Alan Robertson Gemmell FRSE OBE JP (10 May 1913 – 5 July 1986) was Professor of Biology at Keele University and a regular member of the panel on the BBC Radio Home Service (later BBC Radio 4) programme Gardeners' Question Time from 1950 for some 30 years. Disagreements on the programme between Gemmell and fellow panel member Bill Sowerbutts became legendary.
He was born in Glasgow the son of Alexander Nicol Gemmell, a cashier, and his wife Mary Robertson.
He was brought up in Troon and educated at Ayr Academy followed by Glasgow University where he gained a first class BSc in Botany and later, on a Commonwealth Scholarship, the University of Minnesota in 1935 where he did agricultural research in plant pathology gaining an MS in 1937. He specialised in the diseases of cereals but his first paper was published on the diseases of golf course greens.
Returning to Glasgow he obtained a PhD in 1939 and then at the West of Scotland Agricultural College (1937–41). He was a lecturer in Botany at Glasgow (1942–44); a biologist at West Midlands Forensic Science Laboratory (1944–45); lecturer in Botany at Manchester University (1945–50) before joining the then recently established University of Keele, the first new post-war British university which opened in 1950, where he stayed for 27 years as professor and later Emeritus.