Over a period of 3 consecutive years, 9 types of cultural practices in the field have been compared : 3 dates of topping : early topping, non-topping and controlled non-topping, along with 3 plant spacings : 18,200, 28,600 and 35,700 plants per hectare of Virginia D tobacco. Results were as follows : _ Yields in weight ranged from 1,435 kg to 3,490 kg per hectare (relative variation of 1 to 2.4); _ Alkaloid contents ranged from 0.53% to 1.79% of dry matter (relative variation of 1 to 3.4); _ Quality gradings attributed after expertise were fairly strongly influenced by the type of topping and increased with closer plant spacing. Controlled non-topping technique (DELETANG, 1973) _ flower-bud inhibiting _ applied to closely spaced tobaccos (over 30,000 plants per hectare) produced a crop with a satisfactory weight yield and with an average content in total alkaloids inferior to 1% of dry matter.