Bisht, P.S.Mehta, Karan Singh2019-06-202019-06-202004-07http://krishikosh.egranth.ac.in/handle/1/5810109281The present investigation was carried out during Feb. 2003 to June 2004 at the experimental block of Medicinal and Aromatic Plants section, Department of Horticulture, College of Forestry and Hill Agriculture, GBPUA&T, Hill Campus, Ranchauri, Tehri Garhwal, to study the effect of plant density on vegetative growth, flower yield and pyrethrin content in pyrethrum. The experiment was laid out in a Randomized Complete Block Design with nine treatments and three replications. The range of plant densities was taken from 27778/ha to 1,11,111/ha with the plant spacing from 30 cm to 60 cm. During the course of investigation, plant height, plant diameter, number of tillers per plant, number of flowers per plant, number of flowers per tiller, flower diameter, capitulum diameter, fresh weight of 100-flower, dry weight of 100-flower, yield of fresh flower per plot, yield of dry flower per plot, yield of dry stem-leaf matter per plot, harvest index, pyrethrin content in percent and pyrethrin yield per plot were observed. Observations of these parameters were found to be significantly influenced by different plant densities except the plant height. A significant affect on pyrethrin yield was found in different plant densities during the present investigation. It was also found that the pyrethrin yield is significantly and positively correlated with the yield of fresh flower (r=0.88*), yield of dry flower (r=0.91**) and number of tillers per plant (r=0.76*). The pyrethrin yield per plot was also good in closer spacing (30cm x 30cm) due to more number of plants per unit area and thereby, increasing the yield of fresh and dry flower. On the basis of the findings of the present study, it can be concluded that the plant density of 55556/ha with the spacing of 60 cm x 30 cm seems to be the most suitable for obtaining yield of a remunerative crop of pyrethrum under the agro-climatic conditions of Garhwal Himalayas.ennullThesis