Genetic (co)variation in resistance to White Spot Syndrome Virus (WSSV) and harvest weight in Penaeus (Litopenaeus) vannamei

A total of 339 full-sib families (representing 143 paternal half-sib families) and 337 full-sib families (representing 145 paternal half-sib families) were respectively challenged with White Spot Syndrome Virus (WSSV) in a controlled environment and tested for growth performance under commercial growing conditions. The families were derived from two selected lines. The estimates of heritability (h2 ± SE) for the two lines were 0.03 ± 0.02 and 0.07 ± 0.02 for WSSV resistance and 0.21 ± 0.04 and 0.20 ± 0.04 for harvest weight. Moreover, there was an unfavorable genetic correlation of −0.55 and −0.64 in the two lines between resistance to WSSV measured in controlled challenge tests at an average weight of 3 g and growth performance to harvest size in ponds. Thus, for simultaneous improvement of both traits breeding values for WSSV resistance must be obtained from data recorded on sibs of the breeding candidates.