ASSESSEMENT OF SOMACLONAL VARIATION IN IN VITRO PROPAGATED CORMELS OF GLADIOLUS

Abstract

In vitro raised cormels of 3.0 to 4.0 mm diameter of 3 commercial grown varieties of gladiolus viz. Traderhorn, White Friendship and Peter Pears were used to assess percentage of clonal fidelity with each other and with mother cormels using Random Amplified Polymorphic DNA (RAPD) and Inter Simple Sequence Repeat (ISSR) markers. In order to regenerate cormels under In vitro conditions, direct organogenesis was followed using cormel sprout as an explant. Cormel sprouts obtained by culturing the whole cormels (0.6 g) in a polar position on MS medium supplemented with BAP (4 mg L-1). Out of the three varieties, White friendship obtained more number of shoots (22.07). However, statistically similar number of roots was recorded in White Friendship (22.67) and Peter Pears (19.60) when MS supplemented with IBA (2 mg L-1). Cormel production was not affected by any variety of the gladiolus using MS medium supplemented with IBA (1 mg L-1) and sucrose (7%). The In vitro produced cormels were assessed for their clonal fidelity using RAPD and ISSR markers. The RAPD similarity tendencies among In vitro propagated cormels ranged from 80% to 95% in Traderhorn, 88% to 95% in White Friendship and 80% to 90% in Peter Pears. However the similarity tendencies between mother and In vitro propagated cormels, on average were 86% in Traderhorn, 92% in White Friendship and 83% in Peter Pears. In comparison, ISSR primers produced higher percentage of similarity matrix than RAPD. The ISSR cluster analysis for genetic similarity between mother and In vitro propagated cormels had varied degree of differences detected 90% in Traderhorn, 96% in White Friendship and 85% in Peter Pears. The genetic differences among In vitro propagated cormels ranged from 88 to 100% in Traderhorn, 94 to 100% in White Friendship and 82 to 100% in Peter Pears.