The British are a nation of gardeners. And as the memories of Winter fade (although still hanging on from day to day), and Spring exerts her influence daily, it is really wonderful to see all the gardens coming into bloom. Each day there is something new to see. The fine display of snowdrops and crocuses has been over for a few weeks now, but soon all the daffodils will be in flower, their golden trumpets nodding in the breeze of a typical March day. Then they will be followed by tulips in all their glory – my favorite Spring flowers. I’ve already seen primroses during my daily constitutional, and oxslips are now opening in our garden. These floral displays are surely food for the soul, and it’s no coincidence that I made the decision, several decades ago, to become a professional botanist.
Each year, many new flower varieties are released for everyone to admire and enjoy in their own gardens. Just look at this exquisite display of daffodil varieties that I photographed at the Chelsea Flower Show a couple of years ago.
Nevertheless, plant enthusiasts always seem to want what the natural world doesn’t easily give them: the red delphinium, the blue rose, the black tulip, and even a yellow sweetpea (Lathyrus odoratus).
Although many if not most delphiniums are that beautiful blue, red-flowered varieties are now quite common. Plant breeders must have searched for ‘red’ genes in related species. Black tulips have been around for centuries. However, a really deep blue rose remains elusive. The so-called ‘blue’ roses are but a pale imitation of blue, more a pale mauve.
But a yellow sweetpea (Lathyrus odoratus)? From images I’ve viewed on the web, many are not true sweetpeas but other species of Lathyrus. It seems, however, that some creamy-yellow varieties have been developed, although a deep yellow one has not yet been produced that I could sniff out. Most are are white, red, pink, blue, or purple, and shades in between, and most of the varieties on the market have large, blousy and delicately fragrant blooms.
In the 1980s, when I was working at the University of Birmingham, a Malaysian student of mine, Dr Abdul bin Ghani Yunus, made a study of Lathyrus sativus, a common food grain legume in several parts of the world, particularly India and Ethiopia. It’s a so-called ‘ famine legume’, known commonly as khesari dahl, as it can survive and produce seeds under conditions where other crops fail. But it has an important major drawback: the seeds contain a neurotoxin, which can cause an irreversible paralysis if consumed without proper preparation of the seeds before cooking.
Our research was not, I hasten to add, concerned with producing a safer variety – although these have now been developed by a number of research institutes. Rather, we wanted to try and understand the origin of this crop species, and its relationships with other Lathyrus species. And to do that, we assembled a large number of seed samples of as many Lathyrus species as we could obtain from research institutes and botanical gardens around the world.
Ghani’s doctoral thesis focused on the biosystematics of Lathyrus sativus, and included making crosses with several species with yellow flowers . And I still don’t know how it came about, but I was approached by someone from a ‘local’ sweetpea society who asked if we could attempt crosses between these yellow-flowered species and the sweetpea. We did make a few crosses, all unsuccessful I’m sorry to say, but we didn’t have the time or the resources to translate this hobby approach into a meaningful hybridization exercise. I’ve often wondered whether sweetpea breeders ever followed up on what we attempted three decades ago. If they did, I assume they had as little success as Ghani and I did using the yellow Lathyrus types, all of which had rather small flowers.
Breeders of food plants aim to produce healthier, more disease and pest resistant types, resilient to climate change, with better nutritional qualities, and higher yielding. Their aim is to sustain agricultural productivity, and ensure we have enough food to fill our stomachs.
Flower breeders also look for healthier and disease resistant varieties. But they also aim to produce new forms with brighter colours, bigger blooms, and more fragrant where possible, and as such, they are breeding plants as ‘food for the soul’. Just look at what the flower breeders have done in recent years. Aren’t we fortunate?
 Yunus, A.G. & M.T. Jackson, 1991. The gene pools of the grasspea (Lathyrus sativus L.). Plant Breeding 106, 319-328.