Studies on Pollen Viability and Germinability in Accessions of Stevia rebaudiana Bertoni

Stevia rebaudiana produces sweet steviol glycosides extractable from the leaves. With zero calorie contents, it represented inevitable health diet for diabetic patients. Poor seed germination (10%) posed obstacles towards large scale establishment. Pollens play fundamental role in fertilization and seed sets. Studying pollen in vitro germination and growth of pollen tube are essential for explaining lack of fertility in spermatophytes. Limited studies exist on the pollen profile of this crop. Pollen viability and germinability in Stevia accessions MS007, MS012 and SBK were studied. 3000 pollen grains per accession were examined for viability. Evaluated parameter includes pollen staining ability in Cotton blue in lacto phenol. Boric acid concentrations (0.025 g, 0.05 g and 0.1 g) prepared with 20 g of sucrose in 100 ml distilled water were formulated into pollen germination medium (GM), 300 pollens per accession were scored for germinability. Analysis of variance revealed no significant difference with pollen viability at p<.424 among all the accessions; while though gernminabilty showed no significant difference at p<.478 and p<.246 for MS007 and MS012 respectively, the SBK differed significantly, with 0.1% treatment, at p<.000. The pollens were viable and possess germination ability. Optimum germination medium comprised 0.025g Boric acid. Poor seed germination in Stevia is unconnected with its pollen profile.