Black Sigatoka Nematode and Banana Weevil Tolerant ‘Matooke’ Hybrid Banana Released in Uganda Kephas Nowakunda, Alex Barekye, Reuben T. Ssali1, Josephine Namaganda, Wilberforce K. Tushemereirwe, Gertrude Nabulya, Rockefeller Erima, Kenneth Akankwasa, and Edison Hilman National Agricultural Research Laboratories, Kawanda, P.O. Box 7065, Kampala, Uganda Micheal Batte International Institute of Tropical Agriculture (IITA-Uganda), P.O. Box 7878, Kampala, Uganda Deborah Karamura Bioversity International-Uganda, Katalima Road, Plot 106 Naguru, P.O. Box 24384, Kampala, Uganda Additional index words. banana, breeding, Mycosphaerella fijiensis, Radopholus similis, Cosmopolites sordidus 2003). Using the youngest leaf with spots and the number of standing leaves at flowering as indicators of resistance (Craenen, 1998), ‘Kiwangaazi’ produces more leaves than the local variety ‘Mbwazirume’ (Table 3) and the symptoms of black Sigatoka are observed on older leaves subsequently availing more pho- tosynthetic leaf area to allow proper fruit filling. This may partially explain the high yield potential of ‘Kiwangaazi’ as indicated by bunch weight (Table 3). Bunch weight is one of the most important criteria used by farmers to select cultivars they want to grow (Akankwasa et al., 2013; Melinda et al., 2007). We have previously reported ‘Kiwangaazi’ as a tall cultivar (plant height > 3 m), which takes longer for the fruits to mature (about 4 months for fruit filling) (Ssali et al., 2010). Tall banana varieties are usually susceptible to breakage by wind but ‘Kiwangaazi’ is protected by its wider girth (>50 cm—at 1 m height). The results of the assessment of the most promising hybrids’ reaction to the banana weevil (Cosmopolites sordidus, Germar), the most elusive banana pest in Uganda (Gold et al., 2004), are presented in Table 4. In this field experiment, 120 tissue culture plants of each hybrid were established to assess their reaction to the banana weevil. Together with Origin This article presents the attributes of the first East African highland banana hybrid, ‘Kiwangaazi’ (Fig. 1), which was recently selected, released, and added to the national cultivar list in Uganda. The ‘matooke’ hybrid ‘Kiwangaazi’ was conventionally bred at Kawanda by crossing the tetraploid hybrid ‘1201k-1’ (‘Nakawere’ AAA • ‘Calcutta4’ AA) with the improved diploid ‘SH3217’ AA. The main target was black Sigatoka resis- tance, a disease caused by the fungal patho- gen Mycosphaerella fijiensis, ranked as the most important constraint to the production of the East African highland bananas, espe- cially in the low lands (covering most of central and eastern Uganda). ‘Kiwangaazi’, together with other hybrids was evaluated for black Sigatoka response, nematode and weevil damage, yield, and consumer acceptability. The cultivar was evaluated under the code ‘M9’, and released by the national variety release committee as ‘KABANA 6H’. The name ‘Kiwangaazi’ was coined by farmers who participated in the on-farm evaluation studies. In the local language (Luganda), ‘Kiwangaazi’ means ‘‘long lasting.’’ Due to high pest and disease pressure, banana plan- tations can only last for 3–5 years, especially Received for publication 24 Apr. 2014. Accepted for publication 19 Jan. 2015. We thank AGRA and the Government of Uganda for financial assistance. Our appreciation also goes to farmers who participated in the evaluation of this banana hybrid. 1To whom reprint requests should be addressed; e-mail This email address is being protected from spambots. You need JavaScript enabled to view it. . in central and eastern Uganda. However, due to its pests and disease tolerance, farmers observed that ‘M9’ plants remain vigorous after 5 years, hence the name ‘Kiwangaazi’. Description Like the East African highland cooking bananas, ‘Kiwangaazi’ is a triploid AAA, but clearly distinct from any other existing ge- notypes. Traits that distinguish ‘Kiwangaazi’ from the parents and other closely related cultivars are presented in Tables 1 and 2. Whereas most of the East African cooking bananas have deep green leaves, pseudos- tems, and fruits, ‘Kiwangaazi’ has pale, shiny color on the leaves, pseudostem, and fruits (Tables 1 and 2). Availability The cultivar ‘Kiwangaazi’ is maintained by the National Banana Research Program of NARO in Uganda. Farmers