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Background and aims: Boron (B) deficiency depresses grain set and grain yield of wheat and maize while having little effect on their vegetative growth. This paper describes effects of B deficiency in rice and how these vary with planting season and variety. Methods: Three rice varieties (KDML105, CNT1, SPR1) were grown in sand culture without (B0) and with 10 μM (B10) B added to the nutrient solution, in the cool season of 2007/08 and 2008/09 and the hot season of 2011 in Chiang Mai, Thailand (18°47′N, 98°59′E). Boron responses were measured in growth and yield parameters, pollen viability and B concentration of the flag leaf and anthers at anthesis. Results: Grain weight was strongly depressed by B deficiency ranging from 28 % in SPR1 to 79 % in CNT1, and the yield was much lower in the cool season than in the hot season plantings. The variation in grain weight was closely associated with grain set and number of spikelets but not with shoot dry weight or tillering. Grain set was closely related to pollen viability, and both were increased with increasing anther B concentration at >20 mg B kg-1. In addition to its adverse effect on grain set, B deficiency also depressed grain filling and weight of individual grains in rice. Conclusions: Boron deficiency depressed rice grain yield through adverse effects on reproductive growth, panicle and spikelet formation and grain filling, in addition to grain set as in wheat and maize.

The utilization of dwarfing genes Rht-B1b and Rht-D1b in wheat significantly increased grain yield and contributed to the "green revolution". However, the benefit of Rht-B1b and Rht-D1b in drought environments has been debated. Although quantitative trait loci (QTL) for kernel number per spike (KN) and thousand-grain weight (TGW) have been found to be associated with Rht-B1 and Rht-D1, the confounding effect of environmental variation has made a direct association difficult to find. In this study, we used a doubled haploid population (225 lines) of Westonia × Kauz, in which both Rht-B1b (Kauz) and Rht-D1b (Westonia) segregated. The purpose of the study was to determine the interaction of Rht-B1 and Rht-D1 with grain yield components, namely KN and TGW, and to investigate genotype-by-environment interactions in glasshouse and field trials conducted in 2010 and 2011 in Western Australia. A genetic map of 1,156 loci was constructed using 195 microsatellite markers, two gene-based markers for Rht-B1 and Rht-D1, and 959 single nucleotide polymorphisms. The major QTL for TGW and KN were strongly linked to Rht-B1 and Rht-D1 loci and the positive effects were associated with the wild-type alleles, Rht-B1a and Rht-D1a. The major QTL of TGW were on chromosome 2D and 4B. The significant genetic effects (14.6-22.9 %) of TGW indicated that marker-assisted selection for TGW is possible, and markers gwm192a (206 bp) or gwm192b (236 bp) can be used as indicators of high TGW. For KN, one major QTL was detected on chromosome 4D in the analysis across three environments. The association of the wild-type alleles Rht-B1a and Rht-D1a in drought environments is discussed.

Tree declines are increasingly being reported around the world. Since the 1990’s Eucalyptus gomphocephala (tuart) has suffered a significant decline in the Yalgorup region, approximately 100 km south of Perth Western Australia. The complexity of many tree declines makes diagnosis difficult. Robust tools are needed to help identify factors contributing to tree declines. Two experiments tested the effect of trunk applied phosphite, nutrients and combined phosphite and nutrient treatments on wild declining E. gomphocephala. Treatment efficacy was tested as a management option to mitigate crown decline and as an explorative tool to help determine disease causality. Experiment 1 assessed the efficacy of combined treatments of trunk injections of different phosphite concentrations, trunk nutrient implants of different compositions and combined phosphite and nutrient treatments. Experiment 2 assessed the efficacy of different phosphite concentrations. In Experiment 1, phosphite, together with nutrient treatments, increased the average crown condition by 21 %, as measured using a crown health score (CHS) averaged over 4 years, with the greatest improvements evident 6 months after application. Injection of 25 g phosphite/L combined with 0.3 g zinc sulphide gave the greatest increase. In Experiment 2, application of 75 to 375 g phosphite/L increased the CHS compared to the control treatment, with the greatest improvements in trees injected with 150 g phosphite/L. Foliar analysis for Experiment 2 confirmed a significant uptake of phosphite for all phosphite treatments. The increase in the CHS and significant flushes in new growth resulting from phosphite and nutrient treatments highlight the possible involvement of Phytophthora species in the decline, as Phytophthora species are known to be controlled by phosphite application. Further work on combined phosphite and nutrient applications, with a particular emphasis on zinc, is required to help understand and potentially mitigat

The publisher regrets that the co-author Samantha Setterfield name was not included in the original version of the article. The author list mentioned above is the corrected version.

In dryland environments 35year rotations of tree crops and agriculture represent a major potential bioenergy feedstock and a means to restore landscape hydrologic balances and phytoremediate sites, while maintaining food production. In soils with low natural fertility, the long-term viability of these systems will be critically affected by site nutrient status and subsequent cycling of nutrients. A nutrient assimilation index (NAI) was developed to allow comparison of species and tree component nutrient assimilation and to optimize nutrient management, by quantifying different strategies to manage site nutrients. Biomass, nutrient export and nutrient use efficiency were assessed for three short rotation tree crop species. Nutrient exports following harvest at 3years of high density (4000 treesha1) were consistently higher in Pinus radiata, with values of 85kgha1 of N, 11kgha1 of P, and 62kg ha1 of K, than Eucalyptus globulus and Eucalyptus occidentalis. Component NAI was generally in the order of leaf

The health of Eucalyptus gomphocephala is declining within its natural range in south-western Australia. In a pilot study to assess whether changes in mycorrhizal fungi and soil chemistry might be associated with E. gomphocephala decline, we set up a containerized bioassay experiment with E. gomphocephala as the trap plant using intact soil cores collected from 12 sites with E. gomphocephala canopy condition ranging from healthy to declining. Adjacent soil samples were collected for chemical analysis. The type of mycorrhiza (arbuscular or ectomycorrhizal) formed in containerized seedlings predicted the canopy condition of E. gomphocephala at the sites where the cores were taken. Ectomycorrhizal fungi colonization was higher in seedling roots in soil taken from sites with healthy canopies, whereas colonization by arbuscular mycorrhizal fungi dominated in roots in soil taken from sites with declining canopies. Furthermore, several soil chemical properties predicted canopy condition and the type of mycorrhizal fungi colonizing roots. These preliminary findings suggest that large-scale studies should be undertaken in the field to quantify those ectomycorrhiza (ECM) fungi sensitive to E. gomphocephala canopy decline and whether particular ECM fungi are bioindicators of ecosystem health.

