** Australian tech stocks (.AXIJ) fall as much as 4.1%, on track for worst session since May 13 ** The Nasdaq Composite index ended 1.26% lower overnight as rising treasury yields weighed on tech stocks ** Heavyweight Afterpay (APT.AX) drops as much as 6.6%, on track for its worst session since Oct. 5 ** Top index loser WiseTech Global (WTC.AX), falling as much as 7.4% in its biggest drop since Feb. 26 ** Xero Ltd (XRO.AX) declines as much as 3.6% ** Tech index has gained 5.63% year-to-date, as of last close Reporting by Harshita Swaminathan in Bengaluru