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A 20-day trial was conducted to reveal bacterial community dynamics in a commercial nursery of larval Litopenaeus vannamei larvae. The bacterial communities in the ambient water were profiled by high-throughput sequencing of the V4-V5 hypervariable region of the 16S rRNA gene. The results indicated that the dominant bacterial phyla between the metamorphosis stage and postlarval stage were Bacteroidetes, Proteobacteria, Cyanobacteria, and Firmicutes, representing more than 80.09% of the bacterial operational taxonomic units. The relative abundance among bacterial phyla notably differed between the two stages. The relative abundance of Cyanobacteria was higher in the metamorphosis stage, while that of Bacteroidetes was higher and more stable in the postlarval stage. At the class level, the relative abundance of Sphingobacteriia and Alphaproteobacteria increased markedly in the postlarval stage, while that of Flavobacteriia decreased. Redundancy analysis showed that bacterial composition in the metamorphosis stage was positively correlated with salinity, alkalinity, and pH, while in the postlarval stage, it was positively correlated with ammonium nitrogen and nitrite nitrogen. Thus, microbial community diversity in the nursery phase varies per rearing stage.

Marine planktonic bacteria and archaea commonly exhibit pronounced seasonal succession in community composition. But the existence of seasonality in their assembly processes and between-domain differences in underlying mechanism are largely unassessed. Using a high-coverage sampling strategy (including single sample for each station during four cruises in different seasons), 16S rRNA gene sequencing, and null models, we investigated seasonal patterns in the processes governing spatial turnover of bacteria and archaea in surface coastal waters across a sampling grid over ~300 km in the East China Sea. We found that archaea only bloomed in prokaryotic communities during autumn and winter cruises. Seasonality mostly overwhelmed spatial variability in the compositions of both domains. Bacterial and archaeal communities were dominantly governed by deterministic and stochastic assembly processes, respectively, in autumn cruise, probably due to the differences in niche breadths (bacteria archaea) and relative abundance (bacteria archaea). Stochasticity dominated assembly mechanisms of both domains but was driven by distinct processes in winter cruise. Determinism-dominated assembly mechanisms of bacteria rebounded in spring and summer cruises, reflecting seasonal variability in bacterial community assembly. This could be attributed to seasonal changes in bacterial niche breadths and habitat heterogeneity across the study area. There were seasonal changes in environmental factors mediating the determinism-stochasticity balance of bacterial community assembly, holding a probability of the existence of unmeasured mediators. Our results suggest contrasting assembly mechanisms of bacteria and archaea in terms of determinism-vs.-stochasticity pattern and its seasonality, highlighting the importance of seasonal perspective on microbial community assembly in marine ecosystems.

Although the effect of ocean acidification on fertilization success of marine organisms is increasingly well documented, the underlying mechanisms are not completely understood. The fertilization success of broadcast spawning invertebrates depends on successful sperm-egg collisions, gamete fusion, and standard generation of Ca2+ oscillations. Therefore, the realistic effects of future ocean pCO2 levels on these specific aspects of fertilization of Tegillarca granosa were investigated in the present study through sperm velocity trials, fertilization kinetics model analysis, and intracellular Ca2+ assays, respectively. Results obtained indicated that ocean acidification significantly reduced the fertilization success of T. granosa, which could be accountable by (i) decreased sperm velocity hence reducing the probability for sperm-egg collisions; (ii) lowered probability of gamete fusion for each gamete collision event; and (iii) disrupted intracellular Ca2+ oscillations.

Blood clam, Tegillarca granosa, is an important shellfish in Chinese mariculture industry. Investigative research in this species, such as genetic linkage mapping, requires a large panel of molecular markers. In present study, a total of 89 polymorphic microsatellite markers were developed in T. granosa using the sequence database of Life Sciences Technology 454 next generation sequencing technology. All 89 loci were characterized in 20 individual clams from a natural population inhabiting Yueqing Gulf, Zhejiang Province, China. The number of alleles per polymorphic locus varied between 2 and 15, while the observed heterozygosity, expected heterozygosity and polymorphic information content varied between 0.000 and 1.000, 0.102 and 0.921, and 0.048 and 0.886, respectively. Of the 89 loci identified, 32 loci deviated significantly from Hardy-Weinberg equilibrium following Bonferroni correction. Thirty nine markers, which were shown to be polymorphic in a full-sibling family, were tested in Mendelian segregations. As expected, 32 loci were co-dominantly segregated in a Mendelian fashion. These novel developed microsatellite markers represent useful research tools for investigation of population genetic structure and genetic diversity in this species.

