MICROPROPAGATION

Introduction In nature plants propagate either Sexually (seeds generation) results heterogeneity Or Asexually (vegetative multiplication) produce genetically identical plants. Multiplication of genetically identical copies of a cultivar by asexual reproduction is called clonal propagation. Via tissue culture called micropropagation,

What is Micropropagation? “… the asexual or vegetative propagation (multiplication) of plants in vitro “ Implies - regeneration - multiplication - uniformity ??

Basic in vitro propagation ...

Micropropagation (contin) Positives and negatives of micropropagation positives rapid multiplication rates low space requirement negatives labor costs high overhead (equipment, facilities, supplies) loss by contamination danger of variation

STAGES 2. Establish aseptic culture 3. Multiplication 1. Selection of plant material 2. Establish aseptic culture 3. Multiplication 4. Shoot elongation 5. Root induction / formation 6. Acclimatization

2. Establish aseptic culture 3. Multiplication 4. Shoot elongation STAGES 1. Selection of plant material 2. Establish aseptic culture 3. Multiplication 4. Shoot elongation 5. Root induction / formation 6. Acclimatization

Starting material for micropropagation Tip bud Starting material for micropropagation Leaf Axillary bud Internode Root

Selection of plant material ... Part of plant Genotype Physiological condition Season Position on plant Size of explant

Physiological state - of stock plant Vegetative / Floral Juvenile / Mature Dormant / Active Carbohydrates Nutrients Hormones

2. Establish aseptic culture 3. Multiplication 4. Shoot elongation STAGES 1. Selection of plant material 2. Establish aseptic culture 3. Multiplication 4. Shoot elongation 5. Root induction / formation 6. Acclimatization

Disinfestation Stock plant preparation Washing in water Disinfecting solution Internal contaminants Screening

Organic ‘growth factors’ Growth regulators Gelling agent The medium Minerals Sugar Organic ‘growth factors’ Growth regulators Gelling agent Other additives

Physical Environment Temperature Moisture Light

2. Establish aseptic culture 3. Multiplication 4. Shoot elongation STAGES 1. Selection of plant material 2. Establish aseptic culture 3. Multiplication 4. Shoot elongation 5. Root induction / formation 6. Acclimatization

Lateral / Axillary buds Adventitious (de novo, re-differentiation) Origins of new shoots ... Terminal extension Lateral / Axillary buds Adventitious (de novo, re-differentiation) Callus differentiation

Role of growth regulators ... Cell division Differentiation Cell expansion Apical dominance auxins abscisic acid cytokinins gibberelic acid ethylene

2. Establish aseptic culture 3. Multiplication 4. Shoot elongation STAGES 1. Selection of plant material 2. Establish aseptic culture 3. Multiplication 4. Shoot elongation 5. Root induction / formation 6. Acclimatization

Carry-over of hormones Shoot elongation ... Basal ‘hormone free’ medium Gibberellins Carry-over of hormones

2. Establish aseptic culture 3. Multiplication 4. Elongation STAGES 1. Selection of plant material 2. Establish aseptic culture 3. Multiplication 4. Elongation 5. Root induction / formation 6. Acclimatization

Juvenility / rejuvenation Genotype Root initiation ... Auxins Co-factors C : N ratio Light / darkness Initiation vs growth Juvenility / rejuvenation Genotype

2. Establish aseptic culture 3. Multiplication 4. Elongation STAGES 1. Selection of plant material 2. Establish aseptic culture 3. Multiplication 4. Elongation 5. Root induction / formation 6. Acclimatization

- survival of the new plant when removed from the in vitro environment Acclimatization (hardening) - survival of the new plant when removed from the in vitro environment

Micropropagation of almost all the fruit crops and vegetables is possible Some examples: dwarfing sweet cherry, Shade trees, Ornamental shrubs, Roses, Clematis, Lilacs, Saskatoon berries, Nutraceutical Plants, Rhododendron, Azalea, mustard, corn, soybeans, wheat, rice, cotton, tomato, potato, citrus, turf, legumes

Advantages of Micropropagation economical in time and space greater output -can produce millions of uniformly flowering and yielding plants African Biotechnologies - fruit crops banana and indoor pot flowers- 6 million pieces per year disease free elite plants with exceptional characteristics

Advantages Cont’d facilitates safer movements of germplasm across nations - In vitro germplasm assures the exchange of pest and disease free material great for vegetatively reproduced crops crops which produce few seeds or highly heterozygous seeds.

Uses of Micropropagation Used to create transgenic, first generation plants Used in horticulture to produce orchids, African Violets, lilies, and ferns Used in nurseries to grow fruit trees, evergreens, roses, and shade trees

Benefits of Micropropagation Many genetically identical plants can be created from one parent plant Because plants are clones, the uniformity assures quality Allows many plants to grow in a small place in a short time In some species this method will produce healthier plants

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