Consider two identical plants. One is struggling in poor soil, the other is luxuriating in rich soil. Pollen -- the plant equivalent of male sperm -- is taken from each and used to pollinate flowers.

Should there be any difference between the offspring of the two males?

Classical genetics would say no. The genetic "fitness" of the pollen should be equal. While the female's environment often affects the success of her offspring, the male's contribution has been thought to be strictly genetic.

But in a report in last week's Science, researchers from the University of California at Davis and Barnard College present evidence that the male's environment does matter.

Using radishes, they showed that pollen from the poorer environment could not compete well against pollen from the richer environment. When pollen from both sources was placed on the same flower, the pollen from the good environment sired more seeds.

"You can't ignore the role of the environment," said Maureen Stanton, the Davis botantist who did the research with Barnard's Helen J. Young. "The environment, in this case, significantly affects paternity."

Stanton said that her findings will be useful to plant breeders. They have long known that the conditions under which pollen is stored affect its viability. Breeders, she says, may also need to control the conditions under which the pollen is produced.