The first successful hybrid of Amorphophallus titanum

Size: px

Start display at page:

Download "The first successful hybrid of Amorphophallus titanum"

Harriet McLaughlin
6 years ago
Views:

1 C. CLAUDEL, R. D. MANGELSDORFF, W. L. A. HETTERSCHEID, The first successful hybrid of Amorphophallus titanum Cyrille Claudel Biocentre Klein Flottbek and Botanical garden Hamburg University Ohnhorststrasse Hamburg, Germany Ralph D. Mangelsdorff Goethe-University Frankfurt am Main Faculty of Biosciences Department Ecology Evolution and Diversity Max-von-Laue-Str Frankfurt am Main, Germany Wilbert L. A. Hetterscheid Von Gimborn Arboretum Velperengh BZ Doorn, The Netherlands (*31) ABSTRACT The first successful hybrid involving Amorphophallus titanum (Becc.) Becc. ex Arc. is being introduced. It concerns a cross between A. variabilis Bl. (seed parent) and A. titanum (pollen parent) and is described here as a new cultivar. Its origin, morphology and propagation are described. The arguments for recognizing it as a cultivar are given. KEY WORDS Amorphophallus titanum, Amorphophallus variabilis, hybrid, new cultivar, standard specimen. INTRODUCTION On the 23rd of May 2002, the second author applied pollen of Amorphophallus titanum on the stigmas of one inflorescence of Amorphophallus variabilis. The berries took some five months to mature and yielded five viable seeds among many sterile degenerate ones. Some of the plantlets perished very soon but two survived. Because of heavy infestation with nematodes, the plants were transferred in a rescue mission to the hands of the third author. They were cultivated for a few years in the Amorphophallus research collection in the Wageningen University Botanical Gardens in the Netherlands and finally cleared of nematodes. Due to the sudden closure of the botanical gardens in Wageningen, a new shelter was required. One plant was handed over to the Botanical Garden of Leiden University, The Netherlands, and the second one to the Botanical Garden of Hamburg University, Germany, in 2008, where it was nursed by the first author, and was finally brought to flower in June This is the plant we describe here. The Leiden plant is still alive but hasn t flowered yet. Before flowering, the leaf of this plant reached a height of 1.45 m exhibiting typical traits of both A. variabilis and A. titanum. At anthesis, the inflorescence reached nearly 1.50 m, but very likely the ultimate dimensions are not reached yet.

