Creating Opportunities for Domesticating and Commercializing Miombo Indigenous Fruit Trees in Southern Africa - Indigenous Fruit Trees in the Tropics: Domestication, Utilization and Commercialization - page 147

8.3 Tree Crop Development

Tree domestication refers to how humans select, manage and propagate trees;
the humans involved may be scientists, civil authorities, commercial companies,
forest dwellers or farmers (Simons and Leakey, 2004). Wild harvesting
(extractivism) and overextraction have led to market expansion and supply
shortages in many cases (Simons and Leakey, 2004). The greatest potential for
tree domestication resides in the interactions of rural communities with wild tree
populations through retention on farms and homesteads and the cultivation or
management of fruit trees as semi-domesticates. Focusing on wild collection and
management of semi-domesticated trees on farms and homesteads has been
indicated as an effective way of reducing the sunk costs, providing households
with improved species diversity in terms of desired fruit and tree traits (Kruise,
2006). The role of indigenous fruit trees where cultivated and semi-domesticated
trees coexist to adapt to human needs has been well documented in the concepts
of homegardens (Kang and Akinnifesi, 2000; Kumar, Chapter 5, this volume),
forest gardens and agroforestry (Wiersum, 2004). However, producing improved
elite cultivars with superior fruit and traits will require conscious domestication
(Akinnifesi et al. , 2006; Leakey and Akinnifesi, Chapter 2, this volume).

8.3.1 Germplasm collection, provenance and progeny testing

The initial work on domestication of indigenous fruits in southern Africa started
with range-wide tree germplasm collection and testing (Kwesiga et al. , 2000;
Akinnifesi et al. , 2004b). In 1995, 30 germplasm collectors from six southern
African countries were trained. Forty provenances of Sclerocarya birrea were
collected from eight countries in 1996 (Botswana, Malawi, Namibia, Swaziland,
Tanzania, Zambia, Mali and Kenya) and 24 provenances of Uapaca kirkiana
from five countries (Malawi, Mozambique, Tanzania, Zambia and Zimbabwe).
The weight of the germplasm collected and exchanged among Malawi, Zambia,
Zimbabwe and Mozambique exceeded 10 t of fruits. In order to determine the
genotype

environment interactions to isolate superior genotypes, 16
provenances of U. kirkiana and 20 of S. birrea were evaluated in four countries
within the region. The trees were established in each country as multilocational
provenance and progeny trials. The preliminary results have been documented
(Akinnifesi et al. , 2004b).
For S. birrea , the provenances planted in Tanzania varied in their initial
performance. At 12 months, the fastest-growing provenance was Chikwawa
from Malawi (1.37 m), compared with Mpandamatenga provenance from
Botswana (0.6 m). Wami provenance from Tanzania was the second best
(1.28 m). Tree survival 12 months after establishment (MAE) was generally
high (99%) (ICRAF, 2005). The provenances of U. kirkiana and S. birrea
planted in Zambia and Malawi also performed differently. Tree survival at
Makoka was generally good at 30 MAE, ranging from 82 to 96% (Akinnifesi et
al. , 2004b). At 54 MAE, Mulrelwa was the tallest provenance at Makoka (2 m),
and nine out of the 16 provenances were taller than 1.5 m. The result at