A polyolefin composition made from or containing: (A) from 97.0 to 45.0 wt % of a propylene-1-hexene random copolymer, (B) from 2.0 to 50.0 wt % of fibers, and (Q) from 0.3 wt % to 5.0 wt % of a compatibilizer, the sum (A)+(B)+(Q) being 100, wherein (i) the copolymer has a content of 1-hexene derived units ranging from 0.6 wt % to 3.0 wt % with respect to the copolymer, (ii) the copolymer has the melt flow rate (MFR) measured according to the method ISO 1133 (230° C., 2.16 kg) ranging from 0.2 up to 40 g/10 min, (iii) the fibers are selected from the group consisting of glass fibers, carbon fibers, metal fibers, mineral fibers, ceramic fibers, and polymer fibers.