Pollination of kiwifruit: 30 years of applied research leads to a model system for studying the interaction between pollination and flowering stage

Kiwifruit vine artificial pollination was firstly studied in New Zealand and in Italy in the 80s in order to optimize the kiwifruit fruit set and production. Nowadays it is a crucial technique useful to increase fruit quality and size. However, artificial pollination efficiency depends on the timing of application and the pollination system. The main objective of this study is to decipher the relation between the floral stage and the pollination technique. Many parameters were analyzed in different environments in Italy for many years, such as pollen quality (germinability, humidity, conservation), pollination system (dry or liquid) and flowering stage. The petals fall and full bloom-early petal fall stages result in the best moments for dry and liquid pollination respectively. The dry blower pollination system gave the best results because, at the end of flowering, the pistil exudate is at its maximum and a larger number of ovaries are receptive with respect to the liquid pollination at full bloom. This observation leads to the definition of a new model crop fruit set that could be applied in other anemophilous pollinated tree such as olive tree, hazelnut, pistachio.