Identification of the Parental Species of a Putative Hybrid Spruce Picea x notha Using DNA Markers with Contrasting Modes of Inheritance

摘要

Picea x notha, described by Rehder in 1939, is thought to be a putative hybrid between pollen receptive P. glehnii and pollen donating P. jezoensis var. hondoensis; however, such hybrid is questionable because the distributions of P. glehnii and P. jezoensis var. hondoensis do not overlap naturally. Recently, a natural hybrid between P. glehnii and P. jezoensis var. jezoensis, which is morphologically similar to P. x notha, was genetically determined. Therefore, the goal of this study was to identify the parental species of P. x notha using maternally inherited mitochondrial (mt), paternally inherited chloroplast (cp), and biparentally inherited nuclear (n) DNA markers and to elucidate the similarity of P. x notha and natural hybrids occurring in Hokkaido. Genetic analyses indicated that P. x notha harbored P. glehnii mtDNA, P. jezoensis var. jezoensis or P. jezoensis var. hondoensis cpDNA, and P. glehnii and P. jezoensis var. jezoensis nDNA almost equally. This clearly indicated that P. x notha is an F-1 hybrid between pollen receptive P. glehnii and pollen donating P. jezoensis var. jezoensis and that it is similar to natural hybrids found in Hokkaido. This is the first report to demonstrate the parental species of P. x notha and its natural distribution in Hokkaido, Japan.