In order to develop new germplasm of Pyropia,the wild-type strain(PC-WT)of Pyropia churharii from India were treated with ⁶⁰Co-γ ray to induce mutations,and then the new strains(PC-Y1 and PC-Y2)with advantages in growth and quality were obtained.The PC-WT was characterized by slow growth and releasing archeospores excessively.One of the new strains was PC-Y1 with the characterizations of slender blade,rapid growth and almost releasing no archeospores.The other was PC-Y2 with the characterizations of wide blade,fast growth and a few archeospores releasing.When the blades of PC-WT,PC-Y1 and PC-Y2 were cultured for 55 days,their mean lengths were 5.31 cm,91.30 cm and 15.26 cm,respectively,indicating that PC-Y1 and PC-Y2 grew significantly faster than PC-WT.In the 45-days-old blades of PC-WT,PC-Y1 and PC-Y2,the contents of chlorophyll a(Chl.a)in PC-Y1 and PC-Y2 were obviously higher than that of PC-WT;and the contents of phycobiliprotein(PE+PC)in PC-Y1 and PC-Y2 were 119.32 mg/g and 102.29 mg/g,respectively,which were 2.74 times and 2.35 times higher than those in PC-WT,respectively.Thickness of the 45-days-old blades of PC-Y1,PC-Y2 and PC-WT was 20.86 μm,27.98 μm and 32.48 μm,respectively,which showed that both PC-Y1 and PC-Y2 were significantly thinner than PC-WT.The quantities of the released conchospores of PC-Y1,PC-Y2 and PC-WT,were 1.011 6,1.434 4 and 1.751 7 million per shell,respectively.Furthermore,the PC-Y1 was superior to wild-type strain of Pyropia haitanensis in high-temperature(29 ℃)resistance.These results indicated that the characterizations of PC-Y1 and PC-Y2 were similar to those of Pyropia yezoensis,including thin gametophytic blades,good quality and archeospores releasing;in addition,compared with Pyropia haitanensis,PC-Y1 strain had better resistance to high-temperature,releasing more conchospores,higher growth rate and late maturation.Therefore,PC-Y1 strain had great potential to be applied in commercial cultivation.