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The Research Centre for Forest Tree Improvement (RCFTI) is a unit within the Forest Science Institute of Vietnam (FSIV) which specialises in tree improvement research and delivery of genetically improved seed and planting stock to meet the planting requirements of the Government of Vietnam (GoV) as well as community and private sector plantation programs. RCFTI carries out an active program of research at stations throughout Vietnam, with its principal research station at Ba Vi. RCFTI has implemented genetic improvement programs for both many indigenous species and fast-growing exotic species of the genera Acacia, Casuarina, Eucalyptus, Melaleuca and Pinus which dominate short-rotation plantation forestry in Vietnam....

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Nội dung Text: Báo cáo nghiên cứu nông nghiệp " RESEARCH CENTRE FOR FOREST TREE IMPROVEMENT Forest Science Institute of Vietnam and AUSTRALIAN TREE SEED CENTRE Ensis, the joint venture between CSIRO and Scion "

Seed Operation Manual.doc 22/08/2007 Ministry of Agriculture & Rural Development ___________________________________________________________________________ BRIAN GUNN Ha Huy Thinh Phi Hong Hai Nghiem Quynh Chi Nguyen Tuan Hung RESEARCH CENTRE FOR FOREST TREE IMPROVEMENT Forest Science Institute of Vietnam and AUSTRALIAN TREE SEED CENTRE Ensis, the joint venture between CSIRO and Scion HANOI, 2006
Seed Operation Manual.doc 22/08/2007 CONTENT INTRODUCTION ..................................................................................................................... 4 T UT 54H SECTION 1. SEED COLLECTION ......................................................................................... 6 1HTU UT 5H 1.1 Planning ..................................................................................................................... 6 2HTU UT TU UT 56H 1.1.1 Forward planning .............................................................................................. 6 3HTU UT TU UT 57H 1.1.2 Timing of collection .......................................................................................... 7 4HTU UT TU UT 58H 1.1.3 Determination of seed crop maturity ................................................................. 8 5HTU UT TU UT 59H 1.1.4 Training of staff ................................................................................................. 9 6HTU UT TU UT 60H 1.2 Collection strategies ................................................................................................ 10 7HTU UT TU UT 61H 1.3 Collections from planted seed stands ...................................................................... 10 8HTU UT TU UT 62H 1.3.1 Collections from seed orchards ....................................................................... 10 9HTU UT TU UT 63H 1.3.2 Collections from Seed Production Area .......................................................... 11 10HTU UT TU UT 64H 1.3.3 Collections from plantations............................................................................ 11 1HTU UT TU UT 65H 1.4 Collections from natural populations ...................................................................... 12 12HTU UT TU UT 6H 1.4.1 Provenance collections .................................................................................... 12 13HTU UT TU UT 67H 1.4.2 Sampling trees within a provenance ................................................................ 13 14HTU UT TU UT 68H 1.5 Collection methods .................................................................................................. 14 15HTU UT TU UT 69H 1.6 Harvesting techniques ............................................................................................. 15 16HTU UT TU UT 70H 1.6.1 Recording field data ........................................................................................ 16 17HTU UT TU UT 71H 1.6.2 Botanical voucher specimens .......................................................................... 17 18HTU UT TU UT 72H SECTION 1. APPENDICES ............................................................................................... 21 19HTU UT 73H Appendices to section 1 ....................................................................................................... 21 20HTU UT 74H SECTION 2. SEED PROCESSING ........................................................................................ 32 21HTU UT 75H 2.1.1 Pre-processing ................................................................................................. 33 2HTU UT TU UT 76H 2.1.2 Drying .............................................................................................................. 33 23HTU UT TU UT 7H 2.1.3 Seed Extraction................................................................................................ 33 24HTU UT TU UT 78H 2.2 Cleaning................................................................................................................... 34 25HTU UT TU UT 79H 2.2 Registration, documentation and categorising seed ................................................ 35 26HTU UT TU UT 80H 2.2.1 Individual tree and bulk seed........................................................................... 35 27HTU UT TU UT 81H 2.3 Documentation ........................................................................................................ 36 28HTU UT TU UT 82H SECTION 2. APPENDICES ............................................................................................... 38 29HTU UT 83H Appendices to section 2 ....................................................................................................... 38 30HTU UT 84H SECTION 3. SEED TESTING ............................................................................................... 42 31HTU UT 85H 3.1 Sampling .................................................................................................................. 42 32HTU UT TU UT 86H 3.2 Purity analysis ......................................................................................................... 43 3HTU UT TU UT 87H 3.3 Seed dormancy ........................................................................................................ 43 34HTU UT TU UT 8H 3.3.1 Procedures to break seed-coat dormancy ........................................................ 