Questions We're Often Asked: Seedless Fruit

Sooner or later a curious kid will inquire: why does some fruit have seeds and others don't? Even more embarrassing is the follow up: if there are no seeds, where do the plants come from? The answer, like the question, is two-fold. One dates back to the dawning of horticulture. The other emerged from recent discoveries in plant genetics.

---

Many millennia ago a grape vine, being like all grapes not particularly genetically stable, produced some fruit that were sans seeds. An observant horticulturist must have realized the commercial possibilities. Propagating vegetatively, by cuttings or grafting, would have preserved the seedless feature. Grafting was certainly known to ancient Greek writers and most likely, as with cuttings, was practiced eons earlier. So, no more messy spitting of seeds, doubtless welcomed by servants if later abhorred by archaeologists. Although grapes are found across the Northern Hemisphere, dessert and wine grapes appear to have been developed in areas east of the Black Sea. Oranges, lemons and limes, however, originated in today's China--with the same result. Careful selection produced progressively fruit lower in seeds or even completely seedless. Often the these were larger, juicier and even more flavoursome than the original wild forms. Elsewhere, tangerines, bananas, pineapples even breadfruit have all been forced to surrender their seeds until today it is often hard to find them containing any at all. But how about seedless watermelons, the persistent child asks. Here it gets a trifle more complicated. Seedless watermelons are raised commercially from seeds produced by crossing diploid and tetraploid lines of the fruit so that the resulting seeds produce sterile diploid plants. The catch here is that a row of the normal seedy diploid strain must be grown alongside to pollinate them. However, the trouble is rewarded in premium-priced (seedless) produce.

---