can access tissue culture plant from private tissue culture laboratories in Uganda and thousands of farmers have participated in the evaluation and promotion of ‘Kiwangaazi’. Comparative Data Performance in the field. The response of four promising banana hybrids to black Sigatoka, the primary target constraint, is presented in Table 3. Tissue culture plants were established in randomized complete block design at a spacing of 3 m • 3 m, manure was applied at planting, and regular banana man- agement was followed (Tushemereirwe et al., two other banana cultivars, a known resistant variety ‘Yangambi KM5’ and the highly susceptible East African highland banana ‘Atwarira’, the plants were spaced at 3 m • 3 m, manure was applied at planting, and regular banana management was followed (Tushemereirwe et al., 2003). The plants were infested with 10 weevils (female: male ratio of 1:1) at 9 months after planting and corm damage assessment done at harvest (Kiggundu et al., 2003). Total number of mats per genotype in the trial was counted at a 6-month interval. Our results show that ‘Kiwangaazi’ had considerable tolerance to the banana weevils (Table 4). This banana weevil tolerance of ‘Kiwangaazi’ is further highlighted by a significantly low mat disap- pearance rate of 8.5% at Kawanda (central Uganda) over a period of 5 years in compar- ison with the highly susceptible local variety ‘Atwalira’ (70.6%; Table 4). Previous re- search has attributed banana weevil resistance to biophysical factors like corm diameter, resin/sap production, corm dry matter con- tent, corm hardness, and suckering ability (number of suckers) (Kiggundu 2000). Gen- erally antibiosis (factors affecting larval performance) rather than antixenosis (at- traction) appear to be the most important resistance mechanism in banana (Gold et al., 2001). The banana weevils have been contraindi- cated in the short plantation life of banana, especially in central Uganda (Tushemereirwe et al., 2001). Therefore, the results imply that ‘Kiwangaazi’ could be handy in addressing the banana production constraints, espe- cially in central Uganda where the growing traditional cultivars have become difficult due to these pests. This implies that hybrid HORTSCIENCE VOL. 50(4) APRIL 2015 621 Table 1. Distinguishing features of ‘Kiwangaazi’ (M9) from the female parent ‘Nakawere’. Banana descriptor ‘Kiwangaazi’ (M9) Parents (‘Nakawere’) Fruit position Strongly re-curved toward rachis (1) Not re-curved (2) Appearance of leaf upper surface Shiny (2) Dull (1) Color of midrib dorsal surface Red (2) Pale green (5) Color petiole basez Tint of pink Pale green Fruit shape (longitudinal curvature) Cucumber shaped (5) Straight (slightly curved) (1) Immature fruit peel color Light green (2) Deep green (6) Flesh texture Deep Yellow and soft textured Yellow and firm textured zDescriptors not in the INIBAP’s (1996) descriptors for banana (Musa spp.). Numbers in parenthesis are the character states (scores) according to INIBAP’s (1996) descriptors for banana (Musa spp). Table 2. Distinguishing features of ‘Kiwangaazi’ (M9) from other East African highland bananas (Musa sp.). Other highland land Descriptor ‘Kiwangaazi’ (M9) race bananas Color of leaf upper surface Medium green (2) Deep green (4) Pseudostem color Medium green (2) with fewer blotches Green (3) Color of midrib dorsal surface Red (5) Light green (2) Color petiole basez Immature fruit peel color Tint of pink Light green (2) Green Green (3) Fig. 1. ‘Kiwangaazi’ the first East African highland banana hybrid to be released in Uganda. Attri- butes include consumer acceptability, resistance to black Sigatoka and tolerance to banana weevils and burrowing nematodes. ‘Kiwangaazi’ will solve the long-standing problem of short plantation life caused largely by weevils. The hybrid reaction to the banana- in a pot assay are presented in Table 5. R. similis has been identified as the most destructive nematode species in Uganda (Speijer and De Waele, 2001). Results in- dicated that ‘Kiwangaazi’ had a lower per- centage root necrosis than the susceptible control, implying that it was tolerant to nematode damage. Nematodes infect the roots, causing them to rot as they feed. This results in interferences in water and nutrient uptake by plants in addition to week anchor- age, resulting in toppling of