Anther culture is an in vitro technique used to produce haploid plants from male gamete cells. Haploid cells contain only one set of chromosomes. The first report of anther culture was in the 1970s, while the first natural occurrence of haploids was observed in 1922 in Datura plants. Anthers containing microspores are cultured on nutrient media supplemented with hormones and sugars. Depending on the species, haploid plants or callus can regenerate from the cultured anthers within 3-8 weeks. Haploid plants are useful for breeding programs as they can be doubled to generate fertile, homozygous plants in one generation.
2. Introduction
• Anther culture means plant regeneration from the haploid
microspore cells with the aim of haploid and dihaploid plant
production.
• It has been used in numerous species, mainly rice and
tobacco.
• Haploid culture is an in vitro technique used to
produce haploid (cells have half the number of
chromosomes) plants.
• Haploid cells contain a single set of chromosomes. Gametes
are an example of haploid cells produced as a result of
meiosis.
3. • Anther culture was first
reported in the 1970s
through in vitro methods by
Guha and Maheshwari.
• Blackslee et al. (1922) first
reported the natural
occurrence of
the haploid condition in
Datura plants, due to
parthenogenesis (embryo
development from an
unfertilized egg).
History
4.
5. • Haploids can be used to generate genetic homozygotes by one
generation doubling of chromosomes using colchicine.
• Such haploids are called androgenic haploids because they have
been developed from male gamete producing spore, i.e., pollen
grain or microspore.
• Haploid cells contain a single set of chromosomes. Gametes are
an example of haploid cells produced as a result of meiosis.
• Haploids plants are sterile as these plants contain only one set of
chromosomes.
• By doubling their chromosomes number, the plants can be made
fertile and resultant plants will be homozygous diploid.
Haploid Plant
6.
7. • Haploids provide a convenient system for the induction of
mutations and selection of mutants with desired traits.
• Mutants from several plant species that are resistant to
antibiotics, toxins, herbicides etc. have been developed.
• The plant species with salt tolerance are needed for their
cultivation in some areas.
• Production of insect resistance plants.
• Disease resistance genes can be introduced while producing
haploids.
• Production of haploids is highly useful for research related to
plant genetics and breeding.
8. Androgenesis
• In androgenesis, the male gametophyte (microspore or
immature pollen) produces haploid plant.
• The basic principle is to stop the development of pollen cell
into a gamete (sex cell) and force it to develop into a haploid
plant.
• Young pollen grains produced androgenic haploids in anther
cultures.
9. The technique involves excising closed flower buds which have
anthers containing uninucleate microspores
At this stage, microspores are most suitable for the induction of
androgenesis
The excised flower buds are surface-sterilised and anthers are
removed
Care should be taken to avoid injury to the anthers, cultured on
agar-solidified or liquid medium
The cultures are incubated at 24-27°C using light of about 2000
lux for 14 h per day
Anther culture technique
10.
11. Depending upon the plant species, it takes 3-8 weeks for pollen
plantlets to regenerate from anthers
After a month of incubation, the microspores either develop
into embryos or calli, emerging through anther lobes
Subsequently, these calli can be transferred to the regeneration
medium
In some cases, some pollen grains develop into embryos and
others into calli within the same anther
The pollen plantlets at about a height of 12-14 cm are
hardened and then transferred to the soil
12. Nutrient medium
• Anthers can be cultured on a suitable medium containing
sucrose, iron, vitamins, hormones etc.
• The hormonal component of the medium is important for
initiation of growth.
• Usually to the culture medium auxin, cytokinin etc. are added
either singly or in various combinations.
• Low concentration of auxin stimulates callus formation. In a
medium supplemented with auxin embryoid formation
usually occurs at a faster rate as observed in anther culture of
Datura.
• Anthers cultured on a medium containing coconut milk or
kinetin develop embryoids which later form haploid plantlets.
• Callus is formed from pollen grains on a medium
supplemented with yeast extract or casein hydrolysate.
13. Factors Affecting Anther culture
Activated charcoal:
• It has a stimulatory effect on embryogenesis and this has been
observed in anther cultures of potato, rye, tobacco, etc.
Temperature:
• Temperature has significant effect on pollen embryoid deve-
lopment.
• Pre-treatment of anthers at 3—10°C for 2—30 days stimulates
embryogenesis.
Stage of the anther:
• Usually anthers just before or immediately after pollen mitosis
are most suitable for culture.
14. Photoperiod and light intensity:
• Higher number of embryoids are formed when anthers are
taken from plant grown under short days and high light
intensities.
Flowering time:
• Anthers taken from flowers at the beginning of the flowering
period of the plant are most suitable for culture.
Age of the plant:
• Usually anthers from younger plants are more suitable for
culture.
15. • Utility of anther culture for basic research cytogenetic study.
• Study of genetic recombination in higher plants.
• Study of mode of differentiation from single cells to whole
plants.
• Study of factor controlling pollen embryogenesis of higher
plants.
• Formation of double haploid plants that are homozygous and
fertile.
Importance of Anther culture