Applications of Biotechnology in Plant Breeding


22 Οκτ 2013 (πριν από 4 χρόνια και 8 μήνες)

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Applications of Biotechnology in

Plant Breeding

Sadanand Dhekney, PhD

University of Florida / IFAS

Florida Research & Education Center

Apopka, FL 32703

Limitations of Conventional Breeding

Extreme heterozygosity and pronounced
inbreeding depression in plant species

F1 hybrid produced is of intermediate quality

Long juvenile period of
makes screening of
new selections tedious and time consuming

Plant biotechnology

What is plant biotechnology?

Products on the market

Benefits of biotechnology

Plant biotechnology

A precise process in which scientific techniques

are adopted to develop useful and beneficial

Desired gene

Traditional plant breeding

DNA is a strand of genes,

much like a strand of
pearls. Traditional plant
breeding combines many
genes at once.

Traditional donor

Commercial variety

New variety

Desired Gene




(many genes are transferred)

Plant biotechnology

Using plant biotechnology,
a single gene may be
added to the strand.

Desired gene

Commercial variety

New variety



Desired gene

(only desired gene is transferred)

What is Plant Tissue Culture?


Single cell has the ability to regenerate into
a whole plant

What conditions do plant
cells need to multiply in

Freedom from competition

Nutrients and removal of waste

A controlled environment


Seed culture

Increasing efficiency of germination of
seeds that are difficult to germinate in vivo

Precocious germination by application of
plant growth regulators

Production of clean seedlings for explants
or meristem culture

Embryo culture

Overcoming embryo abortion due to
incompatibility barriers

Overcoming seed dormancy and self
sterility of seeds

Embryo rescue in distant (interspecific or
intergeneric) hybridization where
endosperm development is poor

Shortening of breeding cycle

Ovary or ovule culture

Production of haploid plants

A common explant for the initiation of somatic
embryogenic cultures

Overcoming abortion of embryos of wide hybrids
at very early stages of development due to
incompatibility barriers

In vitro

fertilization for the production of distant
hybrids avoiding style and stigmatic
incompatibility that inhibits pollen germination
and pollen tube growth

Anther and microspore culture

Production of haploid plants

Production of homozygous diploid lines
through chromosome doubling, thus
reducing the time required to produce
inbred lines

Uncovering mutations or recessive

Organ culture

Any plant organ can serve as an explant to
initiate cultures

Shoot apical meristem culture

Production of virus free germplasm

Mass production of desirable genotypes

Facilitation of exchange between locations
(production of clean material)

Cryopreservation (cold storage) or

in vitro

conservation of germplasm

Somatic embryogenesis

One major path of regeneration

Mass multiplication

Production of artificial seeds

As source material for embryogenic

Amenable to mechanization and for

Embryogenic Culture System for

Initiation from leaves on NB 2 medium (Gray, 1995)

Leaf explant

Embryogenic callus

Embryo development





One major path of regeneration

Mass multiplication

Conservation of germplasm at either
normal or sub
zero temperatures

Callus Cultures

In some instances it is necessary to go through
a callus phase prior to regeneration via somatic
embryogenesis or organogenesis

For generation of useful somaclonal variants
(genetic or epigenetic)

As a source of protoplasts and suspension

For production of metabolites

Used in i
n vitro


Initiation from Stamens and Pistils

Embryogenic callus

Callus formation from

connective tissue

Callus formation from

filament tip

Embryo development

Embryo germination

Stamen explant

In vitro mutagenesis

Induction of polyploidy

Introduction of genetic variability

Genetic transformation

Introduction of foreign DNA to generate
novel (and typically desirable) genetic

Many different explants can be used,
depending on the plant species and its
favored method of regeneration as well as
the method of transformation

Used to study the function of genes

Genetic Transformation System

Regenerate transgenic



48 h


Wash explants

Agro culture

Callus induction


Select transgenic embryos

using GFP/NPT II system

Embryo development


Embryo explants


Disease resistance

Insect resistance

Salinity tolerance

Heavy metals tolerance

Improved nutritional characteristics

More than 50 biotech food products
have been approved for commercial
use in the United States

Canola (5%)

Corn (21%)

Cotton (12%)



Soybeans (62%)



Sweet corn


Advantages & Limitations


Food quantity

Food quality

Eco friendly


Recent scientific advances

Tangible benefits may not be long term