Category Archives: Guest blog

Farewell to Ben Wang

Ben WangIntroduction to ‘guest blog’ (by Shelagh McCartan)

In 2006, I was lucky enough to meet Ben Wang at the IUFRO conference in Fredericton, Canada. Ben has had a long, productive, and interesting career. At the age of 90, he has decided to ‘retire’! We wish him all the best in the future!

Guest Blog by Ben Wang (just retired)

Hello Friends

It has been 50 years since I started to work with tree seed at Petawawa Forest Experiment Station , Petawawa National Forestry Institute and Petawawa Research Forest as a research Officer, research scientist and emeritus research scientist. After 34 years of tree seed testing  and research with the National Tree Seed Centre, I retired in 1994 and continued with some consultancy, visiting scientist and volunteer work in tree seed.  I would  like to tell you friends that I had a very  interesting career in Tree seed for which I must express my  appreciation to Dr. Milan Simak of the Swedish University of Agricultural Sciences who led and organized the IUFRO Tree Seed Group following the 1973 International Symposium in Bergan, Norway. It was Dr. Simak’s leadership that we had many years of fruitful  interesting tree seed work done internationally. In Canada, we were lucky to have the Tree Seed Working Group and  I am happy to see the Tree Seed Working Group’s News Bulletin are continued worldwide readership after 33 years.  I have a plea to our colleagues that there are more in-depth work required in seed science and technology for us to discover. Good luck and good- bye.

Ben

 

Seed collecting in the British Virgin Islands

Introduction to ‘guest blog’ (by Shelagh McCartan)

Rosemary Newton is an ecologist with a seed background. She is based at RBG Kew, UK. In her blog, she discusses the prickly challenges of collecting seeds for conservation.

Guest Blog by Rosemary Newton ( Career Development Fellow (Islands) at the Royal Botanic Gardens Kew, UK)

One of the strategic outputs of the Science Strategy of the Royal Botanic Gardens, Kew, is to bank 25% of the world’s plant species by 2020.  Kew’s Millennium Seed Bank (MSB) Partnership is working with partners in 80 countries to achieve this target.  One of these partners is the National Parks Trust of the Virgin Islands (NPTVI), based on Tortola, one of the British Virgin Islands (BVI) in the Caribbean.  The Flora of the West Indies documents approximately 940 seed plant species (including non-native species) recorded from the four largest islands in BVI.  The vegetation on the islands comprises mainly tropical dry forest, dry scrub, mesic forest in the higher elevations, salt ponds in low-lying areas and mangrove swamps along the coast.  Since 2003, 112 seed collections of 82 plant species have been made by Kew and NPTVI staff from eight of the approximately 60 islands that comprise the BVI archipelago.

In June 2016, Kew’s United Kingdom Overseas Territories (UKOTs) team travelled to the British Virgin Islands to launch a Tropical Important Plant Areas (TIPAs) project, the aim of which is to assess and map TIPAs in the BVI to enable local authorities to prioritise their protection and conservation efforts.  Following the workshop which was held at the J.R. O’Neal Botanical Gardens, the UKOTs team and regional collaborators embarked on day trips to previously unexplored areas on the islands of Tortola, Beef Island, Virgin Gorda, Great Tobago and Prickly Pear in search of new, rare and threatened plants and also to map the occurrence of invasive plant species.  A new species for the MSB which we were able to collect seed from was the spiny legume Pictetia aculeata, endemic to the Virgin Islands and Puerto Rico.

BVI_June2016
BVI_June2016

Tom Heller and Colin Clubbe collecting Pictetia aculeata seed on Beef Island

Many of the plant species on the islands possess spines or thorns, which makes moving through dense vegetation a painstakingly slow process!  One species of Cactaceae, Opuntia repens, made an unforgettable impression on the team as we made our way across the island of Great Tobago.  Commonly called the jumping cactus, this plant has perfected the art of vegetative reproduction, as segments readily break off from the plant when touched and the barbed spines attach securely to clothing and even the covered skin beneath.  We very quickly learned not to try to remove the segments with our bare hands but to carefully flick them away with a stout stick.  Although the primary mode of reproduction and dispersal in this species is vegetative, these plants produce very attractive flowers.

