Re: [Aroid-l] Intrageneric crossing - a good reference

From: "Peter Boyce" botanist at malesiana.com> on 2006.01.28 at 22:39:56(13782) Hi Marek There's a lot more to it than just ovule number. They have very different inforescence shoot morphology and infructescence/fruit/seed structure, the latter linked to diffent dispersal mechanisms. Before we all get too excited about intergeneric hybrids 'proving' that two genera should be moerged it's wort recalling the number of intergeneric hybrids in the orchids, especially the vandoid orchids, where I beleive up to seven genera (maybe more - I'm a tad out of date) have been used to make a commercial hybrid including crosses involving Phalaenopsis and Vanda. Pete +More ----- Original Message ----- From: Abrimaal To: Discussion of aroids Sent: Saturday, January 28, 2006 11:22 PM Subject: Re: [Aroid-l] Intrageneric crossing - a good reference Maybe someday Colocasia and Alocasia will become one genus... the difference is only in number of ovules in a female flower (I don't know what about cytology). Marek ----- Original Message ----- From: Tony Avent To: Discussion of aroids Sent: Tuesday, January 24, 2006 1:16 PM Subject: Re: [Aroid-l] Intrageneric crossing - a good reference Peter:Your note is quite interesting about the possible mis-classification of Colocasia gigantea. I have always found it unusual that C. gigantea seems to have more phenotypic characteristics of alocasia than colocasia...very interesting. Sounds like a research paper is needed.Tony Avent Plant Delights Nursery @ Juniper Level Botanic Garden 9241 Sauls Road Raleigh, North Carolina 27603 USA Minimum Winter Temps 0-5 F Maximum Summer Temps 95-105F USDA Hardiness Zone 7b email tony@plantdelights.com website http://www.plantdelights.com phone 919 772-4794 fax 919 772-4752 "I consider every plant hardy until I have killed it myself...at least three times" - AventPeter Matthews wrote: H. Yoshino, T. Ochiai and M. Tahara (2000) Phylogenetic relationship between Colocasia and Alocasia based on molecular techniques. In: D. Zhu, P. B. Ezyaguirre, M. Zhou, L. Sears and G. Liu (eds) Ethnobotany and genetic diversity of Asian taro: focus on China. International Plant Genetic Resources Institute and Chinese Society for Horticultural Science, Beijing. pp. 66-73. Summary: A taro strain collected in Nepal in 1973 was considered to be an intergeneric hybrid between Alocasia and Colocasia, on the basis of chloroplast DNA analyses carried out in the 1980s (but see later work with isozymes, noted below). Subsequently, an artificial cross was attempted and numerous seeds were obtained after a cross between C. esculenta var. aquatilis (Hassk.) Kitamura (from Nepal) and Alocasia brisbanensis (F. M. Bailey) Domin (ex Kyoto Botanical Garden). Most seeds did not germinate and only a single plant developed fully. This plant was triploid and chromosome painting using genomic in situ hybridisation (GISH) showed that 14 of 42 chromosomes were derived from A. brisbanensis. It was concluded that the plant was an intergeneric hybrid, formed as an unreduced egg of C. esculenta fertilised with normal A. brisbanensis pollen. Isozyme analyses by V. X. Nguyen (1998), PhD, Okayama University, contradicted the original interpretation of the Nepalese hybrid, indicating that it was a cross between C. esculenta and C. gigantea (i.e. intra-generic, not inter-generic). ***** Comments by PJM: Among other Asian accessions (Nepal and China) Nguyen found further examples of hybridsation between C. esculenta and C. gigantea. Taxonomically, C. gigantea is possibly misplaced in Colocasia, but it is not necessarily to be regarded as closer to Alocasia. As Yoshino points out, and as Tony Avent indicates in this list, there is much to be learned about hyribidisation among these aroids. The experimental survival of a hybrid between genera was made possible by a rare polyploidisation event that allowed odd chromosomes to be carried along by a normal full complement of chromosomes. Vigorous offspring are less likely after intergeneric crosses than after interspecies (intrageneric) crosses. An intergeneric crossing has not yet been proven to occur in the wild, though it is possible in principle. PJM ***** Dear Pete and Marek:The Alocasia x Colocasia hybrid that you mentioned looks a lot like A. macrorhizos. I was fortunate to examine this hybrid several years ago growing at a Hawaii taro research station. It was found in an area of Nepal where the two genera grow together. On our expedition last year to N. Vietnam, we visited a restricted military area near the China border. We found Colocasia gigantea growing with Alocasia macrorhizos. Growing among them were several plants that superficially appeared to be bi-generic hybrids. We have not had these plants tested yet to confirm this yet, so this is just a preliminary observation. If anyone is doing work in that region, I will be glad to direct them to the population for further study.Tony AventPlant Delights Nursery @Juniper Level Botanic Garden9241 Sauls RoadRaleigh, North Carolina 27603 USAMinimum Winter Temps 0-5 FMaximum Summer Temps 95-105FUSDA Hardiness Zone 7bemail tony@plantdelights.comwebsite http://www.plantdelights.comphone 919 772-4794fax 919 772-4752"I consider every plant hardy until I have killed it myself...at least three times" - Avent_______________________________________________Aroid-l mailing listAroid-l@gizmoworks.comhttp://www.gizmoworks.com/mailman/listinfo/aroid-l -- Peter Matthews (Dr)National Museum of EthnologySenri Expo Park, Suita CityOsaka 565-8511, Japan Tel. +81 6 6876-2151 (museum exchange, J. only) Tel. +81 6 6878-8357 (Peter's office) Fax +81 6 6878-7503 (museum) Websites: The Research Cooperative http://www.researchco-op.co.nz A meeting place for research writers, editors, translators and proofreaders **** Sato Project: http://www.satoproject.blogspot.com Plant genetic resources in Eurasia **** _______________________________________________ Aroid-l mailing list Aroid-l@gizmoworks.com http://www.gizmoworks.com/mailman/listinfo/aroid-l _______________________________________________Aroid-l mailing listAroid-l@gizmoworks.comhttp://www.gizmoworks.com/mailman/listinfo/aroid-l _______________________________________________Aroid-l mailing listAroid-l@gizmoworks.comhttp://www.gizmoworks.com/mailman/listinfo/aroid-l _______________________________________________ Aroid-l mailing list Aroid-l@gizmoworks.com http://www.gizmoworks.com/mailman/listinfo/aroid-l

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