INTERGENERIC AND INTERSPECIFIC CROSSINGS OF THE LAVERS (PORPHYRA)

Abstract

Artificial crossings were tried between five species including four local forms of the genus Porphyra.
The fertilization is followed by carpospore formation and Conchocelis development. Most of unfertilized carpogonia became decay, but some of them developed into, carpospore-like cells which germinated leafy thalli. Therefore, the fertilization was confirmed by observing Conchocelis-development.
Crossings easily occurred between any pair of Porphyra species tested. The descendants both from dioecious parents and from monoecious parents grew normally, while those from the dioecious and monoecious combination died in mass at their young stage, though some of them survived into three different groups of thalli: dioecious, monoecious, and abnormal. The abnormal thalli are assumably of a “heterodiploid” nature, having haploid chromosomes from the both parents together in their cells.
Discussion was made in regard to process of fertilization, the moment of the meiosis. in the life cycle, the relationship between Porphyra species studied, and the application of the results to the industry.