Drought and heat-induced forest dieback and mortality are emerging global concerns. Although Mediterranean-type forest (MTF) ecosystems are considered to be resilient to drought and other disturbances, we observed a sudden and unprecedented forest collapse in a MTF in Western Australia corresponding with record dry and heat conditions in 2010/2011. An aerial survey and subsequent field investigation were undertaken to examine: the incidence and severity of canopy dieback and stem mortality, associations between canopy health and stand-related factors as well as tree species response. Canopy mortality was found to be concentrated in distinct patches, representing 1.5 % of the aerial sample (1,350 ha). Within these patches, 74 % of all measured stems (>1 cm DBHOB) had dying or recently killed crowns, leading to 26 % stem mortality six months following the collapse. Patches of canopy collapse were more densely stocked with the dominant species, Eucalyptus marginata, and lacked the prominent midstorey species Banksia grandis, compared to the surrounding forest. A differential response to the disturbance was observed among co-occurring tree species, which suggests contrasting strategies for coping with extreme water stress. These results suggest that MTFs, once thought to be resilient to climate change, are susceptible to sudden and severe forest collapse when key thresholds have been reached.

In dryland environments 3–5 year rotations of tree crops and agriculture represent a major potential bioenergy feedstock and a means to restore landscape hydrologic balances and phytoremediate sites, while maintaining food production. In soils with low natural fertility, the long-term viability of these systems will be critically affected by site nutrient status and subsequent cycling of nutrients. A nutrient assimilation index (NAI) was developed to allow comparison of species and tree component nutrient assimilation and to optimize nutrient management, by quantifying different strategies to manage site nutrients. Biomass, nutrient export and nutrient use efficiency were assessed for three short rotation tree crop species. Nutrient exports following harvest at 3 years of high density (4000 trees ha-1) were consistently higher in Pinus radiata, with values of 85 kg ha-1 of N, 11kg ha-1 of P, and 62 kg ha-1 of K, than Eucalyptus globulus and Eucalyptus occidentalis. Component NAI was generally in the order of leaf < twig < bark < root < stem-wood for N, P, K, S, Ca, and Mg. The NAI ranged from 0.06 Mg kg-1 for N in leaves of P. radiata to 4.7 Mg kg-1 for P in stem-wood of E. occidentalis, indicating highersustainability of wood biomass compared with leaf biomass. The leaves for each species contained between 40 and 60% of the total nutrient contents while comprising around 25–30% of the total biomass. These nutrient exports via biomass removal are similar to those that follow 3 years of wheat production in the same region, indicating there is no additional drawdown of nutrient reserves during the tree cropping phase of the rotation.

Eucalypts are increasingly important in the tropics for meeting growing demand for timber, wood chips, paper pulp and biofuel. Many new plantations are planted on low boron (B) soils, with adverse effects on plant growth and productivity. Two experiments in sand culture with different levels of added B, from 0 to 10 μM B, examined the effect of B deficiency on growth, wood yield and morphology of fibres of three commercially available eucalypt clones: K7 (Eucalyptus camaldulensis × E. deglupta), K51 (E. brassiana × E. grandis) and K57 (E. camaldulensis). In plant height, dry weight and wood production, K7 was more tolerant of B deficiency, but K57 and K51 were more responsive to increasing B. At the level of B that depressed growth by up to 54% and wood yield by up to 65%, no significant effect of B deficiency was observed on fibre morphology. However, as the wood:shoot ratio in K51 and K57 increased with increasing B, there is a possibility that B has a direct effect on wood production in some genotypes, in addition to an indirect effect via better growth. These results indicate that attention to B nutrition in eucalypt plantations would be beneficial to plant growth and productivity before effects of B on individual wood fibres becomes detectable. Selection for B-efficient genotypes could be useful for plantations on low B soils, and the full potential of sites where B is not limiting could be better realised with B-responsive genotypes.

Hed sa med (Boletus griseipurpureus) is a popular edible ectomycorrhizal mushroom associated with stands of Melaleuca leucadendron and Acacia mangium in Thailand. Genetic variation of B. griseipurpureus basidiomes, obtained from the wild, was determined by internal transcribed spacer (ITS) sequence analysis. Sequences of B. griseipurpureus collections showed high similarity and constituted a monophyletic clade. The basidiomes were rich in protein and very low in fat confirming their value for human consumption.

Many Mediterranean-type ecosystems (MTEs) are now vulnerable to climate change, with some regions predicted to undergo a shift towards much drier and hotter conditions. Although MTE woodlands are highly resilient to periods of drought and perturbations such as fire, this shift increases the already wide range of threatening processes they face. Without intervention, such as revegetation, many of these woodlands could degrade to the point where they support little of the original biota. However, in MTEs with hard to predict breaks in the season and nutrient poor soils; seedling establishment success is often very low. Using degraded Eucalyptus gomphocephala woodlands as a case study, we undertook two field trials with five commercially available plant treatments to evaluate their effectiveness in increasing early seedling establishment. We found that the mere addition of seedlings may not be enough to undertake successful revegetation in some degraded woodlands because a) survival rates in controls were, on average 53% at one of the study sites and b) the supplementation of nutrient resources beneath the rootball when planting increased early seedling growth and health compared with other treatments. We suggest that under emerging and well-recognized challenges to revegetation, supplementing abiotic resources, in particular nutrients applied exclusively beneath planted seedlings, may increase early establishment success.

