MODERN BREEDING METHODS (GENETICS).pptx..

Modern breeding methods

1. MODERN BREEDING METHOD SUBMITTED TO MERIN ALICE JACOB ASSISTANT PROFFESSOR DEPT OF BOTANY ST. TERESA’S COLLEGE ERNAKULAM SUBMITTED BY SHWETHA U I MS.C. BOTANY ROLL NO: 12 ST . TERESA’S COLLEGE ERNAKULAM 1

2. What is plant breeding? Plant breeding is the science of changing the traits of plants in order to produce desired characteristics. It has been used to improve the quality of nutrition in products for humans and animals. Modern plant breeding Modern plant breeding may use techniques of molecular biology to select, or in the case of genetic modification, to insert, desirable traits into plants. Application of biotechnology or molecular biology is also known as molecular breeding. 2

3. Modern trends in plant breeding Today's innovations in plant breeding use sophisticated science and technology that includes speed breeding, genomic selection, gene mapping, precision phenotyping, mutations, and marker-assisted breeding (MAB). Some of the most common modern breeding practices include genomic selection, markers assisted breeding. Despite these, plant breeding has fired up the problems of gene erosion due to loss of local landraces and wild-type plants. 3

4. Plant Tissue culture or micropropagation Tissue culture is the technique of growing cells and tissues in an artificial medium separate from the organism. Tissue culture is a technique in which fragments of plants are cultured and grown in a laboratory. The media used for the growth of the culture is broth and agar. It has proved beneficial for the production of disease-free plants and increase plant yield in developing countries. It only requires a sterile workplace, greenhouse, trained manpower, and a nursery. 4

5. The ability of a single cell to give rise to an entire plant is referred to as totipotency . Because of the property of plant cells, plant tissue culture is comparatively easier than animal tissue culture. The parts of the plant used for culturing is known as explants. The explants are cultured in-vitro on a nutrient medium that caters to fulfil its nutritional requirements. The nutrient medium must provide the following:- 5

6. Macronutrients – This includes elements like nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), sulfur (S) which is required for proper growth and morphogenesis. Micronutrients – Elements like iron (Fe), manganese (Mn), zinc (Zn) etc., which are also crucial to the growth of tissues. Carbon or Energy source – This is one of the most crucial ingredients of the nutrient media. Sucrose is the most widely used carbon source among other carbohydrates that serve to provide C, H, and O. Vitamins, amino acids, and other inorganic salts. 6

7. Types of Plant tissue culture Seed Culture Embryo Culture Callus Culture Organ Culture Protoplast Culture Anther Culture/pollen culture 7

8. SEED CULTURE In this culture, the explants are obtained from an in-vitro derived plant and introduced into a laboratory where they proliferate. The explant should be sterilized to prevent it from tissue damage. Seeds may be cultured in vitro to generate seedlings or plants. It is the best method for raising the sterile seedlings. The seed culture is done to get the different kinds of explants from aseptically grown plants which help in better maintenance of aseptic tissue culture . 8

9. EMBRYO CULTURE Embryo culture is the in vitro isolation and culture of immature or mature embryos on a nutrient media under sterile or aseptic conditions for obtaining viable plants. Embryos are often used as explants to generate callus cultures or somatic embryos . Immature embryogenic callus, derived from embryo, is the most popular method of monocot plant regeneration. First attempt to angiosperm embryos was made by Hanning in 1904. 9

10. CALLUS CULTURE Callus is basically more or less unorganized dedifferentiated mass of cell arising from any kind of explant under in vitro cultural conditions. The cells in callus are parenchymatous in nature, but may or may not be homogenous mass of cells. The callus tissue from different plant species may be different in structure and growth habit. Callus growth is dependent on factors like the type of explant and the growth conditions. 10

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12. PROTOPLAST CULTURE Is the culture of plant protoplasts i.e.., culture of cell devoid of cell wall. Isolated protoplasts is usually cultured in either liquid or semisolid agar media plates. Protoplasts are isolated from soft parenchymatous tissue by enzymatic method and then viable protoplasts are purified and cultured . The protoplast cultured is mainly aimed to develop genetically transformed plant where the transgene is put successfully within the plant protoplast and the transgenic plant is regenerated from that transformed protoplast. 12

13. Protoplast are isolated for culture by two techniques: 13

14. ANTHER CULTURE Haploid production by anther or pollen culture which was first established by Guha and Maheswari (1964-1966) in Datura. The anthers bearing the uni-nucleate microspores are selected and allowed to grow in media to produce callus from the pollen mass. Then the triggering of these androgenic calli is directed to produce the embryos and haploid plants are developed from these androgenic embryos. 14