43 35HTU UT TU UT 89H 3.3.2 Procedures to overcome embryo dormancy .................................................... 44 36HTU UT TU UT 90H 3.4 Germination testing ................................................................................................. 44 37HTU UT TU UT 91H 3.4.1 Test conditions ................................................................................................ 45 38HTU UT TU UT 92H 3.4.2 Evaluation ........................................................................................................ 46 39HTU UT TU UT 93H 3.5.1 Re-test .............................................................................................................. 46 40HTU UT TU UT 94H 3.6 Moisture content ...................................................................................................... 47 41HTU UT TU UT 95H 3.7 Other issues ............................................................................................................. 48 42HTU UT TU UT 96H SECTION 3. APPENDICES ............................................................................................... 50 43HTU UT 97H Appendices to Section 3 ...................................................................................................... 50 4HTU UT 98H SECTION 4. STORAGE ......................................................................................................... 56 45HTU UT 9H 2
Seed Operation Manual.doc 22/08/2007 4.1 Moisture content ...................................................................................................... 56 46HTU UT TU UT 10H 4.2 Temperature............................................................................................................. 56 47HTU UT TU UT 10H 4.3 Atmosphere ............................................................................................................. 57 48HTU UT TU UT 102H 4.4 Storage procedures at RCFTI for orthodox seed ..................................................... 57 49HTU UT TU UT 103H 4.4.1 Fumigation....................................................................................................... 57 50HTU UT TU UT 104H 4.4.2 Seed storage ..................................................................................................... 57 51HTU UT TU UT 105H 4.4.3 Maintaining seed identity in storage................................................................ 58 52HTU UT TU UT 106H REFERENCES ........................................................................................................................ 60 53HTU UT 107H 3
Seed Operation Manual.doc 22/08/2007 INTRODUCTION The Research Centre for Forest Tree Improvement (RCFTI) is a unit within the Forest Science Institute of Vietnam (FSIV) which specialises in tree improvement research and delivery of genetically improved seed and planting stock to meet the planting requirements of the Government of Vietnam (GoV) as well as community and private sector plantation programs. RCFTI carries out an active program of research at stations throughout Vietnam, with its principal research station at Ba Vi. RCFTI has implemented genetic improvement programs for both many indigenous species and fast-growing exotic species of the genera Acacia, Casuarina, Eucalyptus, Melaleuca and Pinus which dominate short-rotation plantation forestry in Vietnam. The programs include species, provenance trials and progeny testing, establishment and management of seed orchards and seed production areas, breeding, propagation and testing of superior clones for clonal forestry. Another important mandate of RCFTI is transfer of technological advances in forest tree improvement to government production units. RCFTI has extensive experience in international cooperation in tree improvement research with research institutions in many countries including Australia, China, Denmark and Sweden. The Centre has successfully implemented projects supported by donors such as ACIAR, AusAID, IPGRI and Sida-SAREC. As the result of many research cooperation years between RCFTI and the Australian Tree Seed Centre (ATSC) - part of CSIRO Forestry and Forest Products, a series of seed production areas (SPAs); seedling seed orchards (SSOs) and clonal seed orchards (CSOs) for fast-growing exotic species of the genera Acacia, Casuarina, Eucalyptus, Melaleuca and Pinus were established throughout the country. These seed stands are designed to reduce the dependence on seed from poor quality local land races of the same species. It is expected that the use of good quality seed, together with improved silviculture, will enable substantial productivity and value gains from tree plantations. The Government of Vietnam has recently embarked on a massive tree plantation program, the National Five Million Hectares Reforestation Programme (5MHRP). 5MHRP was issued by Decision No. 661/QD-TTg of the Prime Minister on 29 July 1998 as an urgent task in response to the dwindling forest resource. The forest cover has been shrinking on average at a rate of 100 000 hectares per year because of clearing for food production, shifting cultivation, wild fires and uncontrolled wood and timber extraction. This has led to losses in forest area and degradation of land and forest resources. The overall objective of the programme is to reforest and rehabilitate 5 million ha of forest by the year 2010 comprising: (i) 2 million ha which has 1 million ha for protection and special-purpose forests and 1 million ha for planting new forests; (ii) 3 million ha of production forests - 2 million ha and perennial industrial trees and fruit trees - 1 million ha. This dramatic expansion will require equally dramatic increases in germplasm supply of a wide range of productive species adapted to the different ecological zones in Vietnam. The GoV is committed to improving the quantity and quality of tree seed to maximize success and product yield through increased production of seed from seed orchards rather than relying on seed of inferior or unknown genetic quality and imported seed. The Collaboration for Agriculture and Rural Development (CARD) Project 058/04 VIE “Strengthening Capacity in Forest Tree Seed Technologies Serving Research and Development Activities and ex situ Conservation” has been designed to support the Research Centre for Forest Tree Improvement (RCFTI) in developing seed technologies to meet this requirement. This operations manual is an output from the project with the purpose of standardizing procedures for RCFTI staff required to carry out seed handling activities. 4
