GLOBAL MARKETS-Asia shares, commodities rattled by weaker China flash HSBC PMI Stocks other riskier assets lose ground after China HSBC PMI Flash manufacturing PMI falls to 50.5 in April from 51.6 in March Dollar weighed by weak US housing data, eyes still on 100 yen mark Nikkei eases as yen decline stalls By Chikako Mogi TOKYO, April 23 (Reuters) - Asian shares and other riskier assets lost ground on Tuesday after a preliminary reading showed manufacturing growth in China slowed in April, highlighting recent market concerns about global growth prospects. The flash HSBC Purchasing Managers' Index for April fell to 50.5 in April from 51.6 in March, but was still stronger than February's reading of 50.4. The HSBC report was China's first economic indicator for the second quarter and followed weaker-than-expected growth in first-quarter gross domestic product reported earlier this month, which triggered a sharp market sell-off last week. New export orders contracted, pointing to fragile global demand. "No doubt the market was hoping for a PMI reading closer to 51.5 and while the 50.5 result today is not disastrous, it does reinforce market concerns about the state of growth in the Chinese economy at the moment," said Tim Waterer, senior trader at CMC Markets in Sydney. I am not surprised at the downward reaction by risk assets ... Because a lot of the market rally so far in 2013 has been premised on a strong Chinese economic recovery, this takes away some of that buying enthusiasm. MSCI's broadest index of Asia-Pacific shares outside Japan fell 0.3 percent from around a neutral level before the Chinese data was released. Shares in Australia which is highly sensitive to economic indicators from China, its largest trading partner, were up 1 percent, losing some gains from a 1.3 percent rise before the data. The Australian dollar hit a session low of $1.0222 from around $1.0248 before the data. Chinese shares deepened losses, with Hong Kong slipping 0.8 percent and Shanghai falling 1.4 percent. Weaker-than-expected U.S. existing home sales data overnight added to worries over prospects for the U.S. economy, focusing even more scrutiny on China. China's Ministry of Industry and Information Technology said on Tuesday that companies have no strong desire to invest and face insufficient demand, noting China's economy faces unstable and uncertain factors at home and abroad. Japan's Nikkei stock average slipped 0.1 percent after surging as much as 2.2 percent to nearly five-year highs on Monday. The dollar traded around 99.02 yen, having failed to top the key 100 yen mark on Monday despite coming close to rise as high as 99.90 yen. The weak U.S. housing data weighed on the dollar but traders say the upcoming Bank of Japan meeting on Friday may provide another opportunity to clear that symbolic level. "After expanding its bond purchasing program to 7 trillion yen earlier this month, the BOJ may stick to the sidelines this time around, but Governor Haruhiko Kuroda may broaden the scope of the non-standard measure to include a greater range of asset classes in an effort to encourage a stronger recovery," said David Song, analyst at DailyFX. The BOJ's reflationary plans were accepted by the Group of 20 gatherings in Washington late last week. The dollar hit a four-year peak of 99.95 on April 11. Heavy option barriers lined up around 100 yen have blocked the dollar's smooth climb against the yen, but if and when the 100 level is broken, traders expect stop-loss buying to lift the dollar even higher. The dollar firmed against the euro, which traded down 0.2 percent at $1.3043, weighed by comments by European Central Bank policymakers on Monday stressing falling inflation and poor growth prospects in the euro zone, which suggest the bank may be leaning towards a rate cut. Signs of progress to break political stalemate in Italy outweighed fresh downbeat earnings news and concern over the health of the global economy, helping European shares to inch higher on Monday. Gold recovered some ground after last week's tumble but more gold outflows from exchange-traded funds summed up investors' weakening confidence in the metal. Spot gold was at $1,425.24 an ounce, moving away from a two-year low of $1,321.35 touched last week, but still some $50 below the closing level before the sell-off began. London copper dropped 0.6 percent to $6,892 a tonne. Brent crude futures turned lower, trading down 0.3 percent at $100.14 after rising for a third straight session on Monday. U.S. crude fell 0.3 percent to $88.90 a barrel.