Maryland Gov. Martin O’Malley (D) set aside $4.3 million in his new $39 billion budget to increase the number of 4-year-olds who can enroll in public pre-kindergarten classes. The administration proposed Thursday raising the family income cap so that more children can qualify, a change they hope will allow 1,600 more 4-year-olds to enroll.

Already, Maryland public school systems are required to offer pre-kindergarten to economically disadvantaged or homeless 4-year-olds. To qualify currently, the child’s family must make less than 185 percent of the federal government’s definition of poverty. For a single parent, that would mean making about $28,693 or less. For a family of four, about $43,567 or less. For the 2012-2013 school year, more than 26,400 4-year-olds were enrolled.

The administration wants Maryland to increase the income cap to 300 percent of the poverty rate. For a single parent, that would mean making up to $46,530. For a family of four, up to $70,650. The administration says they have also included money to expand some half-day programs to full-day ones and, in some cases, provide care for up to 12 hours a day at designated centers.

Maryland Lt. Governor Anthony G. Brown (D), who announced the proposal Thursday morning, said that expanding access to pre-kindergarten will help close the achievement gap between poor students and those whose families are more financially stable.

“Look: There’s a difference between a student, a child who starts kindergarten with a 3,000-word vocabulary or 8,000-word vocabulary,” Brown said. “We know that difference is already on display. It’s witnessed in kindergarten, and by fourth grade it’s a meaningful difference as measured in a child’s performance. And by the time the children get to 12th grade, that difference equals significant differences in career options available to those students.”

Brown was joined by Senate President Thomas V. Mike Miller Jr. (D-Charles) and House Speaker Michael E. Busch (D-Anne Arundel), who both pledged their support for the proposal.

Pre-kindergarten has become a common issue between democratic candidates for governor who will face off in a primary June 24. Brown has proposed making pre-kindergarten available to all 4-year-olds, regardless of family income, by 2018. That proposal is estimated to cost about $138 million a year and would likely be covered by proceeds from Maryland’s gambling program.

Attorney General Douglas F. Gansler (D) has pledged to expand the state’s current pre-kindergarten offerings from half-day to full-day programs and increase the eligibility requirement to 300 percent of the poverty definition. Such an expansion would cost about $20 million a year and would be funded with gambling proceeds budgeted from the horse-racing industry.

Del. Heather R. Mizeur (D-Montgomery) has proposed phasing in full-day pre-K programs for all 4-year-olds and half-day programs for 3-year-olds from lower-income families. The cost of the initiative, once fully implemented, would be close to $280 million a year. She suggests that Maryland legalize marijuana and use the tax revenue it generates to fund pre-kindergarten education.