eResearch Archive: reaching global agricultural communities

Queensland Department of Primary Industries and Fisheries Library achieved a significant breakthrough in the provision of Open Access to Australian publicly funded research with the launch of its eResearch Archive (eRA). With more than one thousand publication records, journal articles, conferences papers and research reports now available to farmers, industry representatives, academics, researchers, students and members of the public throughout the world, the archive is the first web accessible multidisciplinary science institutional repository produced by an Australian government department.

Sigastus weevil - an emerging pest of macadamias in north Queensland

A large weevil was found infesting macadamia nuts on the Atherton Tableland during the 1994/95 season. It was unrepresented in various Australian insect collections but thought to belong to the genus Sigastus. This paper reports some preliminary studies on its biology, pest status and control. From 4-6 weeks after first nut-set adult females commence laying single eggs through the husk, after first scarifying an oviposition site. The nut stalk is then cleaved leading to rapid abscission. Nuts were generally attacked up until hard shell formation. Weevil larvae consumed whole kernels, with % survival higher and larval duration shorter in larger nuts. Infestation rates increased with increasing nut diameter, reaching 72.8% of fallen nuts by mid-October. A crop loss of 30% could be attributed to weevils in an unsprayed orchard. However, adult weevils are very susceptible to both carbaryl and methidathion sprays. In addition, exposure of infested nuts to full sunlight over several weeks kills 100% of larvae. Crops should be surveyed for weevil damage from the 5-10 mm diameter stage until mid-December. Methidathion used as an initial spray for fruitspotting bugs should provide control. Organic growers are advised to sweep infested nuts into mown interrows where solarisation will kill larvae.

Fruit maturity and soundness relevant to feeding choice by fruit-piercing moths (Lepidoptera: Noctuidae) in citrus crops in northeast Australia

Fruit-piercing moths are significant pests of a range of fruit crops throughout much of the world's tropics and subtropics. Feeding damage by the adult moths is most widely reported in varieties of citrus. In the years 2003 and 2004, fruit-piercing moth activity was observed regularly at night in citrus crops in northeast Australia, to determine the level of maturity (based on rind colour) and soundness of fruit attacked. 'Navelina' navel and 'Washington' navel orange, grapefruit and mixed citrus crops were assessed, and fruit was rated and placed into five categories: green, colouring, ripe, overripe and damaged. There were no statistical differences in the percentage of fruit attacked in each category across crops. However, within the individual crops significant proportions of green 'Navelina' fruit (58.7%) and green mixed citrus (57.1%) were attacked in 2004. Among all the crops assessed, 25.1% of moth feeding occurred on overripe or damaged fruit. Crops started to be attacked at least 8 weeks before picking, but in two crops there were large influxes of moths (reaching 27 and 35 moths/100 trees, respectively) immediately before harvest. Moth activity was most intense between late February and late March. Eudocima fullonia (Clerck) represented 79.1% of all moths recorded on fruit, with Eudocima materna (L.), Eudocima salaminia (Cramer) and Serrodes campana (Guen.) the only other species observed capable of inflicting primary damage. Our results suggest that growers should monitor moth activity from 8 weeks before harvest and consider remedial action if moth numbers increase substantially as the crop matures or there is a history of moth problems. The number of fruit pickings could be increased to progressively remove ripe fruit or early harvest of the entire crop contemplated if late influxes of moths are known.

Measuring the traction profile on sportsfields: Equipment development and testing

Traction is recognised as an important component of the overall playability and safety of a sportsfield. It relates to the "grip", or footing, provided through an athlete's shoe when in contact with the surface, and is normally measured by the torque generated when a weighted studded disc apparatus is dropped onto the turf and twisted manually. This paper describes the development of an automated traction tester, which mechanises the dropping and twisting of the weighted studded disc. By standardising these operational stages, more repeatable and reliable results can be expected than from the original hand-operated design where positioning of the disc and speed of rotation are controlled manually and so can vary from one measurement to the next. As well as measuring the maximum torque reached during rotation of the studded disc, the automated traction tester generates a profile of torque showing changes over time and calculates the angle through which the studded disc moved before reaching maximum torque. These aspects are now covered by a utility patent (PAT/AU/2004270767). Use of the automated traction tester is illustrated by comparative data for a range of warm-season turfgrasses, by comparisons of traction under different surface conditions generated by wear on Cynodon dactylon cultivars, and by the effects of environment, management and playing patterns on traction across a multi-use sports stadium.

