Annual Report - IHBT

CSIR-IHBT Annual Report 2010-11Development of polyploidsPolyploidy induction was standardized to improve the steviol glycoside content and leaf yield ofthe plants. Colchicine treatment of seeds (0.2% or more) reduced the survival rate to below 50%.In comparison to the diploid plants (control), the 2C value (nuclear DNA content) was foundto be double in the putative polyploids. Further cytological analysis confirmed their tetraploidy(2n=44) in comparison to control (2n=22). The tetraploids produced increased leaf size andthickness, chlorophyll content and reduced internode length. SEM micrographs of abaxial leafsurface showed increased stomata size and trichomes (Fig. 48).Fig. 48 Morphological variation a) diploid and b) tetraploid; Flow cytometry histograms using tomato asinternal standard (M1) a) diploid (M2) and b) tetraploid (M2); Chromosome counts from root tips a)2n=22 and b) 2n=44; Micrographs of stomata a) diploid and b) tetraploid; stomata frequency c) diploidand d) tetraploid52