Identification and association of ISSR markers for thermal stress in polyvoltine silkworm Bombyx mori

Evaluation of genetic resources is an essential prerequisite for their effective utilization. In India, the tropical climate prevails in most of the sericultural belts, where temperature goes beyond the ambient during summer, adversely affecting the silkworm rearing. Although polyvoltine silkworms are poor in silk content, they are mostly tolerant to tropical conditions and diseases. With an aim to identify potential silkworm races/breeds specific to thermo-tolerance for their effective utilization in breeding programme, 15 selected polyvoltine silkworm races were studied for their thermo-tolerance behaviour. Their genomic DNA samples were analyzed for ISSR-PCR using 15 selected primers. The UPGMA analysis based on Nei and Li algorithm has clustered the 15 silkworm races into five groups and one isolate. ALSCAL-multidimensional scaling has not only supported the information generated by the dendrogram, but it has made the genetic distance among races more clear and substantiating their status in terms of thermal stress where pupation rate was taken as indicator. Further, discriminant function analysis (DFA) was done with three groups of silkworms classified for thermal stress viz. susceptible, moderately tolerant and tolerant. The canonical correlation value was estimated to be 0.987 (Wilk's lambda = 0.004; chi2 = 36.044, p < 0.05). DFA clearly discriminated the above three groups. Beta statistics with t value and its significance for the markers identified through stepwise multiple regression analysis (MRA) revealed a total of five bands (807(1300), 808(3000), 808(4000), 834(4000), and 834(3000)) showing correlation with pupation rate after thermal treatment. Out of them, marker 8083000 showed maximum and highly significant correlation (r = 0.757, p < 0.001, t = 4.182) with pupation rate among the silkworm races. The identified putative markers are being used to develop DNA marker to be used in evolving thermo-tolerant silkworm breeds using marker assisted selection programme.     

The scanning electron microscopic study of the infection and conidial development of Aspergillus tamarii Kita on its host, the silkworm, Bombyx mori Linn.

Development of Aspergillosis on the integument of the silkworm, Bombyx mori Linn., was examined by scanning electron microscopy. Aspergillosis is a fungal disease caused by an insect mycopathogen Aspergillus tamarii Kita, which infects the silkworms in countries where sericulture (the rearing of silkworms)is prevalent. The present study showed the course of infection and the conidial development of A. tamarii on the integument of B. mori. Five different strains (KA, NB₁₈, NB₄ D₂, NB₇ and PM) of B. mori were inoculated on their body surface with ca. 1 × 10⁶ conidia/ml. Among the five breeds tested, the conidial germination was greatest on the larval surface of KA breed, and least on PM. Most of the conidia germinated on the cuticle approximately 8–12 hours after inoculation, forming a suctorial appressorium within 24 hours. The hyphae reached the hemocoel, where they grew and multiplied extensively, forming a mycelial complex and causing death of the host larva in about 5–6 days. The death of the host was followed by growth of the fungus through mesodermal and epidermal tissues, leading to larval mummification about 6–7 days post-inoculation. Extensive aerial outgrowths of the fungus followed, mostly through the intersegmental regions of larvae. Abundant branched conidiophores developed, forming a confluent yellow brown mat over the entire host body 7 days after inoculation. Each conidiophore had an apical vesicle bearing numerous phialides from which conidia were developed in long chains.     

The profiles of red fluorescent proteins with antinucleopolyhedrovirus activity in races of the silkworm Bombyx mori

Partially purified red fluorescent proteins (RFPs) secured from the gut juice of 5th-instar multivoltine and bivoltine silkworm races were observed as several bands in electrophoretograms and chromatographic eluates. Interestingly, different races of silkworms had varying numbers of fluorescent protein bands: 11 in Pure Mysore (resistant), 11 in Nistari (resistant), 4 in CSR₂ (moderately susceptible) and 1 in NB₄D₂ (highly susceptible). Bioassay experiments indicated that the fluorescent bands had antinucleopolyhedrovirus (antiNPV) activity. The molar extinction coefficients and fluorescence quantum yields of all RFPs were estimated. The purified tetrapyrroles were characterized by UV–visible absorption and fluorescence spectral analyses. All tetrapyrrole moieties associated with RFPs were found to be different and characteristic of the fluorescent bands. The resulting qualitative and quantitative differences among the individual RFPs from various races of silkworm were related to the susceptibilities of the silkworms to the viral disease. Moreover, light was found to be essential for the synthesis of RFPs, and, therefore, the role of light in the synthesis of RFPs was evaluated. Thus, this work may elucidate the process of RFP synthesis in silkworm, which may be used as a biomarker to measure the degree of susceptibility of silkworm races to NPV. Therefore, the characteristic band pattern may be used as an indicator to define the relative resistance of a race towards the specific virus.     

