The Influence of Dendrobium speciosum In Hybridisation

The Influence of Dendrobium speciosumin Hybridisation

Dendrobium speciosumhas a wide and long distribution along the east coast of Australia, from eastern Victoria to the Annan River district of Cape York Peninsula, with disjunct populations occurring along the Tropic of Capricorn. As discussed by Adams, Burke and Lawson (2006) the results of a 15-year study of 500 living samples indicated that D. speciosum is a single species containing nine varieties. While these varieties may merge the research by Adams et al. (2006) found there was no evidence to support the consideration of separate species, the description of additional varieties or taxa. It has been found that differences in habitat and geographical location influence the variation of characteristics within the varieties, and that these differences are not discrete rather slight differences (Adams et al., 2006).

While naturally occurring hybrids using D. speciosum(e.g. D. X delicatum, D. X gracillimum) do exist, the full potential of this species is most visible in the extensive list of hybrids made in captivity. At the time of publication 222 hybrids using D. speciosumas one parent have been registered, the first modern hybrid beingD.Andrew Persson (D. falcorostrumx D. speciosum) registered by G. H. Slade in 1960 (ANOS, 2018). In recent years individuals have used D. speciosumcontinually in Dendrobiumsection Dendrocoryne hybrids along with hybrids between sections Dendrocryne and Phalananthe. Limited breeding has also been conducted with sections Spathulata and Laturia. The popularity of hybrids containing a high percentage of D. speciosum has grown. The progeny are usually medium to large when fully grown, and most have a high flower count. Many colour variations have been produced due to percentages of D. tetragonum, D. kingianum, D. bigibbumand D. fleckeri(Lawson, 2017). Breeders continue to increase the colour range, as well as the intensity and combinations of existing colours. The need for increased substance and texture has also been satisfied by this species.

A number of cultivars of D. speciosumhave been used by breeders, however a limited number have proved themselves. The most successful being D. speciosum var. speciosum‘Windermere’. ‘Windermere’ has shown to not only let colour through to its progeny but also intensify, while imparting sound shape and texture. A small number of hybrids have been made using D. speciosum var. speciosum ‘National White’ AM/ANOS, however these have had a substantial amount of colour ‘washed out’. Neil Finch was largely responsible for the introduction of D. speciosum var. pedunculatum into breeding programs with the cultivars ‘Herberton’ and ‘Herberton Gold’, the use of these two plants also allowed substantial colour through and produced more rounded, textured segments. D. speciosum var. grandiflorumhas been used in a small number of hybrids with no outstanding results, colour has been lessoned and the length and width of segments has been influential. D. speciosum var. curvicaulehas been successful in breeding. The cultivar ‘Apricot Surprise’ was used by Don Cruickshanks in a number of hybrids (e.g D.Greta Snow). However, the cultivar ‘Daylight Moon’ has been the most outstanding with its ability to impart shape, colour, substance and arrangement. It’s use has however been met with some resistance, stating that ‘Daylight Moon’ allows minimal colour through to its progeny. Through current research this statement has proved not completely true. In fact, any D. speciosumseems to have the ability to inconsistently ‘wash out’ colour.

The current review of Dendrobium hybrids that have D. speciosumas one parent is based on observations made over the last ten years and is informed by the judging standard of the Australiasian Native Orchid Society (ANOS). In terms of shape, symmetrical flowers are optimal, with broad and proportioned segments. D. speciosumcan sometimes impart a narrow labellum and in multi-generational hybrids this is undesirable. The flower count is expected to be quite high, this does vary. However, larger plants with a high percentage of D. speciosum should display multiple inflorescences. Colour should be clean, clear and even, and substance and texture should be substantial. It is important to mention that the influence of various Dendrobium species should be considered when judging these hybrids.

Some primary hybrids have been made that will be forever timeless, these hybrids should continue to be remade using newly available superior parents. One example of such is D.Hilda Poxon (D. tetragonum xD. speciosum). Registered by Noel Grundon in 1977 many varieties of both parents have been used in past remakes. The superior cultivars have symmetrical shape, especially of the lateral sepals and clear colours. Varied amounts of spotting and red colouration of the labellum have also been observed, the most attractive being a yellow based flower with brown markings and a contrasting red/purple labellum.D. Warringah (D. bigibbum xD. speciosum) would have to be one of the most aesthetically pleasing hybrids, registered by W. T. Upton in 1984 this hybrid is another example of the benefits of using D. speciosumin primary hybridisation. It’s usually large flowers of purple to white display themselves in high numbers along either upright or arching inflorescences. These plants usually flower in Autumn, and all observed use D. speciosumas the pollen parent. This hybrid has been remade multiple times, the most successful by the late Brian Gerhard using D. speciosum var. capricornicum ‘Pine Mountain’. These plants presented broader, rounder segments creating circular flowers. This suggests that breeders should consider the use of various varieties that are yet to be used extensively such as D. speciosum var. blackdowense.

