Effect of sowing date and plant density on grain and flower yield of Pot Marigold (Calendula officinalis L.)

Abstract

Pot marigold (Calendula officinalis L.) is a medicinal herb whose dried flower heads are used to heal wounds. In order to study the effects of sowing dates and plant density on grain and flower yield of pot marigold, an experiment was conducted at Agricultural Research Center of Islamic Azad University, Birjand Branch in 2005. Three sowing dates (30 March, 14 April and 30 April) and three plant densities (plant distances on row were 10, 20 and 30 centimeters) were compared in a split- plot experiment based on a randomized complete block design with 3 replications. Seed and flower yields were significantly different at planting dates and plant densities. Sowing date had significant effects on flower and seed harvest index. The latest sowing dates had the highest flower and seed harvest index. Plant density had not significant effect on flower harvest index, but the effect on seed harvest index, was significant. In total our result showed that the first sowing date with 25 plants/m2 had the highest grain and flower yield. Keywords: Marigold, sowing date, plant density, medicinal plant