Morphological and AFLP variation of Porphyra yezoensis Ueda form, narawaensis Miura (Bangiales, Rhodophyta)

Abstract

Detailed morphological observations were made on two strains of cultivated Porphyra : HG-1 (pure line isolated from Dai-1) and Noriken-4 (parental strain of a pure line HG-4) . The two strains were identified as P. yezoensis f. narawaensis based on their macroscopic and microscopic features, such as long linear or oblanceolate blades up to 50 cm in maximum length, division formulae of spermatangia and zygotosporangia, shape of trichogynes and carpogonia, and the second transverse divisional plane formed at the division from c/2 to c/4 in zygotosporangia. Gametophytic blades from two completely homozygous conchocelis strains isolated in this study (HG-1 and HG-4) were cultured under the same conditions and compared to confirm whether the differences in their shapes are genetically determined. The shape of blades from both of conchospores and monospores was always more slender in HG-4 than in HG-1 at the same blade age, suggesting that the difference in the blade shape between the two pure lines is due to genetic variation. To estimate the level of genetic variation the two pure lines were subjected to amplified fragment length polymorphism fingerprint analysis. A total of 230 bands were detected in HG-1 and HG-4 using eight selective primer pairs, and the number of polymorphic bands was only two in HG-1. These results indicate that the two pure lines certainly show genetic variation, which is, however, at an extremely low level. The importance of pure-line breeding and the origin of currently cultivated Porphyra are discussed. This is the first report to identify currently cultivated Porphyra strains in Japan based on combined results of detailed morphological observations and molecular analysis.

Genetic similarity analysis within Pyropia yezoensis blades developed from both conchospores and blade archeospores using AFLP1

“…The self‐fertilized conchocelis released homozygous conchospores that could grow into blades with a high degree of genetic similarity, whereas cross‐fertilized conchocelis released heterozygous conchospores that could grow into blades with a low degree of genetic similarity (Niwa et al. , Li et al. , Shan and Pang ).…”

GENETIC DIVERSITY AND INTROGRESSION IN TWO CULTIVATED SPECIES (PORPHYRA YEZOENSISANDPORPHYRA TENERA) AND CLOSELY RELATED WILD SPECIES OFPORPHYRA(BANGIALES, RHODOPHYTA)1

“…In our previous studies, we identified wild and cultivated strains of P. yezoensis and P. tenera by combining morphological observations and molecular analyses (Niwa and Aruga 2003, Niwa et al. 2004, 2005a,b, 2008b).…”

“…Until the mid 1950s, 11 species were cultivated in Japan, and Porphyra tenera and Porphyra yezoensis were the main species of marine crop (Miura 1988). However, with the progress of Porphyra breeding, P. yezoensis f. narawaensis A. Miura, a vigorously growing cultivar with more elongate blades (Miura 1984, Niwa et al. 2004, 2008a), has more recently become the most commonly used strain in Japanese nori farms (Niwa and Aruga 2003, 2006, Niwa et al.…”

“…For reliable species identification and genetic relationship of cultivated Porphyra strains, combined studies of morphological observations and molecular analyses have been carried out (Niwa and Aruga 2003, Niwa et al. 2004, 2005a, 2008c), and simple diagnostic markers have been developed in PCR‐RFLP analyses by ITS rDNA region and plastid RUBISCO spacer region (Niwa et al.…”

ASSESSMENT OF PHOTOSYNTHETIC PERFORMANCE OF PORPHYRA YEZOENSIS (BANGIALES, RHODOPHYTA) IN CONCHOCELIS PHASE1

“…1999). It is therefore easy to isolate pure lines (complete homozygous conchocelis strains) with target genotypes via the self‐fertilization of blades developed from archeospores released from cell clusters in haploid blades (Niwa et al. 2004).…”