Abstract:belongs to Bangiaceae, Bangiales, Protoflorideae, Rhodophyta. For its high commercial and nutritional value, it becomes one of the most important seaweed cultivars in the coastal area of northern China. For decades, because of incorrect breed conservation and inbreeding, the germplasm of this species had been serious degenerated, which resulted in a decline of yield and quality such as slower growth rate, thicker, matured earlier and more susceptible. These problems seriously affected the economic benefits of the cultivation. Therefore, breeding new varieties of is greatly significant for the sustainable development of this industry. In order to select a new variety of with faster growth rate, higher quality and wild-type color, intraspecific hybridization of the green-type pigmentation mutant and red-type pigmentation mutant in was conducted to isolate an improved strain (LC-14) from the recombinants. After cultured for 70 days, the mean length and wet weight of F1 blades in LC-14 strain was 106.53 cm and 3.07 g, which was 4.39 and 10.27 times of the wild-type strain (WT), respectively. The results indicated that the improved strain had higher growth advantages, and the higher yield compared with WT strain. Being cultured to 55 days, the contents of three major photosynthetic pigments (chlorophyll a, phycocyanin and phycocyanin) in LC-14 strain were 9.85 mg/g, 52.09 mg/g and 23.26 mg/g, with an increasing by 65%, 65% and 49% when compared with WT strain respectively. Meanwhile, the thickness of blades of LC-14 strain was 20.89 μm, which is 32% thinner than that of WT strain. These results showed that the taste was better, and the quality was higher than those of the WT strain. In addition, the daily amount of conchospores released from LC-14 strain could be more than 2 million and the total amount of conchospores for successive 20 days was 761.32×104, which was 1.28 times compared to WT strain. The results showed that conchospores released were sufficient during the stage of seedlings collection and the productive requirements of releasing amount could be fully satisfied. In summary, all of these results above confirmed that LC-14 strain with fast growth rate, high quality, large amount of conchospores and similar color with wild-type was suitable for cultivation, which completely achieved the original intention of this study. Therefore, LC-14 strain is expected to become a new improved variety through the national approval and be applied in the practical production in the near future.
