Since economies are growing at slower than anticipated rates, what impact would have on the valuation of fixed income securities such as bonds?

Just plain vanilla fixed-coupon bonds. I know that the cash flows of bonds won't change given slower economic growth (unless they are linked to inflation) so I am assuming that only the discount rate will change. But I am unsure how slow economic growth will change the YTM?

Two things affect bond values: Interest rates; if interest rates are 10% then a $10,000 bond that matures next year is worth $9,090,91 today. If interest rates change to 9% then that bond is worth $9,174.31. Risk; if a $10,000 bond has a one percent chance of default then the bond can be sold for $9,900. If times worsen and the risk now looks more like a 2% chance of default then the bond's value just dropped to $9,800.

What is your time horizon? Ex-pat gave you the answer for the next 90 days but age constellation of the population and asset allocation fashions also count but more over a period of years. In the US I would expect equities and real estate to decline until 2023 while bonds and precious metal rise in the same time period. That is simply due to the size of birth cohorts over the last 75-80 years in the US