* Yen level in focus until G20 outcome - analysts * Blue-chip exporters fall, small-caps limit downside * Apple suppliers under pressure after Apple's share tumbles * Nomura see Nikkei at around 14,500 in June By Tomo Uetake TOKYO, April 18 (Reuters) - Japan's Nikkei share average retreated on Thursday morning as exporters lost ground on worries about global growth while Apple-linked shares came under pressure on concerns of slowing sales of the iPhone maker's products. The Nikkei fell 0.4 percent to 13,329.36 at the midday break, after dropping as much as 1.4 percent to 13,200.85 during the morning session. Blue-chip exporters faltered, with Toyota Motor Corp losing 1.3 percent and Nikon Corp dropping 1.6 percent. Apple Inc's suppliers in Japan also underperformed the overall market after the tech giant's stock tumbled 5.5 percentin New York as a key supplier, chipmaker Cirrus Logic , gave a disappointing revenue forecast, fuelling worries about weakening demand for the iPhone and iPad. Shares of Toshiba Corp, Murata Manufacturing Co , Ibiden Co and Nitto Denko Corp - all of which are Apple suppliers - shed between 1.4 and 1.9 percent. Overnight, European shares fell to their lowest levels this year on fresh concerns over the global economy. Investors will be watching the weekend meeting of officials from the Group of 20 leading economies. While Japan is not expected to face criticism for its aggressive monetary expansion campaign that has weakened the yen, analysts said investors remain wary. Kenichi Hirano, a strategist at Tachibana Securities, said one focus of the G20 meeting will be whether other countries can benefit from Japan's push to reflate its economy through bold monetary policy. "The market will probably stay nervous until the outcome," he said. The Topix dropped 0.1 percent to 1,134.53. The index was down as much as 1.2 percent early in the day. "The underlying trend is not negative at all. Small-caps are performing quite well today," said Mitsushige Akino, executive director and chief fund manager at Ichiyoshi Asset Management. "Although a wait-and-see mood prevails in the market ahead of the G20 meeting, retail investors and some hedge funds are buying small-caps aggressively and such move limit the downside," he said. DREAMLINER HOPES FOR GS YUASA GS Yuasa Corp bucked Thursday's trend, jumping 7.6 percent. Sources familiar with the matter told Reuters that U.S. regulators are close to approving a key document that could start the process of returning Boeing Co's grounded 787 Dreamliner to service within weeks. GS Yuasa makes lithium batteries for the jet. Shares of All Nippon Airways Co Ltd, the biggest customer for the grounded 787 Dreamliner, rose 4.1 percent, while Japan Airlines Co Ltd added 0.2 percent. The Nikkei has gained more than 50 percent since November, when Shinzo Abe called for sweeping fiscal and monetary expansionary policies. Abe later become prime minister, and his policies have sent the yen to four-year lows of close to 100 to the dollar. Market observers said that the Nikkei won't rise further until companies' full-year earnings for the last business year and forecasts for the current year are out in May. But many traders expect further gains in the mid-to-long term. On Thursday, finance ministry data showed that foreign investors' net buying of Japanese equities hit the highest last week since collection of such data began in 2005, buoyed by the Bank of Japan's stimulus measures unveiled on April 4. They bought 1.57 trillion yen ($16.1 billion) worth of Japanese stocks in the week through April 13, the data showed. While some economies and global markets may slow, Japanese companies have bright forecasts "so investors will likely see buying opportunities in Japanese equities in the coming months," said Hiromichi Tamura, chief strategist at Nomura Securities. He expects the Nikkei to trade around 14,500 in June.