Application of biotechnology in forest tree breeding: A case study of breeding Melia volkensii for drought tolerance in Kenya

1. Stephen Fredrick Omondi (PhD),
Research Scientist, Forest Genetics and
Tree Improvement
Application of biotechnology in forest tree
breeding: A case study of breeding drought
tolerant Melia volkensii for Adaptation to
Climate Change in the Drylands of Kenya

2. • Only 20% humid environment
• Mainly dry lands
– Savannas (8%)
– Semi arid rangelands (14%)
– Arid rangelands (36%)
– Very arid rangelands (22%)
• Important fodder reserves for
wildlife and livestock, especially
during the dry periods
• Need for tolerant species
Distribution of agro-climatic zones in
Kenya

3. Vegetation cover/Land use
The interaction of people and dryland trees and plant remains a
major concern – Over-exploitation
On farm tree planting
Arid land forests
Over-exploitation
Scattered vegetation in the drylands

4. Threats to Drylands Ecosystems
Sandalwood PoachingCharcoal production
Environmental
degradation
Overgrazing
Poor crop
Poverty/malnutrition
Timber harvesting

5. • Dryland species-drought
tolerant
• Fast growing
• High quality timber and
termite resistant.
• Habitat fragmentation and
overexploitation.
• Candidate species
Melia Volkensii (Mukau) important dryland species
Breeding for high yielding
varieties is required
Melia volkensii is
endemic to drylands of
Eastern Africa.
• Kenya
• Somalia
• Ethiopia

6. Melia volkensii Plantation
General seed collection – no improvement
Need for selection of superior plus tree for
improvement and dissemination
Woodlot
Agroforestry

7. Melia volkensii Products
High quality
timber
High quality
timber
Termite
resistance
timber

8. Melia volkensii improvement
• Development of drought tolerant
varieties based on the available
genepool.
• Extend Melia’s range of growth and
increase its adaptability to effects of
climate change.
• Melia grows in agro-climatic zones IV
and V. However, the breeding for
Melia is expected to extend it to the
harsher agro-climatic zone VI.
Our intervention
Climate change

9. Population
identification
DNA analysis
DNA analysis
Specimen
collection
Population
mapping
Seed orchard
establishment
o DNA marker develop.
o DNA marker selection
o Genotype identity
Data analysis
Application
o Population analysis
o Multi phase analysis
o Genetic diversity
conservation strategy
o Draw up distribution range
of superior breed variety
Plus tree selection
Seed, scion
collection
Seed
collection
Seed Stand
establishment
Demo
Forest
Select superior
family
Seed
production
Seed
production
Next cycle of breeding generation
Tree Breeding Drought tolerant
Morphology,
phonology
physiology
study
Extension
Select index
Seed distribution
Propose
Distribution
system
Market
research
Seed
distribution
guideline (Draft)
Extension
materials
Seminar, Third
country training
Seed
distribution
guideline (final)
Improve seed
orchard
evaluation
Progeny
test
The project outline
9

10. Development of microsatellite markers
15 SSR
markers
were
developed

11. Genetic diversity and population structure of M.
Volkensii in Kenya
11 populations sampled; Taveta, Voi, Kibwezi, Kitui, Mutha, Mwingi, Isiolo, Wamba,
Marsabit, Meru and Embu

12. Genetic diversity was high in
Wamba
Ishiolo
Kitui
Genetic diversity was low in
Meru
Embu

13. Genetic structure in natural populations
Clear genetic differentiation and
structure
North, Central and South
Feedback to breeders (selections and
test sites

14. Selection of Melia for tree improvement
• Sites and transects used for
selection of Melia plus trees

15. 1st Generation seed orchard establishment

16. Locus N Na Ho He PIC PE PI
bcmv030 403 8.000 0.742 0.751 0.752 0.710 0.102
bcmv043 403 14.000 0.804 0.838 0.839 0.862 0.044
bcmv055 403 12.000 0.854 0.815 0.816 0.840 0.053
bcmv068 403 12.000 0.878 0.799 0.800 0.805 0.065
Genotyping of M. volkensii seed orchard
Probability of exclusion (PE) overall =99.88%
Probability of Identity (PI) overall =1.6 x 10-7; 1 in 6,250,000

17. Summary of Multilocus Matches by Locus for Increasing
Combinations of the 4 Loci for Codominant Data
Matching versus Unique Genotypes/Locus Combination for all 403 Samples
Number with matching genotype Number with unique genotype
1+2+3+4 402 1
1+2+3 398 5
1+2 396 7
1 392 11
A precise molecular pattern for each of the 100 genotypes
could be assigned and the information produced is
sufficiently robust to ensure the molecular traceability for
each of these materials

18. Progeny testing
• Seed produced from tree improvement breeding
efforts are used to establish progeny tests to:
– 1) Assess the genetic worth of select parents bases on
progeny performance and
– 2) provide an improved population of trees from which
the next generation of select trees is made
• To make selections for the next generation
Strategy for mass propagation for distribution to farmers??
Seedlings production through seeds is a challenge!!!!!
Maintaining uniformity in improved varieties

19. Mass propagation: Development of Melia volkensii In vitro
propagation protocol
Shoot proliferation
MS at pH 5.8 containing
a combination BAP (0.5
mg/l) and IAA (0.2 mg/l)
Somatic embryos
Germinated somatic embryo

20. Root induction
MacCown Woody Plant
medium + 0.2 mg/l IBA

21. Habituation/acclimatization
68 % acclimatization in the growth chambers
Sterile medium

22. Estimation of Melia potential planting area
Climate data
GPS data
(Distribution data)
Ecological
Niche
Modeling
1) Important factors to
determine the distribution
range
2)Potential distribution =
planting
area are estimated!
How will climate change affect future distribution range of M.
volkensii?

23. Result: Important variables determining distribution
of Melia volkensii
13. Precipitation of wettest month (26.1%) 15. Precipitation seasonality (17.1%)
02 Mean diurnal range (15.1)
05 Max temp. of warmest month (13.3%)
08 Mean temp. of wettest quarter (6.2%)
5 variables were found important! (77.8%)

24. Result: Estimated potential distribution area
Recommended area to
Plant Melia volkensii
Not recommended area to
Plant Melia volkensii
high
low
Ecological Niche Modeling (Maxent)

25. Conclusion on M. volkensii DNA analysis
• SSR markers have been developed.
• Genetic diversity and structure in natural populations
have been determined.
• Genetic diversity of CPTs was higher compare to natural
populations, and they will be important genetic resources.
• Clone identification: All the CPT could conclusively be
identified
• Potential planting area was estimated
→give feedback to Extension team
• Scientific output reveals important climatic variables that
determine distribution of M. volkensii.
• Association studies ongoing

26. THANK YOU