Morphological Characterization of Patchouli (Pogostemon cablin Benth.) Result of Gamma-Ray Irradiation Mutation

Abstract

The Patchouli plant (Pogostemon cablin Benth.) is one of the plants that produce patchouli oil which is one of Indonesia's leading export commodities. However, patchouli breeding has limitations because patchouli cultivated in Indonesia is non-flowering flora; thus, it is challenging to develop superior varieties due to the low genetic variability. Induction of physical mutations by gamma-ray irradiation can increase genetic variability. This study aims to determine the variation of morphological characters from gamma-ray irradiation of Aceh patchouli that has high productivity. This study used a Randomized Complete Block Design (RCBD) with 1 factor, the different doses of gamma-ray radiation at intervals of 0, 20 + 40 Gy, 60 + 80 Gy, and control patchouli planted in the field. The study's results observed that increasing the dose of gamma-ray irradiation inhibits plant growth. Plant control A1 (0 Gy) showed the best growth parameters such as internode length, plant height, leaf length, leaf width, stem diameter, number of branches, amount of chlorophyll, fresh weight, and dry weight. Irradiation plant A2 (20 + 40 Gy) resulted in various phenotypes, such as the character of leaf tip shape, stem color, and branch surface texture. The results of this study in the form of patchouli fresh weight and dry weight can be used as a recommendation to estimate the productivity of patchouli in the form of patchouli oil yield.