Natalie Barb reports for BBC News 24

Scientists from the John Innes Centre in Norwich have identified the gene responsible for the unpleasant aroma and, by crossing the pea with an exotic cousin, have managed to breed it out.

The smell is a by-product of the pea's self defence mechanism. Plants produces enzymes, known as Lipoxgenases which engage in various chemical reactions that are designed to protect the plants when they are wounded or come under attack from pests.

It has taken many years of hard work by Dr Rod Casey

The smells produced in these reactions are not always unpleasant but they do appear very quickly - such as with freshly mown grass.

Dr Rod Casey from the Norwich centre says peas are no different in this respect.

"As soon as the pea is harvested - and it's either you doing it in your garden or a company doing it in a field - enzymes begin to act and they generate all sorts of chemicals including these small chemicals that we then perceive as "off" flavours.

"There are two ways around this. One of which is virtually impossible - that you instantly freeze the pea, which you can't do. Or you try to do something to minimise that enzyme activity, and that way is to biologically remove it."

Peas from the Middle East provided the answer

The John Innes researchers analysed the peas to understand the chemical processes at work. They managed to identify the specific gene responsible and were able to eliminate it using controlled cross-breeding techniques.

The variety of pea used to breed out the unwanted behaviour was found in the centre's vast library of seeds - they have a record of more than 3,000 pea varieties in their germ plasm bank. It comes from the Middle East.

"They don't look anything like the sort of pea we are accustomed to seeing," says Dr Casey. "They're jet black, they're rock hard and very difficult to deal with."