Seed Operation Manual.doc 22/08/2007 The manual deals with the physical handling of the seed from the time it is collected off the tree until it is dispatched to the grower. However, the manual takes in to account steps that need to be taken to ensure genetic seed quality is retained. These steps are linked to guidelines also prepared under this project including ‘Seed Production Areas; Guidelines for Establishment and Management Practices and Genetic Improvement for Eucalypts in Vietnam. While the manual is designed specifically for RCFTI and therefore handling seed associated with research activities, the information has application for anyone wishing to handle tree seed. The techniques are also applicable to collecting for conservation of species where it may be necessary to collection from individual trees where identity of seed from each tree is vital. The different processes covering collection, cleaning, processing, testing, storage and finally seed dispatch are discussed with the focus on ensuring accurate identity of the seed and maximizing physical quality of the seed at all times. It is hoped that this manual will be helpful to RCFTI and other forestry research and production units of Vietnam who are interested in growing trees and expand the current knowledge of seed handling. Acknowledgements The financial assistance of the Australian Agency for International Development in supporting the CARD project is acknowledged together with the support of the Vietnam Ministry of Agriculture & Rural Development. Project scientists from Ensis CSIRO : Messrs Khongsak Pyniopusarerk, John Lamour, Mrs Bronwyn Clarke and Mrs Debbie Solomon, as well as Prof. Le Dinh Kha, Mr Nguyen Duc Kien, Ms Can Thi Lan, Mr Mai Trung Kien, Ms Duong Thanh Hoa and RCFTI’s other researchers and staff who have provided many insights and constructive suggestions to this Operation Manual. 5
Seed Operation Manual.doc 22/08/2007 SECTION 1. SEED COLLECTION This section summarises seed collection methods carried out by the RCFTI. Whilst the main emphasis is on the collection of seed, field work also involves the collection of herbarium specimens for botanical studies, leaf samples for analysis, wood samples, scions and pollen for breeding programs. The collection program is strongly influenced by seed demand and project objectives. RCFTI has over 30 seed stands comprising seed orchards and seed production areas as outlined in Appendix 1.3. Most of these seed stands have been converted from research breeding trials in to seed stands and therefore retain considerable importance for research purposes while also serving as a source of genetically improved seed. However, RCFTI is planning to increase the production of seed from current seed stands and to expand the area under seed stands to meet future demand for seed of priority species. Most of the collections are for research purposes involving individual tree collections within the seed orchards. Because seed collections from most of the seed stands are for research purposes, RCFTI staff supervises all collections using local contracted people to climb trees and harvest crops. Prior to collections, RCFTI staff contact the collaborators to assist with collection arrangements 1.1 Planning Seed collection should form part of RCFTI’s overall management strategy of operation. RCFTI’s current collect strategy is based on seed collections to meet tree breeding objectives. However, with the current seed stands reaching full production by 2010 and requirement to generate income from the seed stands, RCFTI will also be looking towards maximising seed production from its seed stands. With this in mind, RCFTI will needs to set in place a long term seed collection program to meet these objectives. For commercial collections, it is important to develop markets for the sale of the seed both in advance of the seed collection and seed held in store. Long term planning needs to be in place to develop resources which ensures that the seed collection targets are met and seed quality is retained. The following provides some guidelines on what to consider when planning. 1.1.1 Forward planning Once the overall priority seed collections plans are in place, forward planning is required to ensure the success of the seed collection. The most critical part of planning is to ensure that the collection team arrives at the collection site to coincide with seed maturity. In some instances the opportunity to collect fully mature seed may only be a matter of a week. By arriving too early, the seed is still immature and will not retain viability in storage or if too late the seed has already shed. In order to plan the collection properly, the seed crop may require to be monitored on a regular monthly basis by field staff who are well trained and equipped to observe phonological development of the species. When planning seed collections you need to know: What is the planned seed collection program for the year or even for the next two to three years? Include here some estimate of the quantity of seed likely to be harvested / required from each location. When will the seed mature? Species may mature at different times across the country so information on flowering and fruiting times for the different seed stands needs to be developed (Appendix 1.2). 6
Seed Operation Manual.doc 22/08/2007 What is the purpose of the seed collection? For example, it might be for establishment of commercial plantations, community use, conservation, provenance trials, family trial or seed orchards. For seed collections from the natural forest, determine the location of the provenances to be collected, the approximate number of trees to be sampled from and quantity of seed required to meet objectives. Who will be involved in the collections? Staff who are involved whether they be RCFTI or from local provincial forestry office must be trained, suitably equipped and understand what is required of them. What documentation and labeling is required to accompany the seed collection and do the collection staff know what is required? What will happen to the fruit once it has been collected? Plan what containers should be used, where to store the seed post harvest and decisions round cleaning the seed. What funds are required to achieve a successful seed collection program? What equipment is required? 