Optimizing and Determination of Natural Bio-catharantin Mutagen in Polyploidization of Triploid Lembah Palu Shallot (Allium wakegi Araki)

Induction of polyploidy can be achieved using chemical mutagen or antimitotic compounds that affect cell division, resulting in doubling number of chromosomes. A new inducer for chromosome doubling mutation agent – bio-catharantin – may be used. This report determined the mortality rate of bio-catharantin used for mutation induction experiments in shallot plants. Two sets of experiments were arranged in a two factorial randomized block design, i.e. five levels of bio- catharantin concentration treatment (0.0, 2.5, 5.0, 10.0, and 15.0%) combined with soaking periods of 6-, 12-, and 24-h. Each combination was repeated three times, with five seed bulbs in each combination. The result shows that the mortality rate of shallot tends to increase with increasing concentration and soaking time. A high percentage of the mortality rate was found at all concentrations other than control at 24-h soaking time. Hence, the mortality rate of prolonged soaking (24 h) is greater at higher concentrations. However, at lower concentrations of 2.5 and 5% for 6- and 12-h soaking time the mortality rate was low (13 and 27%, 7 and 60%, respectively). Meanwhile, at 10%, the result shows relatively high mortality rates (13 and 73%, respectively). Administration of bio-catharantin at 5 and 10% with a 12-h soaking period causes optimal mortality rate, whereas the germination rate shows the opposite trend. To find the accuracy of the efficacy of bio-catharantin concentration between 5–10%, we introduced 7.5% in the second experiment. The concentration of 7.5% has a significant effect on leaf diameter, where it becomes smaller as inhibited by increased concentration (2.5 and 5.0%) but becomes larger again at 7.5% (0.59 mm) nearing control (0.70 mm) and drops again to 0.23 mm (10%). This is not usually the trend of inhibition when a larger concentration is used except when polyploidization has taken effect, presumably at 7.5% bio-catharantin with a 12-h immersion period.