Plant and Animal Breeding 3.2

Question 1

What are selective breeding programmes for?

Answer 1

To breed only individuals with the desirable trait in hope that its passed on.

Question 2

What are the characteristics selected for in crops?

Answer 2

Higher yield 
Nutritional Value
Useful Physical Characteristics
Ability to Thrive in a Particular Environment
Resistance to Pests
Resistance to Disease

Question 3

What is a cultivar?

Answer 3

A plant that has been created or selected intentionally for desirable characteristics that can be maintained by cultivation.

Question 4

What are plant field trials for?

Answer 4

1. Compare the performance or two different plant cultivars
2. Find out the effect of different environmental conditions on a new cultivar
3. Determine the effect of different treatments such as fertilisers and pesticides.

Question 5

Selection of Treatments

Answer 5

All other variables kept constant

Allows for a valid comparison

Question 6

Minimum of 3 replicates to…

Answer 6

Take account of the variability and reduce the effects of experimental error.

Question 7

Randomisation of treatments to…

Answer 7

Eliminate the possibility of bias.

Question 8

What are the two types of variation?

Answer 8

Discrete and Continuous

Question 9

What is discrete variation?

Answer 9

Can be divided up into distinct groups and is normally controlled by a single gene e.g. Pea Pod Colour

Question 10

What is continuous variation?

Answer 10

Flows from one extreme to the other and is controlled by alleles from more than one gene (poly genetic inheritance) e.g. Weight

Question 11

Is discrete variation effected by environmental factors?

Answer 11

No

Question 12

Is continuous variation effects by environmental factors?

Answer 12

Yes

Question 13

What is a test cross?

Answer 13

A cross between an organism whose genotype for a certain trait is unknown and an organism that is homozygous recessive for that trait.

Question 14

What is Outbreeding?

Answer 14

The fusion of two gametes from unrelated members of the same species

Question 15

What is inbreeding?

Answer 15

The fusion of two gametes from close relatives.

Question 16

What does inbreeding eliminate?

Answer 16

Hetrozygotes

Question 17

Continuous inbreeding leads to a

Answer 17

Loss of heterozygosity and an increase in the frequency of individuals who are homozygous.

Question 18

What is inbreeding depression?

Answer 18

The frequency of individuals who are homozygous for recessive, deleterious alleles increases. They will do less well at surviving to reproduce.

Question 19

Crossbreed populations tend to show

Answer 19

Improved characteristics

Question 20

What are F1 Hybrids

Answer 20

An individual resulting from a cross between two genetically dissimilar parents of the same species.

Question 21

What is Hybrid Vigour

Answer 21

F1 generation whose members display increased vigour so they may have increased disease resistance or growth rate.

Question 22

The F2 generation would show too much

Answer 22

Variation

Question 23

How can we stop the too much variation from F2

Answer 23

The two parent breeds can be maintained to produce more crossbred animals showing improved characteristics

Question 24

How is genetic technology useful.

Answer 24

As a result of genomic sequencing, organisms with desirable genes can be identified and used in breeding programmes to improve stock.

Question 25

Single genes for desirable characteristics can be inserted into the genomes of crop plants…

Answer 25

Creating genetically modified plants with improved characteristics

Question 26

What can recombinant DNA tech be used for?

Answer 26

Ir can be used in breeding programmes to produce plants containing bacterial genes to kill insects and to contain genes from other plants which make them resistant to glyphosphate herbicides