Corinne, in the Netherlands asked:
Where do seedless grapes come from?
The correct answer is that the plants that grow them are actually clones. So instead of growing them from seeds, they're grown from cuttings taken from existing plants.
Obviously, the first seedless grapes were from a plant that arose through mutation - a genetic change - that meant that it didn't have seeds. And, presumably, some grower noticed this. He or she would have taken a little shoot or a stem off the plant, put it in the ground, and a new plant - genetically identical to the seedless parent - would have grown.
In fact, this is how a lot of plants are cultivated now, and also a lot of seedless varieties. But, this technique is causing problems in some cases. Bananas, because they're all clones, are getting struck down by fungi - like Panama disease.
And if a population is created by cloning, all of the plants are genetically identical, so they can very easily be wiped out because the plants have the same defences to a pathogen. And if the pathogen evolves to sumount this defence, every cloned plant is susceptible...
Apparently the seedless grapes are descended from a natural mutation causing "aborted seeds". Commercial grown seedless grapes are then treated with the hormones that naturally would have occurred with seeds to produce larger fruits.
Growing fruit from seed can be a long drawn-out affair, particularly in the case of trees. Take a peach stone and plant it in a pot, see how many years it will take before the new tree produces a commercialy viable crop. Alternatively, take a cutting from a peach tree and graft it on to a stock root and you will have a commercialy viable crop in perhaps half the time. The same applies to vines and fruiting bushes. Growing a raspberry bush from seed will take longer than growing from a cutting, or 'stick'.
Cuttings will presumably slowly mutate over time, so potentially one could select the best graft/cutting propagated plants for future planting. However, seed grown plants will certainly have more crop variability, and thus greater potential for selecting beneficial traits. Presumably a research facility will use a combination of cutting propagation and seed propagation.
can anybody tell me when the first seedless grapes would have hit the markets? unnamed, Tue, 11th Feb 2014