Characterization of Pollen Development in Staminate Kiwifruit (Actinidia sp.) Cultivars

Abstract

This study was conducted to determine the timing of flower harvest for pollen collection and preparation in kiwifruit. Here the pollen development of two staminate cultivars, 'Bohwa' and 'Chieftain', which are the major pollinizers used in the region of Jeju in Korea, was investigated. These two staminate cultivars showed a similar tendency in histological pollen development, except for the time of anther dehiscence. The highest pollen quantity was obtained at the 4th developmental stage; thereafter, the quantity of pollen decreased by 23% and 38% at the 5th developmental stage in 'Bohwa' and 'Chieftain', respectively. The pollen viability of 'Bohwa' was slightly higher than that of 'Chieftain' in both 1% iodine potassium iodide and fluorescein diacetate staining with a small increase according to progression in flower development from the 1st to the 5th stage. Pollen germination also increased as flower development advanced, and higher pollen germination of more than 60% occurred in the 4th developmental stage of both staminate cultivars. The results indicate that the appropriate timing for pollen collection might be the 4th developmental stage (full balloon stage) in 'Bohwa' and 'Chieftain' according to the amount of pollen production, viability, and germination.