Construction of a genetic linkage map for Porphyra haitanensis

Porphyra haitanensis is an important economic marine crop in south China. The development of the P. haitanensis cultivation is highly desirable to select or breed new lines of P. haitanensis with strong economic traits and use them for cultivation. Molecular markers and molecular genetic maps are pre- requisites for molecular breeding in any plant species. A comprehensive genetic linkage map for cultivated P. haitanensis has not yet been constructed. In this study,157 double haploid( DH) lines[derived from a YS Ⅲ( wild-type) ×RTPM( red-type artificial pigmentation mutant) cross]were used as a mapping population in P. haitanensis. A total of 100 pairs of sequence-related amplified polymorphism( SRAP) primers and 39 pairs of simple sequence repeat( SSR) primers were used to detect polymorphisms between the two parents and 5 DH lines. Twenty-four SRAP and 16 SSR polymorphic primer pairs were selected to analyze the DH population. A linkage genetic map comprising 104 SRAP markers and 20 SSR markers in five linkage groups,witha total length of 879. 2 cM and an average of 7. 09 cM between markers was constructed. The linkage groups comprised 18 -31 markers ranging in length from 134. 2 to 213. 6 cM. The estimated genome length of P. haitanensis was 955. 3 cM,with a coverage of 92. 0% coverage. This is the first report of a comprehensive genetic map in P. haitanensis. The map presented here will provide a basis for the development of high-density genetic linkage maps,which will facilitate QTL mapping of desirable traits,and provide markers for MAS,map-based cloning of genes,and the introgression of beneficial genes from wild species into modern cultivars in P. haitanensis.