Phenotypic and Molecular Characterization of Physic Nut (Jatropha curcas L.) Populations in Ethiopia
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Date
2010-01
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Addis Ababa University
Abstract
Genetic diversity and fatty methyl esters profile of Jatropha curcas represented by fourteen
populations (eleven from Ethiopia, two from Kenya and one from Tanzania) were characterized.
Twelve different phenotypic traits and five ISSR primers were used to characterize the genetic
diversity whereas Gas Chromatography fingerprints were used to describe the fatty methyl ester
profiles. A total of 140 individuals (10 individuals per population) were planted using randomized
complete block design in three replications at Shewa Robit. Significant variation among the
regions and among the populations at the age of 43 weeks were observed for height, leaf length,
leaf width, average leaf area, leaf dry matter, length of leaf from width to base and apex . On the
other hand, root collar diameter, branch numbers per plant and grain yield were not significantly
differed both among regions and populations. Seeds collected from different populations varied
significantly with respect to 1000-seeds weight, kernel oil content and seed oil content. The Chiro
population performed the best with respect to root collar diameter, height, branch number per
plant and first year grain yield (304.19 kg per hectare). The first year grain yield of Mersa,
Jeweha, and Assossa population were 247.73, 227.45, and 226.89 kilo gram per hectare,
regarding to 1000-seeds weight (540.44 g) and seed oil content (37.4 %). Shewa Robit population
was the second superior genotype regarding seed oil content but the grain yield of this population
was below the average. When oil yield productivity per hectare is considered, Chiro, Assossa,
Mersa and Jeweha populations performed better than others. Growth traits were positively
correlated with leaf and agronomic traits except plant height versus average leaf dry matter. Grain
yield showed positive correlation with growth traits whilst negative correlations were observed
with leaf and agronomic traits. Seed oil content was associated negatively with growth and leaf
traits whereas significant positive correlation was observed with agronomic traits. Amplification
of genomic DNA using five ISSR primers produced 71 DNA fragments and all fragments were
found to be polymorphic. Number of amplified fragments varied from nine for primer (818) to
seventeen for primer (873) with an average of 14.2 fragments per primer. Percent of
polymorphism within population ranged from 21.43 (Kenya II) to 80.39 (Arbaminch). The
Shannon diversity index varied from 0.243 (Kenya II) to 0.759 (Arusha / Tanzania). The Nei’s
gene diversity (h*), Shannon information index (I*), total gene diversity (Ht) and estimated gene
flow were 0.273, 0.431. 0.272 and 0.785, respectively. Analysis of Shannon diversity index, Nei’s
genetic diversity and AMOVA revealed that most of the genetic diversity was due to variation
within population but differentiation among population was also significant. Biodiesel from 14
populations of Jatropha curcas comprised six fatty methyl esters in common (16:0, 16:1, 18:0,
18:1, 18:2, and 18:3). Saturated fatty methyl ester varied from 19.04 % (Mersa) to 28.91%
(Arbaminch) with an average of 22.69%. The unsaturated fatty methyl ester ranged from 71.09%
(Arbaminch) to 80.96% (Mersa) with an average of 77.33%. Biodiesel from Mersa and Assossa
populations exhibited higher monosaturated fatty methyl ester. Jatropha curcas populations of
this study exhibited higher genetic diversity (particularly, at DNA level) than most of previous
studies. Some of these populations produced satisfactory grain yield. Moreover, seed oil content
and fatty acid profiles are comparable with most former studies.
Key words: Jatropha curcas, genetic diversity, phenotypic traits, fatty acid, biodiesel
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Keywords
Jatropha curcas, genetic diversity, phenotypic traits, fatty acid biodiesel