Growth and Survival of the First Hybrid Generation of Chinese and Korean Populations of Scapharca broughtonii

Abstract:

Intraspecific hybridization was investigated using two stocks of the Scapharca broughtonii, China population (C) and Korea population (K). The fertilization rate, larval survival rate, growth, and heterosis were compared between two reciprocal hybrid crosses C♀ × K♂ (CK) and K♀ × C♂ (KC) and two parental groups C♀ × C♂ (CC) and K♀ × K♂ (KK). The fertilization rate of the parental groups was higher than that of the reciprocal hybrid crosses, but the hatchability results indicated that there was no significant difference between the two reciprocal hybrid crosses and the two parental groups. The shell lengths of the KK and KC groups were larger than those of the CC and CK groups in larval, juvenile, and adult stages. The CC and CK groups, however, showed higher survival rate in juvenile and adult stages. The heterosis of the KC cross in terms of the shell length and the survival rate was obvious, but the CK cross did not show positive heterosis in any aspect during the entire experiment. The difference in heterosis between the two reciprocal hybrid crosses might be related to the maternal effects, heredity, and environment.