Gardening: What climate change means for our apple trees

As with everything else in life, climate change is beginning to affect how apple trees grow, so we need to choose trees that can cope with our Scottish weather, bearing in mind that weather patterns are increasingly unpredictable. Although we’re enduring some extreme conditions they’re much less severe than elsewhere.
Many of us, including me, complained about the frost damage to apple blossom this spring, leading to reduced yield. Some of my trees, like Tower of Glamis and White Melrose, got a pasting. 
But this was nothing compared to the devastating drought endured by Spanish growers. With the accompanying water shortage, some Catalans came close to stripping their trees and losing their entire harvest to protect the long-term future of the trees. Luckily the rains came in time. 
These problems are leading to the need for new varieties that can handle temperatures in excess of 40℃. And over the lifetime of an apple tree – 80-140 years – things could get a lot worse, probably significantly worse than for us.
Unfortunately, traditional apple breeding takes 20 to 25 years of research to find, select, grow and ratify a new variety. A breeder might be lucky to produce one new variety in a lifetime. But luckily we are at the beginning of a new phase of plant breeding through gene editing. This process entails manipulating the individual parts, or nucleotides, of a plant’s genome and unlike genetic modification, it does not involve introducing one or more nucleotides from a different species.
A strand of apple DNA comprises 750 million nucleotides or letters. It’s estimated that 25 million of these nucleotides can significantly alter an apple’s taste, appearance and growth when one or more of these letters are moved to a different position within the genome. 
An agricultural research centre in Bern, Switzerland, has been pioneering work in this field. By studying 500 different apple varieties, the researchers could identify nucleotides that affect the key parts of a variety’s citrate, fructose and sucrose and, therefore, an apple’s flavour. 
Genetic editing is in its infancy, but we can hope this process will give us varieties resilient to the weather changes we are beginning to endure.
In the meantime the best option is to select varieties that work well in Scotland just now. Undoubtedly Andrew Lear, the apple tree man, based at Blackhaugh Farm in Spittalfield, Perthshire, is best placed to give advice (plantsandapples.com). 
His wide selection of trees suitable for this country include Scottish heirloom varieties such as Arbroath Oslin and Lass o’ Gowrie. 
And who could resist Bloody Ploughman? The tree reputedly grew from a seedling that had emerged from the bones of a ploughman shot while scrumping apples at Megginch Castle, Perthshire. The apples’ dark red skins tell it all.