Domestication potential of Marula (Sclerocarya birrea subsp. caffra) in South Africa and Namibia: 3. Multiple trait selection

Leakey, Roger (2005) Domestication potential of Marula (Sclerocarya birrea subsp. caffra) in South Africa and Namibia: 3. Multiple trait selection. Agroforestry Systems, 64 (1). pp. 51-59.

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An understanding of the inter-relationships between the traits characterising tree-to-tree variation in fruits and kernels is fundamental to the development of selected cultivars based on multiple trait selection. Using data from previously characterised marula (Sclerocarya birrea) trees in Bushbuckridge, South Africa and North Central Region of Namibia, this study examines the relationships between the different traits (fruit pulp, flesh/juice mass, and nut shell and kernel mass) as a means to determine the opportunities to develop cultivars. Strong and highly significant relationships were found between fruit mass and pulp mass in trees from South Africa and Namibia, indicating that size is a good predictor of fruit pulp production. However, fruit size is not a good predictor of nut or kernel production, as there were weak relationships between fruit and nut and/or kernel mass, which varied between sites and landuses. Generally, the relationships between fruit mass and kernel mass were weaker than between fruit mass and nut mass. Relationships between kernel mass and shell mass were generally weak. The lack of strong relationships between fruit and kernel mass does, however, imply that there are opportunities to identify trees with either big fruits/small nuts for pulp production, or trees with large kernels in relatively small fruits for kernel oil production. However, within fruits from the same tree, nuts could contain 0–4 kernels, indicating that even in trees with an inherent propensity for large kernels, improved pollination may be required to maximise kernel mass through an increase in kernel number. Finally, the relationships between percentage kernel oil content and the measured morphological traits were also very weak. The conclusions of these results are that there is merit in identifying different combinations of traits for the selection of trees producing either pulp or kernels. Consequently, fruit and kernel ‘ideotypes’ are presented as guides to the selection of elite trees for cultivar development. These results have important implications for the domestication of the species as a producer of fruits or kernels for food/beverages or cosmetic oils.

Item ID: 5713
Item Type: Article (Research - C1)
ISSN: 1572-9680
Keywords: agroforestry; domestication; indigenous fruit; Sclerocarya birrea; Southern Africa; cultivar; ideotype; kernel oil
Date Deposited: 22 Dec 2009 03:43
FoR Codes: 07 AGRICULTURAL AND VETERINARY SCIENCES > 0799 Other Agricultural and Veterinary Sciences > 079999 Agricultural and Veterinary Sciences not elsewhere classified @ 60%
07 AGRICULTURAL AND VETERINARY SCIENCES > 0705 Forestry Sciences > 070501 Agroforestry @ 40%
SEO Codes: 82 PLANT PRODUCTION AND PLANT PRIMARY PRODUCTS > 8202 Horticultural Crops > 820214 Tropical Fruit @ 80%
82 PLANT PRODUCTION AND PLANT PRIMARY PRODUCTS > 8201 Forestry > 820103 Integration of Farm and Forestry @ 20%
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