A landmark paper in Plant Biology

Bourgin JP et Nitsch JP, 1967.Obtention de Nicotiana haploïdes à partir d’étamines cultivées in vitro (Production of haploid Nicotiana from excised stamen). Ann. Physio. Veg. 9: 377-382. pdf file here.
One of the most cited paper in plant biology for 25 years, Current Contents Citation Classic 1984 (Current Contents Number 44, October 29, 1984 : pdf).