plants. Lignin and phenolic compounds might be involved in nematode resistance mechanisms in Musa (Fogain and Gowen, 1996; Valette et al., 1998). To satisfy end-user need, it is imperative Flesh texture Soft Soft-firm zDescriptors not in the descriptors for banana (Musa spp.). Numbers in parenthesis are the character states (scores) according to INIBAP’s (1996) descriptors for banana (Musa spp). Table 3. Means (±standard error) of yield and black Sigatoka response of the most promising East Africa highland banana hybrids over 5 years at Kawanda (central Uganda) (n = 40). Genotype Bwt (kg) NSL YLS LHAR ‘Mbwazirume’ 15.47 ± 0.47 7.70 ± 0.12 4.91 ± 0.12 1.20 ± 0.11 M2 23.16 ± 1.14 11.92 ± 0.32 10.85 ± 0.32 5.62 ± 0.27 M14 20.07 ± 1.26 11.88 ± 0.35 10.96 ± 0.35 4.48 ± 0.30 M17 22.42 ± 0.92 10.84 ± 0.26 10.41 ± 0.26 4.43 ± 0.22 ‘Kiwangaazi’ (M9) 21.25 ± 0.76 10.88 ± 0.22 9.16 ± 0.22 4.29 ± 0.18 leaves at harvest. Values in bold are significantly different from the control (landrace East African highland banana, ‘Mbwazirume’) at 5% level of probability using Dunnett’s t test. Table 4. Response of East Africa highland banana hybrids to weevils (based on total cross sectional damage) and mat disappearance over a 5-year period in central Uganda. Cultivar Total cross-sectional damage Mat disappearance (n = 120) % ‘Yangambi KM 5’ (resistant) 06.21 ± 1.38* 5.4* M14 10.69 ± 1.78* 5.5* M17 13.97 ± 1.72* 5.8* M2 15.35 ± 1.72* 12.3* ‘Kiwangaazi’(M 9) 25.16 ± 1.74* 8.5* ‘Atwalira’ (susceptible) 41.72 ± 1.38 70.6 *Significant difference (P > 0.05) from the susceptible control variety ‘Atwalira’ by Dunnett’s test. scored good for taste, texture, and color by that the developed hybrids balance high yields and resistance to pests and diseases with culinary attributes (Nowakunda and Tushemereirwe, 2004). For this reason, the hybrids’ culinary attributes were assessed using consumer methods (Nowakunda et al., 2000) of sensory evaluation tech- niques. Consumer acceptability tests were conducted to document feedback from end- users. Briefly, 40 consumers assessed and scored their perception for sensory param- eters, namely flavor, taste, texture, and color of the food when cooked based on a five-point Likert scale (5 = excellent, 4 = good, 3 = fair, 2 = bad, and 1 = very bad) (Dadzie and Orchard, 1997). Hybrid ‘Kiwan- gaazi’ (‘KABANA 6H’) was consistently most consumers as indicated in Figure 2. Compared with other hybrids, ‘Kiwangaazi’ was rated closet to the local control ‘Mbwa- zirume’ for all the consumer attributes. Combined with its tolerance to the banana weevils, nematodes, and black Sigatoka, this hybrid appeared to have fairly bal- anced traits, hence potential for end-user acceptability. The ‘matooke’ hybrid ‘Kiwangaazi’ was consistently selected as the most preferred variety among those that it has been rated against. This was in respect to agronomic attributes, pests, disease resistance, and end- user acceptability. The genotype combines attributes that address the problems that are constraining banana production, especially in Table 5. Percentage root necrosis on promising East Africa highland banana hybrids, 8 weeks after inoculation with 400 nematodes (Radopholus similis) per plant. Cultivar % Root necrosis ‘Yangambi KM 5’ 1.1 M17 3.1 M2 3.5 M14 3.6 ‘Kiwangaazi’ (M9) 6.1 ‘Mbwazirume’ (susceptible) 10.3 LSD (0.05) 1.38 Values are means of 10–12 replicates. central Uganda. The National Banana Re- search Program filed for its release by the Ministry of Agriculture’s variety release committee and for its inclusion on the 622 HORTSCIENCE VOL. 50(4) APRIL 2015 Fig. 2. Sensory evaluation of banana varieties. Scores based on five-point Likert scale (5 = excellent, 4 = good, 3 = fair, 2 = bad, and 1 = very bad). Means sharing the same letters are not different significantly at 5% level of probability by Duncan’s Multiple Range Test. Values are presented as mean scores. Mwazirume is local commercial banana cultivar. Uganda national cultivar list. It was hence- forth released on 16 Dec. 2010. Though accepted in all agro-ecological zones of Uganda where it was evaluated, the cultivar is recommended mainly for farmers in central, mid-western, and eastern Uganda where the growing of traditional cultivars is increasingly becoming difficult, and the whole of the northern region where farmers have just adopted banana cultivation. Literature Cited Akankwasa, K., G. Ortmann, E. Wale, and W.K. Tushemererwe. 