In vitro viability and preservation of pollen grain of kiwi (Actinidia chinensis var. deliciosa (A. Chev.) A. Chev)

Kiwi is a dioecious plant species, requiring cross pollination for fruit production. The objective of this study was to evaluate the in vitro viability and shelf life of pollen grains of two kiwi varieties. Flowers of the cultivars Matua and Tomuri were collected and the pollen germinated in vitro, in culture medium containing agar (1 %), sucrose (0, 5, 10, 20 and 40 %) and boric acid (0 and 50 mg L-1 H3BO3). Pollen grains were stored in a BOD incubator (25.0 degrees C), refrigerator (4.0 degrees C), freezer (-18.0 degrees C) and in liquid N-2 (-196.0 degrees C), and evaluated after 0, 40, 120, 240 and 365 days. The culture medium enriched with 12 % sucrose and 50 mg L-1 H3BO3 was the most suitable. Pollen grains can be stored for a short period in the refrigerator or freezer, and cryopreserved for at least one year.