More explorative breeding is required using D. speciosum. Explorations have been made by Phil Spence in hybrids between section laturia and D. speciosum,D.Aussie’s Angelic is one example of this. This hybrid is D. atroviolaceum xD. speciosum, a primary hybrid. In just one generation a substantial flower count has been achieved, the flowers have optimal shape and a striking burgundy labellum produced. Further breeding is needed and should be made available to the wider public. However, ease of growth should be considered by hybridisers. Another example of somewhat experimental breeding is D.Samford Moondream (D.Topaz Dream x D. speciosum), a cross that has been made by Ross Harvey and the author. The combination of sections phalananthe, dendrocryne and spatulata is visible with outstanding shape, colour and presentation. This is one cross that supports the view that any D. speciosumcan reduce colour as some seedlings have flowered all shades of pink/purple, while others pure cream. Interestingly, D. speciosum var. curvicaule‘Daylight Moon’ FCC/AOC was used in both breeder’s crosses.

One of the most successful lines of breeding is those hybrids that originate from D. Elegant Heart (Registered by W. T. Upton, 1986). A cross between D.Peewee and D. speciosum.D. Elegant Heart’s breakdown is simply 50% D. speciosum,25% D. bigibbumand 25% D. tetragonum. While many remakes of D. Elegant Heart have been released using different varieties of D. speciosumthe most successful used var. curvicauleand var. pedunculatum. Neil Finch bred the two most outstanding examples these being ‘Harlequin’ and ‘Doreen’ (Farrell, 2017). The subsequent crossing of D. Elegant Heart to D. speciosumresults in D. Jayden (W. T. Upton, 1994). D. Jayden xD. speciosum has been registered as D.Greta Snow (Cedarvale Orchids, 2010) this cross has resulted in perfectly proportioned and balanced flower segments, a broad labellum, clear colour and a very high flower count. It is hybrids such as D. Greta Snow that show the full potential of D. speciosumas a parent and displays the positive traits of its role in hybridisation.

In the mid to late 1990’s growers began to flower heavily influenced D. speciosumhybrids which were of a yellow colour. One of the first was D. Avril's Gold (D. speciosum50%, D. tetragonum25%, D. falcorostrum 12.5%, D. fleckeri12.5%), a hybrid made by Ray Hill and registered by Ray Clement in 1998. The seedlings varied in colour from yellow to deep red and an equal amount of variance in shape, with some having major faults such as segment distortion and crossed lateral sepals. While many plants of this grex are of award quality, D. Cosmic Gold, registered by David Butler in 2009 has produced far superior hybrids that clearly demonstrate the ability of D. speciosumas a parent. Large flowers of clear colour, fantastic substance and a generous flower count. This hybrid is a outstanding example of modern hybridisation.

A hybrid that has been more successful in hybridisation is D. Sunglow, registered by David Cannon in 1980. Although this grex can be slightly difficult to grow (alike the before mentioned D. Avril’s Gold), the flowers present a clear and vibrant colour, fantastic shape and substance and texture. However, the only negative distraction being a slightly pinched labellum. This fault seems to disappear in progeny within the next generation or soon after. Impressive colourful hybrids such asD. Lustrous (D. Sunglow x D.Peewee) have been produced using D.Sunglow, however outstanding results have been seen in diverse hybrids such as D. Kayla (D. Lynette Banks x D.Tweed). When this hybrid is crossed back to D. speciosum, D. Dunokayla is created (Down Under Native Orchids, 2007) and the percentage rises to 68.8% D. speciosum. D. speciosum’s positive attributes as a parent can be seen and 16 further registrations have been created using D.Dunokayla. We are mostly likely yet to see the full potential ofD. Sunglow and D. speciosumderived hybrids.

