Differences among different method.pdf


Preview of PDF document differences-among-different-method.pdf

Page 1 2 3 4 5 6

Text preview


M@hbub 1

Comparison among Hybrid, Synthetics and Composite
Sl. No.
1

Basis

Hybrids

Base population

Inbreds

Synthetics

Composite

Inbreds or clone

Varieties or other
heterozygous source.

2

Parents

Usually 2-4 (6

4-10

Two to many

Random, open

Open pollinated

in triple cross)
3

Pollination

Controlled

pollinated
4

General combining

Tested

Tested

Usually not tested

More

Less than hybrid and

Less than hybrid

ability (GCA)
5

Heterosis

composite
6

Seed used

F1

F1 to F4

F1 to F4

7

Seed cost

More

Less than composite

Less than hybrid

and hybrid
8

Seed replacement

Annual

After 3-4 years

After 3-4 years

9

Varietal maintenance

Di cult

Easy

Easy

10

Re-construction

Possible

Possible

Not possible

Differences between Autopolyploid and allopolyploids
Character
1) Chromosome

Autopolyploid

Allopolyploid

Multiple of one genome.

Multiple of two or several genome.

2) External

Resembling a single diploid

Resembling of two or more

morphology

ancestral.

ancestral.

3) Chromosome

Multivalent, frequent

Mostly univalent, multivalent due to

number

pairing
4) Segregation

auto synthesis.
Polysomic

Polysomic to diosomic

i. Watermelon (Citrullus vulgaris)

i. Cultivated wheat (Triticum

pattern in F2
5) Example

ii. Sugarbeets (Beta vulgaris)

aestivum).

ii. Cultivated Tobacco (Nicotiana

tabacum)
Genetics and plant breeding