CHROMOSOME NUMBERS AND CROSS-COMPATIBILITY IN THE GENUS CYMBIDIUM AND SOME RELATED TROPICAL GENERA (ORCHIDACEAE) A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAII IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN HORTICULTURE AUGUST 1977 By Kenneth W. Leonhardt Dissertation Committee: Yoneo Sagawa, Chairman Haruyuki Kamemoto Henry Y. Nakasone Philip E. Parvin William L. Theobald We certify that we have read this dissertation and that in our opinion it is satisfactory in scope and quality as a dissertation for the degree of Doctor of Philosophy in Horticulture. DISSERTATION COMMITTEE (7 'Cry^o , w A Chairman Chromosome Numbers and Cross-Compatibility in the Genus Cymbidium and Some Related Tropical Genera (Orchidaceae) Abstract Investigations on chromosome numbers and cross-compatibility were made with species and hybrids of Cymbidium and other tropical genera of the family Orchidaceae. Chromosome number determinations were made of 163 plants. One hundred nineteen counts of Cymbidium clones were made of which 92 are reported for the first time. Diploid, triploid, tetraploid, hexaploid and aneuploid individuals were determined. Triploid cultivars of two species, C. insigne 'Bierii' and C. pumilum 'Yashima' were found. Forty- four counts of intergeneric hybrids and genera other than Cymbidium were made. The hybrid status of 17 progenies of intergeneric pollinations was determined by analysis of somatic chromosome numbers. Nine plants derived from colchicine treated protocorms were identified as polyploids; 8 being euploid and 1 a mixoploid. The origin of the polyploid nature of some of the hybrids not subjected to colchicine treatments is dis­ cussed. It was verified cytologically that Cymbidium did hybridize with Ansellia and Catasetum. The origin of seedlings of 6 intergeneric pollinations is discussed. The origin of the registered but questionable hybrid Phaiocymbidium Chardwarense is discussed. Cymbidium species were categorized into 3 groups (I, II, and III) based on morphological features of plants, flowers, and inflorescences. A cross-compatibility study was made utulizing 21 species and 28 hybrid Cymbidium and 26 species and hybrids of other genera. A total of 2,466 iv pollination was made with 265 (10.7%) fruits harvested of which 182 (68.7%,) contained an average of 31.3%, seeds with apparently viable embryos. One hundred forty-two fruits (53.6%, and 78.0%, of those that contained apparently viable embryos) produced seedlings. It has been demonstrated that species of groups I and II are more cross-compatible within groups than between groups. It is also demonstrated that species of groups I and II are more cross-compatible between these groups than they are with species of group III. Thirty-eight intergeneric pollinations resulted in seedlings of which 10 are confirmed hybrids, 2 are false hybrids and 26 were not verified cytologically. The discovery of a unidirectional cross-incompatibility system was made whereby Ansidium seedlings are rarely produced when Ansellia is used as a female parent and are easily produced when Cymbidium is used as a female. Individual Cymbidium species and hybrids were evaluated for their intra- and inter­ generic combining abilities. The diploid and tetraploid forms of _C. Peter Pan 'Greensleeves' were compared for 14 morphological features. A formula was developed for determining changes in symmetry as a result of polyploid induction. A discussion of various incompatibility systems in the Orchidaceae is presented. Criteria and recommendations for a breeding program designed to produce commercially acceptable Cymbidiums capable of flowering at low elevations in Hawaii are presented. V t a b l e of contents PAGE ABSTRACT.................................... iii LIST OF TABLES..................................................... vi LIST OF ILLUSTRATIONS............................................. viii INTRODUCTION...................................................... 1 LITERATURE REVIEW................................................. 2 materials and methods............................................. 12 RESULTS AND DISCUSSION............................................ 35 Chromosome Numbers........................................... 35 Cross Compatibility.......................................... 96 Effects of Polyploidy on Morphology...........................135 GENERAL DISCUSSION................................................. 140 APPENDIX................................... ....................... 149 LITERATURE CITED 266 vi LIST OF TABLES TABLE DESCRIPTION PAGE I Cymbidium species used in this investigation with authors and sources of material........................... 15 II Cymbidium hybrids used in this investigation with parents and source of material.................... 