SELECTION AND EVALUATION OF
ECOTYPES OF POTENTIAL GRASS SPECIES
FOR RESEEDING THE ASALS OF KENYA
PhD Proposal By Kirwa Everlyne Cheptarus B.Sc, M.Sc
Supervisors:
Dr. Kiarie Njoroge, UoN
Dr. George N. Chemining’wa, UoN
Dr. William Ngoyawu Mnene, KARI
Introduction
• ASALs have great potential but overlooked
• The fastest-growing agricultural subsector
• 30% agric. GDP in developing nations (IFAD, 2010).
•
–
–
–
In Kenya:
70% livestock pop.
Valued Kshs 70b
67% of red meat (Juma et al., 2010)
…Introduction
 92% of Nat. Parks &Reserves’ land
 90% wildlife.
 80% of country’s eco-tourism for over Kshs
50b p.a (ALMP, 2005).
 fragile lands & currently degraded
o land subdivisions & changes in land uses,
o
Increasing human & livestock pop.
overgrazing & bush encroachment
o increasing incidence of droughts
 Livestock production constraint esp. feed
availability
o
…Introduction
 Rehabilitation technologies e.g. reseeding, (Kiptarus
2005; Mnene, 2006; Nyariki et al., 2008; Manyeki, et
al., 2011)
 Various grass species tested for reseeding, e.g.
Horsetail grass
(Chloris roxburghiana)
Maasai lovegrass
(Eragrostis superba)
African foxtail
(Cenchrus ciliaris)
 However, seeds not available commercially
Farmer capacity
building
Bush rye
(Enteropogon macrostachyus)
Justification
• To commercialize, must standardize quality & a
sustainable seed system
Grass seeds processing
• Poor establishment still a constraint to reseeding
• Several ecotypes exist
Hand sorting
• Knowledge on the level & structure of
variation within & among these grass
populations for sustainable seed collection,
utilisation & conservation
• And for ecotype seed yield potential by
nutrient level & water interaction
Packaging
Objectives
Broad objective
Grass hay on transit
• To screen for higher productivity in various
ecotypes of four preferred & adapted range
grasses under different production regimes
Grass seeds packaged for sale in informal market
Objectives cont…
Specific Objectives
• To identify the most productive ecotypes of
four range grasses in seed & herbage yield
• To genetically characterize ecotypes of four
range grasses
• To evaluate the effects of N-fertilizer use &
irrigation on quantity & quality of seeds of
selected ecotypes of four range grasses
Research Hypotheses
• The seed & herbage traits of the ecotypes are
related to one another & to some traits of
agronomic importance
• There is differentiation in ecotypes due to ecogeographical variation?
• Fertilizer or irrigation positively affects seed
yield traits of the ecotypes
Materials & Methods
Three (3) experiments to be conducted:
• Identification of the most productive ecotype in seed &
herbage production
• Genetic characterization of ecotypes
• Effect of fertilizer use & irrigation on seed production in grass
ecotypes
Study site
• 4 sites based on climatic variation:
- Kiboko A & B
- Buchuma
- Mariakani
Exp. 1: Identification of the most productive
ecotype in seed & herbage production
Grass seed collection
o
o
o
o
4 counties by Agro-ecological zones (AEZ) & altitude
- Kilifi (AEZ III)
- Taita Taveta (AEZ IV)
- Makindu (AEZ V)
- Kajiado (AEZ VI)
5 purposively selected sites in each county
20 plants harvested using randomly stratified technique (Guarino
et al., 1995)
Viability tests - KARI Kiboko labs
…Experiment 1
o
Seeds to be sown in trays
o
Seedlings transplanted to field at 1x1 m spacing
Experimental design
o
Split plot design, 3 replications, each 16 plots
o
Spp & ecotypes as main & subplot, respectively
o
Plot size of 4 x 4 m with inter-row spacing of 1 m
Data collection
• Agro-morphological traits according to IBPGR (1985) & van de
Wouw et al. (1999)
…Experiment 1
Character
units
Character
units
1. Plant number
No
11. Panicles per plant
No
2. Plant height
cm
12. Total tillers at maturity
No
3. Leaf length
cm
13. Fertile tillers at maturity
No
4. Leaf breadth
mm
14. Fascicle colour
code
5. Growth habit
Code
15. Inflorescence length
cm
6. Stem thickness
mm
16. Inflorescence width
cm
7. Ligule length
mm
17. Inflorescence ratio
-
8. Biomass yield
ton/ha
18. Spikelets number
No
9. Nutritive value
10. Days to start, 50%
& 100% flowering
%
19. 1000-seed weight
g
No
20. Seed viability
%
21. Seedling vigour
g
…Experiment 1
• Weather data for source of seed collections
o Annual mean rainfall (mm), annual mean temperature (°C),
Mean diurnal temperature range (°C), Elevation (m) &
Latitude (Degrees)
Data analysis
• Analysis of variance (ANOVA) & mean separation using
GenStat
• Correlation analysis between the plant traits & the
environmental factors
Exp 2: Genetic characterization of
ecotypes
Plant sampling
• Fresh leaves from 10 plants per ecotype will be randomly
sampled following procedure by Odat et al., (2004)
Laboratory analysis
• Genomic DNA extraction by a modification of a CTAB method
(Doyle & Doyle (1987)
• Amplified Fragment Length Polymorphism (AFLP) analysis
according to the standard procedure described by Vos et al.
