The genetics, nature and occurrence of self-and cross-incompatibility in four annual species of Coreopsis L. by Jagan Nath Sharma A thesis submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in GENETICS Montana State University © Copyright by Jagan Nath Sharma (1971) Abstract: Four annual species of Coreopsis L. (Compositae: Heliantheae: Coreop-sidinae), C. bigelovii. (A. Gray) H. M. Hall, C. calliopsidea (DC.) A. Gray, C. califomica (Nutt.) Sharsmith, and C. tinctoria Nutt., were studied to determine the genetics of their self-incompatibility mechanisms. Diallel -cross, backcross, and F2 studies revealed that these species have a sporo-phytic, multiple allelic, monogenic system of self-incompatibility. C. tinctoria had 7 multiple alleles, while C. bigelovii and C. califomica had 5 multiple alleles each. The number of multiple alleles could not be assigned to C. calliopsidea. Cytological studies' revealed a strong correlation between the sporophytic system of self-incompatibility and the stigma as the site of pollen inhibition. Meiotic chromosome numbers for all four species were determined as n=12. Secondary associations between different bivalents were found in all four species studied; these point toward some form of polyploidy associated with the genus. Significant heterosis for horticultural traits was detected and a method of producing F1 hybrid cultivars in Coreopsis tinctoria, using incompatibility as a technique, has been suggested. THE GENETICS, NATURE AND OCCURRENCE OF SELF- AND CROSS-INCOMPATIBILITY IN FOUR ANNUAL SPECIES OF COREOPSIS L„ ^ / by Jagan Nath Sharma A thesis submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in GENETICS APPROVED: Major Department Co-chairman, Examining^Committee Co-chairman, Examining Qqmmittee ^ 7 ) _________ Deqn, College of Grg^uate Studies MONTANA STATE UNIVERSITY Bozeman, Montana December,..1971 - iii - ACKNOWLEDGMENTS The author would like to express his deepest appreciation to Professor H. N. ■ Metcalf and Dr. S. R. Chapman for their help and guidance during the course of this investigation. He would also like to express his appreciation to the staff of the Plant and, Soil Science, Genetics Institote, for their help and encouragement, and to Montana State University for the use of facilities and financial assistance during the major part of the studies . A special thanks to my wife for her long patience and understanding dur­ ing the past 3 1/2 years while caring for two children all alone, often in difficult circumstances. ) -iv - TABLE OF CONTENTS Page V IT A ............................................................................................................. ii ACKNOWLEDGEMENTS................................................................... !Tii TABLE OF CONTENTS ........................................................... iv LIST OF TABLES.................................................... vi LIST OF FIG U R ES............................................................................ x ABSTRACT...................................................................' ..................... xiii INTRODUCTION........................................ I REVIEW OF LITERATURE ............................................................... 3 Incompatibility ................... 3 The genus Coreopsis L ................................. 17 RESEARCH PROCEDURES, METHODS, RESULTS AND DISCUSSIONS .................................... 22 Plant materials (culture) ................................................. 22 Confirming species identification ........................................... 22 Morphological variations in four annual species of the genus Coreopsis L , .......................... 24 Materials and Methods ............................................................. 24 R e s u lts ................................................. 26 Discussion. .................................................................................... 43 Genetics and incompatibility mechanism operating in four annual species of Coreopsis L ...............................'. 45 Materials and Methods ................................................................. 45 R e su lts .................. 48 D isc u ssio n ................................................................................... 75 Factors associated with "S" gene action ....................... ... 87 Materials and methods ................................. ... ..................... 87 -V- Table of Contents (Continued) Page Results ..................................................... 88 D isc u ssio n ................................ 96 Hybrid vigor studies in Coreopsis tinctoria Nutt, using self-incompatibility as a tool for producing Fj h y b rid s .................... :................................ ................................ 98 Materials and methods .................. 98 R e su lts ............. .......................* ..................... 99 Production of Fi hybrid seed on a commercial scale . 102 Discussion 104 SUMMARY AND CONCLUSIONS ..................................................... HO LITERATURE CITED ...................................................................... 112 -VL- LIST OF TABLES Context Tables Number Page I Chromosome number reported for the genus Coreopsis L. 19 2 Coreopsis species and cultivars used in these investi­ gations with seed sources and notes on growth habits. 23 3 Variability in inflorescence morphology and fertil­ ity ratings of ligulate and disc flowers of four species of Coreopsis L ..................................................... 28 4 Variation in quantitative traits: Summary of the height and spread in four species of Coreopsis L .............. 29 5 Inter-group crossability behavior of the plants com­ prising the three compatibility groups studied in Coreopsis tin c to ria ..................................... ........................... 50 6 Crossability behavior of the 4 plants of Coreopsis tinctoria falling into incompatibility Group I .................. 51 7 Crossability behavior of the 2 plants of Coreopsis tinctoria falling into compatibility Group II...................... 52 8 Crossability behavior of the 3 plants of Coreopsis tinctoria falling into compatibility Group III ..... 53 9 Inter group crossability behavior of the plants com­ prising three intra self cross-incompatible but cross-compatible groups studied in Coreopsis californica as measured by seed set success ...... 55 10 Crossability behavior of the four plants of Coreopsis californica falling into incompatibility . Group I .................... .............................................................. 56 -v ii- Llst of Tables Context Tables (Continued) Number Page 11 Crossability behavior of the three plants of Coreopsis califomica falling into incompati­ bility Group II................................................................... 57 12 Crossability behavior of the three plants of Coreopsis califomica falling into incompati­ bility Group III............. ... o .................... ... 58 13 Intergroup crossability behavior of the plants com­ prising the three incompatibility groups studied in Coreopsis bigelovii as measured by seed set success ........................ 60 14 Crossability behavior of the two plants of Coreopsis bigelovii falling into incompati­ bility Group I ........................................................ ... 61 15 Crossability behavior of the two plants of Coreopsis bigelovii falling into incompati­ bility Group H........................................................ 62 16 Crossability behavior of the three plants of Coreopsis bigelovii falling into incompati­ bility Group III. ............................................................. 63 17 Intergroup crossability behavior of the plants comprising two, intra self and cross-incompatible but inter cross-compatible groups studied in Coreopsis calliopsidea as measured by seed success ..................................... ............ 65 18 Crossability behavior of the six plants of Coreopsis callopsidea falling into incompatibility Group I. 66 -v iii- List of Tables Context Tables (Continued) Number Page 19 Crossability behavior of four plants of Co calliopsidea falling into incompatibility Group n ............... .................. 67 Results of the backcross in C. tinctoria plants showing reciprocal differences in a diallel cross. Reciprocal cross I, plants 5 and 9oo*.e..ooeoooooo.o* 68 21 Results of the backcrosses in C. tinctoria using plants showing reciprocal differences in a diallel cross. Plants chosen here are Nos. I and 4 ................................................ 69 22 Results of the backcross in C. califomica using plants showing reciprocal differences in a diallel cross. Plants 9 and I. „ . 70 23 Results of the backcross in C. bigelovii using plants showing reciprocal differences in a diallel c ro ss. Plants 5 and 6 ................. 72 24 Segregation in Fg generation of a cross between self-incompatible and. self- compatible mutant of C. tinctoria. ............................................ 73 25 Genotypes assigned to the 10 plants (G. tinctoria) chosen for diallel cross.............. 77 26 Genotypes assigned to the 10 plants chosen for diallel cross in C . califom ica.............. ... 78 27 Genotypes assigned to 10 plants chosen for diallel cross in C. bigelovii ............. 80 -ix - List of Tables Context Tables (Continued) Number Page ' 28 Results of