Persistent organic pollutants (POPs) are known to converge into the ocean and accumulate in the sediment, posing great threats to marine organisms such as the sessile bottom burrowing bivalves. However, the immune toxicity of POPs, such as B[a]P, under future ocean acidification scenarios remains poorly understood to date. Therefore, in the present study, the impacts of B[a]P exposure on the immune responses of a bivalve species, Tegillarca granosa, under present and future ocean acidification scenarios were investigated. Results obtained revealed an increased immune toxicity of B[a]P under future ocean acidification scenarios in terms of reduced THC, altered haemocyte composition, and hampered phagocytosis, which may attribute to the synergetic effects of B[a]P and ocean acidification. In addition, the gene expressions of pathogen pattern recognition receptors (TLR1, TLR2, TLR4, TLR6), pathway mediators (TRAF6, TAK1, TAB2, IKKα and Myd88), and effectors (NF-ĸB) of the important immune related pathways were significantly down-regulated upon exposure to B[a]P under future ocean acidification scenarios. Results of the present study suggested an increased immune toxicity of B[a]P under future ocean acidification scenarios, which will significantly hamper the immune responses of T. granosa and subsequently render individuals more susceptible to pathogens challenges.

A genetic linkage map of the blood clam (Tegillarca granosa) was constructed based on simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP) markers. An F1 family consisting of 109 individuals was created using the “two-way pseudo-testcross” mapping strategy. A total of 568 polymorphic markers, including 32 SSRs and 534 AFLPs, were used in the linkage mapping. The female linkage map consisted of 250 marker loci (15 SSR and 255 AFLP), which formed 18 linkage groups with an average marker space of 7.15 cM; they spanned a total length of 1,649.33 cM, covering 84.49% of the estimated genome size. The male map consisted of 290 marker loci (14 SSR and 276 AFLP), which mapped to 22 linkage groups with an average marker spacing of 5.56 cM. They spanned a total length of 1,485.09 cM, covering 84.43% of the estimated genome size. This map is the first genetic linkage map in the blood clam and provides a basis for mapping quantitative trait loci and for breeding applications.

Although it has been shown that ocean acidification generally has a negative impact on fertilisation success of broadcast spawning marine organisms, whether induced fertilisation success reduction is a consequence of elevated pCO2 or decreased pH remains unclear. Therefore, the impacts of HCl- and CO2-induced acidified seawater on sperm motility and gametes fertilisation capability of a broadcast spawning bivalve species, Tegillarca granosa were investigated in the present study. The results showed that the fertilisation capability of both gametes was significantly reduced in either HCl- or CO2-acidified seawater. In addition, significant impacts on sperm motility were observed in the group exposed to CO2-acidified seawater, suggesting that this parameter is sensitive to pCO2 instead of solely pH value. The differences between the two seawater acidification manipulating methods may be due to the intrinsic difference in diffusion capability of CO2 and protons.

Although the effect of ocean acidification on fertilization success of marine organisms is increasingly well documented, the underlying mechanisms are not completely understood. The fertilization success of broadcast spawning invertebrates depends on successful sperm-egg collisions, gamete fusion, and standard generation of Ca

