A note on the development of a practical procedure for promoting the germination of dormant seed of grape (<i>Vitis</i> spp.)

Abstract

The effect of hydrogen peroxide (H₂O₂), gibberellic acid (GA₃) and a short exposure of imbibed seed to 3-5 °C (prechill) on grape seed germination were investigated factorially. All three factors had some effect, either singly or in combination with one or more of the other agents, in promoting the germination of dormant seed. 2,000 ppm GA₃ was the best single agent for breaking dormancy but tetrazolium staining revealed that this treatment caused the death of a small proportion of seed. Comparison of germination tests at 20, 25, 30 and 35 °C showed 25 °C tobe the best constant temperature for rapid full germination. Seed were also tested for germination in two diurnal alternating temperature regimes - 20/30 °C and 20/35 °C, the higher temperatures being applied for 8 hin each 24 h cycle. The alternating temperature of 20/30 °C proved better for testing seed for germination than either 20/35 °C or 25 °C, the best constant temperature. The following germination test procedure was devised for grape seed: a 24 h soak in 0.5 M H₂O₂ , a further 24 h soak in 1,000 ppm GA₃, followed by a 21 d prechill at 3-5 °C with subsequent testing for germination in a diurnal alternating temperature regime of 20/30 °C with the higher temperature being applied for 8 h in each daily cycle. This procedure was tested with dormant seed of seven lots of diverse origin and found to be very effective in promoting the germination of dormant seed whilst not damaging to other seeds. In the opinion of the authors the above procedure represents a suitable practical dormancy breaking procedure for seed of Vitis spp.

Entwicklung eines brauchbaren Verfahrens zur Förderung der Keimung dormanter Samen der Rebe ( Vitis spp.)

Die Grenzen und Möglichkeiten der vorhandenen Verfahren zur Samenkeimung bei Reben werden diskutiert. Folgendes Verfahren zur Prüfung der Keimfähigkeit von Traubenkernen wurde ausgearbeitet: 24 h lang Einweichen in 0,5 M H₂O₂, weitere 24 h lang in 1000 ppm GA₃, danach 21 d lang Stratifikation bei 3-5 °C, anschließend Prüfung der Keimfähigkeit unter diurnalen Wechseltemperaturen von 20/30 °C (16/8 h). Dieses Verfahren, das an den Kernen von sieben Traubensorten erprobt wurde, erwies sich als wirkungsvoll bei der Keimungsförderung dormanter Samen und schonend gegenüber den anderen Kernen.