Construction of a binary transgenic gene expression system for recombinant protein production in the middle silk gland of the silkworm <Emphasis Type="Italic">Bombyx mori</Emphasis>

To construct an efficient system for the production of recombinant proteins in silkworm (Bombyx mori), we investigated the promoter activity of the silkworm sericin 1, 2, and 3 genes (Ser1, Ser2, and Ser3) using a GAL4/UAS binary gene expression system in transgenic silkworm. The promoter activity of the upstream region of Ser1 was strong, yielding high expression of an enhanced green fluorescent protein (EGFP) transgene in the middle and posterior regions of the middle silk gland (MSG) after day 2 of the fifth instar. The Ser3 upstream region exhibited moderate promoter activity in the anterior MSG, but the Ser2 upstream region did not exhibit any promoter activity. Since the strongest promoter activity was observed for Ser1, we devised a system for the production of recombinant proteins using a GAL4–Ser1 promoter construct (Ser1-GAL4). Transgenic silkworms harboring both the Ser1-GAL4 construct and the previously reported upstream activating sequence (UAS)–EGFP construct, which contains the TATA box region of the Drosophila hsp70 gene, yielded approximately 100 μg EGFP per larva. When we then analyzed the TATA box region, signal peptide, and intron sequences for their effects on production from the UAS-EGFP construct, we found that the optimization of these sequences effectively increased production to an average of 500 μg EGFP protein per transgenic larva. We conclude that this binary system is a useful tool for the mass production of recombinant proteins of biomedical and pharmaceutical interest in silkworm.     

Silkworm expression system as a platform technology in life science

Many recombinant proteins have been successfully produced in silkworm larvae or pupae and used for academic and industrial purposes. Several recombinant proteins produced by silkworms have already been commercialized. However, construction of a recombinant baculovirus containing a gene of interest requires tedious and troublesome steps and takes a long time (3–6 months). The recent development of a bacmid, Escherichia coli and Bombyx mori shuttle vector, has eliminated the conventional tedious procedures required to identify and isolate recombinant viruses. Several technical improvements, including a cysteine protease or chitinase deletion bacmid and chaperone-assisted expression and coexpression, have led to significantly increased protein yields and reduced costs for large-scale production. Terminal N-acetyl glucosamine and galactose residues were found in the N-glycan structures produced by silkworms, which are different from those generated by insect cells. Genomic elucidation of silkworm has opened a new chapter in utilization of silkworm. Transgenic silkworm technology provides a stable production of recombinant protein. Baculovirus surface display expression is one of the low-cost approaches toward silkworm larvae-derived recombinant subunit vaccines. The expression of pharmaceutically relevant proteins, including cell/viral surface proteins, membrane proteins, and guanine nucleotide-binding protein (G protein) coupled receptors, using silkworm larvae or cocoons has become very attractive. Silkworm biotechnology is an innovative and easy approach to achieve high protein expression levels and is a very promising platform technology in the field of life science. Like the “Silkroad,” we expect that the “Bioroad” from Asia to Europe will be established by the silkworm expression system.     

Germ line transformation of the silkworm, <Emphasis Type="Italic">Bombyx mori</Emphasis>, using the transposable element <Emphasis Type="Italic">Minos</Emphasis>

We investigated the use of Minos as a vector for transgenesis in the silkworm, Bombyx mori. We first constructed a vector plasmid with the green fluorescent protein (GFP) gene fused with the silkworm cytoplasmic actin gene (A3) promoter, and a helper plasmid with the Minos transposase gene controlled by the same A3 promoter. Injection of the vector and helper plasmid DNA into silkworm eggs produced transgenic animals in the following generation. The efficiency of transgenic silkworm production using this method was much lower than that obtained using piggyBac-mediated germ line transformation. However, >40-fold increase in the efficiency of producing transgenic silkworms was obtained using an in vitro synthesized source of Minos transposase mRNA. We conclude that the Minos transposon is a useful vector for construction of transgenic silkworms, particularly when in vitro synthesized mRNA is used. This is the first report showing that Minos can be used as a vector for germ-line transformation in lepidopteran insects.     

Fat body catalase activity as a biochemical index for the recognition of thermotolerant breeds of mulberry silkworm, Bombyx mori L.

