Phenotypic variation is essential for the development of shallots (Allium ascalonicum L.) in the selection process. This study aimed to evaluate phenotypic variation and chromosome doubling effectiveness at different colchicine concentrations in the Rubaru shallot cultivar. The experiment tested five colchicine concentrations (0, 500, 750, 1000, and 1250 ppm) with a 12-hour bulb immersion, using a completely randomized design (CRD) with six replications. The descriptive analysis of data used means, maximum and minimum, standard deviation, and coefficient of variation tests. Higher colchicine concentrations induced greater variation; however, they also reduced the survival rate. The results showed a colchicine concentration of 1000 ppm effectively increased phenotypic variation and chromosome doubling in shallot bulbs. This concentration caused the highest variation in the number of leaves, tillers, and bulbs; bulb weight; and total bulbs’ weight. Additionally, tetraploidy was evident in the 1000 ppm treatment. This study can be beneficial as a reference for future breeding research to improve the Rubaru shallot cultivars.
Bulbs, chromosome numbers, crossing, improvement potential, phenotyping evaluation, polyploidy induction, selection, tetraploid
Research on using colchicine to increase phenotypic variation in Rubaru shallots is limited. This study demonstrated a concentration of 1000 ppm enhanced variation in several traits. Such information can serve as a foundation for future breeding efforts to improve the Rubaru shallot cultivar.