The impact of invasive plant species in national parks and forests in Vietnam is undocumented and management plans have yet to be developed. Ten national parks, ranging from uncut to degraded forests located throughout Vietnam, were surveyed for invasive plant species. Transects were set up along roads, trails where local people access park areas, and also tracks through natural forest. Of 134 exotic weeds, 25 were classified as invasive species and the number of invasive species ranged from 8 to 15 per park. An assessment of the risk of invasive species was made for three national parks based on an invasive species assessment protocol. Examples of highly invasive species were Chromolaena odorata and Mimosa diplotricha in Cat Ba National Park (island evergreen secondary forest over limestone); Mimosa pigra, Panicum repens and Eichhornia crassipes in Tram Chim National Park (lowland wetland forest dominated by melaleuca); and C. odorata, Mikania micrantha and M. diplotricha in Son Tra Nature Conservation area (peninsula evergreen secondary forest). Strategies to monitor and manage invasive weeds in forests and national parks in Vietnam are outlined.

Background and aims: The loss of iron and zinc during milling to produce white rice can have serious consequences for human health. Therefore, the objective was to evaluate Fe and Zn partitioning between the endosperm, bran and embryo, and the milling loss of these nutrients among Thai rice genotypes. Methods: Concentrations of iron and zinc and their partitioning to different parts of the grain were examined in 15 genotypes of Thai rice (10 belonging to the long-slender grain type) grown together under wetland condition. Results: The depression in grain Fe and Zn concentrations (24-60 and 10-58 %, respectively) on milling differed among rice genotypes and were affected by the extent of differential partitioning of Fe and Zn into different parts of the grain. For example, nearly 70 % of white rice Zn was allocated to the endosperm in contrast to only 43 % for Fe. Conclusions: Because of variation in milling loss of Fe and Zn, that can result from genotypic variation in the degree of milling and partitioning of Fe and Zn into different parts of the grain, we conclude that white rice Fe and Zn concentrations should not be inferred solely from brown rice concentrations of these nutrients.

In wheat (Triticum aestivum L.) drought-induced pollen sterility is a major contributor to grain yield loss and is caused by the downregulation of the cell wall invertase gene IVR1. The IVR1 gene catalyses the irreversible hydrolysis of sucrose to glucose and fructose, the essential energy substrates which support pollen development. Downregulation of IVR1 in response to drought is isoform specific and shows variation in temporal and tissue-specific expression. IVR1 is now prompting interest as a candidate gene for molecular marker development to screen wheat germplasm for improved drought tolerance. The aim of this study was to define the family of IVR1 genes to enable: (1) individual isoforms to be assayed in gene expression studies; and (2) greater accuracy in IVR1 mapping to the wheat genetic map and drought tolerance QTL analysis. Using a cell wall invertase-specific motif as a probe, wheat genomics platforms were screened for the presence of unidentified IVR1 isoforms. Wheat genomics platforms screened included the IWGSC wheat survey sequence, the wheat D genome donor sequence from Aegilops tauschii Coss, and the CCG wheat chromosome 3B assembly: contig506. Chromosome-specific sequences homologous to the query motif were isolated and characterised. Sequence annotation results showed five previously unidentified IVR1 isoforms exist on multiple chromosome arms and on all three genomes (A, B and D): IVR1–3A, IVR1–4A, IVR1–5B, IVR1.2–3B and IVR1-5D. Including three previously characterised IVR1 isoforms (IVR1.1–1A, IVR1.2–1A and IVR1.1–3B), the total number of isoform gene family members is eight. The IVR1 isoforms contain two motifs common to cell wall invertase (NDPN and WECPDF) and a high degree of conservation in exon 4, suggesting conservation of functionality. Sequence divergence at a primary structure level in other regions of the gene was evident amongst the isoforms, which likely contributes to variation in gene regulation and expression in response to wa

Phytophthora ramorum is an invasive plant pathogen and the cause of considerable and widespread damage in nurseries, gardens and natural woodland ecosystems of the USA and Europe. It is considered to be a significant plant disease as it could cause biodiversity loss and severe economic losses in plant industries in areas where it is not yet known to exist, such as Australasia. Foliar susceptibility and sporulation potential were tested using detached-leaf assays for 70 Australian native plant species sourced from established gardens and arboreta in California using a NA2 isolate of P. ramorum. Correa‘Sister Dawn’, Eucalyptus regnans, Isopogon cuneatus, I. formosus, Leptospermum scoparium, L. lanigerum and Melaleuca squamea were identified as potentially highly susceptible host species. Hedycarya angustifolia, Olearia argophylla, Phyllocladus aspleniifolius, Pittosporum undulatum and Podocarpus lawrencei were identified as potentially resistant. All 70 species were able to be infected with P. ramorum, as confirmed by reisolation. Putative sporulating hosts include five members of the Myrtaceae, Agonis flexuosa, Corymbia ficifolia, Eucalyptus haemastoma, E. delegatensis and E. viminalis. As a part of a precautionary strategy, the potentially highly susceptible species found in this study are suitable candidates for targeted surveillance programmes in high-risk incursion areas of Australia and within the global horticultural trade.

Aims: Growers of Eucalyptus globulus Labill. plantations can establish second and later rotations from coppice or by replanting with seedlings. At most locations where E. globulus is grown commercially, water availability is a major driver for productivity. Thus growers must consider which reestablishment technique will maximize productivity whilst sustaining site resources for subsequent rotations. In this study we aimed to compare the stand-scale water balance components of young coppice and seedling E. globulus. Methods: A second rotation E. globulus coppice and seedling trial was monitored for two successive seasonal cycles. Coppice and seedling plots were instrumented with sap flow- and meteorological-sensors so that stand-scale water balance components could be estimated on a daily time step. Results: Stand-scale transpiration rate (E) and rate of interception (EI) were larger in coppice compared to seedlings, but the rate of soil evaporation (ES) was lower. At approximately 2 years of age each coppice stump was reduced to a single dominant stem, a standard management practice for E. globulus growers, which reduced stem biomass by approximately 70% and caused E to fall to a value approximating that in seedlings. The cumulative transpiration of coppice was 425 mm greater than seedlings up to 34 months of age. Without the coppice reduction (down to one stem/stump), we estimate that the difference would have been much greater. The water-use efficiency of stem production (WUEstem) was greater in young coppice compared to seedlings but this benefit is likely to be offset by the loss of biomass (and thus transpired water) during coppice stem reduction. Conclusion: Under the conditions of this study, which included reducing coppice to a single stem, reestablishment with seedling E. globulus resulted in a higher water-use efficiency of stem biomass production compared to coppice of a similar age.

