3.2 pant and animal breeding

Question 1

selective breeding

Answer 1

the process by which individuals with desirable characteristics are breed together to produce offspring with desirable features.

Question 2

what do breeders select for when breeding plants

Answer 2

higher yield
higher nutritional value
resistance to pest and disease

Question 3

what are animals selected for when breeding together cattle

Answer 3

improved milk yield
butterfat content
meat production

Question 4

what are sheep selected for in breeding programmes

Answer 4

improved wool quantity and quality

Question 5

phenotype

Answer 5

physical appearance of an organism

Question 6

genotype

Answer 6

set of genes an organism possesses

Question 7

alleles

Answer 7

different forms of the same gene

Question 8

homosygous

Answer 8

having two identical alleles

Question 9

heterozygous

Answer 9

having two different alleles of a gene

Question 10

dominant allele

Answer 10

allele that is always expresssed

Question 11

recessive allele

Answer 11

allele that is only expressed when homozygous

Question 12

true breeding

Answer 12

organism that always produces the same phenotype when crossed with itself

Question 13

variation

Answer 13

the range of differences between the member of the same species

Question 14

discrete variation

Answer 14

when variation of a characteristic can be divided into 2 or more distinct groups

Question 15

continuous variation

Answer 15

within a range from one extreme to another

Question 16

is being able to roll your tongue a single or poly gene inheritance

Answer 16

single gene

Question 17

is hair colour a single or polygenic gene inheritance

Answer 17

poly

Question 18

what happened if inbreeding is performed for long periods of time

Answer 18

there is a loss of heterozygosity so plants and animals become homozygous for the selected trait.

Question 19

how is inbreeding depression caused

Answer 19

by genotypes emerging that are homozygous for an increasing number of recessive alleles of harmful genes.

Question 20

what can inbreeding depression lead to

Answer 20

decline in vigour,
size,
fertility
yield of the plant or animal

Question 21

how can inbreeding depression be prevented

Answer 21

by choosing a population of parent plants that are homozygous for the desired characteristics heterozygous for everything else

Question 22

inbreeding depression definition

Answer 22

the accumulation of other homozygous alleles can cause the expression of deleterious recessive alleles.

Question 23

what is cross breeding

Answer 23

when new alleles are introduced to plant and animal lines by crossing a cultivar or breed with an individual with a different desired genotype

Question 24

why are F1 hybrids not bred together with other F1 hybrids

Answer 24

shows to much variation

Question 25

what is a benefit of hybridisation

Answer 25

restore hetrerozygosity

Question 26

what have increased in F1 hybrids

Answer 26

vigour
yield
fertility

Question 27

how is genome sequencing a benefit

Answer 27

organisms with desirable gens can be identified and used in breeding programmes

Question 28

why is there a selection of treatments in a field trial

Answer 28

to ensure fair comparisons

Question 29

why is the number of replicates taken into account during field trials

Answer 29

take into account the variability within the sample

Question 30

why are the treatments randomised in a field trial

Answer 30

to eliminate bias when measuring treatment effects