2 82 AROIDEANA, Vol. 35 The overall aspect reminds more of A. titanum since few species reach the size of this and A. variabilis is not one of them. More details of its hybrid morphology are described and discussed below. Out of gratitude the first author chose to name this particular cultivar in honour of a friend and his encouraging help. We therefore designate the new cultivar as Amorphophallus John Tan. The new cultivar is described here for the first time and a standard specimen is designated acc. to Division 5 of the ICNCP (Brickell et al., 2009). DESCRIPTION Amorphophallus John Tan, new cultivar. Standard specimen: C. Claudel (HBG, leaf parts only, inflorescence to be added), collected from a plant cultivated in the Hamburg Bot. Garden, 21 December 2011, originating from an artificial cross in Frankfurt Palmengarten (Germany) between a seed parent plant of A. variabilis Bl. and a pollen parent plant of A. titanum (Becc.) Becc. ex Arc. made 2002 by Ralph Mangelsdorff. The seed parent originated from Leiden Bot. Garden (Netherlands) and the pollen parent from Frankfurt Palmengarten (Germany), both are no longer alive. Figs. 1a d. Tuber depressed globose, to at least 24 cm in diam. and to 15 cm in height, weighing ca. 6 kg, surface whitish-brownish with many raised areas, no offset development. Leaf solitary; cataphylls to 50 cm long, brownish, with white lichenlike spots; petiole to 1.45 m. long, to 8 cm in diam. (base), turgid, smooth, dark green or brownish, with large, whitish lichen-like spots similar to the ones on the petiole of A. titanum; lamina to 1.20 m in diam., poorly dissected in young plants, resembling a young A. titanum lamina, highly dissected in mature plants, showing more resemblance with a typical A. variabilis leaf; leaflets elliptic-lanceolate, to 20 cm long, to 7 cm in diam., acuminate, leathery, upper surface slightly glossy. Inflorescence solitary; peduncle to 55 cm long, ca. 6 cm in diam., coloured as petiole but darker altogether; spathe campanulate, triangular, to 45 cm long, limb spreading, rim-shaped, margin slightly plicate similar to A. titanum but not as strong as in the latter, veins of the limb strongly raised, outside base dirty greenish yellow with whitish spots, base inside verrucate and slightly purple at the base, with a broad yellowish band above and rich purple-red in the upper part. Spadix sessile, longer than spathe, ca. 1 m long; female zone 6 cm long, flowers congested; male zone slightly obconic, 8 cm long, flowers congested like in A. variabilis; appendix elongate fusiform, obtuse, ca. 80 cm long, ca. 9 cm in diam., base truncate and expanded overarching the male zone, similar as in A. titanum, dirty yellowish white, slightly rugose. Ovaries ovate, ca. 5 mm in diam., 3 mm high, orbicular, base yellowish, turning purple in the upper part; style 5 mm long, blackish purple; stigma elliptic, 1 2 mm in diam., ca. 1 mm high, orange, strongly bilobate. male flowers producing abundant pollen. Pollen fertility unknown. Propagation by vegetative means. NOTES Molecular studies, published (Sedayu et al., 2010) and unpublished (by the first author), show that both Amorphophallus variabilis and A. titanum belong to a small subclade of the larger South East Asia Clade (SEA in Sedayu et al., 2010) and it has been shown repeatedly in cultivation that Amorphophallus species of closer phylogenetic proximity may be successfully hybridized. This is not to say that the reciprocal situation is true (that hybridization means phylogenetic affinity) because hybrid formation may well be a synplesiomorphy at several levels in the Amorphophallus phylogeny. The huge size of A. titanum has always been a catalyst in trying to create hybrids of it but unsuccessfully until now. The ultimate and rather playful challenge is to successfully hybridize A. titanum with a species of duckweed (Araceae, subf.

C. CLAUDEL, R. D. MANGELSDORFF, W. L. A. HETTERSCHEID, 2012 83 Fig. 1a. Fig. 1b. Fig. 1c. Fig. 1d. Amorphophallus John Tan Flowering plant. Amorphophallus John Tan Spathe and part of spadix.

3 C. CLAUDEL, R. D. MANGELSDORFF, W. L. A. HETTERSCHEID, Fig. 1a. Fig. 1b. Fig. 1c. Fig. 1d. Amorphophallus John Tan Flowering plant. Amorphophallus John Tan Spathe and part of spadix. Amorphophallus John Tan Detail of lower part of spadix. Amorphophallus John Tan Leaf petiole and part of lamina from below. Lemnoideae). Imagine the result of this cross invading riversystems and wreaking ultimate havoc The resultant hybrid described here does show a remarkable similarity in general appearance to two other giants of Amorphophallus, namely A. gigas Teijsm. & Binnend. (Sumatra) and A. decus-silvae Backer & Alderw. (Java). Both these species belong to the same subclade as A titanum and A. variabilis. Molecular data resolving the origin of these huge species are still lacking, so the production of John Tan nurtures some speculation, which we shall not do in this publication but leave to the imagination of the reader.