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16. ORGAN CULTURE Organ culture can be defined as the organs or plant parts culturing in an artificial media or a culture from isolated medium. Any part of plant can serve as explants in organ culture-like shoot (for shoot tip culture), root (for root tip culture), leaf (for leaf culture), and flower (for anther, ovary, ovule cultures). 16

17. TISSUE CULTURE TECHNOLOGIES 17

18. Basic steps of plant tissue culture 18

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22. STEPS OF PLANT TISSUE CULTURE STEP I : SELECTION OF EXPLANT Any part of the plant like shoot tip, meristem, node, root tip or protoplast used for plant tissue culture is called explant. The explant are taken from disease free mother plant with desirable traits often grown under controlled glass house condition. 22

23. STEP II : SURFACE STERILIZATION The major difficulty in establishing a successful culture is microbial contamination . The explant should be thoroughly sterilized to remove microorganisms. The sterilization of explant surface with distilled water and other surface sterilants to remove microorganisms is called surface sterilization. Steps of sterilization: 23

24. Wash in running tap water many times. Wash with detergent or 70% Ethyl alcohol (initial sterilization). Wash in distilled water after ethanol treatment. Transfer the explant to laminar air flow (LAF) that provide sterile environment for aseptic culture. Treat with 0.1% Mercuric chloride Hgcl 2 (final sterilization ). Wash with distilled water many times. Trim the sides of explant with direct contact to Hgcl 2 as Hgcl 2 kill cells. Now explant is ready for inoculation. 24

25. STEP III : INOCULATION Inoculation in a suitable sterile growth medium like MS medium, whites medium etc. inside laminar air flow (LAF). 25

26. STEP IV : SHOOTING AND ROOTING E stablishment of the culture. The explant often give rise to callus at first . Callus is an undifferentiated mass of cells with meristematic activity capable of division and differentiation. Rooting and shooting is induced by different plant hormone combination. The combination of auxin and cytokinin works with majority of plant in plant tissue culture . 26

27. High auxin low cytokinin ratio favors rooting and low auxin high cytokinin ratio induces shooting. If the nutrients in the culture medium is depleted, we transfer the culture to a fresh medium know as sub-culturing. High auxin : low cytokinin = rooting Low auxin : high cytokinin = shooting 27

28. STEP V : ACCLIMATIZATION AND HARDENING The process of transferring or transplanting a tissue cultured plant from the lab to the land called hardening. The tissue cultured plantlets are gradually transferred from milder condition to field environment in sequential steps. First under the fluorescent light of the laboratory. Then transfer to green house then to shade. 28

29. Once the plant has established with sufficient leaves and well developed roots, then transfer it to the field with regular monitoring. This gradual process of acclimatization of tissue cultured plant from lab to land is called hardening. 29

30. DNA MARKER –ASSISTED SELECTION (MAS) Marker-assisted selection (MAS) is the process of using morphological, biochemical, or DNA markers as indirect selection criteria for selecting agriculturally important traits in crop breeding. This process is used to improve the effectiveness or efficiency of selection for the traits of interest in breeding programs. Sometimes many different genes can influence a desirable trait in plant breeding. The use of tools such as molecular markers or DNA fingerprinting can map thousands of genes. 30

31. This allows plant breeders to screen large populations of plants for those that possess the trait of interest. The screening is based on the presence or absence of a certain gene as determined by laboratory procedures, rather than on the visual identification of the expressed trait in the plant. The purpose of marker assisted selection, or plant genome analysis, is to identify the location and function (phenotype) of various genes within the genome. 31

32. If all of the genes are identified it leads to genome sequence. All plants have varying sizes and lengths of genomes with genes that code for different proteins, but many are also the same. If a gene's location and function is identified in one plant species, a very similar gene likely can also be found in a similar location in another related species genome. 32

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34. REFERENCE https://labassociates.com/7-methods-of-plant-tissue-culture Organ Culture - an overview | ScienceDirect Topics https://www.biologyexams4u.com/2023/03/5-essential-steps-in-plant-tissue.html Kr.Kumar, D. (2006). Plant Breeding Biometry Biotechnology. London: New central book agency (P) Ltd. Singh, B.D. (1993). Plant Breeding: Principles and methods. New Delhi. Kalyani publishers. 34

35. THANK YOU 35