Interspecific hybridization between triploid Senno (Lychnis senno Siebold et Zucc., Caryophyllaceae) and allied taxa of the genus Lychnis

Abstract

Senno (Lychnis senno, Caryophyllaceae), a traditional ornamental plant in Japan, was introduced from China and all the strains of Senno found in Japan are triploid with 2n=3x=36. Hand-pollination was conducted between triploid Senno and allied Lychnis taxa, L. kiusiana (2n=24), L. miqueliana (2n=24), L. miqueliana f. albescens (2n=24), L. chalcedonica (2n=24), L. wilfordii (2n=24), L. sieboldii (2n=24), and L. coronata (2n=24). Immature seeds 17-42 days after pollination were cultured on half-strength Murashige and Skoog media with or without 6-benzyladenine. Although immature seeds were obtained in most cross combinations, seed germination was observed only in three cross combinations, L. senno×L. kiusiana, L. kiusiana×L. senno, and L. senno×L. sieboldii. Seedlings derived from reciprocal crosses between L. senno and L. kiusiana showed an abnormal morphology or a chlorophyll-deficiency, xantha. Seedlings derived from L. senno×L. sieboldii also showed an abnormal morphology or chlorophyll-deficiency, but one seedling grew into a green plantlet. The hybridity of these seedlings was confirmed by random amplified polymorphic DNA analysis. The chromosome number of the interspecific hybrid plantlet between L. senno and L. sieboldii was determined to be 2n=32. The present study shows the possibility of using triploid Senno for breeding by interspecific hybridization, and the effectiveness of immature seed culture for producing interspecific hybrids in the genus Lychnis. © 2009 The Japanese Society for Plant Cell and Molecular Biology.