Genetic variance from a preliminary trial on controlled challenge test of Penaeus semisulcatus families with white spot syndrome virus (WSSV)

The objective of this study was to assess between family differences in resistance to white spot syndrome Virus (WSSV). Juveniles of P. semisulcatus (mean weight 3 ± 0.5 g) from 6 families were tested for survival after challenge with WSSV. Mortality in the challenge test was recorded daily, and the experiment was terminated after 30 days post challenge when the mortality ceased. The overall mortality at the end of the experiment was 69.16 %. Using cross sectional model, heritability of intermediate magnitude was estimated for WSSV resistance, using a linear model on the observed scale (0.37), and using a threshold model (0.48) on the underlying scale. This indicates there is high additive genetic variation for survival in the challenge test and the recorded disease resistance is a heritable trait, and suggests that survival in controlled challenge test experiments may serve as basis for selection for improved resistance to WSSV in P. semisulcatus. However, further investigation is needed to confirm and exactly quantify the additive genetic variation for resistance to WSSV in this species.