Shi Yaohua

Heritable Characteristics in the Pearl Oyster Pinctada martensii: Comparisons of Growth and Shell Morphology of Chinese and Indian Populations, and Reciprocal Crosses

ABSTRACT A complete diallel cross between two geographically distant pearl oyster (Pinctada martensii) populations, an Indian cultured population (I), and a Chinese cultured population (C) was carried out, and the resulting progenies (II, CC, IC, and CI) were cultured and studied for more than 700 days. Shell height and total weight were measured monthly, and shell thickness was measured in the middle and at the end of the experiment. The results reveal that II grew fastest whereas CC grew the slowest. The growth rate of reciprocal crosses CI and IC exhibited no statistically significant difference, with both appearing to be intermediate between the parental species, but superior to the mid parent values. The morphological traits of parents were inherited differently by the two reciprocal crosses. The traits of large size and relative thinness of shell from the Indian population were largely transmitted to CI, whereas relative small size and increased shell thickness of the Chinese population were mostly inherited by IC. The two parental stocks, the Indian population and the Chinese population, were unsuitable for commercial production because of a relatively thin shell and slow growth, respectively, but the reciprocal crosses combined desirable traits of the parents and exhibited considerable potential for commercial production and pearl culture.