GRU Information Resource 1: Guide to how to cross peas.wmv

This practical guide takes you through how to perform crosses in peas starting with the selection of flower buds at the right developmental stage to act as female recipients, through the removal of petals and stamens and going on to a quick method of preparing male flowers to apply pollen to the stigmatic surface. The whole process is repeated in close up together with a commentary and running captions to help show how to perform successful crosses.
Cultivated peas are inbreeding with the anthers bursting and releasing pollen directly onto the stigmatic surface well before the flowers fully open. In order to cross peas therefore you have to start with flower buds at a very early stage. Once selected, the petals are removed followed by the stamens with the intact anthers in the process known as emasculation. This leaves the rudimentary carpel, style and the stigmatic surface ready to receive pollen. The stigma is receptive from this early stage so pollination with pollen from a male donor flower can be performed immediately following emasculation providing the pollen is in good condition ie. bright yellow and clumpy.
At temperatures of around 150 C the success of your pollinations will become apparent in three days when the carpel will start to extend. After two weeks the young pod will reach it's full length and you should be able to see the small developing ovules through the pod wall if you hold the pod up to the light. Under normal weather conditions the success rate of crosses is frequently 100%. In hot weather the process is speeded up so flowers need to be sources at an earlier stage. Under these conditions flowers are often much smaller and pollen production is lower so the procedure is slightly more difficult but success rates of 60% can still be expected.
Mendel chose peas for his studies on the inheritance of characteristics partly because the flowers are large and easy to handle and secondly because the pollination process could be so well controlled. It really is straightforward so why not have a go and start combining characters from different lines.