Download The Importance of Hybridisation in Plant and Animal Breeding

Chapter 21
The Importance of Hybridisation in Plant and Animal Breeding
A Hybrid: is the individual resulting from parents of the same species
but are genetically different.
e.g. greyhounds:
bitch
fast
X
dog
long legs
puppies
long legs and faster
Hybrid tend to show Hybrid Vigour i.e. bigger and better than their
parents due to the re-establishment of Heterozygosity.
Continual inbredding can produce strains that have become
Homozygous. E.g. aabbCCDD can introduce the dominant allele, where
previously only the homozygous recessive existed.
Complete:
AABBccdd
Examples of Important Hybrids.
1) Bedding Plants:
Complete:
1
x
aabbCCDD
Chapter 21
Why are F1 hybrid seeds more expensive to buy than seeds from either of
their parents?
2) Farm Animals
(a) Sheep. The Scottish Halfbred is a hybrid from:
Cheviot
X
Border Leicester
Scottish Half Bred
(improved meat yield and
higher lambing rate)
(b) Cattle.
List some examples of traits showing hybrid vigour in cattle.
List Notes on Artificial Selection and Imported Species.
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