Connecticut needs to commit $100 million for stem cell research if it wants to compete for the best researchers in the pioneering field, scientists from Yale and the University of Connecticut said. That’s five times more than the $20 million, two-year plan proposed by Gov. M. Jodi Rell, but two of the state’s top scientists said researchers won’t choose Connecticut without a long-term commitment, especially with California pumping $3 billion into stem cell research.