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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
strawberries are bright red
Plants are resistant to disease
strawberries are very tasty
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.
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.
If he breeds the two plants together then the offspring
will have a variety of their parent’s 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.
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 (selfpollination). 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).
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)