Background Blood clams (Tegillarca granosa) are one of the most commercial shellfish in China and South Asia with wide distribution in Indo-Pacific tropical to temperate estuaries. However, recent data indicate a decline in the germplasm of this species. Furthermore, the molecular mechanisms underpinning reproductive regulation remain unclear and information regarding genetic diversity is limited. Understanding the reproductive biology of shellfish is important in interpreting their embryology development, reproduction and population structure. Transcriptome sequencing (RNA-seq) rapidly obtains genetic sequence information from almost all transcripts of a particular tissue and currently represents the most prevalent and effective method for constructing genetic expression profiles. Results Non-reference RNA-seq, an Illumina HiSeq2500 Solexa system, and de novo assembly were used to construct a gonadal expression profile of the blood clam. A total of 63.75 Gb of clean data, with at least 89.46% of Quality30 (Q30), were generated which was then combined into 214,440 transcripts and 125,673 unigenes with a mean length of 1,122.63 and 781.30 base pairs (bp). In total, 27,325 genes were annotated by comparison with public databases. Of these, 2,140 and 2,070 differentially expressed genes (DEGs) were obtained (T05 T08 vs T01 T02 T04, T06 T07 vs T01 T02 T04; in which T01-T04 and T05-T08 represent biological replicates of individual female and male clams, respectively) and classified into two groups according to the evaluation of biological replicates. Then 35 DEGs and 5 sex-related unigenes, in other similar species, were investigated using qRT-PCR, the results of which were confirmed to data arising from RNA-seq. Among the DEGs, sex-related genes were identified, including forkhead box L2 (Foxl2), sex determining region Y-box (Sox), beta-catenin (β-catenin), chromobox homolog (CBX) and Sex-lethal (Sxl). In addition, 6,283 simple sequence repeats (SSRs) and 614,710 single nucleotide polymorphisms (SNPs) were identified from the RNA-seq results. Conclusions This study provided the first complete gonadal transcriptome data for the blood clam and allowed us to search many aspects of gene sequence information, not limited to gender. This data will improve our understanding of the transcriptomics and reproductive biology of the blood clam. Furthermore, molecular markers such as SSRs and SNPs will be useful in the analysis of genetic evolution, bulked segregant analysis (BSA) and genome-wide association studies (GWAS). Our transcriptome data will therefore provide important genetic information for the breeding and conservation of germplasm.

Oceanic uptake of CO2 from the atmosphere has significantly reduced surface seawater pH and altered the carbonate chemistry within, leading to global Ocean Acidification (OA). The blood clam, Tegillarca granosa, is an economically and ecologically significant marine bivalve that is widely distributed along the coastal and estuarine areas of Asia. To investigate the physiological responses to OA, blood clams were exposed to ambient and three reduced seawater pH levels (8.1, 7.8, 7.6 and 7.4) for 40 days, respectively. Results obtained suggest that OA suppresses the feeding activity and aerobic metabolism, but elevates proteins catabolism of blood clams. OA also causes extracellular acidosis and decreases haemolymph Ca2+ concentration. In addition, our data also suggest that OA impairs the calcification process and inner shell surface integrity. Overall, OA adversely influences metabolism, acid-base status and calcification of blood clams, subsequently leading to a decrease in the fitness of this marine bivalve species.

A breeding-selection program for the clam, Meretrix meretrix, was conducted since 2004. Two of the selection populationswere generated with the shell color pattern as an additional selection criterion and named as SP (purple stripes) population and SB (black dots) population. The third-generation SP and SB populations (08G3SP and 08G3SB, respectively) were cultured at two commercial clam farms and a nursery pond and their shell lengths were compared. 08G3SB clams had significantly larger sizes than 08G3SP clams at commercial clam farms (p < 0.05), yet 08G3SB individuals were significantly smaller than 08G3SP individuals at the nursery pond (p < 0.05). Then, we examined the growth of the fourth-generation SP and SB populations (10G4SP and 10G4SB, respectively) at a commercial farm, and found that the shell lengths of the 10G4SB clams increased at a significantly higher growth rate than the 10G4SP clams (p < 0.05) from May to September, when the water temperature was between 24.2-27.5A degrees C, while 10G4SB lost the growth advantage in the other months. These results indicated that SP and SB populations responded differently to environmental factors, so it is beneficial for the clam farmers to select a suitable population according to the culture environment. Furthermore, a diallel mating of the SB and SP populations was designed to investigate whether their hybrid population would show heterosis. However, the heterosis was not shown in this study, whichmight result from the slight genetic divergence between SB and SP populations.

The impact of pCO2 driven ocean acidification on marine bivalve immunity remains poorly understood. To date, this impact has only been investigated in a few bivalve species and the underlying molecular mechanism remains unknown. In the present study, the effects of the realistic future ocean pCO2 levels (pH at 8.1, 7.8, and 7.4) on the total number of haemocyte cells (THC), phagocytosis status, blood cell types composition, and expression levels of twelve genes from the NF-kappa β signaling and toll-like receptor pathways of a typical bottom burrowing bivalve, blood clam (Tegillarca granosa), were investigated. The results obtained showed that while both THC number and phagocytosis frequency were significantly reduced, the percentage of red and basophil granulocytes were significantly decreased and increased, respectively, upon exposure to elevated pCO2. In addition, exposure to pCO2 acidified seawater generally led to a significant down-regulation in the inducer and key response genes of NF-kappa β signaling and toll-like receptor pathways. The results of the present study revealed that ocean acidification may hamper immune responses of the bivalve T. granosa which subsequently render individuals more susceptible to pathogens attacks such as those from virus and bacteria.

