The modes of reproduction in crop plants may be broadly grouped into two categories: asexual and sexual. Sexual reproduction involves the fusion of male and female gametes, whereas in asexual reproduction new plants may develop from vegetative parts of the plant (vegetative reproduction) or may arise from embryos that develop without fertilization (apomixis).

1. MODES OF REPRODUCTION IN
CROP PLANTS
Prepared By:
Mr. Asit Prasad Dash
Assistant Professor
DEPARTMENT OF PLANT BREEDING AND GENETICS
INSTITUTE OF AGRICULTURAL SCIENCES
SIKSHA ‘O’ ANUSANDHAN (DEEMED TO BE UNIVERSITY), BHUBANESWAR, 751029

2. MODES OF REPRODUCTION
IN
CROP PLANTS
Sexual
Reproduction
(Involves fusion of male
and female gametes)
Asexual
Reproduction
(Does not involve fusion of
male and female gametes)

3. Asexual Reproduction
Vegetative Reproduction
(New plant develops from a
portion of the parent plant)
Apomixis
(Seeds are formed but the
embryos develop without
fertilization)
1. Underground Stems: Tuber, Bulb, Rhizome,
Corm
2. Sub-aerial Stems: Runner, Sucker, Stolon
3. Bulbils
4. Artificial Vegetative Reproduction: Stem
cutting, layering, budding, grafting and gootee

4. Tuber: Potato Bulb: Onion, Garlic
Rhizome: Ginger, turmeric Corm: arwi
Runner Bulbils Gootee

5. • A desirable plant may be used as a variety
directly regardless of whether it is
homozygous or heterozygous.
• Mutant buds, branches or seedlings, if
desirable, can be multiplied and directly
used as varieties.
Significance of vegetative reproduction:

6. Basis of
classification
Types of
Apomixis
Brief description
(i) Cell involved Parthenogenesis Embryo develops from egg cell.
Apogamy Embryo develops from either synergids or antipodal
cells.
Apospory Embryo develops from the embryosac which has
developed from the cell of archisporeum/ nucellus or
Integument.
Adventive
Embryony
Embryo develops directly from the diploid cell of either
nucellus or integument
(ii) Occurrence Recurrent
Apomixis
Embryosac has diploid cells and embryo develops from
the diploid cells,
Non-Recurrent
Apomixis
Embryosac consists of haploid cells and embryo
develops from haploid cell.
(iii) Frequency Obligate
Apomixis
The reproduction occurs by apomictic means only.
Facultative
Apomixis
The reproduction occurs by both sexual and apomictic
means.
Classification of apomixis

7. • Once a desirable genotype has been
selected, it can be multiplied and
maintained through apomictic progeny.
• This would keep the genotype of a variety
intact.
Significance of Apomixis:

8. Stamen
Anther
Filament
Petal
Receptacle
Stigma
Style
Ovary
Carpel
Sepal
(a) Structure of an idealized flower
SEXUAL REPRODUCTION

9. Sporogenesis (Meiotic division)
(Productions of microspores and megaspores)
Microsporogenesis
Each anther has four pollen sacs,
which contain numerous pollen
mother cells (PMCs). Each PMC
undergoes meiosis to produce four
haploid cells or microspores. This
process is known as
microsporogenesis . The
microspores mature into pollen
grains mainly by a thickening of
their walls.
Megasporogenesis
This occurs in ovules. A single cell
in each ovule differentiates into a
megaspore mother cell. The
megaspore mother cell undergoes
meiosis to produce four haploid
megaspores. Three of the
megaspores degenerate leaving
one functional megaspore per
ovule. This completes
megasporogenesis.

10. Gametogenesis (Mitotic division)
(The production of male and female gametes in
the microspores and the megaspores,
respectively)
Microgametogenesis:
This refers to the
production of male
gamete or sperm
Megagametogenesis:
The development of embryo sac
from a megaspore.
The embryo sac generally contains
one egg cell, two synergids, three
antipodal cells (all haploid), and
one diploid secondary nucleus

11. • The fusion of one of the two sperms with the egg
cell, producing a diploid zygote, is known as
fertilization.
• The fusion of the remaining sperm with the
secondary nucleus, leading to the formation of a
triploid primary endosperm nucleus, is termed as
triple fusion.
• The zygote divides mitotically to produce a diploid
embryo. The primary endosperm nucleus produces
endosperm through repeated mitotic divisions.
• During seed development, endosperm provides
nutrition to the developing embryo.
Fertilization:

12. Fig.1. Microsporogenesis and microgametogenesis (a generalized scheme)

13. Fig. 2. Megasporogenesis and megagametogenesis (generalized scheme)

15. Significance of Sexual Reproduction
• Sexual reproduction makes it possible to
combine genes from two parents into a single
hybrid plant.
• Recombination of these genes produces a large
number of genotypes. This is an essential step in
creating variation through hybridization.
• Almost the entire plant breeding is based on
sexual reproduction.
• Even in asexually reproducing species, sexual
reproduction, if it occurs, is used as an
advantage, e.g., in sugarcane, potato, sweet
potato etc.

16. Thank You