Corteva Inc CTVA.N rose 8.0% after raising its net sales forecast for the year. By Echo Wang Aug 6 (Reuters) - The Dow and the S&P 500 indexes rose to record highs on Friday, boosted by soaring stocks in economy-linked sectors following a better-than-expected rise in jobs in July, while investors shrugged off concerns over the Delta variant impacting a nascent economic recovery. Although the three main indexes are set to end the week with gains following a stellar corporate earnings season, fears of higher inflation resulting in a sudden tapering in monetary policy have hurt sentiment.