Breeding Plants

1
Breeding Plants
Look at this list of characteristics of
strawberry plants.
Strawberries rot quickly
Plants will not die in temperatures below 4ºC
strawberries stay fresh for a week after picking
Big strawberries
Plants produce lots of strawberries
Plants are resistant to disease
strawberries are very tasty
strawberries are bright red
strawberries are juicy
Small strawberries
Plants can survive with little water.
Plants have small leaves
Which characteristics are important to a) A
farmer, b) A shopper? If you were a plant
breeder, which 5 characteristics would you like
your new variety of strawberries to have?
Explain your choices.
2
Breeding Plants
A farmer grows two different varieties of
strawberry plant.
Variety A grows small but very tasty strawberries.
Variety B grows large but tasteless strawberries.
Suggest to the farmer what he could do to improve
the quality of his strawberries.
3
Breeding Plants
If he breeds the two plants together then the
offspring will have a variety of their parents
characteristics.
To get the best strawberries (large and tasty)
the farmer must breed together the best two
offspring, and keep repeating this over and over
until he gets the perfect strawberry.
4
Breeding Plants
Farmers can breed two different plants together
by using cross-pollination. First the farmer
must decide which plant is to produce the pollen
(flower A) and which will receive the pollen in
its stigma (flower B). These must be clearly
marked, perhaps with different coloured thread or
a tag. The next step is to ensure that flower B
is not fertilised by its own pollen
(self-pollination). Some farmers remove the
anthers (the male parts, which produce pollen)
with tweezers. They may need a magnifying glass
to do this. To prevent fertilisation from
another flower farmers tie up the petals of the
flower with a piece of string or put a polythene
bag over the flower to protect the
stigma. To cross pollinate the farmer rubs a
paint brush over the anthers of flower A. They
then remove the protector from flower B and rub
the pollen over its stigma. Hopefully
fertilisation will happen and a new plant is made
(a mixture of the characteristics from both
plants).
5
Breeding Plants

• Your task is to write an article for Plant
  Growers Weekly about using selective breeding to
  grow better plants.
• You need to explain
• Why a plant grower should use selective breeding
  and
• How they can carry it out
• Your article must be aimed towards
• A farmer who grows tomatoes to sell to
  supermarkets or
• A person who grows prize-winning tulips to enter
  shows (prize winning tulips have long stems and
  large brightly coloured flowers)