Susceptibility to branch dieback caused by Phytophthora ramorum was tested using a detached branch assay for 66 Australian native plant species sourced from established gardens and arboreta in California. Six of these species were further tested for their susceptibility to bole cankers caused by P. ramorum using a sealed log assay. Isopogon formosus and Eucalyptus denticulata were identified as potentially highly susceptible Australian branch dieback hosts. Thirteen potentially tolerant Australian host species included Banksia attenuata, B. marginata, E. haemastoma, E. regnans, Pittosporum undulatum and Billardiera heterophylla. Eucalyptus regnans was identified as a potentially highly susceptible bole canker host, while E. diversicolor and E. viminalis were considered potentially tolerant species to bole cankers caused by P. ramorum. Phytophthora ramorum was able to infect all 66 species, as confirmed by reisolation. These results extend the known potential host range for P. ramorum, confirm it as a possible threat to Australian plant industries and ecosystems and highlight additional associated hosts that are important in the global horticultural trade, native forests and plantation forestry.

The plantation area in Vietnam of Acacia auriculiformis, A. mangium and their hybrid has expanded greatly in the last decade. Recently, a new stem canker disease causing symptoms of crown wilt, followed by wood discoloration then death of infected trees has occurred in many ecological zones. Ascomata were obtained by incubating discolored wood pieces in moist chambers or by carrot baiting. Isolates of fungi were obtained on PDA medium by taking spores emerging from the tips of ascomata necks. Ceratocystis was identified based on ascospore morphology and conidial types. Twenty six isolates of Ceratocystis were used for pathogenicity assessment on 8-month old seedlings of A. mangium in a nursery, with 5 seedlings per isolate. Stems were inoculated by inserting an 8 mm diameter PDA plug covered with 15-day old mycelia onto the cambium about 50 cm above the ground. Five seedlings were inoculated with sterile PDA plugs to serve as the control. The wounds and plugs were sealed with parafilm to protect them against desiccation and rain. After 60 days of inoculation, based on lesion development and tree death, the pathogenicity of the isolates were identified: 2 isolates (AA8, AMH12) nil, 4 isolates (AAHX1, AMH40, AMD26, AHDL1) low, 4 isolates (AA22, AMH9, AMMB7, AHXL3) moderate, 3 isolates (AMBL3, AMPL2, AMH5) high, and 13 isolates (AA54, AA62, AMH24, AMH26, AMH41, AMHX1, AMQN1, AMBL4, AHBB1, AHBD1, AHBP1, AHXL1 and AHXL2) very high level of pathogenicity causing plant death. This is the first record of Ceratocystis causing damage to Acacia plantations in Vietnam. The origin of the pathogen is unknown. Work is progressing to determine whether the species is the same as that known to cause damage to A. mangium plantations in Indonesia.

Plantation forestry is making a significant positive contribution to the environment as well as to the livelihoods of millions of people in Asia. This chapter examines some of the major constraints facing commercial acacia and eucalypt plantations in South-east and East Asia and discusses adaptive actions in the face of climate change. Particular emphasis is placed on Vietnam and China but examples are also drawn from other parts of SE Asia where forest plantations are making a significant contribution to forest cover. The area of forest cover in Asia has declined greatly in the past 50 years due to an expanding population, and increasing demand for forest products and land for food and energy crops. For example, based on available documents, in 1943 Vietnam had 14.3 million ha of forests, with 43% forest cover; but by the year 1990 only 9.18 million ha remained, with a forest cover of 27.2%. During the period 1980 to 1990, the average forest lost was more than 100,000 ha each year. However, from 1990 to the present, the forest area has increased gradually, due to afforestation and rehabilitation of natural forest. Based on the official statement in Decision No. 1267/QD/BNN-KL-LN, dated 4 May 2009, as of 31 December 2009, the total national forest area was 13.2 million ha (forest cover of 39.1%), including 2.9 million ha of plantation forest. Recently, China too has also been able to reverse the decline in forest cover due to forest protection and afforestation. According to the 7th national forest resource inventory finished in 2008, there were 195.4 million ha (14.9 billion m3 of standing wood volume) of forest in China, an increase of 20.5 million ha (1.1 billion m3 standing wood volume) over the previous audit 5 years earlier. Of the increased forest area and volume, 3.9 million ha were from natural forests, and 8.4 million ha were from tree plantations. In the region, logging of natural forests is proceeding at alarming rates in some countries and is tightly co

Arbuscular mycorrhizal fungi (AMF) are keystone mutualists inhabiting roots of most plants including the majority of oil crops under cultivation. Therefore, sustainable yield of Jatropha (Jatropha curcas L.) in cultivation is likely to benefit from the inclusion of AMF in crop management cycles. Studies undertaken on acid and alkaline soils in a range of site conditions (productive cropping land, degraded land, mine spoil) indicate close association between Jatropha and AMF since roots were often heavily colonized by AMF in the field. Although a diverse range of AMF genera and species have been identified in the rhizosphere of Jatropha, not all are likely to be effective for sustainable production of Jatropha in plantations. For example, of 34 species of AMF in the rhizosphere of Jatropha in Thailand, only a few species were able to be trapped by Jatropha seedlings. Techniques for assessing the need for inoculation and approaches for inoculum production are discussed. The role of AMF in alleviating stresses is discussed in relation to (1) nutrient and water constraints that are likely to be the main factors limiting the production of Jatropha in many regions of the world and (2) the presence of heavy metals and salinity that will also be challenging for this crop.

