Prepared by Lucy Mwaura Prepared by Lucy Mwaura

ForFor

Allanblackia Allanblackia domestication workshopdomestication workshop

2323rdrd to 27 to 27thth Oct 2006 Oct 2006

Allanblackia Allanblackia seed germination seed germination protocolsprotocols

Outline Outline

AB seed physiology AB seed physiology Conditions required for germination.Conditions required for germination. Possible Possible AllanblackiaAllanblackia seed dormancy seed dormancy Seed germination treatments Seed germination treatments

applied by partcipating countriesapplied by partcipating countries Treatment methods that have been Treatment methods that have been

use on a large scaleuse on a large scale Lesson learntLesson learnt

AllanblackiaAllanblackia seed physiology seed physiology

Fruit/seed weightFruit/seed weight

Seed moisture Seed moisture

Storage Storage

Dormancy Dormancy

GerminationGermination

Fruit/seed weightFruit/seed weight

-A single seed weight -A single seed weight ranged between 5-ranged between 5-10grams when fresh10grams when fresh-A kilo of fresh seeds -A kilo of fresh seeds had between 90-100 had between 90-100 seedsseeds-viable seeds per kilo?-viable seeds per kilo?( not confirmed)( not confirmed)-fruit weight ranged -fruit weight ranged between 2.5-5.5kgbetween 2.5-5.5kg

Moisture contentMoisture content

Seed moisture Seed moisture -AB seed had moisture -AB seed had moisture content of up to 40% when content of up to 40% when fresh.fresh.-Loss of seed moisture was -Loss of seed moisture was found to be proportional to found to be proportional to loss in viability (desiccation loss in viability (desiccation tolerance trial/biochemical tolerance trial/biochemical test 2004 )test 2004 )-The rate of moisture loss is -The rate of moisture loss is high soon after extraction, high soon after extraction, and decreased with time of and decreased with time of exposure to air.exposure to air.

Storage trialsStorage trials

Storage Storage - Extracted seeds can be - Extracted seeds can be stored at -20oC in stored at -20oC in airtight aluminum bags airtight aluminum bags for at least one year for at least one year without loss of moisture without loss of moisture and viability. (desiccation and viability. (desiccation tolerance test of 2004) .tolerance test of 2004) .-Seeds remained viable -Seeds remained viable with high moisture while with high moisture while still enclosed in the fruit still enclosed in the fruit buried, in moist soil/sand buried, in moist soil/sand for three months.for three months.

Conditions required for Conditions required for seed germinationseed germination

In Tanzania and Kenya use of moist sand In Tanzania and Kenya use of moist sand media has been used to pre-germinate seedsmedia has been used to pre-germinate seeds

The germination beds should remain moist The germination beds should remain moist during this period, however minimum watering during this period, however minimum watering is recommended to avoid water logging( seed is recommended to avoid water logging( seed would rot)would rot)

Seeds in nursery beds should be put under Seeds in nursery beds should be put under shade. (In Tanzania seeds are covered with shade. (In Tanzania seeds are covered with dried banana leaves).dried banana leaves).

Temperatures should be between 25-30 Temperatures should be between 25-30 degrees Celsius.degrees Celsius.

AB possible seed AB possible seed dormancydormancy

DormancyDormancy-is the physiological state that prevents normal growth -is the physiological state that prevents normal growth of most seeds when all the conditions are favorable.of most seeds when all the conditions are favorable.

Seed coat dormancy: Seed coat dormancy: gelatinous sticky substances found gelatinous sticky substances found on seeds could contain chemical inhibitory compunds which make the on seeds could contain chemical inhibitory compunds which make the seed coat impermeable to water and gases, this growth inhibitors must be seed coat impermeable to water and gases, this growth inhibitors must be leached out to allow germination (Forest Biology journal 2000).leached out to allow germination (Forest Biology journal 2000).

