Obama: I married Michelle to improve my gene pool

First Lady Michelle Obama has played a major and at times humorous role on the final day of her husband's three-day bus tour through North Carolina and Virginia.

Joining the president at Joint Base Langley-Eustis in Hampton, Virginia, Mrs. Obama announced a new private sector commitment to hire 25,000 veterans and military spouses by the end of 2013. Improving the lives of the military is one of her causes.

Following the First Lady's introduction, the president went off-script as he commented on his wife. Looking out at a sea of military personnel in battle fatigues, Mr. Obama admitted, "I hate following Michelle. She's so good."

To the laughter of the service people he added, "See for you men out there who are not yet married, let me explain. The whole goal is to marry up--to try to improve your gene pool."

Former President George W. Bush often used the "married up" line when publicly praising his wife Laura or the spouses of other leaders but the Obama "gene pool" comment was a first.

Praising his wife's role to "support and honor our military families," the president added, "she does all this and she looks cute."

There was more banter as the Obamas stopped at a roadside farmer's market in Hampton. Standing near a sign promoting "Pumpkin Patch Open Hayrides," the couple shopped for seasonal offerings. The president told the market owners, "You know Michelle does a good job promoting produce. She tries to get everyone to eat their vegetables." Mrs. Obama hefted a gigantic white pumpkin on to a metal cart. The market owner estimated the big gourd weighed 70 pounds.

"Don't hurt yourself," cautioned the president. As Mrs. Obama loaded another pumpkin, he asked, "how many are you going to buy?" No more, she said, adding, "we'll have enough trouble getting these back."

The president indicated the goods would be stowed in the back of the bus that the media have dubbed "Ground Force One." The pumpkins will be displayed at the door to the White House.

It was a campaign-style photo-op moment on a trip the White House insists is not political.

The president tried to emphasize that point at his veterans's jobs event. "Standing up for our veterans is not a Democratic responsibility or a Republican responsibility -- it is an American responsibility," he said.

Mrs. Obama is increasingly assuming political responsibilities at re-election campaign fundraisers and other events. She often ends her speeches to Democratic backers by asking, "Are you in?" Like many other first ladies, she's definitely "in" as the president's top campaign surrogate.

Tonight, Mrs. Obama will return to a non-political role as she and Jill Biden appear at the World Series opener in St. Louis.

They will participate in a pre-game ceremony honoring the military and their families.