Interspecific Hybridization, Ploidy Manipulation, And
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INTERSPECIFIC HYBRIDIZATION, PLOIDY MANIPULATION, AND CYTOLOGICAL AND GENETIC ANALYSES AS TOOLS FOR BREEDING AND IMPROVEMENT OF CALLICARPA L., CRYPTOMERIA D. DON, HIBISCUS L., AND TECOMA JUSS. by RYAN NELSON CONTRERAS (Under the Direction of John M. Ruter) ABSTRACT Research was conducted as part of breeding programs to improve Callicarpa, Cryptomeria, Hibiscus, and Tecoma including field evaluation, polyploidization, genetic and cytogenetic studies, and interspecific hybridization. These techniques were successfully integrated into existing improvement programs. Polyploidy was induced in Hibiscus acetosella ‘Panama Red’ PP20121 to develop a more compact plant. Plant height and fertility was reduced, leaves were smaller, internodes were shorter, and canopy volume were reduced in the induced octoploid. Japanese cedar chromosomes were doubled by spraying seedlings with oryzalin. Eighty-three percent of selected seedlings were tetraploids, 9.3% were cytochimeras, and 7.6% were diploids. Performance of Japanese cedar cultivars was evaluated by measuring chlorophyll and carotenoids and assigning color ratings. There were differences in chlorophyll, ratio of chlorophyll a:b, carotenoids, and color rating (greeness). There were no consistent trends for differences between winter and summer or between traits. Crosses were performed to investigate the genetics of fruit color, leaf variegation, self-compatibility, and apomixis in American beautyberry. Crosses between purple and white fruit showed white fruit is recessive and is controlled by a single recessive gene called white fruit (wf). Progeny developed sexually and all genotypes were self-compatible. We propose that purple, pink, and white fruit are allelic with proposed symbols Wf > wf p > wf. Maternal effects appear to be involved in leaf variegation; however, germination was too low to draw conclusions. Callicarpa americana seeds were treated with sulfuric acid to increase germination. The control, 15 min, and 30 min treatments germinated at 8.9%, 57.8%, and 48.9%, respectively, indicating that scarification benefits germination. Genome sizes of Callicarpa were calculated using flow cytometry and ranged from 1.34 to 3.11 pg. Chromosome counts revealed most were diploid (2n = 2x = 34) but two were tetraploid. Interspecific hybridization in Tecoma was conducted. Fertile hybrids between T. garrocha and T. stans (F1) were backcrossed to parents and self-pollinated. Tecoma garrocha, T. stans, and T. guarume ‘Tangelo’ were self-fertile. Complex hybrids were developed: F1 x T. capensis; F1 x T. guarume ‘Tangelo’. Leaf morphology of F1 was intermediate. GISH successfully identified hybridity. Four copies of rDNA were observed in F1s using FISH. INDEX WORDS: Induced polyploidy, cytogenetics, genome size, inheritance, ornamental plant breeding, in situ hybridization INTERSPECIFIC HYBRIDIZATION, PLOIDY MANIPULATION, AND CYTOLOGICAL AND GENETIC ANALYSES AS TOOLS FOR BREEDING AND IMPROVEMENT OF CALLICARPA L., CRYPTOMERIA D. DON, HIBISCUS L., AND TECOMA JUSS. by RYAN NELSON CONTRERAS B.S. North Carolina State University, 2002 M.S. North Carolina State University, 2006 A Dissertation Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY ATHENS, GEORGIA 2009 © 2009 Ryan Nelson Contreras All Rights Reserved INTERSPECIFIC HYBRIDIZATION, PLOIDY MANIPULATION, AND CYTOLOGICAL AND GENETIC ANALYSES AS TOOLS FOR BREEDING AND IMPROVEMENT OF CALLICARPA L., CRYPTOMERIA D. DON, HIBISCUS L., AND TECOMA JUSS. by RYAN NELSON CONTRERAS Major Professor: John M. Ruter Committee: David A. Knauft Peggy Ozias-Akins Wayne W. Hanna Ronald B. Pegg Electronic Version Approved: Maureen Grasso Dean of the Graduate School The University of Georgia December 2009 iv DEDICATION To Carol English Contreras and Ronald Ramon Contreras v ACKNOWLEDGEMENTS I would like to thank everyone who has made this possible and helped me get to this point in my life; however, this thing is already too long. Therefore, I will say a “royal thanks” to all of the people that have provided support in my life. I would like to mention a few people specifically, though. First, my mother, Carol, who is the biggest reason for any successes I have in life. My father, Ron, who has always encouraged excellence. My brother, Christian, who is still smarter than I am no matter what letters follow my name. Margaret, Buddy, Kay, Rae, Dwain, and the rest of the Becton family (my family); I can’t imagine not having you guys in my life. Bobby, Deborah, Scott, Anna, and the rest of the Christophers; simply an extended family with a different last name. Oh, and Bobby, I’m going to beat you in the next triathlon! To all of my amazing friends and colleagues that are too numerous to list, thanks for providing the example and a high standard to strive for. Finally, I would like to thank my committee. Doc, it has been a fun and productive ride. I have really enjoyed working with you and the outings that we’ve had together. I look forward to hosting you on plant explorations in Oregon! Drs. Hanna, Knauft, Ozias-Akins, and Pegg; it has been an honor and a privilege having each of you serve on my committee. Dr. Hanna, I would specifically like to say thank you for the conversations we have had and pushing me to become the very best cytogeneticist I can be. The words, “Are you sure?” now enter my mind every time I look at one of my photomicrographs. Finally, to the dozens of people that I am omitting from mentioning specifically, please understand that your support and assistance is greatly appreciated and will not be forgotten. vi TABLE OF CONTENTS Page ACKNOWLEDGEMENTS .................................................................................................v LIST OF TABLES ............................................................................................................. ix LIST OF FIGURES ........................................................................................................... xi INTRODUCTION AND LITERATURE REVIEW ...........................................................1 Literature Cited .........................................................................................13 CHAPTER 1 An Oryzalin-Induced Autoallooctoploid of Hibiscus acetosella Welw. ex Hiern. ‘Panama Red’ (Malvaceae) .....................................................................................20 Introduction ...............................................................................................24 Materials and Methods ..............................................................................25 Results .......................................................................................................30 Discussion .................................................................................................32 Literature Cited .........................................................................................38 2 Oryzalin-Induced Tetraploidy in Cryptomeria japonica (Thunb. ex L.f.) D. Don (Cupressaceae) ...........................................................................................................50 Introduction ...............................................................................................54 Materials and Methods ..............................................................................56 Results and Discussion .............................................................................59 Literature Cited .........................................................................................62 vii 3 Pigment analysis and evaluation of Japanese cedar cultivars [Cryptomeria japonica (L.f.) D. Don (Cupressaceae)] in south Georgia .................................................70 Introduction ...............................................................................................73 Materials and Methods ..............................................................................76 Results .......................................................................................................78 Discussion .................................................................................................80 Literature Cited .........................................................................................88 4 Genetic studies investigating the inheritance of fruit color and leaf variegation in Callicarpa americana L. (Lamiaceae) ......................................................108 Introduction .............................................................................................111 Materials and Methods ............................................................................112 Results .....................................................................................................113 Discussion ...............................................................................................115 Literature Cited .......................................................................................119 5 Sulfuric acid scarification of Callicarpa americana (Lamiaceae) seeds improves germination .............................................................................................124 Introduction .............................................................................................127 Materials and Methods ............................................................................128 Results and Discussion ...........................................................................129