Intense Floral Scent Emission in Polianthes tuberosa L. (Tuberose) Variants Sprouted from γ-Irradiated Tubers

Abstract

Tuberose (Polianthes tuberosa L.) is a tuberous, perennial, night-blooming ornamental plant which is commercially cultivated in different parts of India. In the present study, the tubers of tuberose were subjected to γ-radiation in order to identify variants with altered scent profile. The growth of plants sprouted from both control and irradiated tubers at different doses was monitored and the lethal dose was calculated based on the survival rate of plants. The growth rate significantly decreased in plants sprouted from tubers exposed to a higher dose. Growth pattern of plants sprouted from irradiated tubers and control also correlated with the chlorophyll content. The emitted scent volatiles from flowers developed from both control and irradiated plants were analysed. Floral volatile emission rate was increased in the lowest dose (10 Gy) as compared to control plants. The phenomenon of ‘hormesis’ was observed in the plants since tubers exposed to the lower dose (10 Gy) showed enhanced growth rate, higher volatile content in comparison with control plants. Plants sprouted from tubers exposed to a higher dose of radiation showed lethal effects. In order to study genetic variation among the control and plants sprouted from irradiated tubers, inter simple sequence repeat marker analysis was also carried out and it was observed that out of 74 loci, 67 were polymorphic (90.54%). The genetic similarity coefficient values were also calculated among control and variant lines thus validating morpho-physiological variations.