Morphological comparisons of diploid and triploid hybrid grass carp, Ctenopharyngodon idella♀×Hypophthalmichthys nobilis♂

Abstract

Morphological and karyological comparisons of 25–28 hybrid grass carp from each of 3 year‐classes (1979–1981) indicated that diploid fish resulted during 1979 (82.1%) and 1980 (76.0%) the others being triploid. All of the fish tested from the 1981 year‐class were triploid. Most triploid fish differed from diploid fish by having a faster growth rate, fewer scales in the lateral line and transverse series below the lateral line, a relatively longer gut, and fewer deformities.