In this article we will discuss about the process of androgenesis, explained with the Success of anther culture is highly dependent on the genotype of the plant. The success of androgenesis dependent on the variety used, the growth . Razdan M.K, An introduction to plant tissue culture, ().Oxford. In vitro androgenesis is an important component of plant biotechnology when the pollen .. In: Korea-China Plant Tissue Culture Symposium, Academia Sinica.
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In vitro culture of un-pollinated ovaries or ovules is usually employed when the anther cultures give.
The presence of only one ovary per flower is another disadvantage. As the anthers proliferate, they produce callus which later forms an embryo and then a haploid plant Fig.
During the growth of callus, chromosomal doubling occurs by endomitosis.
Flowers from relatively younger plants, flowering at the beginning of flower-season are more responsive. Anther culture is easy, quick and practicable. Some workers choose a breeding approach for improvement of genotype before they are used in androgenesis. In this article we will discuss about the process of amdrogenesis, explained with the help of suitable diagrams. The microspore divides unequally as androbenesis pathways I and II.
Minerals and growth regulators play important roles on embryogenesis but it totally depends on the endogenous level of hormones.
The success of anther or pollen culture largely depends on the genotype of the donor plant. Two approaches based on morphology and genetics are commonly used to detect or identify haploids.
The above markers have been used for the development of haploids of maize. For such plant species, this technique is superior to another culture technique. This technique was later applied for raising haploid plants of rice, wheat, maize, sunflower, sugar beet and tobacco. The process of apomixis or parthenogenesis development of embryo from an unfertilized egg is responsible for the spontaneous natural production of haploids.
The cultured androgenrsis mainly follow four distinct pathways during the initial stages of in vitro androgenesis. Haploid production occurs through anther or pollen culture, and they are referred to as androgenic haploids.
This property can be exploited in some cases to obtain the homozygous plant. Many workers prefer pollen culture, even though the degree of success is low, as it offers the following advantages: In contrast, there are a large number of microspores in one another. androgsnesis
The disadvantages associated with anther culture can be overcome by pollen culture. Development of an egg cell containing male nucleus to a haploid is referred to as androgenesis. The uninucleate microspore undergoes equal division to form two daughter cells of equal size e. Alternately, the multicellular mass may produce the plant through direct embryogenesis Fig. The pollen can be extracted by pressing and squeezing the anthers with a glass rod against the sides of a beaker. There are however, certain plants which can grow well in both light and dark.
Production of Haploid Plants (With Diagram)
The Indian scientists Cuha and Maheswari reported the direct development of haploid embryos and plantlets from microspores of Datura innoxia by the cultures of excised anthers.
Here’s how it works: However, in this case, both vegetative and generative cells can further divide and contribute to hissue development of haploid plant e. The haploids possessing half the number of chromosomes from a polyploid species are regarded as polyhaploids e. It acts as an inhibitor of spindle formation during mitosis and induces chromosome duplication.
It is believed that the activated charcoal removes the inhibitors from the medium and facilitates haploid formation. Anddogenesis a successful in vivo androgenesis, the egg nucleus has to be inactivated or eliminated before fertilization.
This stimulates the axillary buds to grow into diploid and fertile branches. Further, induction of androgenesis is better if anthers are stored at low temperature, prior to culture e. Haploids can be diploidized by duplication of chromosomes to produce homozygous plants.
The young plantlets are directly treated with colchicine solution, washed thoroughly and replanted. Flowers obtained from young plants, at the beginning of the flowering season are highly responsive. The vegetative cell does not divide, e. Subsequently, Bourgin and Hitsch obtained the first full-pledged haploid plants from Nicotiana tabacum. A good knowledge of the various factors that influence androgenesis will help to improve the production of androgenic haploids.
Haploid plants can be produced from immature pollen or microspores male gametophytic cells.
Process of Androgenesis (With Diagram) | Biotechnology
The temperature shock helps in dissolution of microtubules and causes abnormal division androbenesis microspores. Viable and large pollen smaller pollen do not regenerate are concentrated by filtration, washed and collected. These plants may grow up to a flowering stage, but viable gametes cannot be formed due to lack of one set of homologous chromosomes.
For obtaining homozygous diploid lines, the plants derived through anther culture must be analysed for their ploidy level and then the following methods tiwsue be applied: There are four different pathways to form the multicellular condition of pollen from the unicellular pollen Fig. Consequently, there is no seed formation. There is, however, no single medium suitable for anther cultures of all plant species. The flower buds are excised hr.