wild roadside Seedlings free of virus load
Grafting, a process in which two young plants are joined together, is the most common method of propagating fruit cultivars.
It also provides an opportunity for plant virus transmission.
Over the hundred of years and countless generations of grafting heirloom/heritage fruit cultivars, a 'virus load' has built up in many of our popular modern fruit varieties. 'Golden Delicious' apples, for example, generally carry apple mosaic virus.
Most plant viruses have to be introduced into the plant's cells via vector organisms (eg. bacteria, fungi, nematodes, insects) or via human intervention. Every time someone uses unsterilised secateurs to cut a piece of scion wood, or to prune their fruit trees, they risk transmitting more viruses to the next generation of grafted fruit plants.
Such viruses cannot be eradicated, other than by using very expensive laboratory methods that focus on tissue cultures. They simply build up, year after year, decade after decade, in the tissue of the cultivar, passed on by grafting.
Plant infected by viruses can show the following symptoms:
Dwarfing or stunting
Leaf curling
Reduced crop yield
Fruit distortion
Chlorosis (yellowing)
Other colour deviations (eg. variegation of leaves or petals)
'Mosaic' patterns on leaves
Ring-shaped spots on leaves
Wilting and withering
Necrosis (black or greyish-brown discolouration due to the deaths of cells and tissues)
Bark scaling.
Viral infections rarely kill the plant. Most plant viruses multiply at the site of infection, giving rise to localised symptoms such as necrotic lesions on leaves. Plant viruses cause important plant diseases that cause huge losses in crop production and quality in all parts of the world.They cannot be directly controlled by chemical application.
Source: 'Understanding Viruses' By Teri Shors.
Most seedlings are free of viruses.
This is another reason why our wild roadside seedlings are so important - they are usually virus-free!
It also provides an opportunity for plant virus transmission.
Over the hundred of years and countless generations of grafting heirloom/heritage fruit cultivars, a 'virus load' has built up in many of our popular modern fruit varieties. 'Golden Delicious' apples, for example, generally carry apple mosaic virus.
Most plant viruses have to be introduced into the plant's cells via vector organisms (eg. bacteria, fungi, nematodes, insects) or via human intervention. Every time someone uses unsterilised secateurs to cut a piece of scion wood, or to prune their fruit trees, they risk transmitting more viruses to the next generation of grafted fruit plants.
Such viruses cannot be eradicated, other than by using very expensive laboratory methods that focus on tissue cultures. They simply build up, year after year, decade after decade, in the tissue of the cultivar, passed on by grafting.
Plant infected by viruses can show the following symptoms:
Dwarfing or stunting
Leaf curling
Reduced crop yield
Fruit distortion
Chlorosis (yellowing)
Other colour deviations (eg. variegation of leaves or petals)
'Mosaic' patterns on leaves
Ring-shaped spots on leaves
Wilting and withering
Necrosis (black or greyish-brown discolouration due to the deaths of cells and tissues)
Bark scaling.
Viral infections rarely kill the plant. Most plant viruses multiply at the site of infection, giving rise to localised symptoms such as necrotic lesions on leaves. Plant viruses cause important plant diseases that cause huge losses in crop production and quality in all parts of the world.They cannot be directly controlled by chemical application.
Source: 'Understanding Viruses' By Teri Shors.
Most seedlings are free of viruses.
This is another reason why our wild roadside seedlings are so important - they are usually virus-free!