1.1.2 Timing of collection A key factor in planning is to time seed collecting to coincide with peak maturation of the main seed crop. In the case of a number of tropical species including acacias, there may be more than one onset of flowering but only one peak fruiting crop coinciding with a particular season or time of the year. Many rainforest species do not flower and fruit every year and may typically flower at intervals of two to three years or at longer intervals. It is important to monitor information on flowering and fruiting of species across the country to include specific monitoring of seed stands. Appendix 1.2 provides information on seeding times for a range of species handled by RCFTI. This table will need to be updated as more phenological information is gathered under the annual survey according to Appendix 1.1a&b. Phenological Data Form. The following information should be gathered when determining when to undertake seed collections: • When will the seed crop mature? • Are there previous phonological records on the species to be collected? Refer to Appendix 1.2 botanical records and literature. • Are there contacts at the collection site who would provide reliable information on seed phonological development? It may be possible for local forestry staff to send botanical specimens containing flowering or fruit to RCFTI on a regular monthly basis as a way of monitoring phenological activity. • How many trees are flowering and fruiting? This can affect outcrossing rates and the genetic quality of the seed collected. For planted stands such as see productions areas, a rough inventory should be carried out to determine if sufficient quantity of seed is available to warrant collection. Collections should not be made if only a few trees are fruiting. Seed collected from these trees are likely to be of poor genetic quality. Refer to the ‘Guidelines for Establishment and Management Practices for Seed Production Areas’ prepared under the project (Pinyopusarerk 2005). For example, Pinyopusarerk and Harwood (2003) recommend at least 50% of clones within a CSO should flower before making seed collections. Similarly in natural populations, there needs to be seed crops on unrelated trees across the population to enable a collection from at least 10 trees. 7
Seed Operation Manual.doc 22/08/2007 • Under some circumstances it may be necessary to travel to the collection site in advance of making the seed collection to determine development of the seed crop. This is necessary where there is no information available. 1.1.3 Determination of seed crop maturity The ability to distinguish fruit bearing trees, especially from a distance and with tall trees, is dependent on the species and the skills of the collector. Fruit crops are most easily identified on a sunny day, when the sun is at a low angle (i.e. early to mid morning and late afternoon) and the light behind the observer. This is when differences in colour and shape can be best observed. Binoculars with a moderate magnification of x 8 or x 10 with a 25 or 30 mm aperture, is essential for both locating and assessing crops on potential seed trees. Fruit or seed lying on the ground can also provide an indication of crop maturity. It is important though to take into account how long the fruit has been shed from the tree and whether it is representative of the crop. At some stage of crop development, which may not be at the stage of crop maturity, birds and mammals frequently feed off the crop. This often results in large amounts of fruit being dropped to the ground giving the false impression that the tree is shedding its mature crop. While maturity characteristics for dry (orthodox) and fleshy (recalcitrant) seed are similar, there are a few differences mainly associated with moisture content of the seed and their sensitivity to handling and storage. Dry seed should have a low moisture content at maturity while fleshy seed has a high moisture content at maturity. Points to consider when assessing seed crop maturity: Experience based on knowledge of fruit size, colour, embryo development and firmness of the fruit and seed for any given species is a key factor in determining crop maturity. This knowledge needs to be built up over time. Dehiscent fruit (where the fruit splits open to release the seed e.g. Acacia pods) will start splitting just prior to seed shed. This is a very good time to collect provided all the crop can be harvested before the fruit opens fully. If unsure of dehiscent fruit maturity, dry a sample of fruit in a sunny location for a couple of days and observe the progress of fruit opening and seed shed. When observing fruit in the tree crown, ensure that the fruit contain seed. In some species the fruit open to release the seed on maturing, while the fruit is still attached to the tree. The fruit may then close again giving the appearance that they still contain the seed. Some species have male and female flowers on separate trees (dioecious) such as casuariana. Mature seeds have a firm white endosperm (where present) and a fully developed firm embryo. The seeds must not shrink when dried. For rain forest fruit, familiarisation with fruit colouring during development is an important factor in determining maturity. Softness, moisture content and seed shed are also important indicators. Insect damage can reduce the number of viable seeds and may even give fruit a false appearance of maturity by causing a colour change. It is important to continuously monitor the level of insect attack in a seed crop, as this can vary considerably between trees and populations. Examples of assessing crops of specific species: 8