To date, the effects of ocean acidification on toxic metals accumulation and the underlying molecular mechanism remains unknown in marine bivalve species. In the present study, the effects of the realistic future ocean pCO2 levels on the cadmium (Cd) accumulation in the gills, mantle and adductor muscles of three bivalve species, Mytilus edulis, Tegillarca granosa and Meretrix meretrix, were investigated. The results obtained suggested that all species tested accumulated significantly higher Cd (p 2 acidified seawater during the 30 days experiment and the health risk of Cd (based on the estimated target hazard quotients, THQ) via consumption of M. meretrix at pH 7.8 and 7.4 significantly increased 1.21 and 1.32 times respectively, suggesting a potential threat to seafood safety. The ocean acidification-induced increase in Cd accumulation may have occurred due to (i) the ocean acidification increased the concentration of Cd and the Cd2+/Ca2+ in the seawater, which in turn increased the Cd influx through Ca channel; (ii) the acidified seawater may have brought about epithelia damage, resulting in easier Cd penetration; and (iii) ocean acidification hampered Cd exclusion.

The effect of dietary Chinese herb Astragalus membranaceus on the cellular immune response of spotted maigre ( Nibea albifiora ) was investigated. 300 spotted maigre with an average initial weight of 49.6 ± 5.5 g were selected and fed with different levels of water decoction of A. membranaceus (WDA) (0, 0.5, 1.0, 2.0 and 4.0%) for 4 weeks. Non-specific immune responses were measured after 0, 3, 7, 14, 21, 28 days of feeding. We then injected control and WDA treated fish with an intraperitoneal injection of Vibrio vulnificus , and recorded their mortality rate for 7 days post-infection. The results showed that the phagocytic index of phagocytes was significantly higher in 2% WDA treated group as compared to other groups (P

I-type lysozyme is considered to play crucial roles in both anti-bacteria and digestion function of the bivalve, which signifies that it is related to both immunity and growth. In this study, based on the principle of case-control association analysis, using the stock materials with different vibrio-resistance profile obtained by selective breeding, single nucleotide polymorphisms (SNPs) in the DNA partial sequence of an i-type lysozyme of Meretrix meretrix (MmeLys) were discovered and examined for their association with vibrio-resistance and growth. Twenty-seven SNPs were detected and fifteen of them were genotyped in clam stocks with different resistance to Vibrio harveyi (09-C and 09-R) and to Vibrio parahaemolyticus (11-S and 11-R). Allele frequency distribution among different stocks was compared. And wet weight of clams with different genotype at each SNP locus was compared. The results indicated that SNP locus 9 was associated with V. harveyi and V. parahaemolyticus resistance and growth of M. meretrix. Loci 12 and 14 were associated with both V. parahaemolyticus-resistance and growth, and also have the potential to be related with V harveyi-resistance of M. meretrix. Therefore these three SNPs especially locus 9 were the potential markers which may be involved in assisting resistance selective breeding. In addition, this study showed evidence that improvements in clam resistance to vibriosis could be achieved through selective breeding. All results provided encouragement for the continuation of the selective breeding program for vibrio-resistance gain in clam M. meretrix and the application of polymorphisms in MmeLys to the future marker assisted selection. (C) 2012 Elsevier Ltd. All rights reserved.

We isolated and characterized 39 expressed sequence tag (EST)-derived simple sequence repeats (SSR) for the blood clam Tegillarca granosa. The number of alleles of the 39 EST-SSR markers varied from 2 to 8, with a mean of 4.0 alleles per locus. The number of observed, expected heterozygosity and polymorphic information content per locus varied from 0.200 to 1.000, from 0.549 to 0.841 and from 0.253 to 0.849, respectively. No significant deviations from Hardy–Weinberg equilibrium or linkage disequilibrium between pairs of loci were observed. These loci are firstly characterized and will be useful for investigation genetic population structure and molecule-assisted breeding for T. granosa.