The before mentioned D.Lustrous was registered by Neil Finch in 1994 and would directly influence a line of breeding that transformed Australian Dendrobium’s. The first generation was registered by Finch in 1995 as D. Awesome (D. Lustrous x D. speciosum). All D. Awesome’s that originated from Down Under Native Orchids used D. specisoum var. curvicaule‘Daylight Moon’ FCC/AOC or D. speciosum var. pedunculatum ‘Herberton’, the results of this cross directly support the statement that ‘Daylight Moon’ does produce colourful hybrids, more broadly this cross displays the benefits of using D. speciosumto increase size, substance and flower count. Another two generations were produced by crossing directly back to D. speciosum;D.Eclipse (D. Awesome x D. speciosum) and D.Brimbank Eclipsed (D.Eclipse x D. speciosum). Both generations showed improvements in variety of colour, colour intensity, shape of overall flower and individual segments, flower count and flower texture. It is most visible in this line of breeding the advantages of using D. speciosum as a parent.

More interesting colour combinations have been created by using plants with more diverse species composition. One example of such is D.Memoria Brian Gerhard (D. Saigon x D. speciosum), which contains 18% D. tetragonum, 10.2% D. kingianum, 6.3% of D. bigibbum, 6.3% of D. fleckeriand 3.1% of D. falcorostrum. While the flower count seems to be slightly reduced, the size of the flowers and many other characteristics are not lost. In fact, variety of colour and plant size are just two positive attributes. Another example of diverse breeding is D.Gundy Moon (D.Burgundy Cream x D. speciosum), this grex again varies in colour dramatically. However, flower size and shape is not impacted and compact growing plants are produced. Again displaying the positives of logical and diverse breeding using D. speciosumas one parent.

Interesting results have also been achieved in a cross registered by the Australian Orchid Nursery as D. Australian Artist (D. speciosum x D. Cobber). The hybrid contains 56.3% D. speciosum, 20.3% D. kingianum, 10.9% D. tetragonum,and small amounts of D. falcorostrum and D. fleckeri. It is these smaller percentages that create hybrids that are more diverse in many aspects including colour. Further, these percentages also allow plants to be grown more easily in multiple temperate zones. D. Angus (D. Tyabb x D. speciosum) has achieved similar results and displays the traits of D. speciosum clearly. There is a promising future for this line of breeding due to the plants floriferousness and ease of growth.

DendrobiumJesmond Gem(D. Yondi x D. speciosum)was initially registered by John Purvis in 1997 and is composed of D. speciosum 50%,D. kingianum 25%, and smaller amounts of D. fleckeriand D. jonesii.A remake was made by Peter Adams in 1990 using D. Yondi ‘1368’ and D. speciosum ‘Windermere’, and many have now been awarded including two FCC/AOC (Lawson, 2017). Strong erect racemes and presentation of flowers are two positives. However, the most outstanding features include a broad labellum and improved flower shape. This line of breeding has yet to be widely seen in New South Wales, hopefully in the coming years seedlings will become available as breeding is producing large and shapely flowers in a range of pastel colour.

Many quality hybrids have been made and will continue to be made using D. speciosumas one parent. This species provides a multitude of qualities, including superior shape, colour, substance and texture, and floriferousness. Hybridisers have used many cultivars of D. speciosumwith few proving themselves as worthy parents. Individuals should strive to maintain records of which cultivars of D. speciosumhave been used in crosses so that the wider community can better understand the outcomes of their role in hybrids. The use of D. speciosumin hybridisation should always be logical and consideration of a wider diverse species composition considered. Recently hybrids have been flowered or made available that have the potential to almost be replicas of D. speciosum, we should be wary of such hybrids as growers begin to search for smaller plants that flower in a shorter time. However, D. speciosumhas undoubtedly produced many outstanding hybrids and future prospects of Dendrobiumhybridisation remain exciting.

Acknowledgements

Thank you to David Butler, Neil Finch, Peter Adams, Sheryl Lawson and Tony Blewitt for their individual contributions.

References

The Australasian Native Orchid Society. (2018). Orchid Hybrid Database. Retrieved from http://anos.org.au/dendrobiums/?igrex=&ispecies=No&ilist=List1&submit=select

The Australasian Native Orchid Society. (2018). Award Database. Retrieved from http://anos.org.au/awardsselection/?igenus=All+genera&itype=Latest+awards&ipanel=all+panels&isort=Award+number&submit=select

Adams, P. B., Burke, J. M. & Lawson, S. D. (2006). Dendrobium speciosum, the Great Dendrobium, is a single-species complex. The Orchadian,15(5), 208-240.

Farrell, C. (2017). Selected Prodgeny of DendrobiumElegant Heart. The Orchadian, 19(1). 23-26.

Lawson, S. D. (2017). Breeding Cool Growing Australian DendrobiumHybrids