Evaluation of Mutation Induction using Colchicine on Morphophysiological, Anatomical and Cytogenetic Characteristics of Samosir Local Shallots

HistorySamosir local shallots from North Sumatra are considered superior regional commodities, yet their cultivation is constrained by increasingly limited genetic resources and low productivity, primarily due to small bulb size.To address this limitation, genetic enhancement through induced mutation was explored using the chemical mutagen colchicine.This study aimed to assess the effects of colchicine on the morphophysiological, anatomical, and cytogenetic characteristics of Samosir local shallots.A factorial randomized complete block design with two factors and three replications was used.The first factor was the accession of Samosir local shallots (accessions Siunong unong Julu, Simamora 3, and Tipang 2), and the second factor involved soaking shallot bulbs in differing concentrations of colchicine solution for 24 hours, including control with distilled water, as well as concentrations of 200ppm, 400ppm, and 600ppm.The results showed that the Tipang 2 accession had higher plant length 6 weeks after planting (WAP), bulb diameter, dry weight of bulb/plant, bulb grading I, and harvest index compared to the Siunong, Unong Julu, and Simamora accessions.The 600ppm colchicine treatment tended to accelerate harvest time and increase bulb grading I.However, observations of the number and density of stomata showed non-significant differences among the Samosir shallot accessions subjected to colchicine treatment.A significant interaction was observed between Tipang 2 and 600 ppm colchicine, resulting in increased plant height.Additionally, increasing colchicine concentration from 0 to 600ppm enhanced total chlorophyll content in the Tipang 2 accession.Karyotyping and flow cytometry analysis indicated that the number of diploid chromosomes in Samosir local shallots remained stable after colchicine treatment, confirming that polyploidy induction was not observed in the M1 generation.