BVI_June2016
BVI_June2016

The jumping cactus, Opuntia repens, in flower on Great Tobago

An attractive native tree that we encountered and that is widespread across the region is Coccoloba uvifera of the Polygonaceae, locally known as the sea grape.  This dioecious plant is useful for coastal dune stabilisation as it is both wind resistant and salt tolerant.  It is also an attractive ornamental shrub, with the female plants producing large bunches of edible fruit that are purple when ripe and that are consumed raw, used to make jam or fermented to produce sea grape wine.  Unfortunately, we were unable to collect seeds from this species on this trip as the fruits were still green and so not yet ripe.  However, the MSB does have a couple of seed collections of this species conserved in the bank from other localities.

BVI_June2016

BVI_June2016

Coccoloba uvifera, commonly known as the sea grape, with unripe fruits

Fruits on the islands form an important part of the diet of indigenous iguanas.  On the limestone island of Anegada we met up with Kelly Bradley from Fort Worth Zoo, a conservation biologist studying the Critically Endangered Anegada iguana (Cyclura pinguis).  This species was reduced to a population of fewer than 300 individuals due to pressures from feral domestic animals, in particular cats, which kill hatchlings and juveniles for food.  In 1997 a headstart facility was built to enable conservationists to rear hatchlings in captivity.  This facility has been successfully rearing animals until they are large enough to survive alongside cats and can be released back into the wild.  Whether the passage of seeds within fruits through the iguana’s gut facilitates seed dispersal and promotes germination or is detrimental to seed viability is still largely unknown.  As the iguanas’ range became restricted to Anegada during the last deglaciation, the role of the iguana in recruitment of fruit-bearing plants is being investigated by Kelly and Kew staff member, Martin Hamilton, with NPTVI colleagues.

BVI_June2016
BVI_June2016

A juvenile Anegada iguana at the headstart facility

As a relatively new member of the UKOTs team, this field trip was a memorable introduction to the unique flora of BVI and the challenges facing plant conservation in the region.  On this trip we were able to collect seed from plant species on Prickly Pear and Beef Island, two new localities for the MSB.  In total, 12 collections of eight species new to the MSB were accessioned.

Acknowledgements

Thanks to Dr Martin Hamilton for organising the logistics, Kelly Bradley for showing us the Anegada iguana headstart facility, and Kew, NPTVI and Puerto Rico colleagues for sharing their knowledge and expertise of the local flora.  The BVI TIPAs project is funded by HSBC through the 150th Anniversary Fund and the seed collecting work is funded by the Garfield-Weston Foundation through the Global Tree Seed Bank Project.  Regional collaborations and capacity building for NPTVI staff are being made possible through the Darwin Plus funded project [DPLUS030]Building systems and capacity to monitor and conserve BVI’s flora”.

 

The Global Tree Seed Bank Initiative

Introduction to our ‘Guest Blog’ below (by Shelagh McCartan)

I recently spotted an article about the ‘Global Tree Seed Bank Initiative’. I asked Tannis Beardmore, who is involved in the ex situ conservation of native tree species in Canada, to provide some facts and figures about the critically endangered species that are currently under-represented in seed banks.

Guest Blog by Tannis Beardmore (Tree Seed Researcher at Natural Resources Canada, Canada)

There are an estimated 80,000 species of trees in the world. Approximately 450 species are used today in commercial forestry and are stored in forestry seed banks leaving the remaining 79,550 species with uncertain representation in ex situ conservation. Over 9,000 tree species are currently assessed as threatened with extinction, and over 1,100 species are listed on IUCN red lists as Critically Endangered and they are likely to become extinct unless urgent action is taken. Recently, it was identified that 74% of the most threatened trees are absent from ex situ collections. There is such uncertainty with regard to the full impact of a species going extinct. Species diversity ensures ecosystem resilience, giving ecological communities the scope they need to withstand stressors. The U.S. Fish and Wildlife Service have estimated that losing one plant species from an ecosystem can create a cascade of up to 30 other localised plant and animal extinctions.

Seed banking is becoming more important than ever as species populations are disappearing at greatly accelerated rates as a result of a variety of stressors. Given the magnitude and scope of the challenges we face in conserving plant diversity, seed are often the propagule of choice to collect and store. Seed banks can offer the most cost-effective means for storing large numbers of species over long periods of time. Many seed banks were created in the 1970s-80s and were developed to address the global surge in agricultural crop yields. It was recognized that vast amount of agricultural biodiversity was being lost, as farmers abandoned old seeds, often locally developed over centuries, for new hybrids. Excellent initiatives have been developed primarily to address the ex situ conservation of agricultural seed. Recently, there is focus on the ex situ conservation of tree species.

