The strain from row taking a long time (7)
I believe the answer is:
lineage
'the strain' is the definition.
(I have seen 'The strain' mean 'lineage' so perhaps 'strain' could also mean 'lineage')
'row taking a long time' is the wordplay.
'row' becomes 'line' (I've seen this before).
'taking' means one lot of letters go next to another.
'a long time' becomes 'age' ('age' can be a synonym of 'long time').
'line'+'age'='LINEAGE'
'from' is the link.
(Other definitions for lineage that I've seen before include "Line of descendants of an ancestor" , "Line of descent or ancestry" , "Genealogy" , "Old family members" , "Direct descent" .)