Ecology, Environment and Conservation Paper

EFFECT OF DIFFERENT ORGANIC MANURES ON GROWTH, YIELD AND ECONOMICS OF MEDICINAL COLEUS (PLECTRANTHUS FORSKOHLII WILLD.)

S. S. Saraswati, A. B. Mastiholi, D. Srikantaprasad, S. Ajithkumar and S. Raghavendra

Abstract

An investigation on the effect of organic manures on growth, yield, quality and economics of medicinal coleus (Plectranthus forskohlii) was conducted at the Department of Plantation, Spices, Medicinal and Aromatic Crops, Kittur Rani Channamma College of Horticulture, Arabhavi, during Kharif season of 2013. Plectranthus forskohlii Willd. is the only source for forskolin among the plant kingdom. Forskolin has a unique property of activating almost all hormone sensitive adenylate cyclase enzymes in a biological system. At harvest (160 DAP), highest forskolin yield (12.17 kg/ha), net returns (Rs.1,34,077.2/ha) and B: C ratio (3.68) were obtained in poultry manure equivalent to 100 per cent RDN treatment. Whereas highest plant spread, harvesting index, number of tuberous roots, length and diameter of tuberous roots, tuber density, fresh and dry weight of tuberous roots (6.82 t/ha and 1.28 t/ha). However, as per as fresh and dry tuberous root yield concerned, in which the farmers are interested, though significantly higher fresh (26.59%) and dry tuberous root yield (15.65%) was obtained with the application of FYM equivalent to 100 per cent RDN (T1) (10 t/ha) but, poultry manure (1.65 t/ha), pongamia cake (1.19 t/ha), pressmud (4 t/ha) and RDF (108.7:312.5:83 kg NPK /ha + 10 t/ha FYM) application also gave on par dry tuberous root yield. Hence alternatively, in the absence of FYM, the above organic source of nitrogen can be considered for getting optimum yield in medicinal coleus under Ghataprabha Left Bank Command Area of Northern Dry Zone of Karnataka.