10  Summary

The field studies in Sudan and the experiments in the greenhouse in Berlin-Dahlem have shown the following results:

1. The Baobab (Adansonia digitata) is a massive, deciduous tree and native to Sudan. Beside its fruits, the Baobab has an exceedingly wide range of uses ranging from food and beverages to medicinal uses.
   
2. The tamarind (Tamarindus indica) is an aesthetic, evergreen tree and grows wild throughout Sudan. Its fruits are highly appreciated by the people. In addition, the tree provides a diversity of further important forest products.
   
3. A number of under-utilised species with edible fruits were identified in Central Sudan. Fruits of these indigenous species play an important role in the diet of rural people in the savanna belt, especially during famines and food shortages.
   
4. Particularly in Northern Sudan there are vast areas of potentially arable land which are affected by salinity to variable degrees. In order to maintain food security for the increasing population, this land is becoming more and more important.
   
5. The results of the greenhouse experiments over a period of 20 weeks indicate that a salinity level of 20 mM NaCl strongly influences growth and metabolism of Adansonia digitata seedlings. Therefore in the seedling stage the species can be characterised as salt-sensitive.
   
6. Tamarindus indica seedlings tolerated a salinity level of 40 mM NaCl. This indicates that in the seedling stage tamarind is a fairly salt tolerant tree species compared to other fruit trees.
   
7. The conclusion of the greenhouse experiments indicates that the tamarind seems to be the more suitable under-utilized fruit tree species for cultivation in semi-arid areas with salinity problems.
   
8. Further investigations in this research area are necessary and promising.