Peter D. Kube

Extending near infrared reflectance(NIR) pulp yield calibrations to new sites and species

Abstract Recently, we demonstrated that the accuracy of pulp yield predictions for wood samples from a site (Gog) new to their calibration (Tasmania‐wide Eucalyptus nitens) was greatly improved by adding five Gog samples to the calibration set. In this study we investigated the addition of Gog samples to the Tasmania‐wide E. nitens set, with the aim of further improving predictive accuracy. It was demonstrated that the addition of a single Gog sample to the Tasmania‐wide calibration set was sufficient to greatly reduce predictive errors and that the inclusion of at least 3 Gog samples in the Tasmania‐wide set was sufficient to give relatively stable predictive errors. The addition of different sets of 5 Gog samples to the Tasmania‐wide calibration, however, caused predictive errors to vary between sets. The standard deviation of pulp yield for the prediction set (20 Gog samples) was important, with sets having the largest standard deviations giving the best predictive statistics. Finally, the Tasmania‐wide E. nitens calibration was enhanced using samples from a different species (Eucalyptus globulus) and applied successfully to other E. globulus samples.

Genetic Diversity of Cultured, Naturalized, and Native Pacific Oysters, Crassostrea Gigas, Determined from Multiplexed Microsatellite Markers

ABSTRACT Ten polymorphic microsatellite loci were multiplexed to analyze a total of 343 Pacific oysters (Crassostrea gigas) sampled from native (Japan and Korea), naturalized (France and Australia), and cultured (3 Australian programs) populations. Genetic diversity was high within the native and naturalized populations (average allelic richness, 18.7; expected heterozygosity, 0.89), but lower within samples from hatchery populations (allelic richness, 12.3; expected heterozygosity, 0.84). A significant decrease in diversity was found within Australian cultured populations. However, diversity was shown to be similar in samples from a well-managed, family-based selective breeding population and commercial hatchery mass spawning populations. The Bayesian analysis of population structure found no difference between native and naturalized samples, which, together with other results, indicate that the naturalized populations have not changed genetically since their introduction. This suggests that naturalized populations can provide a good source of genetic diversity for breeding programs.

Populations of Pacific Oysters Crassostrea gigas Respond Variably to Elevated CO2 and Predation by Morula marginalba

Ocean acidification is anticipated to decrease calcification and increase dissolution of shelled molluscs. Molluscs with thinner and weaker shells may be more susceptible to predation, but not all studies have measured negative responses of molluscs to elevated pCO2. Recent studies measuring the response of molluscs have found greater variability at the population level than first expected. Here we investigate the impact of acidification on the predatory whelk Morula marginalba and genetically distinct subpopulations of the Pacific oyster Crassostrea gigas. Whelks and eight family lines of C. gigas were separately exposed to ambient (385 ppm) and elevated (1000 ppm) pCO2 for 6 weeks. Following this period, individuals of M. marginalba were transferred into tanks with oysters at ambient and elevated pCO2 for 17 days. The increase in shell height of the oysters was on average 63% less at elevated compared to ambient pCO2. There were differences in shell compression strength, thickness, and mass among family lines of C. gigas, with sometimes an interaction between pCO2 and family line. Against expectations, this study found increased shell strength in the prey and reduced shell strength in the predator at elevated compared to ambient pCO2. After 10 days, the whelks consumed significantly more oysters regardless of whether C. gigas had been exposed to ambient or elevated CO2, but this was not dependent on the family line and the effect was not significant after 17 days. Our study found an increase in predation after exposure of the predator to predicted near-future levels of estuarine pCO2.

Dryland tree establishment in Central Australia

Abstract Since 1974 a series of dryland species trials have been established in the vicinity of Alice Springs to determine which species have most potential for dryland amenity planting or for biomass production. In all trials seedlings were irrigated only during the 6–9 month establishment phase. The initial screening trial indicated that the acacias as a group had good early survival and growth, but generally lost vigour after 3–7 years. Eucalypts had superior biomass production and longevity relative to the other genera tested. In particular the ‘inland and northern box’ group demonstrated an ability to succeed on a variety of sites. These species, along with Eucalyptus gongylocarpa and E. gamophylla, have perhaps the greatest potential for use under dryland conditions in Central Australia. Concurrent trials evaluated responses to fertilization and to the use of water-absorbing polymers in dryland tree establishment. Although a positive response to fertilizer application was recorded, the use of polymers caused no significant increase in seedling health or survival for the species tested.

