OUTCROSSING AND FECUNDITY ADVANTAGE OF FEMALES IN GYNODIOECIOUS CHIONOGRAPHIS JAPONICA VAR. KUROHIMENSIS (LILIACEAE)

The selfing rate of hermaphrodites, inbreeding depression, and relative fecundity of females compared to hermaphrodites were estimated for a gynodioecious population of Chionographis japonica var. kurohimensis to test the models for the evolution of gynodioecy. In spite of the high level of selfing of hermaphrodites, significant amounts of inbreeding depression were found in seed germination and seedling growth. In addition, females produced more fertilized ovules than hermaphrodites. Nevertheless, the conditions theoretically required for maintaining gynodioecy were not satisfied even if the combined effect of these two factors was considered. Additional causes for the evolution of gynodioecy, including biparental inbreeding, are discussed. In some populations of flowering plants, females coexist with hermaphrodites, a condition known as gynodioecy. Because females reproduce sexually only by seeds, they must have some advantage to stably coexist with hermaphrodites. What these advantages are remains an open question in plant evolutionary biology. A number of theoretical works consider the basis for the evolution of gynodioecy. Lloyd (1975, 1976), Charlesworth and Charlesworth (1978), and Charlesworth and Ganders (1979) showed by evolutionarily stable strategy models that gynodioecy can evolve if the product of selfing rate of hermaphrodites (s) and inbreeding depression (d) is over 0.5 when nuclear genes control male sterility. Because viability of selfed progeny is known to be lower

[1]  M. Maki.  Fixation indices and genetic diversity in hermaphroditic and gynodioecious populations of Japanese Chionographis (Liliaceae) , 1992, Heredity.

[2]  D. Charlesworth,et al.  Effects of a change in the level of inbreeding on the genetic load , 1991, Nature.

[3]  N. Ellstrand,et al.  INBREEDING EFFECTS IN CLARKIA TEMBLORIENSIS (ONAGRACEAE) POPULATIONS WITH DIFFERENT NATURAL OUTCROSSING RATES , 1990, Evolution; international journal of organic evolution.

[4]  B. Charlesworth,et al.  INBREEDING DEPRESSION, GENETIC LOAD, AND THE EVOLUTION OF OUTCROSSING RATES IN A MULTILOCUS SYSTEM WITH NO LINKAGE , 1990, Evolution; international journal of organic evolution.

[5]  M. R. Dudash.  RELATIVE FITNESS OF SELFED AND OUTCROSSED PROGENY IN A SELF‐COMPATIBLE, PROTANDROUS SPECIES, SABATIA ANGULARIS L. (GENTIANACEAE): A COMPARISON IN THREE ENVIRONMENTS , 1990, Evolution; international journal of organic evolution.

[6]  K. Ritland.  A Series of FORTRAN Computer Programs for Estimating Plant Mating Systems , 1990 .

[7]  P. Gouyon,et al.  Co-evolution between two symbionts: the case of cytoplasmic male-sterility in higher plants. , 1990 .

[8]  T. Chenier,et al.  Gynodioecy in silene vulgaris (Caryophyllaceae): progeny success, experimental design, and maternal effects , 1989 .

[9]  S. Weller,et al.  INBREEDING DEPRESSION IN SCHIEDEA GLOBOSA AND S. SALICARIA (CARYOPHYLLACEAE), SUBDIOECIOUS AND GYNODIOECIOUS HAWAIIAN SPECIES , 1989 .

[10]  J. Kohn.  Why be female? , 1988, Nature.

[11]  J. Shykoff.  MAINTENANCE OF GYNODIOECY IN SILENE ACAULIS (CARYOPHYLLACEAE): STAGE‐SPECIFIC FECUNDITY AND VIABILITY SELECTION , 1988 .

[12]  F. R. Ganders,et al.  MIXED MATING SYSTEMS IN HAWAIIAN BIDENS (ASTERACEAE) , 1988, Evolution; international journal of organic evolution.

[13]  Deborah Charlesworth,et al.  INBREEDING DEPRESSION AND ITS EVOLUTIONARY CONSEQUENCES , 1987 .

[14]  F. R. Ganders,et al.  Female Frequencies in Gynodioecious Populations Correlated with Selfing Rates in Hermaphrodites , 1986 .

[15]  R. Lande,et al.  THE EVOLUTION OF SELF‐FERTILIZATION AND INBREEDING DEPRESSION IN PLANTS. I. GENETIC MODELS , 1985, Evolution; international journal of organic evolution.

[16]  P. Gouyon,et al.  Mathematical Study of the Evolution of Gynodioecy with Cytoplasmic Inheritance under the Effect of a Nuclear Restorer Gene. , 1981, Genetics.

[17]  K. Ritland,et al.  A model for the estimation of outcrossing rate and gene frequencies using n independent loci , 1981, Heredity.

[18]  D. Charlesworth,et al.  A further study of the problem of the maintenance of females in Gynodioecious species , 1981, Heredity.

[19]  D. Shaw,et al.  A multilocus estimator of mating system parameters in plant populations. , 1981, Proceedings of the National Academy of Sciences of the United States of America.

[20]  D. Charlesworth,et al.  The population genetics of gynodioecy with cytoplasmic-genic male-sterility , 1979, Heredity.

[21]  B. Charlesworth,et al.  A Model for the Evolution of Dioecy and Gynodioecy , 1978, The American Naturalist.

[22]  M. Clegg,et al.  Estimation of life cycle components of selection in an experimental plant population. , 1978, Genetics.

[23]  D. G. Lloyd,et al.  The transmission of genes via pollen and ovules in gynodioecious angiosperms. , 1976, Theoretical population biology.

[24]  D. G. Lloyd,et al.  Theoretical sex ratios of dioecious and gynodioecious angiosperms , 1974, Heredity.

[25]  D. Lewis,et al.  MALE STERILITY IN NATURAL POPULATIONS OF HERMAPHRODITE PLANTS THE EQUILIBRIUM BETWEEN FEMALES AND HERMAPHRODITES TO BE EXPECTED WITH DIFFERENT TYPES OF INHERITANCE , 1941 .