Abstract

This study was conducted as split-plot field experiment in a randomized complete block design with four replications for one year planting. The main factors were the sowing dates (10^th August, 1^st September and 20^th September) and sub factors were the planting densities (4, 8 and 12 plants/m²). The results showed that sowing date and planting density significantly affected grain yield, essential oil yield, essential oil percentage, root length, root diameter, flowering stem number and root yield. Means comparison showed that the highest grain yield and root yield were achieved under the 8 plants/m² planting density and 10^th August sowing date, the highest root length and flowering stem number were achieved under 12 plants/m² planting density and 10^th August  sowing date, the highest root diameter was achieved under 4 plants/m² planting density and 10^th August sowing date, the highest essential oil yield was achieved under 8 plants/m² planting density and 20^th September sowing date and the highest essential oil percentage was achieved under 4 plants/m² planting density and 20^th September  sowing date. It was thus concluded that sowing date and planting density are the main factors influencing the quantity and quality characteristics of valerian. Our finding may give applicable advice to commercial farmers and agricultural researches for management and concern on planting density strategy and estimate of sowing date carefully for increase of quantity and quality characteristics in medicinal and aromatic plants farming and is better that such studies may be validated further by conducting for two or more years.

Key words: Sowing date, planting density, essential oil, valerian.