In 2014, the Global Tree Seed Bank Initiative was developed and became possible through funding by the Garfield Weston Foundation in Canada (funding of £5 million). This initiative is a 4-year project which involves the Global Trees Campaign (GTC) and the Millennium Seed Bank Partnership (MSBP) who will work with partners around the world to provide training on seed collection and establish ex situ seed collections for threatened tree species. The GTC was launched as a joint initiative in 1999 between Fauna & Flora International and Botanic Gardens Conservation International to conserve the world’s threatened tree species, while the MSBP is an international conservation project coordinated by the Royal Botanic Gardens, Kew, United Kingdom. The goal of the Global Tree Seed Bank Initiative is to establish an ex situ collection in each species’ country of origin, while back-up collections will also be established at the Millennium Seed Bank.

This initiative has the goal to secure ex situ collections of seed from 500 priority tree species from around the world with a focus on threatened trees. The partnership also aims to increase capacity for seed collection of threatened trees and raise awareness of the value of establishing seed collections for the world’s threatened trees. Currently, the MSBP has already collected seed from 3900 trees over the last 14 years, and as a result of this new project aims to increase its tree collections by 50% over four years (by March 2019).

This initiative is working with existing and new MSB partners across the world to target seed collection of the rarest, most threatened and useful trees. Fifteen countries across four continents are participating in this initiative. Alongside seed collecting, a research programme is being undertaken to improve our knowledge of tree species leading to improved conservation. Propagation protocols are being established for key species and used for forest restoration projects. A DNA fingerprint library of important timber species is being assembled for pinpointing the geographical origin of timber exports. Storage protocols for recalcitrant tree species like oak (Quercus) and magnolia (Magnolia) are being developed. Genetic studies on rare trees are being carried out to help design species recovery programmes in island habitats. Additionally, methodologies are being established to study tree species traits and their resilience to environmental threats, leading to better prioritisation of species for seed banking. This is an exciting initiative which should have a significant impact on conserving some of the world’s most threatened tree species.

For more information about the Global Trees Campaign go to http://globaltrees.org/about-global-trees-campaign/ or email tannis.beardmore@canada.ca.

Seed ecology research for improved restoration in the Cape Floristic Region

Introduction to our ‘Guest Blog’ below (by Marnie Light)

Through some connections to our blog, it was suggest that we ask Dr Patricia Holmes to give us some information on a project that she has been involved in on the restoration of areas of fynbos in the Cape Floristic Region that have been invaded by alien (non-native) species. While this perhaps is not specifically related to ‘forest seed research’, there are certainly aspects of this study that are pertinent to many of our fellow researchers. We hope you find this guest blog interesting!

Guest Blog by Patricia Holmes (Biophysical Specialist, Biodiversity Management Branch, Environmental Resource Management Department, City of Cape Town, South Africa)

Seed ecology research improves restoration potential
in alien-invaded fynbos of the Cape Floristic Region global biodiversity hotspot

The Blaauwberg Nature Reserve spans 1500 ha of irreplaceable lowland habitat within the City of Cape Town Municipality, South Africa. All three vegetation types present are nationally threatened and under-conserved. One of these, Cape Flats Sand Fynbos, occurs on nutrient-poor, acid sands and is one of the most transformed and poorly conserved vegetation types in the country. It also supports 16 endemic plant species and over 80 IUCN-listed as threatened with extinction. Unfortunately, fynbos in the reserve has long been invaded and degraded by the Australian tree species, Acacia saligna, and is a top conservation priority to restore.

Fynbos, like Australian kwongan, is a species-rich, Mediterranean-climate and fire-driven shrubland with a very high proportion of obligate re-seeding species. Many species depend on canopy or soil-stored persistent seed banks for recruitment after fire. However, invading alien tree species out-compete the fynbos and the seed banks are no longer replenished between fires. The restoration potential, therefore, depends on the size and diversity of the residual persistent seed bank in the soil. Species with canopy seed storage, such as proteas, are among the first to be eliminated following dense alien tree invasion.