Application of Near-Infrared Reflectance Spectroscopy for the Rapid Chemical Analysis of Sydney Rock Oyster (Saccostrea Glomerata) and Pacific Oyster (Crassostrea gigas)

ABSTRACT Near-infrared IR reflectance spectroscopy (NIRS) was applied to the compositional analysis of oysters (Crassostrea gigas and Saccostrea glomerata). Homogenized meat samples of 332 oysters were scanned by NIRS, subsamples were analyzed chemically, and, by combining the sets of information, calibration models were developed to allow prediction of proximate composition (moisture, protein, glycogen, and fat). Predicted and actual (chemically measured) data in independent validation sample sets were compared using R 2 and the ratio of the SE of chemical data to the SE of NIRS prediction (RPD). For S. glomerata, models gave excellent prediction for all components (R 2 = 0.95–0.97, RPD = 2.7–5.5). Prediction within the C. gigas validation set was generally less precise, but still very good for all components (R 2 = 0.92–0.96, RPD = 2.7–4.8). With a smaller subset of samples (n = 48), prediction models were also developed for estimating concentration of polyunsaturated fatty acid and long-chain polyunsaturated fatty acid (R 2 = 0.94 and 0.93, respectively). The major advantages of the methodology are its speed—250—300 samples can be analyzed simultaneously for all components each day—and cost-effectiveness when a large number of samples (e.g., several hundred or more per year) are analyzed. Therefore, the method is ideally suited to applications requiring the rapid analysis of many individuals, such as selective breeding programs for which chemical compositional data can provide information on traits associated with oyster condition or quality.

Genetic resistance in Pinus radiata to defoliation by the pine aphid Essigella californica

Summary The Monterey pine aphid, Essigella californica, has been associated with extensive defoliation and growth losses in radiata pine plantations in south-eastern Australia since it was first detected in 1998. HVP Plantations (HVPP) observed variation in the level of defoliation between clones in clonal seed orchards and archives, and initiated a program of assessment of progeny trials. Between 2001 and 2005, defoliation was assessed in a provenance trial, a subset of clones within a seed orchard, and 18 progeny trials (some repeatedly). Needle retention in upper crowns was scored on a scale of 1–10, rather than needle loss, because this ensured higher scores equated to the desirable state of the assessed trait. There were significant differences in the extent of retained foliage between populations, and between subpopulations within populations. The inland northern (Coastways Ranch) sub-population of Año Nuevo population had the highest level of retained foliage in the upper crown (mean score of 8.3), and the northern (Pico Creek, Haarst Ranch) sub-population of the Cambrian population had the least retained foliage (5.0). Estimates of heritability from progeny trials ranged from 0 to 0.9, and averaged about 0.5 in trials where there was a significant family (maternal) effect. Cross-site analysis using a family model resulted in an overall heritability of 0.4. Genetic correlations between assessments across two trials in 2004 and those in 2001 and 2003 were high, suggesting that defoliation due to aphids is consistent across years and can be considered to be the same trait. In addition to the observed differences between provenances and families, there were significant differences between clones, and average levels of retained foliage among clones ranged from 1.9 to 9.4. HVPP has used this information to develop an aphid-resistant breed of radiata pine which has been deployed on an increasing scale since 2005 into the most susceptible areas of its Victorian estate.