Computer assisted movement tracking was used to characterize the motility of two marine microalgae, Isochrysis galbana and Tetraselmis chui , and to investigate the toxicity of Cu, Pb, and Cd on motile percentage, curvilinear velocity, average path velocity, straight line velocity, linearity, straightness, and wobble. Except for motile percentage, all other motility parameters differed significantly between I. galbana and T. chui . Based on relative motile percentage data, the median effective concentration (EC 50 ) of Cu on the motility of I. galbana and T. chui was 31.4 and 1.3 μmol/L, respectively, while for Pb it was 37.8 and 10.9 μmol/L and for Cd it was 121.6 and 37.8 μmol/L, respectively. Compared to I. galbana , T. chui was more sensitive to all tested metals. The toxic effect of the heavy metals on motility exhibited the following decreasing order for both species: Cu > Pb > Cd. Our results indicate that I. galbana and T. chui motility is sensitive to heavy metals and can be used as an indicator for toxicology bioassays.

The aim of this study was to estimate the genetic parameters of the growth performance of clam Meretrix meretrix. As part of the breeding programme, 25 full-sib families nested within eight half-sib families were produced, planted out and tested to assess the heritability of the total body weight (TW), shell length (SL), shell height (SH) and shell width (SW) at different growth stages. Method of analysis was implemented using the Bayesian method based on the Multiple Trait using Gibbs Sampling under Animal Model program, which was used to estimate the (co)variance components of the traits and conduct genetic analysis. A total of 25 full-sib families, each with 30-35 individuals within family, were used for the analysis. Significant positive genetic and phenotypic correlations between SL, SW, SH and TW with each other were observed. The growth traits showed high-magnitude heritabilities, with values ranging from 0.64 to 0.85, which indicates that these traits should respond to selection and therefore should be included in genetic improvement programmes.

The karyotype and chromosomal characteristics of the yellowtail kingfish Seriola lalandi lalandi were investigated by examining metaphase spreads from kidney cells of 4-month-old fish artificially bred using wild-captured broodstock from the coast of South Australia. A total of 80 mitotic metaphases from 10 individual fish were analysed, with 52 spreads having a mode of 2n=48 chromosomes, representing 65% of the metaphases observed. The diploid consisted of two metacentric, two submetacentric, six subtelocentric and 38 telocentric chromosomes, with the fundamental number of chromosome arms being 52. The total haploid chromosome length was approximately 44.412 μm. This study shows that the karyotype of S. lalandi lalandi differs from those reported previously for other Seriola species in having one pair of metacentric chromosomes.

We studied the ultrastructure of spermatogenesis and spermatozoa in the northern quahaug, the clam Mercenaria mercenaria. Spermatogenetic cells gradually elongate. Mitochondria gradually fuse and increase in size and electron density. During spermatid differentiation, proacrosomal vesicles migrate towards the presumptive anterior pole of the nucleus and eventually form the acrosome. The spermatozoon of M. mercenaria is of a primitive type. It is composed of head, mid-piece, and tail. The acrosome shows a subacrosomal space with a short conical contour. The slightly curved nucleus of the spermatozoon contains fine-grained dense chromatin. The middle piece consists of a centriolar complex which is surrounded by four mitochondria. The flagellum has a standard “9 + 2” microtubular structure. The ultrastructure of spermatozoa and spermatogenesis of M. mercenaria shares a number of features with other species of the family Veneridae. M. mercenaria may be a suitable model species for further investigations into the mechanisms of spermatogenesis in the Bivalvia.

In this study, 28 polymorphic simple sequence repeats (SSR) markers were isolated from an expressed sequence tag (EST) library of Meretrix lamarkii Deshayes. The number of alleles of these 28 EST-SSR markers varied from 2 to 8, with a mean of 3.64 alleles per locus. The observed, expected heterozygosity and polymorphic information content per locus varied from 0.10 to 1.00, 0.10 to 0.86 and 0.09 to 0.81, respectively. No significant linkage disequilibrium between pairs of loci was found, except two of them significantly deviated from Hardy–Weinberg equilibrium after Bonferroni correction. These loci are the first time to be characterized and will be useful for population genetic structure investigation and marker assisted breeding for M. lamarkii.

