Selection response and heritability of growth and high ammonia nitrogen tolerance in Litopenaeus vannamei

Based on index selected method, we evaluated the growth and tolerance to high ammonia nitrogen of Litopenaeus vannamei by comparing the breeding values, the least squares means and phenotypic values of related growth traits between selected line and control line.The realized heritability and genetic gain were estimated.The heritability and genetic correlation of related traits of L.vannamei were also estimated by best liner unbiased prediction method (BLUP).The results show that the selection response for growth traits and high ammonia nitrogen tolerance were 0.493~1.039 and 0.028~0.046, respectively.The realized heritability and genetic gain for growth traits were 0.288~0.315 and 6.45%~20.16%, respectively.The realized heritability and genetic gain for high ammonia nitrogen tolerance were 0.016 and 2.09%, respectively.The heritability estimated by BLUP for growth traits and high ammonia nitrogen tolerance were 0.216~0.284 (P < 0.05) and 0.028±0.026, respectively.The genetic correlation between growth traits was 0.871~0.948 (P < 0.05), and that between high ammonia nitrogen tolerance and body weight was 0.180±0.032 (P < 0.05).It is concluded that index selection method is an effective approach to improve growth traits of L.vannamei; besides, the selection population has moderate heritability to enable further improvement but relatively small improvement for high ammonia nitrogen tolerance, which suggests that breeding selection needs further study to improve high ammonia nitrogen tolerance.