Influence of substrate culture on growth, yield and forskolin content of coleus (Plectranthus barbatus Andr.) varieties/mutants

摘要

Plectranthus barbatus is an important medicinal plant species, contains forskolin, which is mainly used to reduce the blood cholesterol level. Incidence of soil borne diseases like wilt and nematodes are the major limiting factor for growing the cropin soil media. Hence the present work was initiated to evaluate the coleus varieties and mutants against the local check (K-8) under sterilized media (cocopeat) and nutrient solution (864 mg plant ' nitrogen, 768 mg plant"' phosphorous and 960 mg planf*potassium) for growth, yield and forskolin content. Screening of coleus varieties/ mutants resulted in maximum growth parameter values in the mutant, MVj compared to other varieties. Significantly higher root length and root diameter was noticed in MV_4(41.83 and 2.52 cm, respectively). Maximum root to shoot dry weight ratio (3.12), dry matter (148.14 g planf‘), fresh (356.63 g) and dry weight of roots per plant (112.14 g) was observed in MV_4. The dry tuber yield was also found to be maximum (1.68 kgm~(-2) and 16.82 t ha~(-1)) in MV_4. The forskolin content in tuberous roots of various coleus varieties was maximum (1.04 %) in MV_4 followed by MV_7 (0.92 %). Among the different coleus varieties/mutants, MV_4 mutant recorded higher yield parameter values and forskolin content followed by MV_4.