mating systems

Question 1

reasons for choosing mating system

Answer 1

1 increase genetic gain
2 make use of complimentarity
3 heterosis

Question 2

prerequisite for choosing mating combination system

Answer 2

traits of interest
inheritance pattern
**expression pattern
**parental genotype

Question 3

random mating

panmixia

Answer 3

each individual has equal chnce to mate the other individual

Question 4

non random mating

Answer 4

decided by breeder

based on ARTIFICIAL SELECTION

Question 5

RANDOM MATING

Answer 5

selected at random
when no genetic records available
easy

Question 6

non randing mating

2 types

Answer 6

• based on genotypic resemblance

* based on phenotypic resemblance

Question 7

phenotypic resemblance mating 2 types

Answer 7

positive assortative mating

negative assortative mating

Question 8

positive assortative mating

Answer 8

phenotypically similiar individuals mate together

• *more variation
• *more homozygosity

Question 9

outbreeding

Answer 9

• unrelated individuals
• *increase heterozygosity
• *increase variability

Question 10

different types of inbreeding

Answer 10

• *close inbreeding
• *line inbreeding
• *strain formation
• *pure breeding

Question 11

close inbreeeding?

Answer 11

• *mating btw siblings
• *mating btw progeny parent
• • it is for increasing homozygosity
• *undesirable genes are found out

Question 12

most common method of close inbreeding is

Answer 12

**full sib followed by backcross followed by half sib mating

Question 13

line breeding

Answer 13

• • mating btw cousins

* *maintaining a connection with outstanding ancestor while keeping inbreeding low

Question 14

strain formation

Answer 14

a population is mated for 3 to 5 generations

**without entry of any other one

Question 15

inbred line?

Answer 15

***after 2 generation of full sib mating,

inbreeding coefficient becomes 0.375,it is called inbred line

Question 16

pure breeding

Answer 16

• *mating btw purebreds of the same breeds

- -planned matings practised to lower the level of inbreeding

Question 17

uses of inbreeding

Answer 17

• *inbred lines
• *genetic worth calculation
• *recessive gene elimination
• *form distinct lines from breeding stock

Question 18

prepotency

Answer 18

inbreeding increases prepotency
that is ablity to
**produce offsprings with uniform performance without variation

Question 19

inbreeding depression

Answer 19

• *decrease in inbred performance

* *low heritability traits are affected

Question 20

**1%increase in inbreeding

Answer 20

0.14%reduction in mean value of trait

Question 21

introgression or repeated backcrossing

Answer 21

**incorporate an allele to another population

**initial crossing and successive backcrossing

Question 22

grading up or topcrossing

Answer 22

• **to create a purebred population
• *non purebred females X purebred sires
• ***no selection involved
• **repeated backcrossing involved