Factors influencing flower development in kiwifruit vines

A. Richardson, V. Eyre, R. Rebstock, E. Popowski, S. Nardozza
Achieving high yields in kiwifruit depends on the production of an adequate number of flowers. This can be difficult with low-producing cultivars, such as Actinidia chinensis var. deliciosa 'Hayward', and in warm climates lacking winter chilling. Limitation on flower numbers begins at floral meristem initiation as axillary buds form in spring of one season, continues to develop through summer growth, winter dormancy and spring, to reach anthesis in the following season. Initiation of floral meristems is stimulated by leaf signals and there is no further morphological development of floral meristems until budswell in the following spring. However, during summer, high temperatures, vertical shoot growth and late shoot development have negative impacts on subsequent flower production. During autumn, factors that influence vine carbohydrate reserve accumulation, such as phloem girdling, shade or defoliation, also affect the number of flowers produced in the following spring. Chilling accumulation, wood selection, cane orientation and application of budbreak enhancers to vines in winter can affect spring flower production too. Once buds begin to swell in spring, floral meristem development resumes with the differentiation of flowers. At this time, competition for resources among flowers, leaves and shoots can cause floral abortion. We review these factors and their influences on flower development in kiwifruit.
Richardson, A., Eyre, V., Rebstock, R., Popowski, E. and Nardozza, S. (2022). Factors influencing flower development in kiwifruit vines. Acta Hortic. 1332, 141-154
DOI: 10.17660/ActaHortic.2022.1332.20
carbohydrate, differentiation, flower abortion, flower number, initiation, shoot growth, temperature

Acta Horticulturae