Table 1.

Summary of advantages and disadvantages of reproductive systems and polyploidy in angiosperms

Mode	Advantage	Disadvantage
Sexual outcrosser	Maintenance of genetic diversity	Mating partner and pollen vector needed
Sexual selfer	Uniparental reproduction, frequent (as  dominant: c. 20%; as casual: c. 40%)a	Increased homozygosity, potential  inbreeding depression
Autogamy, cleistogamy	Pollinator independent
Geitonogamy, facilitated selfing		Pollinator dependent, pollen and seed  discounting
Polyploid sexual	Novel genomic composition, fixed  heterozygosity, often self-compatible,  reproductive isolation, high frequencies  (40–70%)b	Possible disturbances of meiosis  and gene expression, aneuploidy
Pseudogamous apomixis	Heterozygosity, heterosis	Reduced genotypic diversity
	Reproductive isolation	Pollen dependent
		Potential minority cytotype disadvantages
		Low frequencies (<1%)c
Pseudogamous apomixis with SI		Mating partner and pollen vector needed;  Pollen-discounting, SI reaction among  clone mates
Pseudogamous apomixis with SC   and autogamyd	Uniparental reproduction, pollinator  independent
Pseudogamous apomixis with   SC, geitonogamy or facilitated   selfingd	Uniparental reproduction	Pollinator dependent
Autonomous apomixis	Heterozygosity, heterosis	Reduced genotypic diversity
	Uniparental reproduction, pollinator  independent	Endosperm balance strongly disturbed
	Self-fertility not needed	Very low frequenciesc
	No minority cytotype disadvantages

^aRichards (1997)

^bRamsey and Schemske 1998

^cMogie (1992)

^dOnly the endosperm is fertilized, not the embryo