Genotype by environment interactions for growth and inner shell color disparity in Hyriopsis cumingii under different light conditions

The light plays a pivotal role in influencing the growth and body color for aquaculture animals. The freshwater pearl mussel Hyriopsis cumingii, inhabiting benthic environments naturally, is predominantly cultivated by hanging methods. This aquaculture method altersmutiple environmental factors, with light being one of the maximum variationfactor. In order to comprehend the impact of light change on the growth and inner shell color of H. cumingii, a total of 14 full-sibling families were established and cultivated separately under natural light and dim light conditions for a period of 13 months in this study. The results revealed that under natural light conditions, juvenile mussel exhibited accelerated growth rates, while dim light conditions expedited purple pigmentation in the inner shell. Genetic analysis indicated general heritability range for the entire experimental population falls between 0.07 and 0.28. heritability estimates for all traits under natural light conditions (NL) ranged from 0.33 to 0.72, indicating consistently high heritability. However, heritability estimates for all traits under dim light conditions (DL) ranged from 0.05 to 0.16. The growth and inner shell color traits showed significant G × E interactions under different light conditions. The anal angle radial rib length (AARRL) trait exhibited a significantly higher correlation with body weight (BW) compared to shell height (SH) and total shell height (TSH). Furthermore, the growth and inner shell color traits of different families were compared and evaluated under the two environmental conditions in this study. Families 1 and 6 excelled in various traits under both conditions, making them promising candidates for genetic improvement breeding. In this study, pronounced influences of light exposure on the growth of pearl mussels were identified, emphasizing the need for tailored breeding strategies for both bottom seeding and suspended cultivation methods.