Vermiculite improves early development and survival of low chill stone-fruit embryos rescued in vitro

There are many reports of efficient embryo germination and the method has been optimized to suit subtropical low chill genotypes. However the subsequent growth, vigor, and ability of germinated embryos to develop and survive acclimatization is rarely reported. Many germinated embryos do not survive acclimatization, develop slowly, or fail to develop normally. Methods to improve plant development from in vitro embryo cultures are needed to improve the number of plants that survive to be useful in breeding programs. This paper describes an improved method of embryo rescue that significantly increases embryo shoot and root development that leads to increased plant survival. Four treatments: Woody Plant Media (WPM) solidified with agar, vermiculite with liquid WPM, vermiculite with WPM plus agar, and conventional stratification, were evaluated for embryo growth and subsequent plantlet development and survival for two low-chill peach and one low-chill nectarine cultivar. Highly significant improvements were found for shoot and root development of seedlings germinated in vermiculite based media compared to embryos germinated in conventional agar-based media. Vermiculite with WPM and agar improved plantlet growth subsequent to in vitro culture and significantly increased survival of germinated embryos resulting in more plants reaching the field.

Premature fruit softening, a major physiological problem of persimmon in subtropical Australia.

Premature or abnormal softening of persimmon fruit within 3-7 days after harvest is a major physiological problem of non-astringent persimmon cultivars grown in subtropical regions of Australia. Up to 30% of consignments may soften rapidly frequently overnight, often resulting in the flesh becoming very soft, completely translucent, and impossible to handle. Incidence of premature soft fruit can vary with season and production location. To study the incidence of this problem, we conducted surveys of fruit harvested from five environmentally-diverse regions of Australia over a two-year period. We found wide variation in the rate of both premature softening and normal softening with differences of up 37 days between orchards in percentage of fruit reaching 50% soft. We found that the rate of fruit softening was exacerbated by lower calcium concentrations at fruit set, shorter fruit development periods and heavier rainfall during the fruit development period. The implications of our findings, in terms of orchard management, export and domestic marketing strategies are discussed.

Objective `Safe' Grazing Capacities for South-West Queensland Australia: Development of a Model for Individual Properties

Few tools are available to assist graziers, land administrators and financiers in making objective grazing capacity decisions on Australian rangelands, despite existing knowledge regarding stocking rate theory and the impact of stocking rates on land condition. To address this issue a model for objectively estimating 'safe' grazing capacities on individual grazing properties in south-west Queensland was developed. The method is based on 'safe' levels of utilisation (15%-20%) by domestic livestock of average annual forage grown for each land system on a property. Average annual forage grown (kglha) was calculated as the product of the rainfall use efficiency (kglhdmm) and average annual rainfall (mm) for a land system. This estimate included the impact of tree and shrub cover on forage production. The 'safe' levels of forage utilisation for south- west Queensland pastures were derived from the combined experience of (1) re-analysis of the results of grazing trials, (2) reaching a consensus on local knowledge and (3) examination of existing grazing practice on 'benchmark' grazing properties. We recognise the problems in defining, determining and using grazing capacity values, but consider that the model offers decision makers a tool that can be used to assess the grazing capacity of individual properties.

Post head-emergence frost resistance of barley genotypes in the northern grain region of Australia.

Post head-emergence frost causes substantial losses for Australian barley producers. Varieties with improved resistance would have a significant positive impact on Australian cropping enterprises. Five barley genotypes previously tested for reproductive frost resistance in southern Australia were tested, post head-emergence, in the northern grain region of Australia and compared with the typical northern control cultivars, Gilbert and Kaputar. All tested genotypes suffered severe damage to whole heads and stems at plant minimum temperatures less than -8degreesC. In 2003, 2004 and 2005, frost events reaching a plant minimum temperature of ~-6.5degreesC did not result in the complete loss of grain yield. Rather, partial seed set was observed. The control genotype, Gilbert, exhibited seed set that was greater than or equal to that of any genotype in each year, as did Kaputar when tested in 2005. Thus, Gilbert and Kaputar were at least as resistant as any tested genotype. This contrasts with trial results from the southern grain region where Gilbert was reported to be less resistant than Franklin, Amagi Nijo and Haruna Nijo. Hence, rankings for post head-emergence frost damage in the northern grain region differ from those previously reported. These results indicate that Franklin, Amagi Nijo and Haruna Nijo are not likely to provide useful sources of frost resistance or markers to develop improved varieties for the northern grain region of Australia.

