Effects on planting and different levels of vermicompost on quantitative traits stevia plant (Stevia rebaudianaBertoni)

To evaluate the effect of sowing date and different levels of vermicompost on qualitive characteristics of stevia plant (Stevia rebaudiana Bertoni), an experiment was conducted at the Varamin Agricultural University College of Agriculture located in Tehran province, Varamin, in 2014. This experiment was conducted on a factorial experiment in a randomized complete block design with three replications. The treatments factor were planting date at four levels: 15 April, Persian date Farvardin 30, 15 May and 30th of
May and another factor of vermicompost at four levels: control (no), use 5 tons of vermicompost per hectare, Application 10 tons, 15 tons of vermicompost per hectare and application of vermicompost per hectare. The results showed that planting date and vermicompost had a significant effect on the amount of stevizide, glycoside, ribo-dioside, chlorophyll a, chlorophyll b. The highest amount of stevizide content was related to cultivation on May 15, with the application of 15 tons per hectare of vermicompost with 4.4 percent, and the lowest amount was related to the sowing date of May 30 and control treatment (no vermicompost consumption) with 2.80 percent and the highest content Ribbiosiside was related to the crop cultivation on May 15, with the application of 15 tons of vermicompost per hectare with 10.3 percent, and the lowest was related to the April 15 planting date and the control treatment (no vermicompost consumption) with 1.38 percent and the highest content Stewil glycosides were cultivated on May 15, with the use of 15 tons per hectare of vermicompost with 53.7 percent and the minimum This amount corresponds to the date of planting 15 April and the control (non-use of vermicompost) by 38.4 percent. The highest content of chlorophyll a was obtained from cultivation on May 15 with the application of 15 tons per hectare of vermicompost, 1.35 mg.m, and the lowest content of chlorophyll a Was obtained amount of sowing date was 15 April and control treatment (no vermicompost consumption) with 0.41 mg /m. The highest content of chlorophyll b was observed in the sowing date of May 15 and the application of 15 t of vermicompost with 0.44 mg / m, which had no significant difference with planting date of May 15 and application of 10 t of vermicompost, and The lowest content of chlorophyll b was obtained from sowing date of 15 April and no consumption of vermicompost with 0.15 mg.m. The application of 15 tons of vermicompost at the planting date of May 15 had the greatest effect on measured traits.