Abstract: Compared the cold hardy capacity in different tilapia strains for providing cold hardy capacity tilapia breeding with breeding materials and theoretical support.Through the indoor artificially low-temperature stress,measured eight strains tilapia and 15 hybridized by tilapia varieties′ cold-tolerance,and compared their cold hardy capacity.In 3 strains aureus tilapia Oreochromis aureus,the semi-lethal low temperature respectively were:the USA strains 7.82℃,summer strains 8.22℃,guangdong strains 8.44℃;and mortality respectively were:56.76%,62.25%,79.43%;in 5 strains Nile tilapia the semi-lethal low temperature respectively were;the USA strain 8.86℃、Egypt strain 9.39℃,Guangdong strain 9.30℃,Thailand strain 9.57℃,Gift strain 10.13℃,and the mortality respectivelywere:70.43%,56.43%,67.24%,83.54%,91.66%;In 15 hybrid strains,the strongest cold-tolerance was the strain from Nile tilapia of Egypt strain as female and the USA strain of aureus tilapia Oreochromis aureus as paternal,that semi-lethal low temperature was 8.22℃ and mortality was 51.06%.And semi-lethal low temperature and mortality of correlation showed significant between each species and varieties.Hybrid strains tilapia′ cold hardy capacity were highly correlated with their parents,their cold-tolerance may inheritance by cytoplasmic.To strengthen the screening of the female can obtain faster genetic progress.Through cold hardy capacity performance comparison,determinated the hybridization tilapia from the Egypt strain of Nile tilapia as female and the USA strain of aureus tilapia Oreochromis aureus as paternal for cold hardy capacity breeding materials.

Key words: Tilapia, Cold hardy capacity, Semi-lethal low temperature, Low temperature-mortality

CLC Number: 

• S965