THE INFLUENCE OF PRE- AND POST-BUDBREAK TEMPERATURES ON FLOWERING IN KIWIFRUIT

Five year old vines of kiwifruit (Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson), growing in containers were placed in controlled environment rooms from approx. 40 days prior to field budbreak until flowering.
Prior to budbreak the plants were grown under day/night temperature regimes of 13/3 and 17/7°C and after budbreak at either 17/7 or 21/11°C; responses to all four growth stage x temperature combinations were examined using four plants of the female cv. ‘Hayward’ and three plants of the male cv. ‘Matua’ in each combination.

Budbreak occurred after 37.5 days at 17/7°C and at 13/3°C was delayed by a further 12.5 or 19 days for ‘Matua’ and ‘Hayward’ respectively.
The interval from budbreak to flowering was 50 days at 21/11°C for both cultivars and at 17/7°C was 69 and 80.5 days, respectively, for ‘Matua’ and ‘Hayward’ (i.e. each 1°C decrease in mean daily temperature increased the total time to flowering by 10–12 days).

The proportion of budbreak was highest under the cooler temperature regimes but budbreak occurred over a very prolonged period.
Conversely, the proportion of fruitful shoots was highest under the warmest temperature regime and was dependent on the entire pre- and post-budbreak temperature sequence.
There was a trend for the number of flowers per flowering shoot to be higher in the warmer temperature regimes.

Symposium on Physiology of Productivity of Subtropical and Tropical Tree Fruits

I.J. Warrington, C.J. Stanley

https://doi.org/10.17660/ActaHortic.1986.175.15