THE DEVELOPMENT OF HYBRIDIZATION TECHNIQUES FOR BANKSIA-MENZIESII FOR CUT FLOWER PRODUCTION

Techniques for controlled hand pollination of Banksia were developed using the cut flower species B. menziesii. Florets of known age were identified by removing all open florets and bagging the inflorescence for 24 h. After this period all unopened florets were removed, leaving a ring of 14-23 florets which had undergone anthesis. Self-pollen was removed by moving a looped, synthetic pipe cleaner over the pollen presenter segment of the style. Pollen transfer was achieved by rubbing a pollen-laden pollen presenter from the designated male parent over the stigmatic region of the recipient pistil. Peak stigma receptivity was recorded at three days post-anthesis by observing pollen germination with fluorescence microscopy, and by scanning electron microscopy of changes in the width of the stigmatic groove. Pollen tubes reached the base of the style six days after pollination at peak receptivity, and subsequently 11.1% of the hand pollinated florets set follicles. This was considerably higher than the natural level of percentage fruit set of open-pollinated populations. However this level of fruit set could not be expected over an entire inflorescence due to the size of the mature follicles and the spatial limitations of the infructescence. It is estimated that a maximum of 33 seeds could be expected following hand pollination of an inflorescence of B. menziesii.