H Biology - Unit 3 - KA2 - Plant and Animal Breeding

What are desirable characteristics from breeding?

Desirable characteristics from breeding are;

• Higher food yield

• Higher nutritional value

• Pest and disease resistance

• Ability to thrive in particular environmental conditions such as drought and flooding

What is inbreeding?

Inbreeding is breeding of selected related individuals

How is inbreeding carried out?

Inbreeding is carried out by breeding organisms for several generations until the population breeds true to desired type.

What is true breeding?

True breeding is when organisms are homozygous for a trait

What is eliminated through inbreeding?

Through inbreeding, heterozygotes in the population are eliminated

What is inbreeding depression?

Inbreeding depression is an increase in the frequency of individuals in a population that are homozygous for deleterious alleles. These individuals will do less well at surviving to reproduce.

What is crossbreeding in animals?

In animals, crossbreeding is when individuals from different breeds are crossed

What does crossbreeding in animals produce?

Crossbreeding in animals produces a new population with improved characteristics

What is done to the parent breeds of crossbreeds?

The parent breeds of crossbreeds are maintained

What does the maintenance of parent breeds mean?

The maintenance of parent breeds means more crossbred animals with the desired characteristics can be produced

What is crossbreeding in plants?

Crossbreeding in plants is when two inbred plant lines are crossed

What characteristic do both parent plants have in plant crossbreeding?

In plant crossbreeding, both parent plants are homozygous for the trait

What does crossbreeding in plants produce?

Crossbreeding in plants produces heterozygous offspring. The offspring are F1 hybrids.

What do F1 hybrids have?

F1 hybrids have increased vigour

What are examples of increased vigour on plants?

Examples of increased vigour in plants;

• Growing faster and stronger

• Resistance to disease

• Having increased yield so produce more product

What is not usually done with F1 hybrids?

F1 hybrids are not usually bred together

Why are F1 hybrids not usually bred together?

F1 hybrids are not usually bred together because resulting offspring would show too much variation

What is done in field trials to ensure validity?

In field trials to ensure validity only one variable can be changed

What must the treatment applied to the plots in field trials allow for?

The treatment applied to plots in field trials must allow for valid comparisons

What must be taken into account to ensure reliability in field trials?

To ensure reliability in field trials, since not every plant is the same, there must be multiple plants in the plots (replicates). This takes into account the variability of plants in the plot

For experimenter bias when measuring results to be eliminated in field trials what must be done?

To eliminate experimenter bias when measuring results in field trials, the treatment applied must be randomised

What does randomising the treatment applied to the crops do?

Randomising the treatment applied to the crops eliminates experimenter bias when measuring results

What can genome sequencing be used to do in plant and animal breeding?

In plant and animal breeding genome sequencing can be used to identify organisms with desired genes such as high milk yield or high muscle mass

What can organisms with desired genes identified by genome sequencing be used in?

Organisms with desired genes identified by genome sequencing can be used in breeding programmes

What can recombinant DNA technology be used for with crop plants?

Recombinant DNA technology can be used to insert single genes into the genomes of crop plants. This creates genetically modified plants

What do genetically modified plants have?

Genetically modified plants have improved characteristics such as pest resistance

What can genetically modified plants be used in?

Genetically modified plants can be used in breeding programmes

What are examples of uses of recombinant DNA technology in plants?

Examples of uses of recombinant DNA technology in plants are;

• The insertion of Bt toxin gene into plants to provide pest resistance

• The insertion of Glyphosate resistance into plants to make them tolerant of weed killers