Embryo dormancy: Embryo dormancy: have growth-inhibitors present and have growth-inhibitors present and

lack growth promoterslack growth promoters. . -The embryo in enclosed in endocarp that contains high oil content, this -The embryo in enclosed in endocarp that contains high oil content, this could have chemical inhibitory compound that prevent germinationcould have chemical inhibitory compound that prevent germination-Abscisic acid contained in the embryo makes the seed dormant until -Abscisic acid contained in the embryo makes the seed dormant until certain native enzymes are triggered to permit breakdown of the certain native enzymes are triggered to permit breakdown of the hormones ( intensive work required here)hormones ( intensive work required here)

Seed germination treatments applied Seed germination treatments applied and results obtained by specific and results obtained by specific

countriescountries

Results from an experiment investigating the germination potential of Results from an experiment investigating the germination potential of Allanblackia Allanblackia seeds in a mixture of forest soil and sand (2:1) indicated that seeds in a mixture of forest soil and sand (2:1) indicated that it took 18 months for it took 18 months for A floribundaA floribunda and 19 months for and 19 months for A gabonensisA gabonensis to to reach 50% germination level.reach 50% germination level.

24 months after the trial was set an overall 86% of seeds germinated. 24 months after the trial was set an overall 86% of seeds germinated. Pretreatments experiments were developed to reduce the germination Pretreatments experiments were developed to reduce the germination periodperiod

Preliminary results from pretreated seeds of AB (Preliminary results from pretreated seeds of AB (immersion in 90% immersion in 90% gibberellic acid (GAgibberellic acid (GA33) for 72 hours indicate that a germination rate of 48.33 ) for 72 hours indicate that a germination rate of 48.33 % can be obtained after 7 months (% can be obtained after 7 months (AA. . floribundafloribunda).).

New experiment investigating the New experiment investigating the combined effects of GAcombined effects of GA3 3 concentration concentration and duration of immersion on 4800 and duration of immersion on 4800 A. floribundaA. floribunda seeds subjected to 3 seeds subjected to 3 immersion durations and 4 GAimmersion durations and 4 GA3 3 concentrations in a factorial design; concentrations in a factorial design; (experimental unit of 100 seeds) is being done in Cameroon.(experimental unit of 100 seeds) is being done in Cameroon.

1. Cameroon.

Seed germination trial in Seed germination trial in specific countriesspecific countries

Out of 13 accessions sown at the nursery the Out of 13 accessions sown at the nursery the overall germination was 0.02% as at June overall germination was 0.02% as at June 2005.2005.

Another 21 accessions were sown in the green Another 21 accessions were sown in the green house with three treatments, (with testa, house with three treatments, (with testa, without testa and soaking in water for 24 hrs) in without testa and soaking in water for 24 hrs) in early 2005, overall germination was 0.05% by early 2005, overall germination was 0.05% by February 2006.February 2006.

ITSC also put 600,000 seeds on nursery beds ITSC also put 600,000 seeds on nursery beds of (of (A parvifloraA parviflora), only 0.1% of seedlings was ), only 0.1% of seedlings was transplanted into poly tubes.transplanted into poly tubes.

2. Ghana

Extracted seeds are sown on seed-bedsExtracted seeds are sown on seed-beds Burying the whole fruit in a hole and cover with Burying the whole fruit in a hole and cover with

forest debris and then transfer germinated forest debris and then transfer germinated seeds to the polyethylene tubes.seeds to the polyethylene tubes.

Collecting newly emerged seeds and Collecting newly emerged seeds and raise raise in the polyethylene tubes( rat caches)in the polyethylene tubes( rat caches)

Extracted seeds are soaked in water while Extracted seeds are soaked in water while floater are discarded, the sinkers are removed floater are discarded, the sinkers are removed and nicked on the distal end and later soaked and nicked on the distal end and later soaked in GA31000ppm( refer to note for GA3 in GA31000ppm( refer to note for GA3 preparation)preparation)

Treatments that have been used on a large Treatments that have been used on a large

scale ( best germination results so farscale ( best germination results so far ) )33 TanzaniaTanzania

Seed germination treatments Seed germination treatments from specific countries con’tfrom specific countries con’t

Germination capacityGermination capacity-Seed germination capacity was low -Seed germination capacity was low and slowand slow-tap root emerged first within 3--tap root emerged first within 3-5months5months-a fully developed seedling with two -a fully developed seedling with two alternate leaves occurred after 7 alternate leaves occurred after 7 months of sowing.months of sowing.-seeds that did not germinate after 5 -seeds that did not germinate after 5 months had an enlarged embryo months had an enlarged embryo and remained dormantand remained dormant-seed stained brilliant red indicating -seed stained brilliant red indicating viable tissues with TTZ test.viable tissues with TTZ test.

