Cyanamide advances the maturity of table grapes in central Australia

Abstract

In the hot subtropical desert of Central Australia, a 25 mg/ml cyanamide solution was applied to Sultana H4 and Cardinal grape vines immediately after pruning on 2 May, 30 May, 27 June or 25 July, 16, 12, 8 and 4 weeks prior to the usual time of budburst, about 22 August. Both cultivars responded to cyanamide, the vines bursting bud 2-4 weeks after application. Vines treated on 2 May and 30 May suffered frost damage and produced negligible crops; those treated on 27 June and 25 July flowered significantly earlier than untreated vines, despite slow growth in July and August. Fruit ripening in Sultana H4 was advanced by 4, 3 and 2 weeks by cyanamide applications on 30 May, 27 June and 25 July, respectively. Ripening in Cardinal was advanced by 3.5 and 2.5 weeks by cyanamide applications on 27 June and 25 July, respectively. The ability to advance maturity has significant implications for commercial table-grape production in the region.