Increasing anthocyanin content in Queen Garnet plum and correlations with in-field measures

While plums are traditionally bred for fresh fruit traits such as size, sweetness, yield and disease resistance the Queensland Government breeding program for Japanese plum ( Prunus salicina Lindl.) also selected for anthocyanin content to develop a new plum selection named 'Queen Garnet'. When ripe or overripe, it has a near black skin and deep red flesh colour, which when combined, result in exceptionally high anthocyanin content, reaching up to 277 mg/100 g fruit. The skin fraction contributes 36-66% of the total anthocyanin content of fruit. The plum is now being commercially grown to be processed into a range of functional products from food colourants to premium health products. These are sold on the basis of anthocyanin and antioxidant content. Protocols for increasing anthocyanin content have therefore been researched to maximise the total anthocyanin yield rather than fresh fruit weight and taste. The principal approach is through selective harvest of overripe plums high in colour, although post-harvest storage at 21°C results in further anthocyanin synthesis. Modified processing is also required to ensure recovery of anthocyanins from the skin fraction. The plum products have entered testing for assessing health properties beginning with an initial proof of in vivo bioavailability of the anthocyanins.

Increase in β-Ionone, a Carotenoid-Derived Volatile in Zeaxanthin-Biofortified Sweet Corn

Carotenoids are responsible for the yellow color of sweet corn (Zea mays var. saccharata), but are also potentially the source of flavor compounds from the cleavage of carotenoid molecules. The carotenoid-derived volatile, -ionone, was identified in both standard yellow sweet corn (Hybrix5) and a zeaxanthin-enhanced experimental variety (HZ) designed for sufferers of macular degeneration. As -ionone is highly perceivable at extremely low concentration by humans, it was important to confirm if alterations in carotenoid profile may also affect flavor volatiles. The concentration of -ionone was most strongly correlated (R2 > 0.94) with the -arm carotenoids, -carotene, -cryptoxanthin, and zeaxanthin, and to a lesser degree (R2 = 0.90) with the α-arm carotenoid, zeinoxanthin. No correlation existed with either lutein (R2 = 0.06) or antheraxanthin (R2 = 0.10). Delaying harvest of cobs resulted in a significant increase of both carotenoid and -ionone concentrations, producing a 6-fold increase of ?-ionone in HZ and a 2-fold increase in Hybrix5, reaching a maximum of 62g/kg FW and 24g/kg FW, respectively.

Structural Veneer Based Composite Products from Hardwood Thinning - Part II: Testing of Hollow Utility Poles

Australian utility pole network is aging and reaching its end of life, with 70% of the 5 million poles currently in-service nationally installed within the 20 years following the end of World War II. The estimated investment required for the replacement or remedial maintenance of the aging 3.5 millions poles is as high as 1.75 billion dollars. Additionally, an estimated 21,700 high-durability new poles are required each year, representing further investment of 13.5 million dollars per year. Yet, agreements which progressively phase out logging of native forests around Australia have been signed, giving the industry about 25 years to make the transition from Crown native forests to plantations and private forests. As utility poles were traditionally cut from native forest hardwood species, finding solutions to source new poles currently presents a challenge. This paper presents tests on Veneer Based Composite hardwood hollow utility poles manufactured from Gympie messmate (Eucalyptus cloeziana) plantation thinning. Small diameter poles of nominal 115 mm internal diameter and 15 mm wall-thickness were manufactured in two half-poles butt jointed together, using 9 veneers per halfpole. The poles were tested in bending and shear, and experimental test results are presented. The mechanical performance of the hollow poles is discussed and compared to hardwood poles cut from mature trees and of similar size. Future research and different options for improving the current concept are proposed in order to provide a more reliable and cost effective technical solution to the current shortage of utility poles. © RILEM 2014.