Seed Operation Manual.doc 22/08/2007 For Eucalyptus, Melaleuca and other genera within Myrtaceae which produce capsules. The lines of dehiscence on the capsule become pronounced as the fruit matures, and once fully mature, the valves of the capsule usually open partially although the seed are not released. Non-viable immature seed are frequently pale in colour and the embryo is milky and rather soft when squashed. The seed can be inspected by cutting open the capsule with a pair of secateurs revealing the seed which should have white firm embryos with dark seed coats, and brown chaff towards the top of the capsule (Boland et al. 1980). Acacia pods and seed are usually dark in colour while the seed has a hard seed coat. Seed that is still green or dark and soft when pressed may mature depending on the species, drying conditions and the stage of development. Where it is uncertain whether the crop is sufficiently mature to collect, take a sample of pods and leave them to dry in a shady location for a few days. If the seed remains swollen and seed coat turns hard, then there is a strong likelihood that the seed is sufficiently mature to collect. Drying can also take place in the sun but this method is more severe. Pine cones must be harvested before opening. Cone maturity is normally based on colour with maturity fairly consistent each year. Most species hold on to their cones for a reasonable period of time but knowledge of each species will define more preciseltre the timing and duration available for collecting. Once dislodged from the trees, cones are individually collected and bagged ready for drying. Xylia xylocarpa var. xylocarpa (Cam xe –Vietnamese name). Fruits are harvested when they have turned dry and yellow and the first fruits have started to open; seeds should have lost their greenish immature colour. Fruits may be harvested directly from the tree before dehiscence, as the seeds are lost when the pods open. Harvesting implies climbing or use of long handled tools. Harvested fruits are dried in the sun to dehisce, so the seeds are released when the pods open. The pods are removed manually. Seed can be cleaned by screening and blowing; it is easy to achieve a high purity. Illicium verum fruits (Hoi – Vietnamese name) are harvested directly from the tree when they are still green and dried first in the shade and then in the sun. After a short sun drying the seeds are extracted manually. Dead or damaged seed can be separated from fresh seed by flotation Schima wallichii (Voi thuoc) seeds are mature when the fruit turns from green to yellow-brown, seed grey-brown and seed wing yellowish (L Schmidt and Nguyen Xuan Lieu 2004). Dacrycarpus imbricatus (Thong nang) is dioecious. Seeds are mature and will disperse once the aril (receptacle) turns bright red or brownish. Best to harvest from the tree. If collected from the forest floor, the ground should be cleaned since the fruit are small and inconspicuous once the aril loses colour (L,. Schmidt and Nguyen Duc To Luu 2004). 1.1.4 Training of staff As indicated at the start of this section, staff are involved in all collections from RCFTI seed stands. At each collection location, staff engage local contract labourers to assist with the physical activities involving climbing, seed harvesting and processing. All staff must receive training in collection methods, aspects of safety following procedures detailed in the project workshop on ‘Safe tree climbing and seed collection’. Inexperienced staff must be accompanied by experienced staff in order to learn on the job. Tree climbers who may be based at the field station must receive training in safe tree climbing techniques. 9
Seed Operation Manual.doc 22/08/2007 1.2 Collection strategies Seed collections are either obtained from planted stands as in the case of seed orchard (SO), seed production area (SPA), seed stand or from natural stands. The method of seed collection from planted and natural stands is often different and may influences the genetic quality of the seed collected. In the case of planted stands, the origin of the parent tree may be known as in the case of a seed orchard whereas parent trees in a SPA are not known. However, in SPAs, the origin of the seedlot used should be known. In the case of trees occurring in the natural forest, the seed collector can establish the origin of the seed, otherwise referred to the provenance but does not know the relatedness of one tree to the other. The following provides guidelines when collecting seed from different seed sources. 1.3 Collections from planted seed stands RCFTI have over 30 seed stands comprising SPAs, SSOs and CSOs represented by over 15 species. A list of the current seed stands is provided in Appendix 1.3. It is anticipated that these stands will produce in excess of 500 kg per year once mature. Plans are underway to increase the area of genetically improved seed stands by 2010. It is therefore very important that rigid procedures be put in place for collections from these genetically improved stands to ensure that the genetic quality of the seed is retained and that care is taken to ensure that subsequent seed crops are not jeopardised by excessive damage to the tree crowns. 1.3.1 Collections from seed orchards Well-designed and managed seed orchards are a means of obtaining large quantities of genetically improved seed. It is important to know the history of the seed orchard, including the following: origin of the material used to establish the orchard (provenance and family origin, numbers of families, and whether it is a first-generation orchard using material collected from natural stands, or whether it is an advanced generation orchard based on material collected from plantations or a breeding program) field layout (if family identity has been retained) history of the orchard – extent of thinning, material after thinning relative to that initially used to establish the orchard. Do not collect seed from orchards until at least 30% of individual trees (or clones, in the case of a clonal orchard), flower and set seed to produce the crop that is being collected. Avoid collecting from trees that have flowered out of phase with the others in the orchard (early or late flowering), as this seed may be highly inbred. Seed orchard seed is generally more valuable than seed from natural provenances, so greater care is needed during harvesting, to avoid disrupting later crops. • it will generally be appropriate to maintain separate individual seedlots of the best trees in the orchard with individual tree identity retained. • when recording the seed orchard details, provide information on reference documents describing the seed orchard, its physical location, whether it is a seedling seed orchard (SSO) or clonal seed orchard (CSO), and the original genetic material (natural provenance source). Where possible provide a reference document describing the history of the seed orchard. 10
