Improving Rural Livelihoods through Domestication of Indigenous Fruit Trees in the Parklands of the Sahel - Indigenous Fruit Trees in the Tropics: Domestication, Utilization and Commercialization - page 194

appears to be more diversity in native African populations of tamarind than in
those introduced from the South and South-east Asian regions. Diallo (2001)
confirmed the high degree of diversity and phenotypic difference among the
African populations, and attributed this to geographical isolation and gene
mutation.
Preliminary results from tamarind provenance trials revealed considerable
variation in growth and biomass production among Sahelian provenances (B.O.
Diallo, unpublished results). Considerable variation in pod production within
and among provenances was also reported from a 15-year-old provenance trial
in Dinderesso, Burkina Faso.
Néré ( Parkia biglobosa )
Results of an isozyme analysis based on samples collected from 11 countries in
West Africa has shown very high genetic diversity in Parkia biglobosa at the
inter- and intrapopulation levels (Teklehaimanot, 2004). This diversity should
be considered during the planning of any genetic conservation or improvement
programme.
Karité ( Vitellaria paradoxa )
Bouvet et al . (2004) reported an analysis of molecular diversity from 80
populations covering most of the natural range from Senegal to Uganda. Using
random amplified polymorphic DNA (RAPD) analysis, results from 118
individual trees indicated variation among individuals within populations.
Studies carried out in 2002 across the species range indicated that human
activities have affected genetic variation in this species (Teklehaimanot, 2004).
Kelly et al . (2004) reported that populations in crop fields have the highest mean
number of alleles and the highest expected heterozygosity when compared with
populations in fallows and forests. On the basis of fruit characteristics and on
ecological local knowledge in Mali, Vitellaria paradoxa can be divided into five
classes (H. Sanou, unpublished results), but the differences may be due to
environmental rather than genetic differences. However, H. Sanou (unpublished
results) reports that selection of quality germplasm must consider the variation
within populations in the improvement of karité.
Two subspecies have been proposed, V. paradoxa subsp. paradoxa and V.
paradoxa subsp. nilotica (Hall et al ., 1996), but there is no clear distinction
between them based on leaves, inflorescences and flowers, fruits or morphology.
Hall et al . (1996) concluded that the difference is based on the origin of the
populations, which originated in the eastern (subsp. nilotica ) and western (subsp.
paradoxa ) parts of the natural range of the species. Using isozymes, Lovett and
Haq (2000) found high genetic diversity within populations of V. paradoxa in
Ghana. Fontaine et al . (2004), using molecular markers, recommended a
separation between western and eastern populations. Moreover, chemical
analysis by Maranz et al . (2004) indicates different fatty acid profiles across Africa
and following an east-west trend among the natural populations.
It is clear that the genetic characterization of the shea tree needs further
work, and genetic and environmental effects on the expression of different traits