Implications of geometric plasticity for maximizing photosynthesis in branching corals

Reef-building corals are an example of plastic photosynthetic organisms that occupy environments of high spatiotemporal variations in incident irradiance. Many phototrophs use a range of photoacclimatory mechanisms to optimize light levels reaching the photosynthetic units within the cells. In this study, we set out to determine whether phenotypic plasticity in branching corals across light habitats optimizes potential light utilization and photosynthesis. In order to do this, we mapped incident light levels across coral surfaces in branching corals and measured the photosynthetic capacity across various within-colony surfaces. Based on the field data and modelled frequency distribution of within-colony surface light levels, our results show that branching corals are substantially self-shaded at both 5 and 18 m, and the modal light level for the within-colony surface is 50 mu mol photons m(-2) s(-1). Light profiles across different locations showed that the lowest attenuation at both depths was found on the inner surface of the outermost branches, while the most self-shading surface was on the bottom side of these branches. In contrast, vertically extended branches in the central part of the colony showed no differences between the sides of branches. The photosynthetic activity at these coral surfaces confirmed that the outermost branches had the greatest change in sun- and shade-adapted surfaces; the inner surfaces had a 50 % greater relative maximum electron transport rate compared to the outer side of the outermost branches. This was further confirmed by sensitivity analysis, showing that branch position was the most influential parameter in estimating whole-colony relative electron transport rate (rETR). As a whole, shallow colonies have double the photosynthetic capacity compared to deep colonies. In terms of phenotypic plasticity potentially optimizing photosynthetic capacity, we found that at 18 m, the present coral colony morphology increased the whole-colony rETR, while at 5 m, the colony morphology decreased potential light utilization and photosynthetic output. This result of potential energy acquisition being underutilized in shallow, highly lit waters due to the shallow type morphology present may represent a trade-off between optimizing light capture and reducing light damage, as this type morphology can perhaps decrease long-term costs of and effect of photoinhibition. This may be an important strategy as opposed to adopting a type morphology, which results in an overall higher energetic acquisition. Conversely, it could also be that maximizing light utilization and potential photosynthetic output is more important in low-light habitats for Acropora humilis.

The avocado problem solver field guide

This guide has been produced to assist Australian avocado growers and others involved in the avocado supply chain to identify the wide range of pests, diseases, nutrient deficiencies and toxicitites, and other disorders that may affect orchards and the quality of fruit reaching the consumer

Lost and found: recovery of the holotype of the ocellated angelshark, Squatina tergocellatoides Chen, 1963 (Squatinidae), with comments on western Pacific squatinids

The ocellated angelshark, Squatina tergocellatoides, Chen, 1963 is redescribed from the holotype, which was thought to be lost. Its recent recovery has allowed for a revised description, including new data, and comparison to other Western Pacific squatinids. Squatina tergocellatoides can be distinguished from its congeners by three pairs of prominent large black spots, each with a diameter greater than eye length; two on each pectoral fin at anterior and posterior angles and one on each side near the tail base; another three pairs of lesser defined spots, one large spot on base of each dorsal fin and one located laterally on each side of tail located below first dorsal fin. Ventral surface is uniformly white to cream coloured, and margins of pectoral fins and tail similar in colour to dorsal side. Pectoral fins with angular lateral apices and rounded posterior lobe, pelvic fin tips not reaching origin of first dorsal fin, strongly fringed nasal barbels, small inter-orbital space, head and mouth lengths, broad internarial width and pelvic fin base, a very small pelvic girdle width, and a caudal fin with triangular ventral lobe greater in length than dorsal lobe. Comments on additional specimens are provided, as well as observations on biogeography. A review of western Pacific squatinids is also provided.

Structural Veneer Based Composite Products from Hardwood Thinning - Part I: Background and Manufacturing

In Australia, plantation forests have increased in area by around 50% in the last 10 years. While this expansion has seen a modest 8% increase for softwoods, hardwood plantations have dramatically increased by over 150%. Hardwood plantations grown for high quality sawn timber are slow to mature, with a crop rotation time potentially reaching 35 years. With this long lead-time, each year the risk from fire, pests and adverse weather events dramatically increases, while not translating into substantially higher financial returns to the grower. To justify continued expansion of Australia's current hardwood plantation estate, it is becoming necessary to develop higher value end-uses for both pulpwood and smaller 'sawlog' resources. The use of the low commercial value stems currently culled during thinning appears to be a necessary option to improve the industry profitability and win new markets. This paper provides background information on Australian forests and plantations and gives an overview of potential uses of Australian hardwood plantation thinning logs, as their mechanical properties. More specifically, this paper reports on the development of structural Veneer Based Composite (VBC) products from hardwood plantation thinning logs, taking advantage of a recent technology developed to optimise the processing of this resource. The process used to manufacture a range of hollow-form veneer laminated structural products is presented and the mechanical characteristics of these products are investigated in the companion paper. The market applications and future opportunities for the proposed products are also discussed, as potential benefits to the timber industry. © RILEM 2014.