Cytogenetic Studies on the Origin of Camellia * vernalis. V. Estimation of the Seed Parent of C. * vernalis that Evolved about 400 Years Ago by cpDNA Analysis

Abstract

It was determined from the morphology, chromosome and isozyme analyses that Camellia × vernalis (Makino) T. Tanaka et al. resulted from hybridization between C. sasanqua and C. japonica. Since the chloroplast in Camellia is entirely maternally inherited, the presence of C. sasanqua chloroplasts in C. × vernalis would indicate the species is the seed parent of these hybrids. PCR products of the atpI-atpH gene region from all accessions of C. sasanqua and C. × vernalis showed a single band at ca. 800 bp, while those of C. japonica showed one at ca. 1200 bp, suggesting that 1) the seed parent of the putative primary (F1) hybrid, ‘Gaisen’ is C. sasanqua, 2) the seed parents of the first backcross generation to C. japonica, triploid cultivars of C. × vernalis, are considered to be ‘Gaisen’, and 3) the seed parents of the second backcross generation, the ‘Egao’ type tetraploid cultivars, are derived from triploid C. × vernalis cultivars. That C. × vernalis originated about four hundred years ago as determined from the age of the oldest tree on Hirado Island and from the records in the Japanese books published in 1630 was confirmed by our data. Furthermore, we conclude from our evidence that the seed parent of C. × vernalis is C. sasanqua.