Genetic and Morphological Variation among Hatchery Stocks of Thai Silver Barb Barbonymus gonionotus (Bleeker, 1850)

Abstract

Microsatellite loci and truss morphometrics were used to discriminate eight hatchery stocks of silver barb (Barbonymus gonionotus) in Northeast Thailand. The results showed significant genetic (P < 0.0017) and morphological differences (P < 0.0017) in 18 and 25 out of 28 pair-wise comparisons, respectively. However, cluster analyses revealed a weak association between genetic differentiation and morphometric variation. Principal components analysis identified three truss measurements in the abdominal regions as the most powerful variables to distinguish stocks. Discriminant function analysis, based on 13 truss elements, assigned individuals to four distinct groups, and one group consisted of samples from four stocks. Among distinct stocks that showed variation in body shape, the Buri Ram samples displayed the largest body size as a result of breeding selection. The identity of a stock could be constructed from three measurements for body shape that were significantly correlated. Findings demonstrated the use of the truss morphometric approach in discriminating different hatchery stocks of silver barb within the studied stations.