experiment included three water quality treatments: fresh water, secondary treated effluent, and tertiary treated effluent. The quality of the secondary-treated effluent was high and quite similar to the tertiary one, and as a result the crop response was almost the same, thus we concentrate in this paper only on two treatments. Winter of 2008 had an outstanding number of frost nights, which severely injured the Grevillea plants at the experimental field. This gave us the opportunity to compare the response of Grevillea cultivars irrigated with treated effluent to frost, and to document the interactive effects of frost and effluent irrigation on the studied Grevillea varieties. The response of the plants to irrigation with the treated effluent depended on the cultivar used. More damage was observed in soil-planting compared to planting in perlite cushions. Response of the Grevillea plants to frost was found to depend on the combination between cultivar, the rootstock used for grafting, and the quality of the irrigation water. Grafting on 'Calundra Gem' ('Calgem') improved resistance to both chilling and water quality. Planting on perlite cushion was preferable to planting in soil. © 2011 Science From Israel / LPPltd.