The fifth instar larvae of the silkworm Bombyx mori L. were exposed to selected high temperatures (35 and 40 °C) in order to understand the changes in the level of catalase activity in the three tissues of fat body, midgut and haemolymph of the five selected bivoltine breeds and their 9 quantitative traits, namely larval weight, cocoon weight, shell weight, shell ratio, filament length, filament weight, denier, renditta and effective rearing rate (ERR), also the correlation between them under high temperature conditions were examined. Catalase activity resulting in fat body revealed a positive correlation between the control (28±1 °C) and 40±1 °C. The CSR₂ breed showed the most level of thermotolerance and catalase activity, compared with the CSR₄, JROP, NB₄D₂ and KA breeds. It was found that the level of catalase activity in fat body may be a reliable biochemical index to recognize thermotolerant breeds in order to develop resistant hybrids for tropical areas.     

Expression of <Emphasis Type="Italic">Trichoderma</Emphasis><Emphasis Type="Italic">viride</Emphasis> endoglucanase III in the larvae of silkworm, <Emphasis Type="Italic">Bombyx mori L.</Emphasis> and characteristic analysis of the recombinant protein

Endoglucanase is a part of cellulase which hydrolyzes cellulose into glucose. In this study, we cloned endoglucanase III (EG III) gene from Trichoderma viride strain AS 3.3711 using a PCR-based exon splicing method, and expressed EG III recombinant protein in both silkworm BmN cell line and silkworm larvae with an improved Bac-to-Bac/BmNPV mutant baculovirus expression system, which lacks the chiA and v-cath genes of Bombyx mori nucleopolyhedrovirus (BmNPV). The result showed that around 45 kDa protein was visualized in BmN cells at 48 h after the second generation recombinant mBacmid/BmNPV/EG III baculovirus infection. The enzymes from recombinant baculoviruses infected silkworms exhibited significant maximum enzyme activity at the environmental condition of pH 8.0 and temperature 50°C, and increased 20.94 and 19.13% compared with that from blank mBacmid/BmNPV baculoviruses infected silkworms and normal silkworms, respectively. It was stable at pH range from 5.0 to 9.0 and at temperature range from 40 to 60°C. It provided a possibility to generate transgenic silkworms expressing bio-active cellulase, which can catabolize dietary fibers more efficiently, and it might be of great significance for sericulture industry.     

Effects of oral recombinant VP28 expressed in silkworm (Bombyx mori) pupa on immune response and disease resistance of Procambarus clarkii

The envelope protein VP28 of white spot syndrome virus (WSSV) was overexpressed in the silkworm Bombyx mori, which was achieved by using a baculovirus (HyNPV) expression system and by making silkworm pupa as an alternative host, and then it was directly supplemented in diet at a dose of 20 g kg⁻¹ without purification. During a 30 day feeding period, the levels of phenoloxidase (PO) and superoxide dismutase (SOD) in the haemolymph of the tested Procambarus clarkii increased greatly (P < 0.05) when compared to the control crayfish fed with wild-type HyNPV baculovirus-infected silkworms or normal silkworms. Compared with two controls, the crayfish which had been infected for 20 days showed a significantly lower (P < 0.05) mean cumulative mortality (15.6%), which respectively, resulted in relative percent survivals (RPS) of 83.7 and 84.4%. The efficacy to inhibition of viral infection was further studied by in situ hybridization with a WSSV-specific DNA probe. The high levels of PO and SOD might be important for developing resistance against WSSV in these crayfish.     

Impact of heat shock on heat shock proteins expression, biological and commercial traits of Bombyx mori

We report the thermotolerance of new bivoltine silkworm, Bombyx mori strains NB₄D₂, KSO₁, NP₂, CSR₂ and CSR₄and differential expression of heat shock proteins at different instars. Different instars of silkworm larva were subjected to heat shock at 35°C, 40°C and 45°C for 2 hours followed by 2 hours recovery. Heat shock proteins were analyzed by SDS‐PAGE. The impact of heat shock on commercial traits of cocoons was analyzed by following different strategies in terms of acquired thermotolerance over control. Comparatively NP₂ exhibited better survivability than other strains. Resistance to heat shock was increased as larval development proceeds in the order of first instar > second instar > third instar > fourth instar > fifth instar in all silkworm strains. Expression of heat shock proteins varies in different instars. 90 kDa in the first, second and third instars, 84 kDa in the fourth instar and 84, 62, 60, 47 and 33 kDa heat shock proteins in fifth instar was observed in response to heat shock. Relative influence of heat shock on commercial traits that correspond to different stages was significant in all strains. In NB₄D₂, cocoon and shell weight significantly increased to 17.52% and 19.44% over control respectively. Heat shock proteins as molecular markers for evaluation and evolution of thermotolerant silkworm strains for tropics was discussed.     