Can Greenlip (Haliotis laevigata) Abalone Breeding Programs Tolerate Fluctuations in Reproductive Performance

ABSTRACT Fluctuations in reproductive performance (i.e., spawning success, hatching rate, larval survival) are a common occurrence in abalone breeding programs, in particular during the early stages of their development. Such fluctuations affect the numbers of families available for progeny testing and selection, and can have consequences for genetic gains and inbreeding. We used stochastic computer simulations to understand how genetic gains and levels of inbreeding are affected when greenlip (Haliotis laevigata) breeding programs encounter varying severity and frequency of reproductive failure. We simulated breeding programs for greenlip abalone with both conservative and aggressive selection approaches over 35 y (10 generations). Without reproductive failure, genetic improvements of 36%–55% could be achieved after 10 y of selection in a single trait in a commercial abalone breeding program with a conservative selection approach, and gains of twice that could be achieved with a selection approach that allowed high rates of inbreeding. A conservative selection approach would be sustainable even at high rates of reproductive failure, whereas a more aggressive approach would lead to nearly twice the recommended level of inbreeding. It was concluded that breeding programs for greenlip abalone may be buffered against unexpected fluctuations in reproductive performance if the selection approach is chosen strategically.

Sensory and Physicochemical Assessment of Wild And Aquacultured Green and Black Lip Abalone (Haliotis laevigata and Haliotis rubra)

ABSTRACT Abalone is a highly valued food product in many countries, in large part a result of its unique sensory properties. Wild and cultured abalone both attract premium prices, but generally this is not based on sensory characteristics. Yet, abalone aquaculture is developing to provide an alternative to a dwindling supply of wild abalone, and this provides an opportunity to optimize the sensory properties if they are better understood. In most natural food products, farming practices and growing environment are responsible for the sensory properties of the final product; therefore, the comparison of both wild and aquacultured abalones sensory characteristics could contribute to a better understanding of the impact of the growing and farming practices on the sensory properties. Our study focused on the development of a descriptive sensory analysis methodology to measure abalone sensory properties, and the observation of differences among the abalone sampled. Wild and aquacultured abalone were prepared according to a standardized cooking protocol. A sensory panel of trained assessors developed and defined a descriptive vocabulary and a method of assessment, and then quantified the sensory properties of abalone. A vocabulary of 16 terms describing aroma, texture, flavor, and aftertaste of the abalone was developed. Very significant differences were found between abalone sourced from the wild and aquacultured abalone from different sources. The wild-caught blacklip abalone, which were larger in size, were perceived as more firm, springy, and chewy, but also rated significantly higher in aroma, flavor, and aftertaste impact as well as earthy and metallic flavors. Significant differences in sensory properties were also found between cultured abalone fed different diets. Compositional analysis showed significant differences between abalone in their content of glycogen (range, 4.8%–23.2% of dry weight (DW)), moisture (69.4%–73.7% live weight), and taste-active free amino acids, especially glycine (3.4–18.2 mg/g DW) and glutamate (1.0–3.6 mg/g DW). Correlations were found between sensory attributes and some chemical compounds. This study indicates that growing conditions as well as growing techniques may have a large influence on abalone sensory characteristics. However, because the design of the study was not balanced for key growth or production variables, additional studies are required to identify and quantify which factors were most influential. The descriptive sensory method developed was successful in measuring the sensory properties of abalone and can now be applied more broadly.

Evolution of Sex Determination Loci in Atlantic Salmon

Teleost fish exhibit a remarkable diversity in the control of sex determination, offering the opportunity to identify novel differentiation mechanisms and their ecological consequences. Here, we perform GWAS using 4715 fish and 46,501 SNP to map sex determination to three separate genomic locations in Atlantic salmon (Salmo salar). To characterize each, whole genome sequencing was performed to 30-fold depth of coverage using 20 fish representing each of three identified sex lineages. SNP polymorphism reveals male fish carry a single copy of the male specific region, consistent with an XX/XY or male heterogametric sex system. Haplotype analysis revealed deep divergence between the putatively ancestral locus on chromosome 2, compared with loci on chromosomes 3 and 6. Haplotypes in fish carrying either the chromosome 3 or 6 loci were nearly indistinguishable, indicating a founding event that occurred following the speciation event that defined Salmo salar from other salmonids. These findings highlight the evolutionarily fluid state of sex determination systems in salmonids, and resolve to the sequence level differences in animals with divergent sex lineages.