19 III Species and hybrids of genera other than Cymbidium used in this investigation with authors or parents and source of material...................... ....................... 31 IV Chromosome numbers of Cymbidium species.................. 49 V Chromosome numbers of Cymbidium primary (interspecific) hybrids.......................... ...................... 57 VI Chromosome numbers of Cymbidium secondary (species as one parent) hybrids...................................... 62 VII Chromosome numbers of Cymbidium advanced hybrids......... 70 VIII Chromosome numbers of intergeneric hybrids............... 92 IX Chromosome numbers of species and hybrids of genera other than Cymbidium..................................... 94 X Summary of results of intergroup and intergeneric crosses attempted using Group I species as females.............. 108 XI Summary of results of intergroup and intergeneric crosses attempted using Group II species as females............. 109 XII Summary of results of intergroup and intergeneric crosses attempted using Group III species as females............. 110 XIII Summary of results of intergroup and intergeneric crosses attempted using Group I x III hybrids as females........... Ill XIV Summary of results of intergroup and intergeneric crosses attempted using Group III x III hybrids as females......... 112 XV Summary of results of intergroup and intergeneric crosses attempted using other hybrids (ungrouped) as females 113 XVI Summary of results of intergroup and intragroup crosses attempted using species and hybrids as males and females.......................... ....................... 114 Vll LIST OF TABLES (CONTINUED) TABLE DESCRIPTION PAGE XVII Summary of results of intergeneric and intrageneric crosses attempted using genera other than Cymbidium as females............................................... 118 XVIII Summary of results of intergeneric crosses attempted between Ansellia and Cymbidium........................... 120 XIX Cymbidium species which flowered and were tested for their crossability with various species groups, intergroup hybrids and genera other than Cymbidium....... 124 XX Cymbidium hybrids which have crossed with various species groups, intergroup'hybrids, and genera other than Cymbidium........................................... 128 XXI Measurements of diploid and tetraploid forms of Cymbidium Peter Pan 1 Greensleeves'....................... 136 XXII Evaluation of some horticultural qualities of warm temperature tolerant and fertile Cymbidium species and hybrids in the research collection................... 146 Vlll LIST OF ILLUSTRATIONS FIGURE DESCRIPTION PAGE Vegetative morphology of Phaiocymbidium Chardwarense and Phaius Ashworthianus.............................. 45 1 Phaiocymbidium Chardwarense (0.10X) 2 Phaius Ashworthianus (0.13X) Floral morphology of Phaiocymbidium Chardwarense and Phaius Ashworthianus.................................. 46 3 Phaiocymbidium Chardwarense (0.75X) 4 Phaius Ashworthianus (0.50X) Vegetative and floral morphology of Cymbidium species. 99 5 C. dayanum (0.11X) 6 C. lancifolium (0.18X) 7 C. hoosai var kinkwalan sub var fayden (0.17X) 8 C. soshin 'Tetukotsu' (0.18X) Vegetative and floral morphology of Cymbidium species. 100 9 _C. lancifolium (1.75X) 10 _C. pumilum var album (0.88X) Vegetative and floral morphology of Cymbidium species. 101 11 C. formosanum (1.06X) 12 _C. ensifolium var album (1.88X) Vegetative and floral morphology of Cymbidium species. 102 13 _C. aloifolium (0.11X) 14 _C. aloifolium (0.19X) 15 C. aloifolium (1.44X) Vegetative and floral morphology of Cymbidium species. 103 16 C. canaliculatum var sparkesii (0.17X) 17 C. canaliculatum var sparkesii (2.33X) Vegetative and floral morphology of Cymbidium species. 104 18 C. eburneum (0.20X) 19 C. eburneum (1.10X) 20 _C. madidum (2.00X) Vegetative and floral morphology of Cymbidium species. 105 21 C.,parishii var sanderae (0.18X) 22 C. parishii var sanderae (0.46X) 23 _C. parishii var sanderae (1.07X) Floral morphology of Ansellia africana................ 121 24 Ansellia africana 'UH-10' (1.09X) ix LIST OF ILLUSTRATIONS (CONTINUED) FIGURE DESCRIPTION PAGE Vegetative and floral morphology of Cymbidium hybrids... 132 25 C. hoosai x C. lancifolium (1.25X) 26 _C. hoosai x C. lancifolium (0.16X) Vegetative and floral morphology of Cymbidium hybrids... 133 27 C. Peter Pan 1 Greensleeves' (UH-2) (0.09X) 28 C. Peter Pan 'Greensleeves1 (UH-2) (0.75X) Vegetative and floral morphology of Cymbidium hybrids... 134 29 _C. Vogelsang (0.11X) 30 C. Vogelsang (1.11X) Floral morphology of diploid and tetraploid forms of Cymbidium Peter Pan 'Greensleeves'.................... 137 31 C. Peter Pan 'Greensleeves' (UH-1), diploid, and