Variasi Kadar Saponin Total dan Aktivitas Alelopati Ekstrak Kulit Kayu Acacia mangium Willd. Generasi Ketiga di KHDTK Alas Kethu, Wonogiri

Rizkiyah, Masendra, S.Hut., M.Agr., Ph.D.

2026 | Tugas Akhir | D4 PENGELOLAAN HUTAN

Acacia mangium Willd. merupakan salah satu spesies pohon cepat tumbuh (fast-growing species) yang banyak dimanfaatkan dalam industri pulp dan kertas di Indonesia. Kulit kayunya mengandung senyawa bioaktif, seperti saponin, yang berpotensi dimanfaatkan sebagai alelokimia. Penelitian ini bertujuan untuk menganalisis variasi kadar saponin total dan aktivitas alelopati ekstrak kulit kayu A. mangium generasi ketiga, mengestimasi nilai heritabilitas, mengelompokkan famili berdasarkan karakter yang diamati, serta menganalisis hubungan antara kadar saponin total, aktivitas alelopati, dan sifat pertumbuhan. Sampel kulit kayu berasal dari 20 famili polinasi terbuka (half-sib family) berumur 10 tahun di KHDTK Alas Kethu Wonogiri, Jawa Tengah. Data dianalisis menggunakan model linier efek campuran, korelasi pearson, Principal Component Analysis (PCA), dan analisis klaster. Hasil penelitian menunjukkan bahwa kadar saponin total dan aktivitas alelopati bervariasi antar famili, serta memiliki heritabilitas yang tinggi dengan nilai berturut-turut 0,557 dan 1. Analisis PCA mengelompokkan 20 famili menjadi tiga klaster. Famili 5, 6, 10, dan 12 (Grup II) berpotensi sebagai kandidat seleksi berdasarkan kadar saponin total (KST) pada kulit. Adapun Famili pada Grup III (9, 13, 17 dan 35) memiliki aktivitas inhibisi alelopati yang tinggi sehingga berpotensi sebagai kandidat seleksi untuk pengembangan sumber bahan bioaktif bioherbisida. Kadar saponin total tidak berkorelasi signifikan dengan aktivitas alelopati, menunjukkan bahwa efek alelopati diduga dipengaruhi oleh senyawa bioaktif lain selain saponin.

Acacia mangium Willd. is one of the fast-growing tree species widely used in the pulp and paper industry in Indonesia. Its bark contains bioactive compounds, such as saponins, which have the potential to be used as allelochemicals. This study aims to analyze variations in total saponin content and allelopathic activity of third-generation A. mangium bark extracts, estimate heritability values, group families based on observed traits, and analyze the relationship between total saponin content, allelopathic activity, and growth characteristics. Bark samples were collected from 20 open-pollinated families (half-sib families) that were 10 years old at the Alas Kethu Wonogiri Forest Research Station (KHDTK), Central Java. Data were analyzed using a mixed-effects linear model, Pearson's correlation, Principal Component Analysis (PCA), and cluster analysis. The results showed that total saponin content and allelopathic activity varied among families and exhibited high heritability, with values of 0.557 and 1, respectively. PCA analysis grouped the 20 families into three clusters. Families 5, 6, 10, and 12 (Group II) have potential as selection candidates based on total saponin content (TSC) in the bark. The families in Group III (9, 13, 17, and 35) exhibit high allelopathic inhibitory activity, making them potential candidates for selection in the development of bioactive compounds for bioherbicides. Total saponin content did not correlate significantly with allelopathic activity, suggesting that the allelopathic effect is likely influenced by bioactive compounds other than saponins.

Kata Kunci : Acacia mangium, kulit kayu, kadar saponin total, alelopati, pemuliaan pohon