chapter 11

Question 1

heterosis:

Answer 1

the amount of superiority or inferiority observed or measured in crossbred or outbred animals compared with the average of their purebred parents.

Question 2

Heterosis is also obtained when ______ _____ lines or distantly related lines within a breed.

Answer 2

crossing inbred

Question 3

The term __________- is used interchangeably with the term heterosis.

Answer 3

hybrid vigor

Question 4

____________ mating individuals within a breed that are less closely related than average.

Answer 4

outbreeding

Question 5

_____ the offspring resulting from the crossing of two purebreds of different breeds.

Answer 5

F1

Question 6

________the offspring resulting from mating two F1 of the same breed composition.

Answer 6

F2

Question 7

_______ the mating of a crossbred back to a purebred of one of the parent breeds

Answer 7

backcross

Question 8

how do you calculate % heterosis?

Answer 8

(average of x bred) - (average of parent breeds)/(average of parent breeds) x100

Question 9

________: heterozygote equal to best homozygote

Answer 9

dominance

Question 10

__________: heterzygote is superior

Answer 10

overdominance

Question 11

______: individuals superior withat least one big A and one big B

Answer 11

epistasis

Question 12

factors that influence amount of heterosis: ______, ________, breed, genes, environment

Answer 12

trait, species

Question 13

trait: greatest for __________ traits. suffer from inbreeding ________.

Answer 13

fitness and depression

Question 14

_______ combining ability, the amount of heterosis obtained on aberage when a specific breed is mated to a group of other breeds.

Answer 14

general

Question 15

breeds that are _____ related to eachother have higher genral combining ability.

Answer 15

higher

Question 16

crossbred performance formula:

Answer 16

[average breed means + breeding values of parents] x [1 + % heterosis]

Question 17

average breeding value of parents:

Answer 17

avg ETA of males + avg ETA of females

Question 18

if parents are two totally different breeds then the % of maximum heterosis is ______%

Answer 18

100

Question 19

if the parents have a fraction of a breed in common the the amount of heterosis loss is the __________of the fractions found in common.

Answer 19

product

Question 20

D X (.5 D .5 H)=% HETEROSIS?

Answer 20

50% MAX

Question 21

D X (.75 D .25 H)=

Answer 21

25% MAX

Question 22

what rotation do they use most in cattle?

Answer 22

3 breed rotation