Fungal diseases caused by native pathogens and pathogens introduced with planting stock have a significant impact on exotic plantation forestry in the tropics. Teratosphaeria destructans (formerly Kirramyces destructans) is a serious pathogen causing leaf, bud and shoot blight diseases of Eucalyptus spp. in plantations in the sub-tropics and tropics of south-east Asia. This pathogen was first discovered in Indonesia in 1995 and has subsequently spread to Thailand, China, Vietnam and East Timor. The biology, ecology and genetics of this important pathogen have not been explored yet. The objective of this study was, thus, to determine the genetic diversity and movement of T. destructans throughout south-east Asia using multi-gene phylogenies and microsatellite markers. Out of nine gene regions only two microsatellite markers detected a very low nucleotide polymorphism between isolates; seven other gene regions, ITS, β-tubulin, EF1-α, CHS, ATP6 and two microsatellite loci, reflected genetic uniformity. The two polymorphic molecular markers resolved six haplotypes among isolates from Indonesia and only a single haplotype elsewhere in Asia. The low diversity observed among isolates in the region of the first outbreak is as expected for a small founder population. The spread of a single clone over large distances throughout the region supports the hypothesis of spread via the human-mediated movement of germplasm.

In Huai Teecha village in Northern Thailand, local cowpeas were grown on acidic low phosphorus soil without stress symptoms. Arbuscular mycorrhizal fungi from this system have been found to promote growth of many crops but there is no information about their benefit in cowpea. In a field experiment, three improved cowpea lines (ITD - 1131, Ubon Ratchathani and IT90K - 227 - 2) and a local line (Teecha 1) were grown in 3 farmer's fields on acid low P soils. Roots of the cowpea lines were all heavily colonized by the fungi and their leaf P was within the sufficient range. In a pot experiment, the cowpea line Ubon Ratchathani was grown in acidic and non acidic (pH 5 and 6.7, respectively) soil with three rates of phosphorus (50, 104 and 141 mg phosphorus pot-1) with and without arbuscular mycorrhizal fungi inoculation. Total dry weight of inoculated cowpea was not affected by soil acidity while it was depressed in un-inoculated plants. The fungi increased total dry weight at 50 and 104 mg phosphorus ha-1 but had no effect at 141 mg phosphorus pot-1. Therefore, the fungi had been shown to enhance P uptake by cowpea roots, which resulted in direct benefit to cowpea growth in acidic low P soil.

This study tested the efficacy of smokewater to determine the potential germination from soil seed bank in three management sites of the same National Park: a forest site prior to restoration, an ex-pine plantation site and an ex-mine site. This will provide further information to land managers so that more accurate planning can occur. Results showed that smokewater significantly increased the germination from the soil seed bank, and significant differences in the level of germination of weed species from the soil seed bank were seen between the three management sites. This use of smokewater may be a useful tool to help predict differences in the soil seed bank compared with predicting soil seed bank based on land-use history and recent condition.

Inoculation with beneficial soil microorganisms has the potential to enhance success of restoration, particularly in harsh Mediterranean-type ecosystems (MTEs). We investigated the effects of microorganisms (mycorrhizal fungi and root nodule bacteria) and planting material (seed and nursery-raised seedlings) on early establishment and growth of two key postdisturbance colonizing species with different life histories, life forms and functional types (Eucalyptus gomphocephala and Acacia saligna) under field conditions. Establishment and growth were monitored at 13months, following the first MTE drought period. For E. gomphocephala, establishment was higher for seedlings (81%) than for seeding (7.5%). Inoculation with ectomycorrhizal fungal spores was not beneficial. For A. saligna, establishment was also higher for seedlings (84%) than for seeding (42.5%). Mycorrhizal fungal inoculum had no effect on establishment or growth. This study has shown that in harsh MTE conditions, the use of seedlings is more effective than seeding in degraded woodlands even when attempting to reintroduce key colonizing species. The microorganism treatments tested did not result in significant improvement in establishment or growth.

Symbiotic seed germination of Pecteilis susannae (L.) Rafin was investigated using 11 fungal isolates recovered from roots of four Thai terrestrial orchids (P. susannae, Eulophia spectabilis, Paphiopedilum bellatulum and Spathoglottis affinis). Seed germination and protocorm development were evaluated up to 133 days after sowing. Protocorm development was most advanced, up to stage 5 (elongation of the first leaf), when seeds were cultured with 4 Epulorhiza isolates obtained from roots of P. susannae (CMU-Aug 028, 4.3%, CMU-Aug 007, 4.2%, and CMU-Aug 013, 2.2%) and E. spectabilis (CMU-STE 014, 3.9%). Moreover, stage 4 protocorm development (emergence of the first leaf) occurred with fungal isolates CMU-STE 011, 5.7%, (Epulorhiza sp.) and CMU-AU 212, 4.3%, (Tulasnella sp.) obtained from roots of E. spectabilis and S. affinis respectively. When seed was incubated without fungi (control), development was limited to stage 3 of protocorm development (appearance of promeristem). This is the first report of protocorm stage 5 development in P. susannae using compatible fungal symbionts. Optimization of seed germination and seedling fitness will assist the conservation and propagation of this orchid species and other terrestrial orchids in Thailand.

We identify the 10 major terrestrial and marine ecosystems in Australia most vulnerable to tipping points, in which modest environmental changes can cause disproportionately large changes in ecosystem properties. To accomplish this we independently surveyed the coauthors of this paper to produce a list of candidate ecosystems, and then refined this list during a 2-day workshop. The list includes (1) elevationally restricted mountain ecosystems, (2) tropical savannas, (3) coastal floodplains and wetlands, (4) coral reefs, (5) drier rainforests, (6) wetlands and floodplains in the Murray-Darling Basin, (7) the Mediterranean ecosystems of southwestern Australia, (8) offshore islands, (9) temperate eucalypt forests, and (10) salt marshes and mangroves. Some of these ecosystems are vulnerable to widespread phase-changes that could fundamentally alter ecosystem properties such as habitat structure, species composition, fire regimes, or carbon storage. Others appear susceptible to major changes across only part of their geographic range, whereas yet others are susceptible to a large-scale decline of key biotic components, such as small mammals or stream-dwelling amphibians. For each ecosystem we consider the intrinsic features and external drivers that render it susceptible to tipping points, and identify subtypes of the ecosystem that we deem to be especially vulnerable.

