"Gene movement from crops to their wild relatives is an ongoing process that can spur rapid evolutionary adaptation in weeds that will be ultimately harmful to crops," Snow said.
Snow presented the findings August 9 in Madison, Wisc. at the annual Ecological Society of America meeting.
The researchers studied four populations of hybrid and wild radish for six years in Michigan. At the outset, each field consisted of 100 first-generation crop-wild radish hybrids and 100 wild radishes. To monitor the continuation of crop radish genes in the populations, the researchers looked for four genetic traits: two enzymes, flower color and pollen fertility.
On average, the wild radishes reached peak flowering one month before the hybrid plants. The hybrids also produced fewer seeds per fruit than wild plants and fewer viable pollen grains. A large portion of hybrids never produced fruits (60 to 78 percent), while 92 to 97 percent of the wild plants did.
Even so, traits from the original crop - such as white flower color - persisted in subsequent generations of hybrid radishes.
"Even though the effects of delayed flowering and reduced fertility inhibited the movement of certain crop traits to later generations, we did find evidence of crop genes in every generation," Snow said.