Effect of agro-techniques on the performance of natural sweetener plantstevia (Stevia rebaudiana) under western Himalayan conditions

Two separate field experiments were conducted during 2007, 2008 and 2009 to evaluate the effect of agro- techniques on the performance of natural sweetener plantstevia ( Stevia rebaudiana Bertoni) under western Hi- malayan conditions. In the first experiment during 2007 and 2008 two doses of farm yard manure (FYM) and seven inorganic fertilizers were compared with untreated plot (control). Application of 50:60:50 kg NPK/ha re- corded significantly higher plant height, stem, flower and total weight/plant (dry) and consequently recorded higher dry leaf yield as compared to other treatments. However, stevioside and rebaudioside contents were found to re- duce due to the application of manures/fertilizers. FYM application recorded higher marker compounds than inor- ganic fertilizers. Owing to higher dry leaf yield, 50:60:50 kg NPK/ha recorded highest steviol glycoside (stevioside and rebaudioside A) yield/ha than other treatments. In second experiment during 2008 and 2009, effect of land configuration and harvesting time on growth, yield and steviol glycosides of stevia was evaluated. Planting stevia in broad bed and furrow (BBF) recorded 31 and 23% higher leaf biomass over flat and camber bed methods, re- spectively. Steviol glycosides (stevioside and rebaudioside-A) concentration was higher when stevia was planted in camber bed as compared to flat and BBF. Significantly higher leaf biomass was obtained from stevia plants which were harvested once at 50% flower bud stage compared with those harvested once at the 60 and 90 days after transplanting (DAT). Rebaudioside -A content was higher when leaves were harvested at 50% flower bud stage. Owing to higher dry leaf yield, stevia planted in BBF and harvested at 50% flower bud stage recorded high- est net return and B:C ratio than other treatments.