National High Technology Research & Development Program of China ("863" Program) [2006AA10A413]; National Natural Science Foundation of China [40806065]; Construction Program of Science and Technological Platform of Fujian Province, China [2007 N2011]The first doubled haploid (DH) population of Porphyra haitanensis was created by crossing a wild-type line with a red type, artificial pigmentation, mutant line, by means of single somatic cell clone cultivation. Six quantitative traits (frond length (FL), frond width (FW), frond thickness (FT), fresh weight (W), growth rate of frond length (LGR), and growth rate of fresh weight (WGR)) from the DH population were analyzed. The frequency of each quantitative trait is in accordance with a normal distribution. Variable coefficients were between 20.43% and 57.35%, and while the mean of each quantitative trait was between the parents, it was closer to the paternal for six traits. Correlation analysis among the six traits showed significant positive correlations between FL and W, FW, and W, LGR and W, and WGR and W. There appears to be no correlation between FT and W. Heritability, number of genes controlling each quantitative trait and gene interactions, were also analyzed. Heritability of the six traits was greater than 70%, and heritability was not correlated with the number of genes controlling the corresponding quantitative trait. Frond thickness was the most heritable trait (95.30%), but this had the fewest control genes (7.52). According to the estimated coefficients of skewness and kurtosis, gene interaction was absent for LGR, but complementary gene interaction was observed in FW and W. In FL, FT, and WGR it is possible that complementary or duplicate gene interaction is involved. Our results enrich our understanding of Porphyra genetics and will help determine selection and breeding procedures for P. haitanensis
