Báo cáo nghiên cứu nông nghiệp " Development and Management of Seed Production Areas " ppt

z We may not know the genetic origin of the plantation – it could be inferior, or the genetic base too narrow z No selective thinning to remove inferior trees in the plantation z The

Development and Management

of Seed Production Areas

Khongsak Pinyopusarerk CSIRO/Ensis-Genetics Canberra, Australia

Why not just collect seed out of

plantations?

z We may not know the genetic

origin of the plantation – it could

be inferior, or the genetic base too narrow

z No selective thinning to remove

inferior trees in the plantation

z The inferior trees contribute their

pollen to the other, better trees in the plantation, lowering seed quality

z Because the trees are growing at

close spacing, flowering may be poor, resulting in inbreeding and poor genetic quality of seed

Seed Production Area

z Seed production area is a stand

developed and managed specifically for seed production purpose.

z Two ways to develop seed production area:

– Develop from existing planted stand

– Develop from specially planted new stand

Existing stand suitable for conversion

to seed production area

z Known seed origin

z Trees are mature but not too old

z Near full stocking and good phenotypes

Stand not suitable for conversion to

seed production area

Very poor plantations with evidence of disease attack

Development of seed production area from specially planted stand

z Site should be representative of target planting areas

z Evidence of flowering and seed set at the location

z Seed from most suitable provenance or several

provenances

z Start like a new plantation

z Initially close spacing (more trees for selective

Establishing new seed production area

z A seed production area of E

Size of seed production area

z 4-5 ha is appropriate for most species

z May be smaller (< 1 ha) for heavy seed producer, e.g eucalypts

z Area should be close to square, not long narrow block to promote more cross pollination

Isolation is important to minimise contamination from outside pollen !!!

Selection of trees in seed production area

z Development of SPA involves 2-3 thinnings to remove undesired trees, retaining good trees to produce seed

z Retained trees should have the following characteristics

– Fast growth

– Straight single stem

– Good crown development

– Good self pruning

– Free from insects and diseases

z No trees below standard should be kept, regardless of the gap

z For dioecious species (e.g casuarinas), make sure to have enough male trees (at least 30%) for pollination

Thinning seed production area

z An essential activity to remove poor-performing trees

z Aim to reduce stocking to 150-200 trees/ha

z At least 2-3 thinnings each time selectively removes 50% of trees

z Thinning in small groups, e.g 16 (4 x 4) trees, for ease of comparison

z Avoid thinning in typhoon season, strong winds can cause wind-throw and crown damage

z Avoid damage to adjacent trees

A mature plantation old enough for conversion to seed production area

1250 stems/ha

Seed production area before first thinning

Thin in groups: remove poorest

Seed production area - after first selective thinning

Stocking:

before : 1250 trees/ha after: 600 trees/ha

Seed production area – after second selective thinning

Two selective thinnings each removing 50% of trees

Stocking:

Initial : 1250 stems/ha After 1 st thin : 600

After 2 nd thin: 300

Collect seed from remaining, superior, trees after mass

flowering following thinning

Seed production area – after third selective thinning

Three selective thinnings each removing 50% of trees

Stocking:

Initial : 1250 stems/ha After 1 st thin : 600

After 2 nd thin 300 After 3 rd thin 150

Collect seed from remaining, superior, trees after mass

flowering following thinning

A seed production area after three thinnings

150 trees/ha

A specially planted seed production area, before first selective thinning at 2 years old

of 50+

unrelated, superior seed families

Initial spacing

3 m x 3 m

(1110 stems/ha

Selection before first thinning

– remove poorest 8 out

of every 16 trees

After first selective thinning

After second selective thinning, age 4 years

Stocking:

Initial : 1100 stems/ha After 1 st thin : 550

After 2 nd thin 275

Collect seed from remaining, superior, trees after mass

flowering following thinning

After third selective thinning, age 6 years

Two selective thinnings each removing 50% of trees

After 2 nd thin: 275 After 3 rd thin: 125-150

Collect seed from remaining, superior, trees after mass

flowering following thinning

Thinning seed production area

Seed production area Acacia mangium

Sarawak

4 years old, selectively thinned to best 250 trees per ha

Acacia mangium SPA, Bansud,

Mindoro Oriental Island

3.5 years old, thinned from 1000 to 400 stems/ha

Over 50% of retained trees have fruits/flowers

Management of

seed production area

z Remove cut material after thinning

z Control weed growth

z Control coppice growth, e.g eucaypts

z Fertilisation

z Protection

Importance of weed control and nutrition –

E urophylla SPA, Philippines

Potassium deficiency symptoms – year 2000

Poor maintenance

3/2005

z Flowering characteristics (flowering time, seed set)

z Annual seed collection (quantity, number of trees)

Example of flowering survey in Acacia

mangium seed production area

Reproductive status survey: SPA 1

no green pods

Scale - 10 metres

Example of flowering survey in Acacia

mangium seed production area

Reproductive status survey: SPA 1, Sim ilajau

no green pods

Scale - 10 metres

Survey once per month

Calculate % of trees in SPA with heavy, medium and light, crops of flowers and no flowers

% of trees with crops of green pods

Predict timing for collection of seed crop resulting from peak flowering when highest % of trees flowered

Identify early-flowering and flowering individuals/branches – avoid collecting from them

late-Reproductive status survey: SPA 1, Sim ilajau

no green pods

Scale - 10 metres

z Avoid collecting seed from early- or late-flowering trees

z If you can’t do survey of flowering At least do a survey of seed crops - at least 40-50 % of trees should carry seed crops

z May divide SPA into 3 sections and collect seed in each section in a year

Seed production areas have three important attributes

1 Seed quality better than seed from

commercial collections from routine plantations

2 The origin of seed is known

3 Reliable sources for well-adapted and

inexpensive seed