4. Kenya

Pre-sowing methodsPre-sowing methods

sowing without treatmentsowing without treatment- No seed treatment has been - No seed treatment has been found effective to improve found effective to improve germination percentages.germination percentages.-First trial 2004 done without -First trial 2004 done without treatment (germination was treatment (germination was 4%)4%)

Sowing with treatmentSowing with treatment-seeds were stored for a -seeds were stored for a month, soaked in water 24hrs, month, soaked in water 24hrs, and dried for 2 days then and dried for 2 days then cracked to open the seed cracked to open the seed coat( germination was 1%)coat( germination was 1%)

Pre-sowing methods Pre-sowing methods cont’cont’

Preparation and soaking in GA-3 Preparation and soaking in GA-3 and and KNOKNO33

-Gibberellic acid (GA-3) was -Gibberellic acid (GA-3) was dissolved in 1 ml ethyl-alcohol/waterdissolved in 1 ml ethyl-alcohol/water 250ppm, 500ppm,1000ppm( refer to 250ppm, 500ppm,1000ppm( refer to notes)notes)

-Potassium -Potassium nitrate(nitrate(KNOKNO3 3 )) 0.2%,0.5%,and 1%(ref: ISTA news 0.2%,0.5%,and 1%(ref: ISTA news bulletin No 130 Oct 2005)bulletin No 130 Oct 2005)

-Combined treatment (-Combined treatment (KNOKNO33 0.2% and 0.2% and 250ppm)250ppm)-one seedlot was not treated-one seedlot was not treated

Treatments cont’Treatments cont’

Experimental set upExperimental set up -seeds were put in -seeds were put in various treatment and various treatment and soaked for 48hrs at room soaked for 48hrs at room temperature.temperature.-Deep flower pots were -Deep flower pots were filled with sterile sand at filled with sterile sand at ¾ level, sown seeds ¾ level, sown seeds were covered with a thin were covered with a thin layer of sand.layer of sand.-similar set-up was put at -similar set-up was put at the nursery same time.the nursery same time.

Germination progress.Germination progress.

SowingSowing-Dec 2005, seeds were sown -Dec 2005, seeds were sown 2 cm apart in containers, and 2 cm apart in containers, and incubated at 25incubated at 25ººC night and C night and 3030ººC day temperature, the C day temperature, the sand was kept moist without sand was kept moist without logging. logging.

MonitoringMonitoring-Minimum watering with -Minimum watering with distilled water was done.distilled water was done.-Daily monitoring and -Daily monitoring and recording was continuously recording was continuously done.done.

Germination chartGermination chart

0

5

10

15

20

25

30

%germinated seeds

250ppm GA3soak 48hrs

500ppm GA3soak 48hrs

1000ppm GA3soak 48hrs

KNO3 0.2%48hrs

KNO3 0.5%48hrs

KNO3 1.0 %48hrs

Cold w atersoak 48hrs

250ppm GA3+KNO3 0.2%

48hrs

Control

Treatments

A stuhlmannii germination report

Lesson learnt Lesson learnt

We still have a big challenge ahead of us to find ways to improve We still have a big challenge ahead of us to find ways to improve seed germination.seed germination.

Use of local knowledge practice in Tanzania is so far the best Use of local knowledge practice in Tanzania is so far the best practice that improves seed germination. practice that improves seed germination.

More research needs to be done using KNOMore research needs to be done using KNO3 3 and GA-3 and GA-3 treatments.treatments.

Bioassay study will be important to find out whether hormones Bioassay study will be important to find out whether hormones ratios found in seeds have any influence on physiological seed ratios found in seeds have any influence on physiological seed activities (germination? dormancy?).activities (germination? dormancy?).

We need to set-up seed propagators in central nurseries where We need to set-up seed propagators in central nurseries where environmental conditions can be controlled and temperatures environmental conditions can be controlled and temperatures monitored.monitored.