The fascination of making a plant hybrid, only sweeter - mechanisms responsible for the sugar-enhanced interspecific hybridization of Actinidia

B. Guthrie, J. Thole
For both intraspecific and interspecific Actinidia crosses, a mixture of preserved (dried and frozen) pollen and dry finely-ground sucrose applied on the moist stigmatic surface markedly enhanced pollen-tube germination. The presence of the exogenic sucrose led to observed early browning of the stigmas and styles, while the introduced pollen grains are partially enveloped by the stigma's polyp-like structures. The added sucrose also leads to an observed increased fruit set with initially larger berries compared to when just pollen is applied to the stigma, and improves the potential for viable seed production. Since the stored pollen takes longer to germinate, for Actinidia, the pollen-sugar mixture should be applied on an individual blossom within the three days of flowering in order to increase the potential for a successful cross. As preserved pollen remains viable for 7 to 10 years, and because the attributes of male pollinizers are not always known, it is possible to repeat promising crosses in subsequent years by mixing the stored pollen with the sucrose. This investigation details the utility of this process and documents the developments observed during the initial stages of interspecific hybridization. This is a simple yet effective technique that Actinidia plant breeders should consider for use to effect difficult crosses.
Guthrie, B. and Thole, J. (2022). The fascination of making a plant hybrid, only sweeter - mechanisms responsible for the sugar-enhanced interspecific hybridization of Actinidia. Acta Hortic. 1332, 87-94
DOI: 10.17660/ActaHortic.2022.1332.12
https://doi.org/10.17660/ActaHortic.2022.1332.12
Actinidia species, pollen preservation, sucrose, wide crosses, scanning electron microscope (SEM), stereomicroscopy
English

Acta Horticulturae