Centres of cultivated plants and selection methods
Answers are for parents and teachers.
1
List the main methods of selection and give an example of each.
Selection (pure line), hybridisation (triticale), mutagenesis, polyploidy, heterosis.
2
Two lines yield 40 and 44 c/ha and the F1 hybrid 50 c/ha. How much is the heterosis gain over the parents’ mean?
8
3
Why is individual selection used mostly in animal selection?
Animals have few offspring and are costly, so each individual is assessed separately.
4
What function do seed banks serve?
They keep crop diversity and are a source of genes for creating resistant varieties in future.
5
Write three of Vavilov’s centres with their crops.
For example: South America — potato; Central America — maize; South Asia — rice.