Cyphomandra betacea is a woody plant belonging to the Solanaceae family. It is commonly known as Tamarillo or tree tomato (Correia et al., 2009). The name “Tamarillo” was adopted in New Zealand and has become the standard commercial designation for the fruit (Morton, 1987). Tamarillo is grown mainly for their edible fruits and, to a lesser extent, as an outdoor ornamental. They have several culinary uses and can be eaten raw in salads or as dessert but preferably cooked (Guimarães et al., 1996). In Jamaica and the West Indies, the fruits are considered to have beneficial effects in relieving disorders of the liver (Guimarães et al., 1996).
Tamarillo is an important component in Rwanda’s exotic fruit industry and consumption of the fruit is traditionally recommended for people suffering from stomach ailments. In this country, it is mainly used for making jams and juices but unfortunately in low quantities because of low productivity, mainly due to viral diseases. Tamarillo is considered an interesting crop from the nutritional viewpoint as it is comparatively high in protein (1.5–2 g/100 g of food), vitamin C (30–45 mg/100 g), and E (1.85 mg/100 g), provitamin A, mineral elements (K, P), low in carbohydrates (4.7 g/100 g), and in calories (about 28 Kcal/100 g) (McCane and Widdowson, 1992). The plant is propagated mainly through seeds, cuttings, or by grafting (Fouque, 1973; Prohens et al., 2001). Propagation through seeds is not recommended as this method is known to produce high degree of genetic variability that negatively affects fruit color resulting in rejection of fruits on the international market. On the other hand, vegetative propagation by cuttings has been found to transmit deadly viral diseases. Therefore, there is a compelling need to develop alternative methods to propagate the plant in Rwanda. Tissue culture offers a feasible solution to produce large numbers of disease-free planting materials. It is also known that in vitro propagated Tamarillo plants produce higher yields and shorter gestation period compared with traditional methods (The Indian Agriculture Information Wing, 2009). Another advantage offered by tissue culture methods is the large scale availability of planting materials at any time of the year irrespective of the season. This study aimed to developing an efficient and rapid propagation protocol for C. betacea plant through tissue culture techniques.
An increasing number of studies describing in vitro propagation of Tamarillo using axillary buds have been reported (Barghchi, 1998; Obando et al., 1992; Waweru et al., 2011). Somatic embryogenesis has also been reported by Espinosa et al. (2005), Obando and Jordan (2001), Correia et al. (2009), Guimarães et al. (1996), and Correia et al. (2011). However, there are no documented studies on the direct organogenesis in Tamarillo. An important advantage of direct organogenesis is the potential for maintaining genomic stability of regenerated plants, whereas regeneration via an intermediate callus phase increases the possibility of somaclonal variations (Kahia, 1999). Furthermore, a highly efficient and reproducible in vitro regeneration system is an absolute prerequisite for producing transgenic plants.
Barghchi, M. 1998 In vitro regeneration, plant improvement and virus elimination of Tamarillo [Cyphomandra betacea (Cav.) Sendt)], p. 173–185. In: M.R. Davey, et al. (eds.) Tree biotechnology—towards the millennium. Nothingham University Press, Nothingham, UK
Burbulis, N., Blinstrubienė, A. & Kuprienė, R. 2011 Effect of genotype and medium composition on linseed (Linum usitatissimum) ovary culture Biologia 66 465 469
Cheesman, L., Finnie, J.F. & Van Staden, J. 2010 Eucomis zambesiaca baker:Factors affecting in vitro bulblet induction. SOUTH AFRIC J. Bot. 76 543 549
Correia, S.I., Lopes, M.L. & Canhoto, J.M. 2009 Somatic embryogenesis in Tamarillo (Cyphomandra betacea): Recent advances Acta Hort. 839 157 164
Correia, S.I., Lopes, M.L. & Canhoto, J.M. 2011 Somatic embryogenesis induction system for cloning an adult Cyphomandra betacea (Cav.) Sendt. (Tamarillo) Trees (Berl.), doi: 10.1007/s00468-011-0575-5.