Earlier research in Sand Fynbos, as well as current research at Blaauwberg (the latter funded by Arcadia through the Millenium Seed Bank Partnership, Kew), have indicated that soil-stored seed banks are indeed highly depleted and that active restoration, in the form of species re-introduction by seed, is required post-alien clearance. Sources of seed for important functional components of the vegetation are in short supply and it is imperative to optimize restoration success through an improved understanding of the required pre-sowing treatments to break dormancy and promote germination and establishment. Current research has focussed on applying fire-related germination cues in the growth chamber, nursery and also in field trials. Some species were found to be stimulated by heat pulse alone (or in combination with smoke), smoke, scarification and diurnal temperature fluctuations for various durations. Application of appropriate pre-treatments to species prior to sowing in the field is showing positive results and demonstrates the importance of seed research in ecological restoration.

For more information on The Centre for Invasion Biology, Stellenbosch University, which is the research partner hosting the students involved in the project, click here.

A patch of Cape Flats Sand Fynbos surrounded by dense alien Acacia saligna at Blaauwberg Nature Reserve
A patch of Cape Flats Sand Fynbos surrounded by dense alien Acacia saligna at Blaauwberg Nature Reserve
An aerial image of the 100ha restoration site indicating the two main alien clearance treatments as well as the uncleared areas
An aerial image of the 100 ha restoration site indicating the two main alien clearance treatments as well as the uncleared areas
Establishment of fynbos species 18 months post-restoration sowing
Establishment of fynbos species 18 months post-restoration sowing

The UK National Tree Seed Project

Introduction to our ‘Guest Blog’ below (by Shelagh McCartan)

During the past three years, I have co-ordinated a collection of juniper berries (Juniperus communis) for the UK National Tree Seed Project, which is overseen by Royal Botanic Gardens, Kew. As such, I have scrambled up mountains and squelched through bogs in England, Scotland and Wales, collecting the sometimes elusive purple berries. I asked the project co-ordinator, Clare Trivedi, to provide background information about this ambitious 5-year project, which involves banking seeds from fifty native trees and shrubs.

Guest Blog by Clare Trivedi (UK Conservation Partnerships Co-ordinator, RBG KEW, UK)

In 2013, Royal Botanic Gardens, Kew (RBG Kew) launched the UK National Tree Seed Project (UKNTSP). The project will build a national ex situ seed collection that is both genetically comprehensive and comprises sufficient seeds to support research and conservation. It will also improve our understanding of how best to sample, source, store, germinate and use seeds from the UK woody flora. Over recent years, a series of high level reports and strategies have made the case for conserving, restoring and extending woodland cover in the UK in order to develop a coherent ecological network, resilient to environmental change. It is widely agreed that this requires an increase in the species and genetic diversity of planting material but there is ongoing debate over what guidance should be given to practitioners on which particular species, of which provenance, are most appropriate for any given tree planting project. In addition, the need to manage the risks from increasing incidence of pest and disease outbreaks in the UK are well recognised and a priority for research activity and practical actions. It is in this context that the UKNTSP was launched by Kew’s Millennium Seed Bank. Thanks to support from players of People’s Postcode Lottery, we are now halfway through a five year initial workplan, focused on a priority list of 50 species. The resulting collections will be accessible to researchers in order to meet the many challenges facing UK trees and woodlands. The job is too big for Kew to take on alone and so we have developed a significant consortium of partner organisations. These range from small, local NGOs through to conservation organisations and government agencies. We have welcomed considerable support from the Woodland Trust, the Wildlife Trusts and the UK forestry agency, the Forestry Commission.

A key challenge for the project has been deciding where and how to make collections of each species in order to ensure they represent the UK genetic diversity of the species. Given that relatively little is known about the population genetics, it was decided that for every target species, seed collections will be made in each of the Forestry Commission Seed Zones where it is native. These seed zones are based on biogeographic data. The first step was to understand the distribution of the target species across the UK. This was achieved by first putting distribution data from the Botanical Society of the British Isles (BSBI) into Geographical Information System (GIS) software. The seed zones map was used as an overlay to determine the seed zone occurrence of each species. Having determined within which seed zones the species should be collected, the next step is to find appropriate woodlands in a given area to visit, in order to collect the target species. We need to ensure that we only collect from trees that are native to the woodlands in which they are found. We also need enough target trees to make a quality collection. This takes time and effort but the result will be a much improved knowledge of the local provenance of seed sources for a wide range of species. Our partners play a significant role in this part of the project. Importantly, we keep collections from every mother tree stored separately in the seed bank, and each tree is geo-referenced and tagged. Overall, we aim for collection sizes of thousands of seeds from each woodland. It is hoped these strategies will maximise the value of the collections for studies such as provenance trials and screening for traits such as pest and disease resistance. We are now halfway through this ambitious project, and expect a significant number of collections to arrive at the bank in the forthcoming collecting season. While we always set out to build a UK National Tree Seed Bank, it is exciting to recognise that we are also building a wide and strong consortium of organisations interested in working to improve the conservation and supply of UK tree seeds.

