四种杂交组合奥尼罗非鱼及其亲本的生长对比研究

COMPARATIVE ANALYSIS OF GROWTH VARIATIONS AMONG FOUR HYBRID SUBGROUPS OF OREOCHROMIS NILOTICUS♀×O.AUREUS♂ AND THEIR PARENTAL STRAINS

通过RFID电子标记注射、跟踪和生长性状测量,对2个奥利亚罗非鱼品系(ZZ、AA)、2个尼罗罗非鱼品系(XX、EE)自交群体及其杂交奥尼罗非鱼4个群体(XZ、XA、EZ、EA)进行生长对比研究,罗非鱼亲本来自国家罗非鱼产业技术体系研发中心。结果表明:XZ、XA、EZ、EA四个奥尼罗非鱼群体雄性率均达94%以上,全长、体长、头长、体高等性状特征值显著高于亲本品系(P<0.05),奥尼罗非鱼的生长速率相对其亲本品系具有一定的优势,同时4个奥尼群体间生长性状特征值也存在显著差异(P<0.05);生长性状相关分析显示罗非鱼各配组群体的体质量与尾柄长相关性较低(0.690—0.846),与全长、体长、体高、体厚相关性较高;对罗非鱼各配组群体的比例性状进行主成分分析,第1主成分主要代表BS、HS、CDS、BWS性状特征,第2主成分主要代表TS、HS、CLS性状特征,通过第1、第2主成分作图可将AA与其他6个罗非鱼配组群体有效区分。

In the development of tilapia industry,excellent quality of tilapia fry is a key point to guarantee the rapid growth rate and good economical benefits of marketable fish.At present,the domestic fry market is increasing rapidly,but the tilapia fry are on various levels of quality.The hybrids of Oreochromis niloticus♀ × O.aureus♂ are one of the most popular commercial types for tilapia farmers,because of rapid growth rate,strong resistance to disease and low temperature for the hybrids.But due to complex origin of the fry parents,the hybrid effects and the cultured benefits are being reduced greatly.Therefore choosing superior hybrid combination of different parental strains is essential.In order to understand and utilize heterosis and select the perfect hybrid subgroups of combinations,differences of growth characters among numerous subgroups should be objectively evaluated.In our research,two strains of Oreochromis niloticus（XX,EE strain） and two strains of O.aureus（ZZ,AA strain） and their hybrid subgroups of Oreochromis niloticus♀ × O.aureus♂（XZ,EZ,ZA,XA） were produced and injected with RFID electronic tags to track and measure growth characteristics for comparative analysis.All the tilapia parents came from technology research center of national tilapia industrial system,which was one of the most important tilapia breeding bases in China.All the fry of combinations except ZZ strain had been hatched out,fifty individuals of each combination were picked out for our analysis.All the individuals for analysis were cultivated in the same pond and fed twice daily,the air pump had been installed in the pond.The results showed that the male ratios of XZ,XA,EZ,EA subgroups were 96.0%,94.0%,98.0%,95.7%,while the ratios of XX,EE,AA strains are 58.0%,66.0%,52.0%,respectively.After 380 days of cultivation,at least four morphological characteristics such as total length,standard length,head length and body depth of four hybrid subgroups were significantly more than those of their parental strains（P〈0.05）,while there were more advantages of growth rate in hybrid tilapia subgroups than parental strains.Meanwhile,there was significant difference（P〈0.05） in growth characteristics among the four hybrid subgroups.Significant correlations were existed in body weight and other morphological characteristics,the correlation coefficients between body weight and caudal peduncle length（0.690-0.846） were obviously lower than that between body weight and total length,standard length,body depth and body width.Data on body weight and morphological characteristics were used for principal component analysis,the characteristics including body weight,total length,head length,body depth,caudal peduncle length,caudal peduncle depth and body width were divided by standard length.In order to eliminate the influence of differences in body size among the tilapia individuals,we obtained seven proportion characteristics including BS,TS,HS,BDS,CLS,CDS and BWS respectively.In the characteristic coefficients plots of principal components factor scores,those seven proportion characteristics were divided into two groups,the first group concluded BS,BDS,CDS and BWS,the other concluded TS,HS and CLS.We draw a scatter plot through the score coefficients of tilapia individuals in principal component factors PCR1 and PCR2.In the plot the individuals of AA strain could obviously differentiated from other subgroups.