Dadjo, C., Kahia, J., Sila, D., Muthuri, C., Diby, L. & Kouame, C. 2015 Induction and regeneration of somatic embryos from Vitex doniana (Lamiaceae) leaf explants. Intl. J. Biotechnol. Mol. Biol. Res. 6:28–34
D’Onofrio, C. & Morini, S. 2005 Development of adventitious shoots from in vitro grown Cydonia oblonga leaves as influenced by different cytokinins and treatment duration Biol. Plant. 49 17 21
Espinosa, O., John, A., Gonzalez, T.O., Sanchez, H., A, R., Kafrri, A. & Londono, C. 2005 Potential of in vitro propagation for the tomato TREE PARTENOCARPIC Cyphomandra betacea Cav. (sendt). Rev. Fac. Nal. Agr. Medellín 58(1):2685–2695
Fouque, A. 1973 Solanacées. Fruits 28:41–42
Guimarães, M.L., Tomé, M.C. & Cruz, G.S. 1996 Cyphomandra betacea (Cav.) sendt, (Tamarillo), p. 120–137. In: Y.P.S. Bajaj (ed.). Biotechnology in agriculture and forestry, trees IV. Springer Verlag, Berlin
Kahia, W.J. 1999 In vitro propagation of the new Coffea arabica cultivar-Ruiru 11. University of London, London, UK, PhD thesis
Khan, H., Siddique, I. & Anis, M. 2006 Thidiazuron action inhibitor silver nitrate induced somatic embryogenesis and plant. Acta Physiol Plant 26(3):299–305
Lata, H., Chandra, S., Wang, Y.H., Raman, V. & Khan, I.A. 2013 TDZ-induced high frequency plant regeneration through direct shoot organogenesis in Stevia rebaudiana Bertoni: An important medicinal plant and a natural sweetener Amer. J. Plant Sci. 4 117 128
Manisha, B.P. & Patel, R.S. 2013 Impact of plant growth regulators (PGRs) on callus induction from internodal explants of Tecomella undulata (Sm.) seem-A multipurpose medicinal plants. Intl. J. Scientific Res. 3(11)
Maity, S., Ray, S. & Banerjee, N. 2005 The role of plant growth regulators on direct and indirect plant regeneration from various organs of Leucaena leucocephala Acta Physiol. Plant. 27 473 480
Mathew, M.K., Rao, Y.S., Pradipkumar, K., Madhusoodanan, K.J. & Potty, S.N. 1999 In vitro culture system in vanilla. Osmania University, Hyderabad, India. p. 171–179. (Proc. Natl. Conf. Plant Tissue Cult. Biotechnol. Emerging Trends)
McCane, J. & Widdowson, D.A. 1992 In: Fruit and nut Suppl. To the composition of food, 5th ed. p. 74–77. Unwin & Buss, London, Holland
Mehta, U.J., Barreto, S.M. & Hazra, S. 2004 Effect of thidiazuron in germinating tamarind seedlings In Vitro Cell. Dev. Biol. Plant 40 3 279 283
Mok, C.M., Mok, W.S.D., Turner, J.E. & Mujer, C.V. 1987 Biological and biochemical effects of cytokinin-active phenylurea derivatives in tissue culture systems J. Hort. Sci. 22 1194 1197
Morton, J.F. 1987 Tree tomato, p. 437–440. In: J.F. Morton (ed.). Fruits of warm climates. Miami, FL
Murashige, T. & Skoog, F. 1962 A revised medium for rapid growth and bioassays with tobacco tissue cultures Physiol. Plant. 15 473 497
Ndoye, M., Diallo, I. & Gassama, Y.K. 2003 In vitro multiplication of the semi-arid forest tree,Balanites aegyptiaca (L.) Del Afr. J. Biotechnol. 2 11 421 424
Obando, M., Goreux, A. & Jordan, M. 1992 In vitro regeneration of Cyphomandra betacea (Tamarillo) and Andean fruit species Cienc. Investig. Agrar.19:125 130
Obando, M. & Jordan, M. 2001 Regenerative responses of Cyphomandra betacea (Cav.) Sendt. (Tamarillo) cultivated in vitro Acta Hort. 560 429 432
Rai, M.K., Jaiswal, V.S. & Jaiswal, U. 2009 Shoot multiplication and plant regeneration of guava (Psidium guajava L.) from nodal explants of in vitro raised plantlets. J. Fruit Ornam. Plant Res. 17(1):29–38
Subramaniam, S., Rathinam, X., Poobathy, R. & Sinniah, U. 2008 In vitro production of multiple bud clumps (Mbcs) from Cavendish Banana cultivar, Brasilian (AAA) American-Eurasian J. Sustainable Agr. 2 3 300 307
The Indian Agriculture Information Wing 2009 Micropropagation of Tamarillo. Agricultural newsletter, p. 8. Agricultural Information Offset Press, Fruit Garden Meghalaya, Shillong, India
Vasudevan, A., Selvaraj, N., Sureshkumar, P. & Ganapathi, A. 2001 Multiple shoot induction from shoot tip explant of cucumber (Cucumis sativus L.) Cucurbit Genet. Coop. Rep. 24 8 12
Waweru, B., Ishimwe, R., Kajuga, J., Kagiraneza, B., Sallah, P.Y.K., Ahishakiye, V., Kalisa, S., Asiimwe, T., Kahia, J. & Gahakwa, D. 2011 In vitro plant regeneration of Cyphomandra betacea (Tamarillo) through nodal culture. Rwanda J. 24: 58–66
Zaffari, G.R., Kerbauy, G.B., Kraus, J.E. & Romano, E.C. 2000 Hormonal and histological studies related to in vitro banana bud formation Plant Cell Tissue Organ Cult. 63 3 187 192