The clam Meretrix meretrix is an important commercial bivalve distributed in the coastal areas of South and Southeast Asia. In this study, marker trait association analyses were performed based on the stock materials of M. meretrix with different vibrio-resistance profile obtained by selective breeding. Forty-eight EST-SSR markers were screened and 27 polymorphic SSRs of them were genotyped in the clam stocks with different resistance to Vibrio parahaemolyticus (11-R and 11-S) and to Vibrio harveyi (09-R and 09-C). Allele frequency distributions of the SSRs among different stocks were compared using Pearson's Chi-square test, and three functional EST-SSR markers (MM959, MM4765 and MM8364) were found to be associated with vibrio-resistance trait. The 140-bp allele of MM959 and 128-bp allele of MM4765 had significantly higher frequencies in resistant groups (11-R and 09-R) than in susceptive/control groups (11-S and 09-C) (P < 0.01), which suggested that the clams carrying these two alleles have stronger resistance against vibrio. Clam individuals of 11-S were divided into three subgroups based on the survival time post-challenge, and the multi-dimensional scaling (MDS) analysis showed that clusters generated by genetic similarity revealed by the three SSR markers were consistent with the three subgroups distinctions. The putative functions of contig959, contig4765 and contig8364 also suggested that the three SSR-involved genes might play important roles in immunity of M. meretrix. All these results supported that EST-SSR markers MM959, MM4765 and MM8364 were associated with vibrio-resistance and would be useful for marker-assisted selection (MAS) in M. meretrix genetic breeding. (C) 2013 Elsevier Ltd. All rights reserved.

The effects of polysaccharides, saponins, and water decoction of the Chinese herb Astragalus membranaceus on the immune response of spotted maigre (Nibea albiflora) were investigated. Fish with an average initial weight of 49.6±5.5 g were fed a diet containing 2% extract for four weeks. The lysozyme and phagocytic activities of the fish were determined and compared with those of control fish fed an unsupplemented feed on days 0, 3, 7, 14, 21, and 28. Both activities were significantly higher in groups fed the Astragalus extract than in the control group (p0.05). Most important, the Astragalus-fed groups were significantly protected against Vibrio vulnificus challenge compared to the control group (p

Computer assisted movement tracking was used to investigate the toxicity effect of commonly used aquiculture disinfectants (potassium permanganate and bleaching powder) on the motility of two marine microalgae Isochrysis galbana and Tetraselmis chui. Both disinfectants tested showed significant effect (p 50 of potassium permanganate on motility of I. galbana and T. chui was 0.85 and 5.00mg/L, respectively. For bleaching powder, it was 4.98 and 5.09mg/L for I. galbana and T. chui, respectively. Compared to T. chui, I. galbana was more sensitive to Potassium permanganate. Our results reveal a dose-response relationship between tested disinfectants and motility characters and indicate that the motility of I. galbana and T. chui is sensitive to disinfectants tested and can be used as an indicator for toxicology bioassays.

The bloody clam, Tegillarca granosa, is an important commercial bivalve which is extensively cultured from South Korea to Malaysia. Due to its economic value, it is important to cultivate rapid growth strains for the sustainable development of aquaculture industry of T. granosa. The emergence of molecular markers provides a rich theoretical basis for the rapid cultivation varieties. By the method of group selec-tion, the rapid growth strains of T. granosa were bred though two generations. According to the compari-son test, the rapid growth strains showed significant advantages in shell length, shell height, shell width and total weight than control group under the same environmental conditions. AFLP marker was applied in this study to evaluate the genetic variation of the rapid growth strains, and to screen the molecular markers associated with the traits of growth. A total of 2180 bands were amplified from 64 individuals of the rapid growth strain and control group by 40 primer combinations. The analysis of Nei’s genetic diversity index and Shannon’s genetic information index of two groups indicated that the genetic diversity of breeding group was slightly higher than the control group. The genetic distance between two groups was about 0.011 3, the value of GST was 0.022 4 and Nm was 22.281 1, from which we concluded that there is a little genetic differentiation after selection. Of all amplified bands, 7 bands showed significant differences in frequency between two groups. 2 bands of all were only found in rapid growth strains, with the frequency of 0.812 5 and 0.343 8, respectively. And 2 bands showed significantly higher frequencies in rapid growth strains, while 3 bands showed significantly higher frequencies in control group. The bands with higher frequencies in rapid growth strains may be associated with the traits of growth. The unique AFLP markers associated with growth traits would be useful for growth-related gene cloning, quantitative trait locus (QTL) mapping, and molecular-assisted selection (MAS) of T. granosa.