Anther culture

anther culture is used in tissue culture process producd complete plants

1. Anther Culture Mrs. Praveen garg VITS College, Satna

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. Haploids  can be used to generate genetic homozygotes by one generation doubling of chromosomes using colchicine . S uch  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

5. 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.

6. 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.

7. 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

8. 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

9. 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 .

10. 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 deve­lopment . 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.

11. 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.

12. 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

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