4 84 AROIDEANA, Vol. 35 Table 1. Character comparison of Amorphophallus John Tan with A. titanum and A. variabilis showing a mosaic of similarities. marks similarity of the hybrid with either parental species. A. titanum A. variabilis overall plant size tuber petiole background (spots) (background color) lamina division (youth) (mature) peduncle length rel. to spathe spathe size spathe margin spathe opening spathe venation ovary size style length stigma shape appendix base appendix size So far A. John Tan shows a growing cyclicity more similar to that of A. variabilis. The leaf dies after ca. 9 months (versus months in A. titanum) after which the plant rests for ca. 3 months. A subject to be debated could be the choice to name this hybrid at the cultivar level or name it at all. The mere fact that it is the first successful hybrid involving A. titanum seems to us as good a reason as any to identify it nomenclaturally. The choices were to give it a hybrid name according to the rules of the Hybrid Appendix of the botanical code (ICBN, McNeill et al., 2006) or give it a cultivar name according to the rules of the cultivated plant code (ICNCP, Brickell et al., 2009). As we consider artificial hybrids not being representatives of the natural world but of the world of human industry (Hetterscheid & Brandenburg, 1995a, 1995b; Hetterscheid & van den Berg, 2008), we decided in favour of the cultivar name option. The philosophy being that names for organisms in the wild, being subject to natural selection and related processes, should not be confused with names for artificially developed organisms. One objection against publishing the new cultivar name is that it concerns only one single living plant at this moment. Cultivar names are better restricted to plants being propagated in significant numbers and distributed among the public (mostly for commercial reasons). In light of this, material of A. John Tan is being propagated by means of tissue culture and will be released when enough plants are available. The standard specimen for establishing names of cultivars is a different concept from the well-known nomenclatural type specimen as mandatory part of the publication procedures of ICBN-governed names of new species of plants. A type specimen is only one specimen to which a plant name is permanently attached and the specimen itself need not be representative of the habit of the species to which the name is given. A standard specimen for a cultivar has both a nomenclatural and a descriptive function. Therefore to the standard specimen of a cultivar may be added material after its deposition in a public herbarium. In the case of A. John Tan, it is our intention to add an inflorescence of the cultivar to the leaf parts conserved at this moment. Also pictures are planned to be added as this is also allowed to enhance the descriptive function of standard specimens.

5 C. CLAUDEL, R. D. MANGELSDORFF, W. L. A. HETTERSCHEID, Because A. John Tan is of hybrid origin, it is mandatory that its reproduction only follows by vegetative means in order to maintain it as a clone. This is necessary to maintain its integrity. The name A. John Tan thus remains reserved for this one clone only. In due course the name A. John Tan will be presented for registration by the International Aroid Society, the International Cultivar Registration Authority (ICRA) for Araceae. ACKNOWLEDGMENTS The authors wish to thank the staffs of the Frankfurt Palmengarten (Germany), the Frankfurt Botanical Garden, and the Hamburg Botanical Garden for skillfully cultivating the plant. Cyrille Claudel wishes to thank Mr. John Tan (Singapore) for his substantial support for his work on Amorphophallus. LITERATURE CITED C. D. Brickell, C. Alexander, J. C. David, W. L. A. Hetterscheid, A. C. Leslie, V. Malecot & iaobaijin (eds.), International Code of Nomenclature for Cultivated Plants. Reg. Veg 151: 184 p (also issued as Scripta Horticulturae 10, ISBN ). Vienna. Hetterscheid, W. L. A. & W. A. Brandenburg. 1995a. Culton versus taxon: conceptual issues in cultivated plant systematics. Taxon 44: Hetterscheid, W. L. A. & W. A. Brandenburg. 1995b. The culton concept: setting the stage for an unambiguous taxonomy of cultivated plants. Acta Hort. 413: Hetterscheid, W. L. A. & R. G. van den Berg The Crop-Group and the inconsistent use of Linnean names in the taxonomy of domesticated plants. In N. Groendijk-Wilders, C. Alexander, R. G. van den Berg & W. L. A. Hetterscheid (eds.), Proc. V th Int. Symp. on Taxonomy of Cultivated Plants. Acta Hort. 799: J. McNeill, F. R. Barrie, H. M. Burdet, V. Demoulin, D. L. Hawksworth, K. Marhold, D. H. Nicolson, J. Prado, P. C. Silva,J.E.Skog,J.H.Wiersema&N.J. Turland (eds.), International Code of Botanical Nomenclature (Vienna Code): Adopted by the Seventeenth International Botanical Congress Vienna, Austria, July Regnum Vegetabile 146. Ruggell, Liechtenstein: Gantner. Sedayu, A., M. C. M. Eurlings, B. Gravendeel & W. L. A. Hetterscheid Morphological character evolution of Amorphophallus (Araceae) based on a combined phylogenetic analysis of trnl, rbcl and LEAFY second intron sequences. Bot. Stud. 51:

Endemic Amorphophallus (Araceae) from Madagascar: a revised key, a new species and molecular phylogeny

Hetterscheid and Claudel Botanical Studies 2014, 55:2 RESEARCH Open Access Endemic Amorphophallus (Araceae) from Madagascar: a revised key, a new species and molecular phylogeny Wilbert L A Hetterscheid