Primed Immune Responses to Gram-negative Peptidoglycans Confer Infection Resistance in Silkworms

A heightened immune response, in which immune responses are primed by repeated exposure to a pathogen, is an important characteristic of vertebrate adaptive immunity. In the present study, we examined whether invertebrate animals also exhibit a primed immune response. The LD₅₀ of Gram-negative enterohemorrhagic Escherichia coli O157:H7 Sakai in silkworms was increased 100-fold by pre-injection of heat-killed Sakai cells. Silkworms pre-injected with heat-killed cells of a Gram-positive bacterium, Staphylococcus aureus, did not have resistance to Sakai. Silkworms preinjected with enterohemorrhagic E. coli peptidoglycans, cell surface components of bacteria, were resistant to Sakai infection. Silkworms preinjected with S. aureus peptidoglycans, however, were not resistant to Sakai. Silkworms preinjected with heat-killed Sakai cells showed persistent resistance to Sakai infection even after pupation. Repeated injection of heat-killed Sakai cells into the silkworms induced earlier and greater production of antimicrobial peptides than a single injection of heat-killed Sakai cells. These findings suggest that silkworm recognition of Gram-negative peptidoglycans leads to a primed immune reaction and increased resistance to a second round of bacterial infection.     

Aspergillus bombycis genotypes (RFLP) from silkworm cultivation

 Eighteen isolates of Aspergillus bombycis from samples of dust, insect frass, and soil collected from eight silkworm rearing facilities in Japan, as well as single silkworm rearing facilities in Indonesia and Malaysia, were subjected to DNA fingerprinting. PstI digests of total genomic DNA from each isolate were probed using the pAF 28 repetitive sequence. Among 18 isolates analyzed, 7 distinct DNA fingerprint groups were identified, including GTAb-2 isolated from rearing facilities in four prefectures of Japan. Aspergillus bombycis isolates share several features in common with domesticated yellow-green aspergilli, the koji molds used in traditional Oriental food fermentations, including a loose and deep colony texture, smooth-walled stipes, and the absence of sclerotia. Although aflatoxin is unknown from koji molds, all isolates of A. bombycis produced B and G aflatoxins. Aflatoxin has been linked to increased virulence in Aspergillus disease of silkworms, and there should be strong selection for aflatoxin production among clonal populations of A. bombycis adapted to silkworm cultivation. A hypothesis is offered that A. bombycis isolates from silkworm cultivation represent highly adapted forms of yet to be discovered “wild” populations that may infect Bombyx mandarina. Received: December 24, 2002 / Accepted: March 10, 2003 RID="*" ID="*" Disclaimer: Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the products, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable Acknowledgments We thank Dr. Akira Nakagiri, Institute for Fermentation, Osaka, for providing Aspergillus cultures isolated from diseased silkworms.     

High constitutive peroxidase activity and constitutive thermotolerance in <Emphasis Type="Italic">Neurospora crassa</Emphasis>

 During the isolation of mutations in the heat-inducible hsp70-1 gene of Neurospora crassa by RIP (repeat-induced point mutations), several transformants were generated by electroporation of conidia with a plasmid harboring an incomplete copy of this gene. One isolate, designated E-45, containing ectopically integrated hsp70-1 DNA, exhibited a slow growth rate, low-temperature sensitivity, constitutive thermotolerance (without prior heat shock), and high constitutive peroxidase activity. The constitutive form of peroxidase (CP) was distinguishable from the heat-inducible form (HIP) by immunoinactivation employing polyclonal antiserum against the latter enzyme and by electrophoretic resolution in nondenaturing polyacrylamide gels. This enzyme was purified to near homogeneity and some of its properties examined. The relative molecular mass of native CP was in the range of 118–136 kDa, as estimated by gel filtration analysis on size exclusion matrices, whereas SDS-PAGE analysis yielded a size of ∼37 kDa for the polypeptide. Substrate saturation kinetics studies were conducted using ABTS [2,2′-azino-bis (3-ethylbenzthiazole-6-sulfonic acid)] and H₂O₂ as substrates: K _m, V _max, and K _cat values for H₂O₂ were ∼22 μM, ∼447 nmol mg⁻¹, and 0.33 s⁻¹, respectively, and those for ABTS were ∼55 μM, ∼453 nmol mg⁻¹, and 0.3 s⁻¹, respectively. Guaiacol was not used as a substrate by this enzyme. CP peroxidase was shown to be a heme-containing enzyme, stable at temperatures up to 58°C. Received: August 5, 2002 / Accepted: January 22, 2003 Acknowledgments This work was supported by an operating grant from the Natural Sciences and Engineering Research Council (NSERC) of Canada (to M.K.). The financial support provided to A. M. in the form of a graduate studentship award by the AHFMR (Alberta Heritage Foundation for Medical Research) and of a graduate teaching assistantship to A. S. by the Department of Biological Sciences, University of Calgary, is gratefully acknowledged. Correspondence to:M. Kapoor     

