Effect of Colchicine on Morphological and Ornamental Traits of Gladiolus grandiflorus L.

Abstract

Gladiolus is one of the most important lucrative cut flower crops that is cultivated globally, valued for its diverse spike shapes, sizes and vibrant colour combinations. Gladiolus, with its inherent heterozygosity, is well-suited for polyploid induction and the development of new genotypes. Colchicine serves as the most widely utilized antimitotic agent for inducing polyploidy by inhibiting spindle fibre formation. Owing to its high ornamental value, the present study was undertaken to induce colchicine in Gladiolus grandiflorus L. variety “Arka Amar” and to assess its effects through detailed observational analysis. The corms of this variety were treated by immersing them in colchicine solutions of different concentrations. The treatments consisted of four colchicine concentrations (0% as control, 0.1%, 0.2%, and 0.3%) in combination with three exposure durations of 24, 36, and 48 hours for the corms. These treatments were evaluated in factorial completely randomized design (FCRD) with three replications. Colchicine at 0.2% for 24 hrs enhanced the ornamental quality of gladiolus by increasing floret diameter, number of florets, floret length, spike length and field life. However, the increase in colchicine concentration or exposure duration resulted in reduced survival and flowering percentage of corms. Higher concentrations of colchicine were associated with a prolonged delay in corm sprouting, spike initiation and first floret opening. Compared to other treatments, 0.2% colchicine resulted in the highest measurements of plant height, number of leaves, sprouts per corm, rachis internodal length and leaf width. The findings of this study highlight the effectiveness of colchicine in promoting advantageous traits in gladiolus, offering opportunities for breeding new varieties with improved traits.