This presentation describes different approaches/mechanisms by which the sex of a plant determined.

1. Upendar Rao Golla
Department of Biological Sciences
IISER Bhopal

2. Bryophytes
Tracheophytes
Introduction to Plant Kingdom

3. Sex determination in Bryophytes

4. Sex determination in Bryophytes
Homosporous Ferns
The Plant Cell, Vol. 16, S61–S71

5. Sex determination in Angiosperms

7. 1) Active-Y System of Sex Determination
Ex: Cannabis, Humulus, Silene, Asparagus – XY sex chromosomes
2) X-to-Autosome Balance System of Sex Determination
Rumex Acetosa: X-to-autosome ratio (≥1= females, ≤0.5= males)
3) Hormonal regulation of Sexuality
Mercurialis annua- three independent segregating genes-A1, B1, B2.
Dominant B1-b2 genes influence the degree of “maleness”
4) Evolution of Sexual Dimorphisms in Plants
Mutation causing male or female sterility. Ex: Asparagus
Despite all the above mechanisms in plants may have common origin-
Selective pressure for increased genetic fitness
Sex determination in Angiosperms

9. Genotype Fenotipe
M_F_
M_ff
mmF_
mmff
Ginoecious
Monoecious
Hermaprodite
Andromonoecious
Genotipe Fenotipe
A_G_
A_gg
aaG_
aagg
Monoecious
Ginomonoecious
Andromonoecious
Hermaprodite
Appearance on cucumber sex
Appearance on melon sex

10. Preserve plant life