Pollination Success among Standard Hybrids and Indonesian Species of Phalaenopsis

Abstract

One of the constrains limitting the succes of Phalaenopsis breeding is incompatibility between the parents. The objective of this study was to evaluate pollination compatibilities among Indonesian Phalaenopsis species and the standard hybrid group. The species used were Phal. violaceae ‘Sumatera’, Phal. cornu-cervi ‘Kalimantan’, Phal. amboinensis, Phal. tetraspis and Phal. modesta and Phal. amabilis. The Phalaenopsis standard hybrids used were eight commercially available hybrid accessions in the Indonesian flower market. The pollination schemes evaluated include: self- and cross-pollination among standard hybrids (intrahybrids) and reciprocal crosses among standard hybrids and the Indonesian species of Phalaenopsis (inter-hybrids). Prior to pollination, the following parental characters were noted: inflorescence length, flower number at anthesis, flower sizes, leaf stomatal size and stomatal density, respectively. After pollination, the following characters were recorded: pod set number, pod size, and seed set, respectively. Samples of mature pods of intra-hybrid crosses were harvested, the seeds were germinated aseptically, and the protocorm growth from the seeds were evaluated. Results of the evaluation indicated Indonesian Phalaenopsis species in general showed smaller inflorescence length, flower number at anthesis, and flower sizes than the standard hybrid accessions. The species also exhibited smaller stomatal cell size and higher stomatal cell densities than the hybrid ones. Standard Phalaenopsis hybrids commercially available in Indonesia might have different ploidy level than the Indonesian Phalaenopsis species. Such hypothesis was supported by the the contrasting morphological characters, stomatal cell sizes and stomatal density. Furthermore, it was supported by the failure to obtain either pod set or seed set in the majority of reciprocal cross pollination among Phalaenopsis standard hybrids and the species. Growth and multiplication of protocom derived from two intrahybrid populations into protocorm like bodies (PLBs) was not affected by the medium composition but by the genetic background of the parents. Protocorm originated from cross pollination of White  Pink standard hybrid accessions gave higher multiplication rate than that of Pink  White standard hybrids.