Seed Operation Manual.doc 22/08/2007 1.3.2 Collections from Seed Production Area As with SO, a well-designed and managed SPA can provide valuable genetically improved seed. It is important to maintain records relating to the origin of the seed used to establish a SPA to include: origin of the material used to establish the orchard (provenance and family origin, numbers of families, and whether it is a first-generation SPA using material collected from natural stands, or whether it is an advanced generation SPA based on material collected from plantations or a breeding program); history of the SPA – extent of thinning, material after thinning relative to that initially used to establish the SPA. Do not collect seed from SPA until at least 30% of individual trees (or clones, in the case of a clonal orchard), flower and set seed to produce the crop that is being collected. Avoid collecting from trees that have flowered out of phase with the others in the orchard (early or late flowering), as this seed may be highly inbred. SPA seed is generally more valuable than seed from natural provenances or genetically unimproved stands, so greater care is needed during harvesting, to avoid disrupting later crops. When recording the SPA details, provide information on reference documents describing the SPA, its physical location and the original genetic material. Where possible provide a reference document describing the history of the seed orchard. There are various options for seed harvesting in SPAs. As indicated by Pinyopusarerk (2005) in his Guidelines for Establishment and Management of SPAs under the CARD 058/04VIE Project, excessive lopping of branches can result in the trees taking many years to recover to the stage where it will reproduce seed again. The author has suggested the following. Divide the SPA in to equal sized sections based on rate of recovery in years resulting from lopping the branches (eg. if the species takes 4 years to recover from lopping the branches then the SPA is divided into 4 equal portions). Each section is then designated for seed production. Alternatively, if the species only has peak fruiting crops every 3 – 4 years, then it may be more desirable to harvest as much of the crop in that leak year then allow the trees to recover in time for the next big crop. Market forces may also impact on the amount of seed to be collected. Note: The key difference between a SO and a SPA is that in the case of an SPA the family identity of each tree (ramet) is not known. 1.3.3 Collections from plantations Seed collections from plantations should only be considered where appropriate information on the origin of the seed used to establish the plantation is available and the genetic based considered appropriate to use for future plantings. The stand must contain an adequate genetic base in terms of the species, provenance and the number of unrelated parent trees. Collections would not normally be made from plantations that have been established from seedlots comprising fewer than 10 unrelated seed trees. Where plantations have the desired attributes, seed collections can be made from selected trees with the desired characteristics. Phenotypic selection is more likely to result in genetic gain in plantations compared with natural stands, because the trees in a plantation are of uniform age and exposed to a more uniform environment. 11
Seed Operation Manual.doc 22/08/2007 The field collection data sheet is still used to record the collection details except that a clear reference under ‘Location’ requires to be made that the collection is from a planted stand and name the original source (provenance). 1.4 Collections from natural populations 1.4.1 Provenance collections Provenance is the natural place of origin from which a seed collection is made. It comprises a geographical area and environment in which the trees have developed through natural selection. The idea of provenance implies that genetic patterns of variation are associated closely with the ecological conditions in which the species evolved (Turnbull and Griffin 1986) and that some morphological or other traits can be recognized to characterize them. No taxonomic structure is applied to provenance naming. The ‘ideal’ provenance based on Barner (1975) is: composed of a community of potentially interbreeding trees of similar genetic constitution (and of significantly different genetic constitution from other provenances) sufficiently large for the seed collection to provide sufficient seed to meet objectives the boundaries of provenances depend on the natural distribution pattern of the species. If a species is restricted to a single site or the distribution is limited and discontinuous, the term ‘provenance’ may be synonymous with ‘site’ and can be readily defined. The problem of delineating provenances is much more difficult with species that occur over an extensive area – during initial sampling, provenance boundaries may have to be set in an arbitrary way in the absence of hard information on geographic variation. Provenance names often refer to the nearest landmark e.g. river, nearest road, town, geographic feature followed by the local provincial region. It is essential that the location of the collection be sufficiently precise to enable others to return to the location The choice of provenances collections to represent species should take into account variation in climate, soil, elevation and species distribution. There are no hard and fast rules. The number of provenance collections to represent a species depends on the objective of the collection and the extent of the distribution of the species. Some guidelines are provided below: For species which occur across a very uniform environment then an arbitrary selection of provenance sites can occur representing the geographical range. For species with a very restricted and disjunctive distribution, it may be necessary to sample all sites even for use in a species trial. For species in which comprehensive provenance trials have already been conducted, the published results are an important source of information when determining which provenances to focus on. Acacia mangium is an example where considerable scientific literature is available on provenance performance across many different sites. Sampling provenances within species can be split according to two distinct requirements: 12
