Pollen from the genetically engineered 'HoneySweet' (Prunus domestica) plum won't contaminate wild plum species the way that pollen from genetically engineered corn has contaminated native corn in Mexico. But where it lands is sure to create controversy.

The 'HoneySweet' is unlikely to cross with native or wild varieties of plums because it has more chromosomes than the natives. "The probability of hybridizing with native plums is low," says Dan Parfitt of UC Davis' pomology department.

Nor is it likely to cross with other stone fruits like peaches or apricots. (The pluot is a cross between an apricot and a diploid Prunus salicina-type plum, not the P. domestica.)

But when bees and other pollinating insects carry 'HoneySweet' pollen to organic or conventional P. domestica plums, one of the most commonly grown species of plum worldwide, cross-pollination will occur. Again, however, with results that differ somewhat from cross-pollination in corn.

Even if we eat plums from trees that have inadvertently been pollinated by the 'HoneySweet,' we won't consume any transgenes from the 'HoneySweet' because the skin and flesh of plums contain only maternal genes (genes from the tree the plum is hanging on). Only the inedible plum seeds will contain both maternal and paternal genes.

In the case of corn, the parts of the plant that we eat, the kernels, are the seeds of the plant. Like the plum seed, corn kernels contain genes not only from the plant they grew on, but any "paternal" genes that might have drifted in during pollination as well.

The FDA does not require genetically engineered packaged and whole foods to be labeled. Those who don't want to eat genetically engineered foods must buy certified organic. Yet, because of pollen drift, an organic crop may contain transgenes.

In the case of plums, however, consumers who eat certified organic plums don't have to worry about eating transgenes, even if the organic field was contaminated by genetically engineered plum pollen (assuming they don't eat the pits or try to grow a new tree from them).