2013. Determinants of con- sumers’ willingness to purchase East African Highland cooking banana hybrids in Uganda. Afr. J. Agr. Res. 8:780–791. Craenen, K. 1998. Technical manual on black Sigatoka disease of banana and plantain. Interna- tional Institute of Tropical Agriculture, Ibadan, Nigeria. Dadzie, B.K. and J.E. Orchard. 1997. Routine post harvest screening of banana/plantain hybrids: Criteria and methods. INIBAP Technical Guidelines 2. International Plant Genetic Re- sources Institute. Rome, Italy: INIBAP ISBN: 2-910810-22-4. Fogain, R. and S.R. Gowen. 1996. Investigations on possible mechanisms of resistance to nem- atodes in Musa. Euphytica 92:375–381. Gold, C.S., J.E. Pena, and E.B. Karamura. 2001. Biology and integrated pest management for the banana weevil Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae). Integrated Pest Mgt. Rev. 6:79–155. Gold, C.S., G.H. Kagezi, G. Night, and P.E. Ragama. 2004. The effects of banana weevil, Cosmopolites sordidus, damage on highland banana growth, yield and stand duration in Uganda. Ann. Appl. Biol. 145:263–269. INIBAP. 1996. Descriptors for banana (Musa spp). 28 May 2014. . Kiggundu, A., C.S. Gold, M. Labuschagne, D. Vuylsteke, and S.V.D.M. Louw. 2003. Levels of host plant resistance to banana weevil Cosmopolites sordidus (Germar) (Coloeptera: Curculionidae) in African Musa germplasm. Euphytica 133:267–277. Kiggundu, A. 2000. Host-plant interactions and resistance mechanisms to banana weevil Cos- mopolites sordidus (Germar) in Ugandan Musa germplasm. MSc Thesis. Univ. Orange Free State, South Africa. Melinda, S., W.K. Tushemereirwe, P.N. Abodi, F. Bagamba, M.G.S. Byabachwezi, S. Edmeades, R. Kalyebara, E. Katungi, E.M. Kikulwe, J.M. Nkuba, and S. Wood. 2007. Conclusions and implications for research policy, p. 157–163. In: Melinda, S., and W.K Tushemereirwe (eds.). An economic assessment of banana genetic im- provement and innovation in the Lake Victoria basin. Research Report of the International Food Policy Research Institute. Nowakunda, K. and W.K. Tushemereirwe. 2004. Farmer acceptance of introduced banana genotypes in Uganda. Afr. Crop Sci. J. 12 (1):1–6. Nowakunda, K., P.R. Ruibaihayo, and W. Tushemereirwe. 2000. Consumer accept- ability of introduced bananas in Uganda. Infomusa 9(2):22–25. Speijer, P.R. and D. De Waele. 2001. Nematodes associated with East African highland cook- ing bananas and cv. Pisang Awak (Musa spp.) in Central Uganda. Nematology 3: 535–541. Ssali, R.T., K. Nowakunda, A. Barekye, R. Erima, M. Batte, and W.K. Tushemereirwe. 2010. On farm participatory evaluation of East African highland bananas ‘EAHB’ hybrids (Musa spp). Acta Hort. 879:585–591. Tushemereirwe, W.K., D. Karamura, H. Ssali, D. Bwamiki, I. Kashaija, C. Nankinga, F. Bagamba, A. Kangire, and R. Sebuliba. 2001. Bananas (Musa spp). In: K. Mukiibi Joseph (ed.). Agri- culture in Uganda, vol. 11 (Crops). Fountain Publishers, Technical Centre for Agricultural and Rural Cooperation/National Agricultural Research Organization, Kampala. Tushemereirwe, W.K., C. Nankinga, I. Kashaijja, and W. Tinzara. 2003. Banana production manual. 2nd ed. Fountain Publishers, Na- tional Agricultural Research Organization, Kampala. Valette, C., C. Andary, J.P. Geiger, J.L. Sarah, and M. Nicole. 1998. Histochemical and cytochem- ical investigations of phenols in roots of banana infected by the burrowing nematode Radopho- lus similis. Phytopathology 88:1141–1148. HORTSCIENCE VOL. 50(4) APRIL 2015 623
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The vast majority of the bananas currently grown and consumed were not conventionally bred but are selections made over probably thousands of years from naturally occurring hybrids. Cultivated bananas are very nearly sterile and as a consequence are not propagated from seed but rather through vegetative propagation, primarily suckers as well as more recently micropropagated or tissue cultured bananas. These factors, very old selections, near sterility and vegetative propagation, mean that these bananas have not been genetically improved either for resistance or improved quality and are becoming increasing in affected by serious pests and diseases.

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