Seed Operation Manual.doc 22/08/2007 1. Sampling methods for species introduction trials. 2. Wide-ranging sampling of many provenances to represent part or whole of the distribution for use in provenance trials. For the first requirement, where there is little known about the species variation, several provenance collections should be made to include: Sampling from that part of the natural range where the species appears to be growing best. Part of the range that most closely matches the climate for which the seed is required. Marginal sites within the natural range. For the second requirement (wide-ranging sampling for provenance trials) the number of sources sampled will depend on the extent of the natural distribution, the diversity of the species, ease of access, seed availability, time available, money, staff resources, and other resources available to mount a collecting expedition. A knowledge of the breeding system of the target species and its pollen and seed dispersal mechanisms will assist in determining the collection strategy. Because of the frequent limitations placed on resources, there is a trade-off between numbers of provenances collected and numbers of trees sampled per provenance. It is frequently a question of whether to collect from a few provenances with a large number of trees per provenance as against a large number of provenances with limited trees per provenance. 1.4.2 Sampling trees within a provenance The following guidelines should be used to determine how many trees to sample within a provenance: For each provenance, collect from a minimum of about 10 trees. In the case of proven provenances showing high levels of genetic diversity, it may be desirable to collect from up to 100 or more trees as part of a base population for intensive breeding programs. Larger numbers of trees per locality, 50-100 or more, are sampled after provenance trials have shown which provenances are best and where there is a requirement to obtain large quantities of seed. These large samples become base populations for further selections (plus trees). Selections should aim to sample unrelated trees that cover the genetic variability of the population. To reduce the probability of sampling trees that are siblings, seed should be collected from trees which are at least seed-fall distance apart from each other; this means about twice the average height of the trees (Eldridge et al. 1993). 100 m is a useful rule of thumb for tall forest trees. Collect from trees of above average form. Avoid trees that show signs of disease and where timber characteristics are important, avoid trees exhibiting spiral grain. Normally no particular attention is given to selecting and collecting plus-trees in natural stands as environmental and competition effects are unknown. Selected trees must be carrying a mature seed crop. It is desirable to collect approximately equal quantities of seed from each tree. However, in practice the aim is to collect sufficient seed not only to meet the immediate aims of the collection but also to maintain seed stocks to meet future requests (e.g. minimum of 100 - 300g/tree for eucalypts). 13
Seed Operation Manual.doc 22/08/2007 1.5 Collection methods Harvesting from standing trees: The method is the most commonly applied method particularly in the case of SO and SPA where trees are not to be felled as part of harvesting the seed. An exception to this is when felling as part of a thinning operation to coincide with seed maturity. Harvesting from standing trees is either through climbing into the crown of the tree to dislodge the fruit using tree climbing spurs, ladders or other aids or by accessing the seed crop from the ground using throwing ropes or sling shots. A description of different aids is provided below: Collection methods vary according to the size of the tree, species and conditions prevailing at the site of the collection. Throwing rope: A rope (4-6 mm diameter and 25 m long) with a weighted end can be thrown over branches up to 12 m above the ground. For small branches (
Seed Operation Manual.doc 22/08/2007 their possible low physiological quality, compared with those obtained direct from the crown due to collecting a higher proportion of immature, empty and unsound seed, insect damaged, and early onset of deterioration or germination greater risk of contamination of the fruit or seed surface with soil-borne pathogenic fungi impractical for the collection of fine seed The method is best suited to bulk collections of large fruit or seed as in the case of a number of rainforest species. Fruit containing sound seed should be collected as soon as possible (daily) after shedding to minimise fungal, insect and animal attack and to reduce the incidence of mortality and germination. In the case where seed or fruit is in the process of shedding at the time of collection, large tarpaulins can be strategically spread out on the ground to catch the fruit or seed from under the harvested tree. Collecting from felled trees: This method can be used where felling operations are in progress which coincide with seed maturity. The method has the potential to produce large quantities of seed. Where genetic quality of seed is more important than quantity of seed, select superior trees from which to make the collection. Under these circumstances avoid collecting from a thinning operation where inferior trees are harvested. 1.6 Harvesting techniques Harvesting involves the picking and bagging of the fruit from off the ground. As much of the unnecessary material like branchlets and leaves are first removed by hand in order to reduce the bulk and make seed cleaning easier. The degree to which the crop should be free of impurities needs to be a balance between ease of cleaning in the field versus ease of cleaning using mechanical or manual techniques once the seed is dry and ready for seed extraction. In the case of eucalypts that have small capsules, it is very time consuming to remove capsules when they are located within the mass of leaves. By contrast, casuarina cones should be separated from the needles at the time of harvest. Needles left with the fruit break off making them the same size as the seed. Sieving to get pure seed is then very difficult. For fleshy fruit extreme care must be taken to avoid them from dehydrating. Fleshy fruit are often large and easy to harvest. To avoid them dehydrating, they should be placed in plastic bags and kept in a cool place out of the sun at all times. In the case of Aquilara for example, they have such a short storage life that it may be necessary to store the seed in a moist medium such as sawdust or cocoanut husk even if the seed germinates. Containers for bagging the seed must allow for good circulation, strong enough not to get