For more information, please contact Clare Trivedi at c.trivedi@kew.org or see the project website here.

Dornoch, Scotland Glen Ridding, Cumbria Nant y gamar

The Importance of Tree Seed Banking

Introduction to our ‘Guest Blog’ below (by Shelagh McCartan)

Forests and woodlands are increasingly under threat from overexploitation, habitat destruction, climate change, and pests and pathogens. Consequently, there are many efforts to preserve seeds in seed banks worldwide. I asked Katherine O’Donnell for background information about the ‘Global Seed Conservation Challenge’, which she is co-ordinating for Botanic Gardens Conservation International.

Guest Blog by Katherine O’Donnell (Global Seed Conservation Challenge Coordinator, BGCI, UK)

Given the array of ex situ conservation techniques currently available (seed banking, cultivation, tissue culture etc.) there is no technological reason why any plant species should go extinct. Of these various techniques, seed banking is by far the most efficient and effective. By storing seed in seed banks a species is safeguarded from extinction and a source of seed is available when required. Orthodox seeds can be collected from plants, dried and stored in cool conditions for decades and sometimes even centuries until they are required for research, restoration or reintroduction. With 1 in 5 plant species estimated to be at risk of extinction, seed banking is a vital component of plant conservation.

Botanic gardens are the main institutions involved in ex situ conservation of threatened species with one third of wild plant species found in botanic garden collections. Botanic gardens have the expertise to save wild species from extinction. This involves collection in the field, to taxonomic identification in herbaria, research in laboratories, propagation in nurseries and ultimately restoration and reintroduction in the wild. Over 400 botanic gardens around the world maintain effective seed banks for wild plant species, contributing to long term storage of plant diversity. These seed banks store seed from more than 5,000 tree species. Threatened species include the wild relatives of coffee (Coffea macrocarpa and Coffea myrtifolia), mahogony (Swietenia mahagoni) and several species of hibiscus (Hibiscus clayi, Hibiscus scottii, Hibiscus taiwanensis).

Botanic Gardens Conservation International (BGCI) has recently launched the Global Seed Conservation Challenge. This initiative will encourage botanic gardens to work ‘outside the garden walls’ to collect and bank seed of threatened species towards Target 8 of the Global Strategy for Plant Conservation (a program of the UN’s Convention on Biological Diversity). This target calls for ‘at least 75% of threatened species to be in ex situ collections by 2020’. Various prizes will be awarded at BGCI’s next Global Botanic Garden Congress to institutions that, for example, conserve the greatest number of taxa or conserve the most threatened species.

At BGCI we are building the most comprehensive list of tree species in the world. TreeSearch, which is due to be launched next year, currently contains around 70,000 species of which more than 9,000 are known to be threatened with extinction. This data will enable botanic gardens to prioritise banking of species most at risk of extinction, focusing efforts on those that are not already in ex situ collections.

For more information about the BGCI go to Botanic Gardens Conservation International, or to get involved email katherine.odonnell@bgci.org.

Global seed conservation challengeThe location of seed banking institutes with relation to plant diversityErythrina sandwicensis seeds cleaned and ready for storage (Tien Austin)

Erythrina sandwicensis seeds cleaned and ready for storage (Tien Austin)

Ash seed orchards and implications of Chalara

Introduction to our ‘Guest Blog’ below (by Shelagh McCartan)

In Europe, ash (Fraxinus) species are under threat from an emerging disease caused by the fungus Hymenoscyphus fraxineus. Ash dieback (also known as Chalara) is characterised by leaf loss, bark lesions, and crown dieback and is often fatal particularly in young trees. In Britain, the first report of ash dieback was in 2012, but it has since been recorded at over 1000 sites. As a result, there is a ban on the movement of live ash material. Dr Jo Clark, Forestry Research Manager for Earth Trust, has been involved in breeding broadleaved trees including ash (Fraxinus excelsior) for several years. I thought it would be interesting to have a tree breeder’s perspective on the implication of this serious pathogen on ash seed orchards and future breeding programmes.