Maize (Zea mays L.) is an important crop in central Thailand where fallow is widely practiced and farmers are interested in crop rotation and beneficial soil biota. A pot experiment using a Typic Paleustult (topsoil + subsoil) from the National Corn and Sorghum Research Centre, Nakhonratchasima Province, Thailand was undertaken over three successive crops to evaluate effects of agronomic practices on populations of arbuscular mycorrhizal (AM) fungi and to determine whether reintroduction of a local Glomus was beneficial to maintain maize yield. The three crops and their treatments were: (1) preceding crop: maize grown in all pots; (2) subexperiment 1: agronomic practices [maize, fallow +/- soil disturbance, fallow with solarization, non-AM host (cabbage)]; and (3) subexperiment 2: maize +/- Glomus sp. 3 at three rates of P fertilization (0, 33, 92 kg P ha(-1)). The AM-fungal community was established under the preceding crop. In subexperiment 1, the three fallow treatments decreased (30%-40%) the total AM spore number in the topsoil whereas there was no change under maize or cabbage. Glomus, the dominant genus, showed sensitivity to fallow. In subexperiment 2, inoculation with Glomus sp. 3 enhanced total AM spore number and root colonization when applied following the three fallow treatments. Furthermore, inoculation promoted grain yield; at nil P following fallow +/- soil disturbance, at 33 kg P ha(-1) following fallow without soil disturbance, and following solarization. Two treatments, maize following maize and maize following cabbage, did not respond to inoculation with Glomus sp. 3. Overall, the results suggest that reintroduction of Glomus sp. 3, a local AM fungus in this soil, may overcome negative effects of fallow and promote effectiveness of P fertilizer. Further work is needed to evaluate the benefits of other indigenous AM species that persist under modern fertilization practices.

Boron (B) deficiency depresses wheat, barley and triticale yield through male sterility. On the basis of field responses to B fertilization, maize (Zea mays L.) is affected by B deficiency in five continents. In a series of sand culture trials with maize subject to B0 (nil added B) and B20 (20 mu M added B) treatments, we described how B deficiency depressed maize grain yield while showing an imperceptible effect on vegetative dry weight. With manual application of pollen to the silk of each plant, B0 plants produced 0.4 grain ear(-1) compared with 410 grains ear(-1) in B20 plants. Symptoms of B deficiency was observed only in B0 plants, which exhibited symptoms of narrow white to transparent lengthwise streaks on leaves, multiple but small and abnormal ears with very short silk, small tassels with some branches emerging dead, and small, shrivelled anthers devoid of pollen. Tassels, silk and pollen of B0 plants contained only 3-4 mg B kg(-1) DW compared with twice or more B in these reproductive tissues in B20 plants. A cross-fertilization experiment showed that, although the tassels and pollen were more affected, the silk was more sensitive to B deficiency. Pollen from B20 plants applied to B0 silk produced almost no grains, while pollen from B0 on B20 silk increased the number of grains to 37% of the 452 grains plant(-1) produced from B20 pollen on B20 silk. Therefore, the silk of the first ear may be targeted for precise diagnosis of B status at maize reproduction, for timely correction by foliar B application, and even for B-efficient genotype selection.

Eight endophytic fungi were isolated from roots of the threatened terrestrial orchid, Pecteilis susannae (L.) Rafin. Phylogenetic analysis based on an alignment of internal transcribed spacer regions of nuclear rDNA indicated that seven isolates belonged to the genus Epulorhiza and one to Fusarium. All fungal isolates were cultured with orchid seeds collected from three field sites near Doi Suthep-Pui National Park, Chiang Mai, Thailand. Seed germination and protocorm development were evaluated up to 70 days after sowing. Percent symbiotic seed germination was highest (86.2%) when seeds were cultured with Epulorhiza (CMU-Aug 013). The protocorm development was the most advanced up to stage 2, continued embryo enlargement, or rupture of the testa, and the highest percentage was 17.8% when seeds were cultured with Epulorhiza (CMU-Aug 007). Without fungi, seed germination and protocorm development were 62.1% and 11.1%, respectively. The dependency of P. susannae on fungal symbionts for early seedling development is yet to be determined. Optimizing seed germination and seedling fitness will assist the conservation of this threatened orchid in Thailand.

The most common factor affecting wheat production and grain quality in Australia is water deficit - "drought." Drought and heat are considered the top priority among 15 abiotic stresses affecting wheat production in Western Australia (WA). In the WA wheatbelt, water deficit intensifies from anthesis to about 4 weeks later and severe drought usually occurs from a month after anthesis to maturity. Thus, terminal drought is a major problem for wheat production in WA and drought tolerance in wheat is a priority for research. A major limitation in this field is the lack of efficient approaches of drought tolerance screening and availability of drought tolerant germ plasm. Our study has found that stem water soluble carbohydrate (WSC) mobilization has great significance for converting biomass into the grain under terminal water-deficit. However, stem WSC level is not, on its own, a reliable criterion for drought tolerant. The genes involved in the mobilization of stem WSC, 1-FEHs have been studied and the gene expression data, as a potential drought tolerant marker, define their crucial role in contributing to water deficit tolerance. QTL recently discovered provide some evidence for the possible gene function of the contribution to the grain yield components. This and other markers of grain yield components may be useful for wheat breeding in the future. Lack of drought tolerant germplasm significantly slows down drought tolerant breeding in wheat. Introducing new germplasm from China will give great benefit to the Australian wheat breeding program. Hopefully the combination of genes from such diverse environments will enhance the production of new drought tolerant wheat in conventional breeding.

Teratosphaeria destructans was first described in 1996 from north Sumatra, Indonesia, where it caused a severe leaf and shoot blight on Eucalyptus grandis in nurseries and young plantations. Since then it has been reported in nurseries and plantations in Vietnam, Thailand and China, with its host range extending to include E. camaldulensis and E. urophylla. Teratosphaeria destructans has also been reported from native E. urophylla in East Timor and was considered a significant biosecurity threat to Australia’s native eucalypt forests and plantations. A study on the population diversity of K. destructans isolates throughout south‐east Asia in which 8 gene regions were sequenced (four nuclear genes, one mitochondrial gene and three microsatellite markers) detected very low nucleotide polymorphism. This genetic uniformity is indicative of an introduced population which has subsequently spread throughout Asia via human‐mediated movement of germplasm. Surveys of sentinel plantings in northern Australia (Queensland, Northern Territory and Western Australia) revealed a complex of Teratosphaeria spp. Among which K. destructans was detected. The same gene regions and markers were sequenced as for the Asian study and the diversity among the K. destructans isolates in Australia was found to be much greater than that in Asia. We believe that K. destructans in native to Australia where is resides asymptomatically within the native vegetation. The disease is only expressed when non‐endemic eucalypts are planted. As such the pathogen is a major encumbrance to the establishment of commercial eucalypt plantations in Northern Australia. The disease has not been observed in native ecosystems, but the effect of inoculum build up within plantations on adjacent native eucalypt remnants is not known.

