* Apple-related shares underperform after Apple shares tumble * Yen level in focus until G20 outcome - analysts * Nomura expects Nikkei to trade 14,500 in June By Ayai Tomisawa TOKYO, April 18 (Reuters) - Japan's Nikkei share average fell on Thursday as exporters lost ground on worries about global growth while Apple-linked shares underperformed on concerns of slowing sales of the iPhone maker's products. The Nikkei dropped 1.3 percent to 13,215.62, with a short-term resistance level pegged at its 5-day moving average of 13,317.42. Exporters faltered, with Toyota Motor Corp losing 2.0 percent and Sony Corp dropping 1.5 percent. Apple-related stocks underperformed after the iPhone maker's shares dropped in New York, with Toshiba Corp falling 2.3 percent, Murata Manufacturing Co dropping 2.0 percent and Ibiden Co shedding 2.7 percent. Apple's shares were hurt after a key supplier, chipmaker Cirrus Logic , gave a disappointing revenue forecast, fueling worries about weakening demand for the iPhone and iPad. Overnight, European shares fell to their lowest levels so far this year on fresh concerns over the global economy. Investors are also likely to keep an eye on the weekend meeting of officials from the Group of 20 nations. While Japan isn't expected to face criticism for its aggressive monetary expansion campaign that has weakened the yen, analysts said that investors remain wary. "Whether international leaders will agree that Japan's push to reflate the economy with bold monetary policy will benefit other countries is in focus," said Kenichi Hirano, a strategist at Tachibana Securities. "The market will probably stay nervous until the outcome." The Topix dropped 1.0 percent to 1,124 53. The Nikkei has gained over 50 percent since Prime Minister Shinzo Abe called for sweeping fiscal and monetary expansionary policies in November, sending the yen to four-year lows of close to 100 to the dollar. Market observers said that the Nikkei's gains may pause 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 the ministry started collecting the data in 2005, buoyed by the Bank of Japan's bold 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. "There is a risk of global markets' possibly showing further slowdown in their economies such as the U.S. and China. But Japanese companies' forecasts are seen bright, so investors will likely see buying opportunities in Japanese equities in the coming months," said Hiromichi Tamura, chief strategist at Nomura Securities, adding that he expects the Nikkei to trade around 14,500 in June.