Guest Blog by Dr Jo Clark (Forestry Research Manager, Earth Trust, UK)

In the UK, The Future Trees Trust, Earth Trust and Forest Research have been working on improving the quality of ash trees for timber for over 20 years.  We started with the selection of superior phenotypes from across the UK, collected seed from them and raised them in a nursery as half sib families.  These were planted out in replicated field trials across four sites and the trees assessed over 15 years to identify which families performed best in terms of form (apical dominance, branching habit) and vigour (height and diameter increment).  Some families performed well across all sites, and others badly across all sites, and as might be expected, other families performed well to a variable degree across sites.   After thinning approximately two thirds of the poorest families, we achieved tested status under the Forest Reproductive Material Regulations (FRM regs) with genetic gains in the region of 8%.  This is the highest category of FRM and the first tested seed for a broadleaved tree available in the UK.  The first seed year after thinning was 2012, the year ash dieback officially arrived in the UK and a ban on movement of live ash material was put in place.

So what now?  The partners, along with the Sylva Foundation, have started a five year work programme called The Living Ash Project to screen the various categories of FRM to identify 400 trees that show a degree of tolerance to ash dieback from which to start a new breeding programme.  Evidence on the continent indicates that about 1% of trees show a good degree of tolerance (less than 10% crown dieback) to Chalara.  We are using the help of citizen science to screen ash trees that are in woodland in the UK and of the lowest category of FRM – source identified.  However, as tree breeders and foresters, it’s important to us that a number of trees that pass the screening process are of good timber quality so we are screening all our ash resources of which we have over 40,000 trees in trials and orchards.  We have stratified the seed that was collected from the tested orchard, and these will be planted out in field trials in winter 2015 in areas of high infection.

We would love for you to get involved.  You can help us find tolerant trees from right across the UK.  We are using Ashtag (a mobile app for your smartphone) to tag trees which are entered in to a database.  You can obtain FREE tree tags from the Sylva Foundation which includes full instructions of what you need to do to help, available from the project website.

For more information please contact Jo.clark@earthtrust.org.uk or see the project website www.livingashproject.org.uk.

2 BSO final thin3 Ash tag

The quest for sterile seed in black wattle

Introduction to our ‘Guest Blog’ below (by Marnie Light)

Shelagh and I thought that an article by Dr Sascha Beck-Pay would be an interesting addition to the blog. Sascha, one of my colleagues, worked on a project for several years with the aim of developing a sterile black wattle tree in order to reduce the seed load of this commercially important, yet invasive species, in South Africa. So, in one sense this research does fly in the face of seed scientists (we love to see seeds germinate!), but it does highlight some interesting research…

Guest Blog by Sascha Beck-Pay (Senior Research Scientist at the Institute for Commercial Forestry Research, South Africa)

In South Africa, black wattle (Acacia mearnsii) is a leading commercially grown forestry tree species. However, it is also considered to be an exotic invader of indigenous vegetation. This ‘alien invader’ status adds pressure on the forestry industry, making future afforestation to black wattle difficult, particularly for small-scale growers. Thus, the production of a sterile or seedless variety of black wattle was considered a favourable solution to help reduce the contribution of seed to the existing seedbank, thereby potentially removing the invasive status of black wattle whilst allowing the forestry industry to continue as a thriving contributor to the South African economy.

A project was conducted within the Acacia Breeding Programme at the Institute for Commercial Forestry Research (ICFR) in South Africa to try and produce a sterile or seedless tree using the following two approaches:

  • The production of a triploid variety; and
  • The use of gamma irradiation techniques to produce sterile trees.

With the first approach, tetraploids were successfully induced and controlled-crosses were made with diploids. Due to the fact that no triploids were produced from the controlled-crosses, reproductive biology studies were conducted to investigate possible barriers that could be preventing this. Fluorescent microscopy revealed that, in the cross between diploids and tetraploids, the pollen tubes were reaching the ovary and ovules indicating that fertilisation was possible and that the barrier preventing seed maturation was located within the ovary. Embryo rescue, using tissue culture techniques, was then attempted at varying stages of pod development post-fertilisation. Due to the small size of the pods, however, it was impossible to identify and isolate a clean embryo, devoid of maternal tissue, until 11 months post-fertilisation, at which stage embryo abortion would have occurred.