Expression of hGM-CSF in silk glands of transgenic silkworms using gene targeting vector

The silk gland of the silkworm is a highly specialized organ that has the wonderful ability to synthesize and secrete silk protein. To express human granucyto-macrophage colony-stimulating factor (hGM-CSF) in the posterior silk glands of gene-targeted silkworms, a targeting vector pSK-FibL-L-A3GFP-PH-GMCSF-LPA-FibL-R was constructed, harboring a 1.2 kb portion of the left homogenous arm (FibL-L), a 0.5 kb portion of the right homogenous arm (FibL-R), fibroin H-chain-promoter-driven hGM-CSF and silkworm actin 3-promoter-driven gfp. The targeting vector was then introduced into the eggs of silkworm, and the transgenic silkworms were verified by PCR and DNA hybridization after being screened for the gfp gene. Western blotting analysis using an antibody against hGM-CSF demonstrated a specific band with a molecular weight of 22 kD in the silk glands of the G3 generation transgenic silkworms. The level of expression of hGM-CSF in the posterior silk glands of the G3 generation transgenic silkworms was approximately 2.70 ng/g of freeze-dried powdered posterior silk gland. These results showed that the heterologous gene could be introduced into the silkworm genome and expressed successfully. Further more, the exogenous genes existing in the G5 transgenic silkworm identified by PCR confirmed its integration stability. In addition, the silk glands containing expressed hGM-CSF performed the function of significantly increasing leukocyte count of CY-treated mice in a time-and-dose-dependent manner.     

Toyama Kametaro and Vernon Kellogg: Silkworm Inheritance Experiments in Japan,Siam, and the United States, 1900–1912

Japanese agricultural scientist Toyama Kametaro’s report about the Mendelian inheritance of silkworm cocoon color in Studies on the Hybridology of Insects (1906) spurred changes in Japanese silk production and thrust Toyama and his work into a scholarly exchange with American entomologist Vernon Kellogg. Toyama’s work, based on research conducted in Japan and Siam, came under international scrutiny at a time when analyses of inheritance flourished after the “rediscovery” of Mendel’s laws of heredity in 1900. The hybrid silkworm studies in Asia attracted the attention of Kellogg, who was concerned with how experimental biology would be used to study the causes of natural selection. He challenged Toyama’s conclusions that Mendelism alone could explain the inheritance patterns of silkworm characters such as cocoon color because they had been subject to hundreds of years of artificial selection, or breeding. This examination of the intersection of Japanese sericulture and American entomology probes how practical differences in scientific interests, societal responsibilities, and silkworm materiality were negotiated throughout the processes of legitimating Mendelian genetics on opposite sides of the Pacific. The ways in which Toyama and Kellogg assigned importance to certain silkworm properties show how conflicting intellectual orientations arose in studies of the same organism. Contestation about Mendelism took place not just on a theoretical level, but the debate was fashioned through each scientist’s rationale about the categorization of silkworm breeds and races and what counted as “natural.” This further mediated the acceptability of the silkworm not as an experimental organism, but as an appropriately “natural” insect with which to demonstrate laws of inheritance. All these shed light on the challenges that came along with the use of agricultural animals to convincingly articulate new biological principles.     

