Germplasm Supply, Propagation and Nursery Management of Miombo Fruit Trees - Indigenous Fruit Trees in the Tropics: Domestication, Utilization and Commercialization - page 360

matter (Muller-Samann and Kotschi, 1994). In some species there is a special
symbiotic relationship between the roots and fungi and/or bacteria. The fine roots
of most miombo indigenous fruit trees form symbiotic associations - mycorrhizas
- with various fungi. The symbiotic relationship between plant roots and certain
mycorrhizal species can increase the plant's uptake of important nutrients, as well
as make the plant more tolerant of drought and disease (Bolan, 1991). It might
be worthwhile to collect microsymbionts when collecting scions of indigenous
fruit trees from the wild.
Trees mainly develop two types of mycorrhizas: ectomycorrhizas (ECM)
and vesicular-arbuscular mycorrhizas (VAM), which are distinct in morphology
(Gerdemann, 1968). In Zambia, Uapaca kirkiana , Uapaca nitida , Uapaca
sansibarica and Parinari curatellifolia form ectomycorrhizal associations while
Strychnos innocua , Strychnos spinosa and Syzygium guineense form
endomycorrhizas in their natural stands in the miombo (Högberg and Piearce,
1986). Uapaca kirkiana has also been shown to form endomycorrhizas in
Tanzania (Högberg, 1982). A genuine dual ECM/VAM association in Uapaca
staudtii has also been reported in Cameroon (Moyersoen and Fitter, 1999),
although a tendency towards greater fractional colonization with ECM and
lower colonization with VAM has been observed in samples from dry areas
than from waterlogged habitats (Moyersoen and Fitter, 1999). A natural
mycorrhizal association was observed on roots of Sclerocarya birrea subsp.
birrea in Mali (Soumaré et al. , 1994). In Zimbabwe, McGregor (1995) has
reported an association between S. birrea subsp. caffra and a mushroom. Table
19.3 gives the types of mycorrhiza associated with selected indigenous fruit
trees of the miombo.
In natural stands of Uapaca kirkiana in Zambia, the roots of the seedlings
are associated with seven species of fungus (Mwamba, 1995). Though certain

Table 19.3. Mycorrhizas associated with selected indigenous fruit trees of the miombo and
related species.

Miombo fruit Mycorrhizal Country of

tree species status report Reference

Diospyros consolata VAM Tanzania Högberg, 1982

Sclerocarya birrea subsp. caffra VAM Botswana Mateke and Tshikae, 2002

Sclerocarya birrea subsp. caffra ECM Zimbabwe McGregor, 1995

Strychnos henningsii VAM Tanzania Högberg, 1982

Strychnos innocua VAM Zambia Högberg and Piearce, 1986

Strychnos madagascarenis VAM Tanzania Högberg, 1982

Strychnos spinosa VAM Zambia Högberg and Piearce, 1986

Uapaca kirkiana Dual ECM/VAM Tanzania Högberg, 1982

Uapaca kirkiana ECM Zambia Högberg and Piearce, 1986

Uapaca nitida ECM Zambia Högberg and Piearce, 1986

Uapaca sansibarica ECM Zambia Högberg and Piearce, 1986

Uapaca guineensis ECM Senegal Thoen and Ba, 1989

Uapaca staudtii Dual ECM/VAM Cameroon Moyersoen and Fitter, 1999

ECM, ectomycorrhiza; VAM, vesicular-arbuscular mycorrhiza.