Corymbia ficifolia is a widely planted amenity tree worldwide. Recently, the species has been observed to be in decline in urban environments. This study investigated the causes of the decline in 246 trees in roadsides/median islands, parks, streets within residential areas in five urban areas in the City of Melville, 77 trees on the Murdoch University campus, and 82 trees in other urban areas and in its natural habitat in south‐western Australia. Tree diameter, height, and canopy/crown densities ranged from 5.5‐104.1 cm, 2.4‐18 m and 5‐100%, respectively. Most adult trees in urban areas suffered from canker disease caused by Quambalaria coyrecup which was commonly associated with branch flagging and dieback. No canker symptoms were found in natural stands of C. ficifolia. Occurrence of canker, dieback, flagging, and foliar diseases across all sites ranged from 0‐80%; 26.6‐80%; 4.7‐57.1%; and 29.2‐100%, respectively. Foliar symptoms caused by biotic and abiotic causal agents were also present. Whilst leaf disease is widespread, stem cankers are of major concern in larger trees. The health and structural condition of trees were scored and correlation among tree parameters with disease presence was assessed. Some diseases were common on C. ficifolia at a particular plant growth stage or in particular areas. The research indicates that disease problems in urban C. ficifolia trees are common and that more than one causal agent is responsible.

Paul Barber discuss factors in the urban forest that contribute to tree decline and how taking the time to correctly diagnose a disease can make the difference between sustaining and removing a tree.

The dependence of physic nut (Jatropha curcas L.) on beneficial soil fungi for growth is not known. Therefore, the spore density and species diversity of arbuscular mycorrhizal fungal (AMF) associated with physic nut was assessed by extracting spores from physic nut plantings from 10 sites across 6 provinces in northern and north-eastern Thailand. Approximately 700 AMF spores, obtained using the wet sieving and sucrose gradient centrifugation methods, were identified into morphospecies. Colonization by AMF was assessed under a compound microscope using root samples stained with trypan blue. The following 34 morphospecies of AMF were identifed: Acaulospora (16 species), Entrophospora (1 species), Gigaspora (2 species), Glomus (10 species) and Scutellospora (5 species). The diversity index ranged from 0.28 to 0.86 (average 0.64) and the species richness of AMF ranged from 3 to 11 (average 6.2). Roots of physic nut were colonized by AMF at all sites sampled and infection levels ranged from 38 to 94% of root length. The presence of mycorrhizas in soils varying in pH from acidic to calcareous, of low to moderate organic matter and of low to high available P suggests that physic nut may be highly dependent on AMF.

Jatropha curcas is being considered as a biofuel crop for Thailand. Seedlings of J. curcas were used as bait plants to trap compatible arbuscular mycorrhizal fungi (AMF) in field soils in northern Thailand. Of the ten species of AMF that were trapped, two species, Scutellospora heterogama (CMU33) and Entrophospora colombiana (CMU05) produced abundant spores (>50 spores/100 g soil) and heavily colonized the roots of the trap plant. In a second experiment, the two AMF species were used to assess the effectiveness of four annual cereal crop plants (job’s tears, Coix lacryma-jobi; rice, Oryza sativa; sorghum, Sorghum bicolor; maize, Zea mays) as suitable nurse plants for AMF spore multiplication. Higher mycorrhizal colonization and spore production were found after 120 days in sorghum than in the other crop species. Spore multiplication did not occur with corn and CMU33, nor with rice and CMU05. Except for the shoots of rice, inoculation increased the root and shoot dry weight of all four crop species. Sorghum is a suitable host for spore multiplication of E. colombiana but an alternative host, with the potential to produce higher spore yields, is required for S. heterogama.

The tropical black bolete Phlebopus portentosus is highly favored in the cuisine of northern Thailand. It is suspected to form ectomycorrhizae with many host trees. Mycelium of P. portentosus isolated from a basidiome in Chiang Rai Province in 2003 grew well on modified Gamborg, modified Melin-Norkans, and Murashige and Skoog media at 30°C and at pH 4. In vitro fructification of P. portentosus on sorghum grain medium without a host plant is presented for the first time. Basidiomes emerged 3 months after inoculation on the medium, and the produced basidiospores germinated on agar, indicating the completion of its life cycle in vitro without a host. Five putative host plants (Castanopsis tribuloides, Dipterocarpus alatus, Dimocarpus longan, Pinus kesiya, and Syzygium cumini) were inoculated with mycelium on sorghum grain medium in a greenhouse to confirm its ectomycorrhizal status. Ectomycorrhizal roots were observed only on Pinus kesiya, suggesting that P. portentosus may be facultatively ectomycorrhizal. Identification of the synthesized ectomycorrhizae was confirmed by PCR amplification of ITS with a designed specific primer (HAR2A).

Restoration of degraded Mediterranean-type ecosystems (MTEs) with long, hot and dry summers is challenging. To develop management guidelines, we evaluated techniques that could improve seedling establishment in two degraded Eucalyptus gomphocephala DC (tuart) woodlands, given weed and herbivore control. These techniques aimed to mimic favourable conditions for species that primarily recruit following disturbance events (e.g. fire). Trial 1 investigated the response of 5-month-old seedlings and broadcast seed in plots that contained a created ashbed, were ripped, or were ripped and contained an ashbed. Trial 2 examined the response of 5-month-old seedlings to treatments providing a nutrient or moisture source (slow-release fertiliser tablet, chelating agent, slow-release fertiliser tablet plus chelating agent, zeolite, hydrated hydrophilic co-polymers and dry hydrophilic co-polymers). Results indicated that created ashbeds enhance establishment for a range of species and reduce weed cover, with or without ripping. Broadcast seeding was not successful in returning species to site. Higher growth rates were recorded in seedlings treated with a nutrient source. The present study has shown that it is possible to re-establish local plant species in degraded woodlands through several techniques that mimic disturbance (e.g. fire). Strong early growth may be the vital start seedlings need in MTEs in the face of reinvading weed species, herbivory and a drying climate.

