Quantitative and qualitative characterization of novel features of Kalanchoë interspecific hybrids

Abstract

Kalanchoe blossfeldiana and its cultivars are important worldwide as potted plants. Their improvement relies mainly on cross-breeding and interspecific hybridization, although the use of the resource of wild species was limited. The present study aimed to characterize novel features of interspecific hybrids that can increase attractiveness of these commercially important ornamental plants. We investigated the new traits of selected hybrids resulting from hybridization between K. blossfeldiana and three wild Kalanchoe species, namely K. nyikae, K. pubescens and K. marnieriana. The selected qualitative and quantitative traits of plant growth and flowering were analyzed in hybrids and parental species. The analysis demonstrated generally intermediate character of hybrids. Following principal component analysis, clear separation among plants forming three distinct clusters was observed, where hybrids were situated between the two parental species. The plants were clearly grouped according to flower characteristics, plant height and timing of flowering in all investigated groups. Quantitative analysis also revealed significant differences among parental plants and hybrids for all examined characteristics. Transgressive segregation and heterosis were observed in relation to specific traits such as days until first open flower, plant height, number of inflorescences, flower diameter and number of flowers. Pollen analysis of the interspecific hybrids revealed low viability of pollen or complete sterility. The interspecific hybrids exhibited novel features valuable for breeders. Thus, wide hybridization can contribute to the development of new cultivars and this study clearly demonstrates the usefulness of interspecific crosses in the improvement of Kalanchoe cultivars.