Assessing the heat tolerance of 17 beef cattle genotypes

Cattle production plays a significant role in terms of world food production. Nearly 82% of the world’s 1.2 billion cattle can be found in developing countries. An increasing demand for meat in developing countries has seen an increase in intensification of animal industries, and a move to cross-bred animals. Heat tolerance is considered to be one of the most important adaptive aspects for cattle, and the lack of thermally-tolerant breeds is a major constraint on cattle production in many countries. There is a need to not only identify heat tolerant breeds, but also heat tolerant animals within a non-tolerant breed. Identification of heat tolerant animals is not easy under field conditions. In this study, panting score (0 to 4.5 scale where 0 = no stress and 4.5 = extreme stress) and the heat load index (HLI) [HLI_BG<25°C = 10.66 + 0.28 × rh + 1.30 × BG – WS; and, HLI _{BG> 25°C} = 8.62 + 0.38 × rh + 1.55 × BG – 0.5 × WS + e^{(2.4 – WS)}, where BG = black globe temperature (^oC), rh = relative humidity (decimal form), WS = wind speed (m/s) and e is the base of the natural logarithm] were used to assess the heat tolerance of 17 genotypes (12,757 steers) within 13 Australian feedlots over three summers. The cattle were assessed under natural climatic conditions in which HLI ranged from thermonuetral (HLI < 70) to extreme (HLI > 96; black globe temperature = 40.2°C, relative humidity = 64%, wind speed = 1.58 m/s). When HLI > 96 a greater number (P < 0.001) of pure bred Bos taurus and crosses of Bos taurus cattle had a panting score ≥ 2 compared to Brahman cattle, and Brahman-cross cattle. The heat tolerance of the assessed breeds was verified using panting scores and the HLI. Heat tolerance of cattle can be assessed under field conditions by using panting score and HLI.     

The screening of mutants and construction of mutant library for <Emphasis Type="Italic">Oryza sativa</Emphasis> cv. Nipponbare via ethyl methane sulphonate inducing

Following the sequencing of rice genome, the functional analysis of unidentified genes is gaining wide importance. Mutant isolation is one of the effective ways to isolate and clone the target genes and analyze their functions. To find the various mutants in the same genetic background, seeds of Oryza sativa cv. Nipponbare were treated with ethyl methane sulphonate (EMS). A total of 1056 mutants were screened for five categories in M₂ generation with the seedling frequency of 26.29‰ at three-leaf stage, but only 264 mutants were verified in M₃ generation with a frequency of 6.57‰. Among the mutants verified in M₃ generation, the frequency of leaf mutation was the highest (2.22‰), followed by seedling height (1.74‰) and the abiotic stress tolerance mutant (1.47‰). Nineteen characteristic mutations, including a big group of abiotic stress tolerant mutants such as herbicide resistant, salt tolerant and drought tolerant were identified at this stage. By observation of rice growth characteristics at different developmental stages, another 220 mutants have been isolated and verified in the M₃ generation with the mutant frequency of 53.9‰ covering about 28 mutant traits. Among those identified, the highest frequencies were obtained for appearance of brown rice mutant with 18.37‰, followed by panicle mutant with 13.47‰, and grain mutants with 9.06‰. All the mutants screened above were suitable for gene function analysis and for utilization in agronomy.     

Stiffness and checking of <Emphasis Type="Italic">Eucalyptus nitens</Emphasis> sawn boards: genetic variation and potential for genetic improvement

A trial was undertaken to assess the extent to which variation in sawn-board quality traits of plantation-grown Eucalyptus nitens is under genetic control and amenable to genetic improvement. Five hundred and sixty trees from 129 families and three central Victorian races were sampled from an open-pollinated progeny trial in Tasmania, Australia. Acoustic wave velocity (AWV) was assessed on standing trees and sawlogs. Wedges from disks extracted from sawlogs were assessed for basic density and checking. Processed boards from 496 of the trees were assessed for board stiffness (static modulus of elasticity, MOE), and internal and surface checking. Genetic differences among races were significant for AWV and MOE traits. The Southern race had the highest mean values for these traits. Significant additive genetic variation within races was observed in all traits, demonstrating that the quality of plantation-grown E. nitens boards could be improved through breeding. Estimated narrow-sense heritabilities were 0.85 for standing-tree AWV, 0.71 for log AWV, 0.37 for board MOE, and ranged from 0.20 to 0.52 for checking traits. A strongly positive genetic correlation (r _g = 1.05) was observed between standing-tree AWV and board MOE, indicating that AWV could be used as a selection trait to improve E. nitens board stiffness. The genetic correlation between basic density and board MOE was also positive (r _g = 0.62). However, a significant and adverse genetic correlation (r _g = 0.61) was identified between basic density and surface check length. Wood stiffness and checking traits were more-or-less genetically independent, and genetic correlations between surface and internal checking were positive but only moderate (r _g = 0.48–0.52).