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

Abstract

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 crop in 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−1 nitrogen, 768 mg plant−1 phosphorous and 960 mg plant−1 potassium) for growth, yield and forskol in content. Screening of coleus varieties/mutants resulted in maximum growth parameter values in the mutant, MV2 compared to other varieties. Significantly higher root length and root diameter was noticed in MV4 (41.83 and 2.52 cm, respectively). Maximum root to shoot dry weight ratio (3.12), dry matter (148.14 g plant−1), fresh (356.63 g) and dry weight of roots per plant (112.14 g) was observed in MV4. The dry tuber yield was also found to be maximum (1.68 kg m−2 and 16.82 t ha−1) in MV4. The forskolin content in tuberous roots of various coleus varieties was maximum (1.04%) in MV4 followed by MV7 (0.92%). Among the different coleus varieties/mutants, MV4 mutant recorded higher yield parameter values and forskolin content followed by MV7.