Induksi Mutasi menggunakan Iradiasi Sinar Gamma pada Tunas In Vitro Kapulaga Sabrang (Elettaria cardamomum (L.) Maton)

Abstract

Kapulaga sabrang (Elettaria cardamomum (L.) Maton) merupakan tanaman rempah bernilai ekonomi tinggi yang berpotensi dikembangkan melalui pemuliaan mutasi. Penelitian ini bertujuan untuk mempelajari pengaruh iradiasi sinar gamma terhadap pertumbuhan dan perkembangan eksplan tunas kapulaga sabrang secara in vitro, serta mendapatkan nilai LD50 sebagai dasar penentuan dosis iradiasi untuk memperoleh mutan putatif. Penelitian dilakukan menggunakan Rancangan Acak Lengkap (RAL) satu faktor berupa dosis iradiasi gamma, yaitu 0, 10, 20, 30, dan 40 Gy. Eksplan tunas in vitro diamati selama 10 minggu setelah perlakuan (MSP) dengan subkultur pada 4 MSP dan 8 MSP. Parameter yang diamati meliputi persentase hidup, browning, kontaminasi, kematian eksplan, persentase bertunas, berakar, dan berdaun, serta tinggi tunas, jumlah daun, dan jumlah akar. Data dianalisis menggunakan ANOVA pada taraf nyata 5%, sedangkan nilai LD50 ditentukan menggunakan analisis regresi linear. Hasil menunjukkan bahwa peningkatan dosis iradiasi gamma cenderung menurunkan persentase hidup dan kemampuan regenerasi eksplan. Dosis 10 Gy menunjukkan respons pertumbuhan terbaik, sedangkan dosis 30 dan 40 Gy meningkatkan browning, kontaminasi, serta kematian eksplan. Nilai LD50 sebesar 15,625 Gy menunjukkan radiosensitivitas eksplan yang tinggi terhadap iradiasi gamma. Iradiasi sinar gamma berpengaruh terhadap viabilitas dan pertumbuhan eksplan serta berpotensi meningkatkan keragaman genetik tanaman.

True cardamom (Elettaria cardamomum (L.) Maton) is a high-value spice crop with potential for development through mutation breeding. This study aimed to investigate the effect of gamma-ray irradiation on the in vitro growth and development of true cardamom shoot explants and to determine the LD50 value as a basis for selecting irradiation doses to generate putative mutants. The experiment employed a Completely Randomized Design (CRD) with a single factor gamma irradiation dose consisting of 0, 10, 20, 30, and 40 Gy. In vitro shoot explants were observed for 10 weeks post-treatment (WPT), with subculturing performed at 4 and 8 WPT. Observed parameters included survival rate, browning, contamination, explant mortality, percentages of shoot, root, and leaf formation, as well as shoot height, leaf number, and root number. Data were analyzed using ANOVA at a 5% significance level, while the LD50 value was determined via linear regression analysis. The results indicated that increasing gamma irradiation doses tended to reduce explant survival and regeneration capacity. The 10 Gy dose yielded the best growth response, whereas doses of 30 and 40 Gy increased browning, contamination, and explant mortality. The LD50 value of 15.625 Gy indicated high radiosensitivity of the explants to gamma irradiation. Gamma-ray irradiation influenced explant viability and growth and holds potential for enhancing the plant's genetic diversity.