Appendix
8.3 Tree Crop Development
8.3.3 Tree management systems
mycorrhiza is present. Repeated exposure of the difficult-to-root microcuttings ofPappea capensisto 0.5 mg/l IBA improved rooting from 42 to 62%, and the number of roots per plantlet averaged 3 (Mng’omba, 2007). Somatic embryos of P. capensis were successfully germinated into plants (65%), and 65% of plantlets survived after hardening off in a mist chamber.
Graft compatibility increased more with homografts than with heterografts between Uapaca kirkiana clones, species and provenances. Uapaca kirkiana and U. nitida had weak compatibility and they may exhibit delayed incompatibility. Although JatrophaandUapaca kirkianabelong to same family, there is outright incompatibility or early rejection. The technique seems promising for the detection of early incompatibility between close and distant related propagule sources. On the basis of a series of results, reproducible micropropagation protocols have been developed for the rapid multiplication of mature Uapaca kirkianaandP. capensis(Mng’ombaet al., 2007a, b).
amendment practices, except for the strategic application of irrigation of green manure alone (F.K. Akinnifesi, unpublished results). The results of this study did not support the commonly held assumption that the miombo indigenous fruit trees, especially Uapaca kirkiana and Sclerocarya birrea, require fertilization, manure and dry season irrigation to increase growth and survival. On the other hand,V. infaustaperformed better when managed with a combination of light dry-season irrigation and manuring. Similar results were reported in Botswana forStrychnos cocculoides,Sclerocarya birreaandV. infausta(Mateke, 2003).
However, combining the use of manure, fertilizer and irrigation is not recommended for any of the miombo fruit trees. Spacing of trees in the wild Table 8.2. Mean growth increment (mm/month) and survival (%) of four fruit tree species with fertilizer, compost manure amendment and dry-season irrigation at Makoka, Malawi during the 33 months after establishment.
Species Fertilizer Manure Irrigation Height Survival
Uapaca kirkiana No No No 55.8 85
No No Yes 59.3 100
No Yes No 46.4 75
No Yes Yes 57.8 63
Yes No No 54.9 83
Yes No Yes 48.6 67
Yes Yes No 49.6 67
Yes Yes Yes 43.7 25
Sclerocarya birrea No No No 91.9 100
No No Yes 102.8 83
No Yes No 93.4 100
No Yes Yes 94.4 69
Yes No No 92.9 83
Yes No Yes 98.3 75
Yes Yes No 98.3 75
Yes Yes Yes 90.2 83
Vangueria infausta No No No 118.7 94
No No Yes 116.5 100
No Yes No 118.7 83
No Yes Yes 113.4 100
Yes No No 117.1 100
Yes No Yes 115.6 100
Yes Yes No 115.1 100
Yes Yes Yes 118.4 96
Mangifera indica No No No 92.7 100
No No Yes 96.7 100
No Yes No 97.9 100
No Yes Yes 92.5 100
Yes No No 98.8 100
Yes No Yes 103.2 100
Yes Yes No 107.4 100
Yes Yes Yes 104.1 100
Source: F.K. Akinnifesi, J. Mhango, G. Sileshi and T. Chilanga, unpublished results.
improved fruit yield (Mwamba, 1995a). In addition to tree management, an understanding of edaphoclimatic boundary requirements can help to guide management towards desired fruit orchard production in miombo indigenous fruit trees.
Vangueria infaustafruited early compared with mangoes in the fruit orchard at Makoka (Table 8.3). Although very few Uapaca kirkiana flowered in the second and third years, fruits were not retained. Sclerocarya birreagrew relatively quickly but had not started to flower or fruit after 36 months. Experience of fruit retention in another trial (Table 8.4) showed that grafted Uapaca kirkiana flowered and fruited but fruit started to be retained from year 4 onwards.
On-farm planting and scaling up
Many communities in southern Africa retain or nurture semi-domesticates of wild fruits in their homesteads and fields. Therefore, introducing superior cultivars to farmers is an important aspect of accelerated domestication.
Farmers in the Bushbuckridge region of South Africa, for instance, planted
Table 8.3. Percentage of Vangueria infausta andMangifera indicatrees fruiting 24, 31 and 36 months after planting (MAP) at Makoka, Malawi.
