Restoring Fertility for Novel Interspecific Hybrids between Kalanchoe garambiensis and K. nyikae Using Colchicine Treatment.

Yi Kuang,Fu-Chiun Hsu,Chi-Hsuan Lu

doi:10.3390/plants10020209

Abstract

Interspecific hybridization is an effective strategy in Kalanchoe breeding programs for the introduction of new traits. Wild species within the Kalanchoe genus are valuable genetic resources for providing new horticulture traits and to improve environmental adaptations. However, reproductive barriers associated with fertilization and hybrid sterility must be overcome to produce fertile hybrid progenies. To approach the breeding objectives for Kalanchoe cut flower cultivars with long stem traits and adaptation to tropical/subtropical regions, a tropical species endemic to Taiwan, Kalanchoe garambiensis Kudo, was used as a parent to cross with other long stem Kalanchoe species. Reciprocal crossing was effective in overcoming interspecific unilateral incompatibility in our crossed pairs. One superior hybrid, ‘103-1’, produced capsules without seeds by selfing and backcrossing with pollens from either parent. Other than the seedless trait, failure of pollen releasing from anther, pollen aggregation and no pollen germination in ‘103-1’ suggested its F1 sterility. Colchicine treatments on apical buds of ‘103-1’ successfully overcame potential meiotic abnormalities by doubling ploidy. For the first time, fertile interspecific hybrids of K. garambiensis and K. nyikae Engler were generated. The fertile hybrid has further produced progeny populations by crossing with K. nyikae or K. blossfeldiana von Poelln, ‘Ida’.

Highlights

IntroductionKalanchoe is the second most important house plant, with 94–100 million plants worth
To identify potential genetic resources from section Kalanchoe for cut flower breeding, we evaluated the crossability of collected germplasms
K. garambiensis ‘Type 2’ were two clones selected from endemic K. garambiensis Kudo populations collected from lowland areas of tropical Taiwan

Summary

Introduction

Kalanchoe is the second most important house plant, with 94–100 million plants worth. Most Kalanchoe germplasms were first collected from highland areas (at 1800–2000 m altitude) of Madagascar and East Africa [8]. Recent studies revealed a native species, Kalanchoe garambiensis, from the lowland of tropical Taiwan, and this early flowering germplasm is suitable for cultivation in tropical and subtropical regions [9,10,11]. Utilization of such wild species with valuable traits as a genetic source would be a key for reaching current breeding objectives

Methods

Results

Conclusion