• A sexual reproduction does not involve fusion of male and female gametes.
• New plants may develop from vegetative parts of the plant (vegetative reproduction) or may arise from embryos that develop without fertilization (apomixis).

1.  Vegetative Reproduction:

• In nature, a new plant develops from a portion of the plant body.
• This may occur through modified underground and sub-aerial stems, and through bulbils.

2. Underground Stems:

• The underground modifications of stem generally serve as storage organs and contain many buds.
• These buds develop into shoots and produce plants after rooting. Examples of such modifications are given below.

Tuber: Potato

Bulb: Onion, Garlic

Rhizome: Ginger, turmeric

Corm: Bunda, arwi

3. Sub-aerial Stems:

• These modifications include runner, stolon, sucker etc.
• Sub-aerial stems are used for the propagation of mint, date palm etc.

4. Bulbils:

• Bulbils are modified flowers that develop into plants directly without formation of seeds.
• These are vegetative bodies; their development does not involve fertilization and seed formation.
• The lower flowers in the inflorescence of garlic naturally develop into bulbils.

5. Artificial Vegetative Reproduction:

• Stem cuttings are commercially used for the propagation of sugarcane, grapes, roses, etc.
• Layering, budding, grafting and gootee are in common use for the propagation of fruit trees and ornamental shrubs.

Significance of Vegetative Reproduction

• A desirable plant may be used as a variety directly regardless of whether it is homozygous or heterozygous.
• Further, mutant buds, branches or seedlings, if desirable, can be multiplied and directly used as varieties.

6. Apomixis:

• In apomixis, seeds are formed but the embryos develop without fertilization.
• In apomictic species, sexual reproduction is either suppressed or absent.
• When sexual reproduction does occur, the apomixis is termed as facultative.
• But when sexual reproduction is absent, it is referred to as obligate.

7. Parthenogenesis:

• The embryo develops from embryo sac without pollination. It is of two types:

a) Gonial parthenogenesis – embryos develop from egg cell.

b) Somatic parthenogenesis – embryos develop from any cell of the embryo sac other than the egg cell.

8. Apogamy:

• In apogamy, synergids or antipodal cells develop into an embryo.
• Like parthenogenesis, apogamy may be haploid or diploid depending upon the haploid or diploid state of the embryo sac.
• Diploid apogamy occurs in Antennaria, Alchemilla, Allium and many other plant species.