Pollen Meiotic Behavior in Relation to Phalaenopsis Breeding

Abstract

The breeding of Phalaenopsis orchids involves the cross-pollination of two selected parental plants. Parents with re gular meiotic behavior can often produce seeds successfully. Currently most Phalaenopsis hybrids are obtained after inter- specific hybridization. Unfortunately bree ding barriers may occur during the meiotic process thereby affecting fertilization even ts and reducing seed set. Through pollen tetrad analysis, a correlation between successf ul seed set and a high tetrad percentage was observed in both Phalaenopsis and Doritaenopsis orchids. To improve the breeding of hybrid polyploid cultivars, mitotic inhibitors were applied to young flower buds before pollen meiosis in order to monito r changes in the production of tetrads. When compared to the control, a higher number of dyads were observed after treat- ment with mitotic inhibitors. Treated pollen gr ains were then attached to the stigma of female parents for self- and cross-pollination, resulting in successful fruit set in several cases.