Survival and karyological analysis of reciprocal diploid and triploid hybrids between mud loach (Misgurnus mizolepis) and cyprinid loach (Misgurnus anguillicaudatus)

Abstract Diploid and triploid hybrids between mud loach ( Misgurnus mizolepis ) and cyprinid loach ( M. anguillicaudatus ) and their reciprocal hybrids were produced by artificial fertilization and by cold shocks. Means of fertilization, hatching, and survival of all diploid groups were similar ( P > 0.05). Triploid hybrids had lower hatching and early survival than their diploid counterparts ( P P > 0.05). Mud loach has 2 n = 48 chromosomes, consisting of 12 metacentric (m), four submetacentric (sm), and 32 acrocentric (a) chromosomes. Cyprinid loach has 2 n = 50 chromosomes, consisting of ten m, four sm and 36 a. Both species has an arm number (NF) of 64. The karyotype of diploid hybrids is intermediate between the parental species and is 2 n = 49; both are composed of 11 m, four sm, 34 a and has NF = 64. The karyotypes of triploid hybrids are composed of a diploid maternal set and a haploid paternal set. Triploid mud loach ♀ X cyprinid loach ♂ is 3 n = 73, and consists of 17 m, six sm, 50 a and has NF = 96. Triploid cyprinid loach ♀ X mud loach ♂ is 3 n = 74, and is composed of 16 m, six sm, 52 a and has NF = 96.