Onions are not the most difficult vegetables to grow but there's one problem which can destroy a whole crop in no time - downy mildew. So as we're all now so reluctant to spray our vegetables the arrival of the first onion variety which is resistant to downy mildew is quite a breakthrough.
‘Santero' is a ‘Rijnsburger' type onion with coppery, round to oval bulbs. It's an early maincrop onion for planting in spring as sets and compares well with other varieties of this type - with the addition of that invaluable disease resistance.
Research on creating a downy mildew resistant onion began in the 1980s. Natural resistance to downy mildew was found in a wild species of onion growing in rocky places in the Mediterranean region, Allium amethystinum, which is occasionally seen in gardens. Its resistance was transferred across into our familiar onions using traditional plant breeding techniques but it took a great deal of work to retain all the good growing and cooking qualities of our garden onions and only the disease resistance from the wild species.
Fortunately, you can now order onion ‘Santero' from Thompson and Morgan for spring planting.
Update: And it's now also available from Dobies.