Plant and Animal Breeding Flashcards
What are plant field trials?
Plant field trials are carried out in a range of environments to compare the performance of different cultivars or treatments and to evaluate GM crops.
Describe how they are designed.
In designing field trials account has to be taken of: the selection of treatments to ensure valid comparisons, the number of replicates to take account of the variability within the sample and the randomisation of treatments to eliminate bias when measuring treatment effects.
Why do breeders inbreed crops and livestock?
In inbreeding, selected related plants or animals are bred for several generations until the population breeds true to the desired type due to the elimination of heterozygotes.
What are the problems with inbreeding?
A result of inbreeding can be an increase in the frequency of individuals who are homozygous for recessive deleterious alleles. These individuals will do less well at surviving to reproduce. This results in inbreeding depression.
Why do breeders crossbreed crops and livestock?
In animals, individuals from different breeds may produce a new crossbreed population with improved characteristics. The two parent breeds can be maintained to produce more crossbred animals showing the improved characteristic.New alleles can be introduced to plant and animal lines by crossing a cultivar or breed with an individual with a different, desired genotype.
Why is it good to crossbreed to F1 plant hybrids?
In plants, F1 hybrids, produced by the crossing of two different inbred lines, create a relatively uniform heterozygous crop. F1 hybrids often have increased vigour and yield. Plants with increased vigour may have increased disease resistance or increased growth rate.
How is genome sequencing used in breeding programs?
As a result of genome sequencing, organisms with desirable genes can be identified and then used in breeding programmes. Single genes for desirable characteristics can be inserted into the genomes of crop plants, creating genetically modified plants with improved characteristics.
Name two examples of recombinant DNA technology?
Recombinant DNA technology in plant breeding includes insertion of Bt toxin gene into plants for pest resistance and glyphosate resistance gene inserted for herbicide tolerance.
