Plant and Animal Breeding

Question 1

State 4 things breeders look to develop in crops and animals.

Answer 1

1. higher food yield
2. higher nutritional value
3. pest and disease resistance
4. ability to thrive in particular environmental conditions

Question 2

What is the purpose of inbreeding?

Answer 2

Selected related plants/animals are bred for several generations until the population breeds true to the desired type.

Question 3

What is eliminated by inbreeding?

Answer 3

heterozygotes

Question 4

What is inbreeding?

Answer 4

Fusion of gametes from 2 close relatives

Question 5

What is outbreeding?

Answer 5

Fusion of gametes from 2 unrelated members of the same species.

Question 6

What causes inbreeding depression?

Answer 6

When the genotypes that result are homozygous for an accumulation of recessive, deleterious alleles.

Question 7

What is the result of inbreeding depression?

Answer 7

Individuals will do less well at surviving to reproduce.

Question 8

What is an advantage of cross breeding?

Answer 8

Individuals from different breeds may produce a new crossbreed with improved characteristics.

Question 9

What must be maintained to continually produce crossbreeds?

Answer 9

The two parent breeds

Question 10

What are the advantages of F1 hybrids in plants?

Answer 10

Usually increased vigour and yield

Question 11

What is the genetic make-up of the F1 hybrids?

Answer 11

Relatively uniform heterozygous crop

Question 12

In inbreeding animals and plants, why are F1 hybrids not usually bred together?

Answer 12

The F2 population produced shows too much variation.

Question 13

What has resulted desirable genes being identified and then used in breeding programmes?

Answer 13

Genome sequencing

Question 14

How can recombinant DNA technology be used to improve crops?

Answer 14

Where one or more genes are inserted into the genome with improved characteristics.

Question 15

What is a cultivar?

Answer 15

A plant variety produced from selective breeding

Question 16

State 3 things field trials are used for.

Answer 16

1. Compare the performance of different cultivars under the same conditions
2. Compare different treatments on the same cultivars
3. evaluate GM crops

Question 17

State 3 requirements for a field trial.

Answer 17

1. change only one thing
2. randomisation
3. appropriate number of replicates

Question 18

What is the reason for randomisation?

Answer 18

to prevent bias

Question 19

Why are several replicates needed in a field trial?

Answer 19

To take account of variability within the sample.

Question 20

Why is it important only one thing is changed?

Answer 20

So a fair comparison can be made