Low turnout expected in today's primary elections [Updated]

A Field Poll released Tuesday morning estimates that only about a third of California's 17 million registered voters will cast ballots in today's primary elections.

Reasons for the expected low turnout include the lack of competition in Democratic races -- neither gubernatorial candidate Jerry Brown nor U.S. Senate incumbent Barbara Boxer have credible competition from within their own party -- and the absence of controversial ballot measures, the pollsters explain.

The poll also estimates that, for the first time, more than half of the ballots, 53%, will be cast by mail. [For the record, 1:14 p.m.: It would not be the first time in California that more than half the ballots would be cast by mail, just the first time in a gubernatorial primary.]

-- Jack Dolan in Sacramento