Using Cut–Column Pollination Method to Overcome Crossing Barriers in Phalaenopsis Sunrise Goldmour 'KHM637'

Abstract

Crossing barriers occur frequently when crossing between commercial Phalaenopsis cultivars with desirable horticultural traits are attempted. In this study, Phalaenopsis Sunrise Goldmour 'KHM637', a tetra- ploid with 2n=4x=76 chromosomes, known to be difficult in hybridization was chosen to examine crossing barriers and to explore the cut-column pollination method to overcome these barriers. P. Sunrise Goldmour 'KHM637' was either self-crossed, or used as the pollen or pistillate parent in reciprocal crossings with three tetraploid cultivars, including P. Brother Irene Irene 'Feng Fong', P. Sogo Yukidian 'V3', and P. Tai Lin Red Angel 'V31' that do not exhibit breeding barriers. Results showed that both stigma cavity closure and pollen tube growth did not occur when P. Sunrise Goldmour 'KHM637' was used as the pistillate parent. No offspring was obtained when using P. Sunrise Goldmour 'KHM637' as either pollen or pistillate parent. To explore performance of cut-column pollination method, P. Sunrise Goldmour 'KHM637' was used as the pistillate parent, after the removal of the upper part of column but with the stigma cavity intact, and then pollinated with pollinia of these three tetraploid cultivars and one species, P. violacea, respectively. The results showed that 22.2%-100.0% capsule sets were achieved from the four combinations, and offsprings were successfully obtained from three combinations. The authors suggested that the cut-column pollination method be applicable to other Phalaenopsis cultivars with similar crossing behaviors of P. Sunrise Goldmour 'KHM637' for overcoming the crossing barriers, and the applicability of the given method tended to be less limited to pollen parents without breeding barriers.