Species Date Percentage fruitinga
M. indica December 2005 (24 MAP) 33.3 (9.83)
July 2006 (31 MAP) 99.0 (1.04)
December 2006 (36 MAP) 70.8 (5.36)
V. infausta December 2005 (24 MAP) 94.8 (3.00)
July 2006 (31 MAP) 66.7 (5.14)
December 2006 (36 MAP) 93.8 (3.10) Source: Akinnifesi et al.(2006).
aFigures in parentheses are standard error of the mean.
Table 8.4. Relative tree growth and indicative fruiting of Uapaca kirkianatrees at Makoka orchard from grafted, marcotted and seedling stocks, at 4 years after establishment.
Parameter Marcotts Grafts Seedling stock
Tree height (m) 2.4 ± 0.11 2.0 ± 0.13 2.7 ± 0.14
Bole height (m) 0.39 ± 0.04 0.35 ± 0.04 0.46 ± 0.64
Root collar diameter (cm) 8.50 ± 0.32 9.14 ± 0.35 10.3 ± 0.36
Crown depth (m) 2.0 ± 0.13 0.35 ± 0.04 2.4 ± 0.76
Crown spread (m) 2.7 ± 0.14 2.3 ± 0.13 2.4 ± 0.160
Number of primary branches 17.2 ± 1.33 15.8 ± 0.95 15.3 ± 2.00 Number of secondary branches 25.0 ± 2.60 19.9 ± 2.60 15.3 ± 2.00 Number of tertiary branches 15.0 ± 2.97 10.3 ± 2.91 5.6 ± 1.32
Minimum number of fruits 2 3 0
Maximum number of fruits 414 127 0
Mean number of fruits 78 52 0
Source: F.K. Akinnifesi (unpublished results).
Sclerocarya birrea after the successful liqueur made from marula (Amarula Cream) had become an incentive for rural enterprises. Half of the farmers sampled in four villages were managing self-seeded recruits of S. birrea, while 30% planted from seeds, truncheons or transplants of wildings. However, there has been no planting of trees with desired traits in any of the projects (Shackleton, 2004). About 79% of the households had at least one tree of S.
birrea. This was a spin-off effect of massive project support to the communities in the Bushbuckridge region. Tree domestication efforts that build on existing farmers’ knowledge and practices in the country are likely to succeed.
Several thousands of farmers have been trained in the five countries in nursery establishment, propagation and tree management. Monitoring and evaluation results confirm that an estimated total of 12,702 farmers were trained in nursery establishment and management, propagation techniques between 2001 and 2005. In 2005 alone, 758 individual and group nurseries were established and managed by farmers during the period (315 group and 443 individual nurseries): 458 in Malawi, 165 in Tanzania, 36 in Zambia and 99 in Mozambique (ICRAF, 2005). Over 6000 farmers have been testing indigenous fruits and other high-value trees in the five countries.
On-farm management showed lower survival for Uapaca kirkiana and Strychnos cocculoides in Malawi and Zambia (F.K. Akinnifesi et al., unpublished results; Mhango and Akinnifesi, 2001). In a survey of farmer- managed fruit orchards of Uapaca kirkiana, Ziziphus mauritiana and Sclerocarya birrea, tree survival declined to 51% after 8 months and 12% after 20 months. Strychnos cocculoidesalso declined from 55% at 8 months to 18%
after 20 months. At 29 months, Sclerocarya birreamaintained survival at 48%
on farmer’s fields, while Ziziphus mauritianamaintained survival at 50% at 29 months (Mhango and Akinnifesi, 2001). Farmers attributed poor tree survival and growth to inefficient management, lack of water, grazing and pests. About 87% of farmers did not apply any management measure. Farmers indicated that most of the trees that died did so within 6 months after establishment. The gap between on-station researcher-managed orchards and farmer-managed orchards warrants further tree management investigations and the development of appropriate on-farm management protocols. Although our work has shown that miombo indigenous fruits do not require soil fertility replenishment or intensive irrigation, weeding and protection from browsing animals are important. In addition, mycorrhizal inoculation has been stated to be a necessity, especially at the early stage.