Re: How could you start a field of seedless grapes without vegtativepropagation

Seedless grapes cultivars are vegetatively propagated by grafting or 
rooting of stem cuttings. Grape breeders use a tissue culture technique 
called embryo rescue to save the developing embryo before it dies. The 
grape breeders can then use the seedling in breeding because seedless 
grapes produce functional flowers. 

If you look inside a seedless grape fruit, you can find the remains of the 
embryo(s). Seedless grapes requires pollination and fertilization to set 
fruit, but the embryo dies before the seed is fully developed. This type of 
seedless fruit formation is called stenspermocarpy. Most seedless fruits 
are formed by parthenocarpy in which fertilization is not required.

Another interesting question is where do the seeds to grow seedless 
watermelon come from? A diploid (2N) and tetraploid (4N) are crossed to 
produce triploid (3N) seeds. The triploid produces seedless fruit but 
requires pollination from a diploid because the triploid does not produce 
pollen.