Pollen storage and use for enhancing fruit production in kiwifruit (Actinidia deliciosa A. Chev.)

Abstract: Insufficient pollination due to asynchrony between staminate and pistillate blossoms in kiwifruit and unfavourable environmental conditions results in reduced fruit size and unequal fruit shape. In the present investigation an attempt was made to develop a simple and reliable method for storage of kiwifruit pollen and their utilization in hand pollination in following year. Pollen were stored at different temperatures [room temperature (25 ? 2 ⁰C), 4, 0 and -20 ⁰C] for a period of one year. Pollen viability was determined at monthly intervals using 2,3,5-triphenyltetrazolium chloride (TTC) staining and percent in vitro germination using 14 % sucrose,1.7 mM calcium nitrate and 3mM Boric acid. Initial TTC stainability (78.83 %), in vitro germination (65.55%) and absolute viability (51.72 %) of fresh pollen went on reducing with storage periods. -20 ⁰C was the best temperature at which maximum viability of kiwifruit pollen can be retained up to one year. Pollination using pollen stored for one year showed that pollen stored at -20 ⁰C were able to set 100 % fruits, pollen stored at 0 ⁰C could set 36 % fruits, while there was no fruit setting with pollen stored at room temperature and 4 ⁰C. These findings have practical implications for kiwifruit production in India. Artificial pollination with stored pollen can circumvent several uncertainties of natural pollination and guarantee adequate pollination in kiwifruit.