(1995).
…Experiment 2
AFLP-based data analysis
• Genetic diversity, ordination analysis & Analysis of Molecular
Variance (AMOVA) with GenAlEx software (Peakall & Smouse,
2009)
• Cluster analysis using PopGen32 population genetic analysis
software (Yeh et al., 1997)
o Genetic distance, matrix dendrogram, F statistics, gene
diversity over loci, proportion of polymorphic loci, Shannon
index & gene frequency (Nei 1987; McDermott & McDonald
1993)
Exp 3: Effect of N-fertilizer use & irrigation on
seed production of grass ecotypes
Experimental design
• Soil sampling along plot diagonals & analysis for OC, EC, pH, total
N, available P, K, Ca & Mg
• Sowing of the ecotypes in split-split plot design, 3 reps
• Irrigation, fertilizer & ecotype as main plot, sub-plot & sub-sub
plot, respectively
• Treatments: with/without irrigation, with/without N-fertilizer
…Experiment 3
Data collection
Character/Trait
1. Days to start, 50% & 100%
flowering
2. Panicles per plant
3. Total tillers at maturity
4. Fertile tillers at maturity
5. Inflorescence length
units
No
No
No
No
cm
Character/Trait
6. Inflorescence width
7. Inflorescence ratio
8. Spikelets number
9. 1000-seed weight
10. Seed viability
11. Seedling vigour
units
cm
No
g
%
g
• Weather records will be kept during the experimentation period
Data analysis
• ANOVA & mean separation using GenStat
Expected outputs
• The most productive ecotypes of four range
grasses in seed & herbage production identified
• Ecotypes with wide adaptation to different
ecological settings identified through genetic
characterization
• Effect of fertilizer use on quality & quantity of
seeds of ecotypes of four range grasses under
irrigation evaluated & documented
Budget summary
Activity
1. To identify the most productive ecotype of four
Amount (Ksh)
418,000
range grasses in seed & herbage production
2. Genetic characterization of ecotypes of
966,225
potential range grasses
3. To evaluate effect of fertilizer use on quality &
302,000
quantity of seeds of ecotypes of four range
grasses under irrigation
Grand Total
1,686,225
Workplan
Period: Q2 2012-Q4 2014; Start April 2012- Dec 2014
Activity
Experiment 1
Site identification
Seed collection
planting
Data collection
Data analysis
Thesis writing
Experiment 2
Planting of seeds
Laboratory analysis for
genetic characterization
Thesis writing
Apr –Dec 2012
Jan – Dec 2013
Q2Y1
Q1Y2 Q2Y2
Q3Y1
Q4Y1
Q3Y2
Jan – Dec 2014
Q4Y2
Q1Y3 Q2Y3
Q3Y3
Q4Y3
…Workplan
Period: Q2 2012-Q4 2014; Start April 2012- Dec 2014
Activity
Experiment 3
Soil sampling
Seedbed preparation
Planting
Data collection
Data entry & analysis
Thesis writing
Apr –Dec 2012
Jan – Dec 2013
Q2Y1
Q1Y2
Q3Y1 Q4Y1
Q2Y2
Q3Y2
Jan – Dec 2014
Q4Y2
Q1Y3 Q2Y3
Q3Y3
Q4Y3
Thank you all