The influence of temperature during floral development and germination in vitro on the germinability of kiwifruit pollen

Abstract Kiwifruit (Actinidia deliciosa ‘Matua’) vines were grown under five maximum/ minimum temperature regimes (21/17,21/13,21/7, 17/7 and 13/7°C) from budbreak to post-flowering. Assessments were made of the germinability and viability of pollen extracted from flowers off these vines. Percentage germination was evaluated, after 3.5 h incubation, under different incubation temperatures ranging from 7 to 35°C. Highest germination (90%) was obtained under the warmest (21/17°C) development temperature regime. Percentage germination declined as the development temperature decreased and was only 25% at 13/7°C. Maximum percentage germination under all development treatments occurred at incubation temperatures between 22 and 28°C; very little germination occurred at and below 13°C or at 35°C. Pollen tube distortions were common atc 35°C. Percentage germination was similar to percentage viability for pollen from warm development temperatures but only half of the viable pollen from the coolest temperature germi...