Samaneh Poursaied - Department of Fisheries, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, Noor, Mazandaran
Mohammad Reza Kalbassi - Department of Fisheries, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, Noor, Mazandaran
Bahram Falahatkar - Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Guilan
Iraj Efatpanah - Dr. Yousefpour Fish Hatchery Center, Siahkal, Guilan
Mehdi Rahmati - Dr. Yousefpour Fish Hatchery Center, Siahkal, Guilan
Bahman Meknatkhah - Dr. Yousefpour Fish Hatchery Center, Siahkal, Guilan

In this study, cytogenetic characteristics of F1 progeny produced by cross breedingof female Asp and male Kutum (Aspius aspius ♀ × Rutilus frisii ♂) was determinedusing tissue-squashing method of kidney and giemsa staining. Nucleolus organizerregions were also localized using AgNOR3R. Chromosome number was determinedfrom the total of 85 metaphases plates achieved from 20 hybrid specimens with anaverage weight 49.7 ± 2.5 (S.E) g. Karyogram and ideogram were arranged from thebest metaphase plates and the different characteristics of karyotype including thenumber of chromosome arms, the length of short and long arms, the centromic index,the arm ratio, and the relative and total length of chromosomes were calculated. Thenumber of diploid chromosomes and chromosome arms were 2n=50 and NF=80,respectively. The karyotypes consisted of 10 pairs of metacentric, 5 pairs ofsubmetacentric and 10 pairs of acrocentric to subtelocentric (10 m+5 sm+10 a-t). Therange of centromic index, arm ratio and relative length were 0-0.443, 1.266-∞ and2.265-6.554 μm, respectively. The total length of chromosomes in haploid series was30.39 μm. The longest and shortest chromosomes were a pair of submetacentric andtelocentric chromosomes, respectively. Nucleolus organizer regions were localizedon the ends of longer arms of the longest pair of acrocentrics. These findings confirmthat F1 hybrids inherited the number and type of chromosomes from their parents.

Karyotype, Chromosome, Hybridization, Cyprinidae, Nucleolus organizer regions