104 CHAPTER 4
the airborne fungal leaf-spot disease black Sigatoka (Mycosphaerella fijien- sis Morelet) (Gold 1998, 2000; Gold et al. 1998; Gold, Pena, and Karamura 2001; Tushemereirwe et al. 2003b). Consequently, the National Banana Research Program of the National
Agricultural Research Organisation (NARO) in Uganda has developed a breeding program that employs a range of traditional crop-breeding meth- ods and a portfolio of biotechnologies to address the crop’s most debilitating problems caused by pests and diseases (Kikulwe et al. 2007). The short- term breeding strategy includes the assembly of local and foreign germplasms for evaluation and selection of varieties resistant or tolerant to existing produc- tivity constraints. Resistance to a limited set of pests and diseases (for example, black Sigatoka) was identified in hybrid banana varieties. Though character- ized by bigger bunches, the hybrid varieties are not widely grown in Uganda (Nowakunda 2001; Smale and Tushemereirwe 2007). Producers and consum- ers prefer the East African highland cooking bananas, but these are also highly susceptible to black Sigatoka (Nowakunda et al. 2000; Nowakunda 2001) and bacterial wilts (Tushemereirwe et al. 2003a). Susceptibility to diseases prompted the national researchers to adopt a long-term breeding strategy that includes the generation of new genotypes and other new approaches to intro- duce resistance. The highest yielding highland cooking bananas proved to be sterile, which
slows down their improvement through conventional breeding (Ssebuliba 2001; Ssebuliba et al. 2006). With major biotic constraints not easily addressed through conventional breeding and management practices, recent efforts have been made to employ genetic engineering for the insertion of resis- tance traits into selected banana background planting material. Unlike cross- breeding, genetic engineering allows for improving the agronomic traits (for example, disease and pest resistance), as genes are inserted into potential host varieties (cultivars) while not changing other production and product attri- butes (for example, cooking quality). The genetic modification approach has shown potential for the improvement of the crop (Tripathi 2003). Edmeades and Smale (2006) argue that the choice of a host variety for a
genetic transformation largely determines its acceptability by producers and consumers. In those regions strongly affected by biotic constraints, it is likely that GM banana cultivars will be more beneficial to poorer and subsistence- oriented farmers. In addition, the insertion of multiple traits into East African highland bananas, although associated with additional R&D costs (for exam- ple, transformation and regulatory costs), could further increase the benefits generated by the adoption of the technology in Uganda. Multiple traits may
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