The second approach tested the use of gamma irradiation to induce sterility in seeds. Samples of seed were irradiated, the seedlings raised in a nursery, and then established in a field trial. It was apparent that reductions in flowering and seed production occurred at doses of 350, 400, 450 and 520 Gy. Although seed production was not completely eliminated, reductions of up to 50 % were recorded. Where seed was produced, the seed was determined to be viable, leading to the conclusion that, although seed production can be reduced, the viability of the seed is not affected and thus gamma irradiation does not affect the female reproductive structures of the plant. This suggested that reduced flowering and resultant lower seed production could be as a result of male sterility, although this still needs further investigation. At the doses tested, there was no detrimental effect on the growth of the trees, which makes this approach to reducing seed production quite promising.

The project was conducted over a period of 12 years from 2000 to 2012 and, although a number of advancements were achieved in trying to produce a sterile or seedless variety of black wattle, the project was closed due to funding constraints. For more information contact Sascha Beck-Pay, or for click here for further reading.

Black wattle inflorescences Diploid and tetraloid polyadsStigma with multiple polyads attached

Small spores, but potentially big impact!

Introduction to our ‘Guest Blog’ below (by Shelagh McCartan)

During December, I was routinely assessing seeds that had failed to germinate during a germination test. Sometimes, ungerminated seeds can be overwhelmed by various moulds, particularly when incubated at warm temperatures for a few weeks.  On this occasion, I spotted an unusual-looking mould, which I passed onto Caroline Gorton for identification. She identified it as an Aspergillus mould – from which a person can develop health problems. It is, therefore, important to be aware of this, and take the necessary precautions. The bottom line is to ‘work smart and stay safe’!

Guest Blog by Caroline Gorton (Diagnostician in the Tree Health Advisory and Diagnostic Service, Forest Research, Britain)

Aspergillus is a ubiquitous mould found in air and soil.  Aspergillus, like other moulds, thrives in humid environments and spores can reach high levels in damp housing and compost.  Most people are immune to infection; however, people with damaged lungs, allergies or a compromised immune system may develop aspergillosis.  The type of disease can vary from an ‘allergy’ type response to life threatening invasive infections.

These images were taken of Aspergillus which had grown in a germination box containing seeds of European silver fir (Abies alba).  As Aspergillus is a common member of the microbial flora, it may well be present on seeds which are incubated and the moist conditions are perfect for its growth.  It is, therefore, worth being aware of when assessing seeds as the spores can cause significant health problems.  It is advisable to work in a well-ventilated environment or to wear a HEPA filter face mask if moulds are present.  Further information is available here.

Aspergillus 3 Aspergillus

Manufactured seed – Is this the future?

Introduction to our ‘Guest Blog’ below (by Shelagh McCartan)

During September, I was able to attend a very well-organised conference in Vitoria-Gasteiz, Spain (IUFRO Working Party 2.09.02 – Somatic Embryogenesis and Other Vegetative Propagation Technologies). For more information on the conference click here. I learned a great deal, particularly around the problems regarding ‘maturation of embryos’ and ‘conversion to plantlets’, and I believe that there is scope for input from seed scientists. I was particularly fascinated by the presentation by Jeff Hartle and his colleagues from Weyerhaeuser on ‘manufactured seeds’, and requested Jeff to send us some more information on this interesting topic.

Guest Blog by Jeff Hartle (MSeed Development Scientist, Weyerhaeuser Co.)

Modern agriculture often requires the planting of large numbers of genetically identical plants that have been selected to have advantageous properties. Production of new plants by sexual reproduction, which yields botanic seeds, is usually not feasible. Asexual propagation, via several pathways has been used for many years to produce large numbers of genetically identical individuals. In many species these are called varieties. One method to produce varieties is to use somatic embryogenesis. At Weyerhaeuser, we have developed machinery, protocols and logistics for the large-scale automated production of conifer somatic embryos. We have also developed a synthetic seed technology we call ‘manufactured seed’ that are made on an automated assembly line. This system allows large quantities of manufactured seed to be produced with minimal labor. As compared to most clonal techniques, the use of somatic embryos with manufactured seed allows steady-state manufacturing. As manufactured seed are created, they can be stored allowing a large quantity to be produced over time. When conditions are right for planting, the manufactured seed can be pulled from storage and planted en-masse. Manufactured seed also allows for centralized manufacturing with shipping to various facilities for planting. We have tested manufactured seed with several conifer species, but also found good performance with dissected corn, wheat and soybean embryos.  For further information, click here.

JH1-r JH3-r JH2-r