Microsporogation studies on chrysanthemum (Dendranthema grandiflora Tvelev)

Abstract

The investigations were conducted on chrysanthemum (D. grandiflora Tvelev) at IIHR, Bangalore, for optimizing the nutrient medium for multiple shoot induction, for in vitro rooting and to evaluate the efficacy of low cost gelling agents in chrysanthemum. Shoot tips of 5 mm and 10 mm long gave better establishment (60%0, and when cultured on various media started growing within a week after inoculation. Sterilization of chrysanthemum shoot tip explants using mercuric chloride at 0.1% for two minutes gave better survival for ‘Ravikiran’ (80%), ‘M-14’ (73.3%) and ’87-17-1’ (60%). For ‘Yellow Gold’, 0.05% mercuric chloride for three minutes was better. For nodal segment explant, mercuric chloride at 0.1% for two minutes was found to be better for all the four genotypes. After eight weeks of inoculation an average of six shoots was induced by BAP (2 mg/1) as well as kinetin (2 mg/1) when supplemented in MS basal medium. Cultivar Ravikiran produced eight shoots on BAP (2 mg/1). Maximum shoot length (3.25 cm) was obtained in cultivar Ravikiran in MS basal medium supplemented with BAP 1.5 mg/1. The medium with IBA 1mg/1 was effective in inducing maximum root length and number of roots for all the four genotypes. At four weeks the root length ranged from 2.5 cm to 3.2 cm. Cultivar Ravikiran was superior with an average of 18.8 roots having 3.28 cm root length. Gelrite and Agar as gelling agents performed better compared to Isubgol and Sago for multiplication of Chrysanthemum when nodal segments were used as explants. The shoot length was more (1.98 cm) and number of leaves was maximum (7) in gelrite. The survival of plantlets transferred to pots containing cocopeat and sand was high in cultivar Ravikiran (80%) followed by M-14 (75%).