damaged and designed so that they do not spill seed. The selection depends on what is available and found to be most suitable. This can range form tarpaulins for large bulk seed crops, calico sheets (2 x 2 m) to various size cotton bags. Avoid plastic as it causes the fruit to sweat and go mouldy losing seed viability with the exception of very fleshy fruit where moisture must be kept in the fruit. Once the crop has been bagged, the crop must be clearly labelled either by writing on the bag or using a label which will not be lost. Once bagged care must be taken to ensure that the fruit are not damaged or lost during transportation. At the time of bagging check there are no holes through which seed can escape. Sheets containing fruit must be kept upright and tied effectively in order to minimize the risk of seed loss. Where transporting entails more than a few days particularly under hot and poorly ventilated conditions (e.g. back of a closed in vehicle or trailer), the fruit must be checked regularly for fungal or insect activity and whenever possible spread out to air dry. 15
Seed Operation Manual.doc 22/08/2007 The decision of whether to dry the fruit in full sun or in shade depends on the condition of the fruit and seed type. For dry fruit with low moisture content (e.g. arid zone acacia pods, mature capsules of eucalypts and melaleucas) drying in full sun is desirable. However, for immature or green fruit, moist fruit or sensitive seed (e.g. Chukrasia), the material should be dried in the shade to avoid excessive rapid drying which may have an adverse effect on the viability of the seed. Fruit can either be extracted on site or transported to a seed processing facility. The decision depends on a number of factors including ease of extraction, whether the seed is stored as a fruit or requires the seed to be extracted, quantity of fruit, transport arrangements and climatic conditions affecting air drying. 1.6.1 Recording field data It is essential that all relevant information related to the seed collection site and trees sampled are recorded at the time of collection. Seed collection data sheets and Botanical Field Note Books are standard forms for recording field information for each collection. A blank and completed data sheet is shown in Appendix 1.4. Information which should be recorded includes: Species: To be written out in full giving genus, species and subspecies. Location name: For planted stands it would be the name and type of stand (eg. Ba Vi SSO Ref#) making sure the same name is used for each collection and transferred to the seed database. For collections from natural stands it would be the provenance name. When recording the provenance location it is essential to provide the precise location in sufficient detail for future collectors to return to the same site. Recording the location of each tree is not normal practice. However, it may be done for specific projects where selected trees need to be sampled over several years. Latitude and longitude: Use a Geographical Positioning Systems (GPS) to determine the co-ordinates. For seed stands where repeated collections have been made, refer to the co-ordinates used previously for consistency. Altitude: Recorded in metres representing the average for the collection site. If the collection is made over a large elevational range then a record can also be made of the range in elevation. Field Collection No: One way of identifying field collections especially provenance collections from natural stands is to allocate a field number. The number is generated by the leader of the collection team. The field number is linked to the Botanical Field Note Book (Appendix xxx) and acts as a record of all collections made by the collector. The number is made up of the persons initials (e.g. Nguyen Tuan Hung might be NTH) followed by the next number from the filed book. In the case of Mr Hung his first number would be NTH001 then NTH002 and so on. The same number is never repeated. This numbering is particularly important for individual tree collections as it is the number which will stay with the seed and used in the seed database. Apart from being recorded on the data sheet, Botanical Field Note Book, the same number is used on the seed label, botanical label, or any other collection item which is linked to the tree. Seedlot number: This is the registered number for the collection representing the seed stand or provenance. It is a unique number issued from the seed register book back at RCFTI in Hanoi and not in the field. Number of trees: The number of trees collected from must be recorded. Where seed from individual trees within a seed stand or provenance are mixed together this is referred to as a ‘Bulk’. This can be done in the field or later in the seed store. A 16
Seed Operation Manual.doc 22/08/2007 record must be made of the number of trees represented in the bulk to include the weight of seed. This information is recorded on the Field Data Sheet and Seed Record Card. 1.6.2 Botanical voucher specimens Botanical specimens are taken to vouch for the botanical identity of the seed collections or as herbarium specimens. This will mainly be undertaken where collections are made from indigenous species where there is uncertainly over the identification or in planted stands were there may be variation to question the identity of the species (e.g. hybrids in a trial thought to be of a specific species). The botanical specimen must have a secure tag to retain identity and a description of where the specimens was collected etc. written into the Forest Plant in Vietnam. 17
Seed Operation Manual.doc 22/08/2007 PLATE 1. Natural Forest and Seed Stands of main forest tree species Fig. 4. Pinus merkusii CSO in Ba Vi Fig.1. Acacia mangium SPA in Ba Vi Fig. 2. Acacia auriculiformis SPA in Ba Vi Fig. 5. E. pellita SSO in Bau Bang Fig.3. Eucalyptus urophylla SPA in Ba Vi Fig.6. Natural Forest in Kon Ha Nung 18
Seed Operation Manual.doc 22/08/2007 PLATE 2. Seed Collection Fig. 6. Seed collection from natural forest using tree climbing rope Fig. 7. Using ‘big shot’ (left) and using climbing spurs (right) Fig. 8. Climbing by ladders (left) and using long handle pruning saw to remove seed bearing branches (right) 19
Seed Operation Manual.doc 22/08/2007 PLATE 2 (continued) Fig.10. Checking soil’s pH Fig.9. Recording information on field data sheet Fig.11. Harvesting the fruits Fig.12. Bagging and transport of fruit. 20