The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

inheritance and Variation

it’s very difficult to get red flowering pea plants that breed true. explain why you cannot guarantee to breed by self pollination pea plants that only have red flowers
Reply 1
Avatar for BDavies1
BDavies1
8
"breed true"- means when you cross red-flowered plants with red-flowered plants, you only get red-flowered offspring

often if you cross red with red you get white-flowered offspring

R-allele for Red flowers 9dominant)
r allele for white flowers (recessive)

This is because the allele for red flowers is dominant, so red plants may be RR (homozygous dominant) or Rr heterozygous.

If you cross two Rr plants (red flowers), you can show using a cross diagram that 25% of offspring are rr so will have white flowers.

Second part of your question "you cannot guarantee to breed by self pollination pea plants that only have red flowers" if you self pollinate a plant with red flowers that is Rr you are effectively doing Rr x Rr cross so you will get 25% white

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you