In most plant families, boron (B) is phloem immobile. For plants such as peanut which bury their fruit, the mechanism for B delivery and the B source for fruit and seed growth remains enigmatic. Therefore, this study aimed to establish evidence of B retranslocation in peanut and to identify its importance in plant development. In a sand culture experiment, the increase in B contents in new organs after B withdrawal and the corresponding decline in B contents in older organs was evidence of B redistribution. In a foliar 10B experiment, the 10B abundance of treated-leaves decreased and 10B was detected in leaves and flowers formed after the application of foliar B. Application of 10B to the roots for a period also provided evidence for the retranslocation of 10B accumulated during the first growth period. The 10B abundance in older plant parts declined and 10B appeared in new organs (flowers, pegs, leaves) that had developed after the 10B supply had been replaced by 11B. In the fourth experiment, foliar application of B reduced hollow heart, a symptom of B deficiency in seeds, in cv. TAG 24 from 39 to 8% and in Tainan 9 from 63 to 18%. These experiments all provide evidence for B retranslocation in peanut, but further work on the relative importance of the xylem and phloem pathways for B loading into the fruit is needed.

The recent decline and death of young cedar, Cedrela odorata L. (Sapindales: Meliaceae), plantations in Vietnam is caused by Aclees sp. (Coleoptera: Curculionidae), a wood-boring brown weevil. A field study was undertaken in three-year-old plantations in two districts in Thanh Hoa province in August 2008. Trees were heavily impacted by the weevil, Aclees; the infestation level (P) ranged from 80 to 100% and the average damage index (R) ranged from 1.8 to 2.8. Observations over one year enabled the life history to be determined. Eggs were laid (February to March, September to November) inside the bark from the base of the trunk up to 60 cm in height. Larvae formed extensive feeding tunnels in the inner bark and sap wood. Pupation occurred in feeding tunnels or pupal chambers in the sapwood. Adults emerged twice a year, February to March and August to October. It is concluded that Aclees is a threat to C. odorata plantations in tropical regions of the world, and quarantine measures should be implemented to reduce the risk of spread.

Essential oils and their constituents have potential as ecologically acceptable pesticides that may also have novel modes of action. In this work hydroxy and ester derivatives of the naturally occurring monoterpenoids 1,8-cineole 3, the main component in most eucalyptus oils, and 1,4-cineole 4 were prepared and their pre-emergence herbicidal activity against annual ryegrass (Lolium rigidum) and radish (Raphanus sativus var. Long Scarlet) investigated in laboratory-based bioassays. 1,8-Cineole, eucalyptus oil and all derivatives showed a dose-dependent herbicidal activity against annual ryegrass and radish with many of the derivatives showing improved herbicidal activity relative to 1,8-cineole and high-cineole eucalyptus oil. Increased activity of cineole ester derivatives compared to their associated hydroxy-cineole and carboxylic acid was not observed. No relationship between lipophilicity of the carboxylic acid portion of cineole ester derivatives and herbicidal activity was observed. The results indicate that these cineole derivatives could be environmentally acceptable herbicides.

The leguminaceous rosewoods, Afzelia xylocarpa (Caesalpiniodeae) and Dalbergia cochinchinensis (Faboideae) are threatened by habitat loss and exploitation for their extremely highly-prized timber throughout their range. This paper examines the current conservation status of A. xylocarpa and D. cochinchinensis in Cambodia, draws together information on silviculture and trade, and summarizes current conservation measures in the country. Urgent measures are required to conserve and sustainably use the remaining genetic resources. Opportunities and challenges for achieving these goals, through use of the two threatened species in reforestation, are discussed. The suitability of the species for reforestation combined with increasing domestic and international prices for rosewood provide an opportunity for promotion of the species in planting programmes. This would not only alleviate the pressure on their natural habitats, but also bring about economic benefit. The paper outlines some important steps in the development of domestication strategies including testing and improving silvicultural practices, and increasing the supply of genetically superior seeds from seed production areas and/or seed orchards. As a first step, a network of in situ gene banks has been established in natural forests in Cambodia. A wide range of stakeholders need to participate in such programmes in order to address socio-economic development and poverty reduction. This is in line with the main objective of the National Forest Programme of Cambodia.

This review critically examines the role of boron (B) in forests in view of recent findings on B nutrition and the continuing occurrence of B deficiency. Many perceptions about the role of B in plants and its uptake and mobility have been altered since the last review on B in forest trees in 1990. Now there is evidence for a fundamental role of B in the formation of the pectic structure in primary cell walls in plants, and further roles in membrane function are being explored. In plants, channel-mediated B uptake, active B uptake and B uptake by mycorrhizas have been shown, B transporters have been identified, and B retranslocation has been shown. We explore these findings and their consequences on forest trees and on ecosystems that they dominate. Particular emphasis is placed on B retranslocation and B in mycorrhizal symbiosis, given their importance in trees.Following from impaired development of the primary cell wall in B-deficient trees, disorders in the structural development of organs and whole plants are manifested. This has consequences for tree form, affecting wood quality and productivity. At a stand level, at least part of the value of wood production is lost by the time the deficiency symptoms appear. As symptoms identifying deficiency in many tree species are too easily confused with many other effects, greater use should be made of foliar analysis but this requires establishing robust prognostic values for the trees of interest. There is still no explanation as to why root tip and mycorrhiza development are among the first phenomena to be affected as the B supply decreases. Whether B is required by, or whether it is useful for fungi, is still an open question.Boron remobilisation within trees may be a key factor in the occurrence of forests in areas with very low B availability, as most of the B in the whole stand can be in the standing biomass. The ability to remobilise B varies considerably between species, but we suggest that there is a continuum r