3.2 Animal and Plant breeding

Question 1

Selective breeding

Answer 1

Breeding programmes set up to improve characteristics of organisms to help sustainable food production

Breeders developed crops and animals with higher yields, higher nutritional values, pest and disease resistance and ability to thrive in particular environmental conditions

Question 2

Desirable characteristics for crops

Answer 2

Higher nutritional values

Quick growth

High crop yield

Question 3

Desirable characteristics for livestock

Answer 3

Higher nutritional values

Quick growth

Resistant to disease

Question 4

Plant field trials

Answer 4

Carried out in different environments to compare performance of different cultivators or treatments and evaluate GM crops

Factors to consider when designing: selection of treatments, number of replicates, randomisation of treatments

Question 5

Inbreeding

Answer 5

Fusion of two gametes from close relatives

Selected related plants or animals bred for several generations until population breeds true to desired type and heterozygotes eliminated

Increase in the frequency in individuals who are
homozygous for recessive deleterious alleles

Individuals will do less well at surviving to reproduce, resulting in inbreeding depression

Question 6

Crossbreeding

Answer 6

F1 hybrid is an individual from a cross between two genetically dissimilar parents

It attempts to produce a hybrid that has both desirable characteristics

Hybrid vigour is the increase in: vigour, yield, fertility

Question 7

Genetic technology

Answer 7

Single genes for desirable characteristics inserted into genomes of crop plants, creates genetically modified plants with improved characteristics

Recombinant DNA technology in plant breeding- insertion of Bt toxin gene into plants for pest resistance, glyphosate resistance gene inserted for herbicide tolerance