Variabilitas dan Hubungan Kekerabatan Begonia seksi Sphenanthera di Pulau Jawa dan Bali Berdasarkan Karakter Morfologis dan Molekuler

TRI WARSENO, Abdul Razaq Chasani, S.Si., M.Si., Ph.D.; 2. Prof. Dr. Budi Setiadi Daryono, M. Agr. Sc.

2023 | Tesis | MAGISTER BIOLOGI

Salah satu tumbuhan yang memiliki keragaman yang tinggi di Indonesia adalah Begonia. Adanya variasi yang terdapat di alam menunjukkan adanya intermediate character antar spesies, batasan jenis antar anggota Begonia seksi Sphenanthera yang belum jelas, dan munculnya beberapa Begonia spesies baru dan silang alami mempengaruhi klasifikasi dan sistematika Begonia seksi Sphenanthera di Jawa dan Bali. Penelitian ini bertujuan untuk mengidentifikasi variabilitas dan menentukan hubungan kekerabatan spesies Begonia seksi Sphenanthera dari Jawa dan Bali berdasarkan karakter morfologis dan molekuler. Dalam penelitian ini dilakukan pengambilan data karakter morfologis dan molekuler dari Begonia seksi Sphenanthera koleksi Kebun Raya "Eka Karya" Bali dan Kebun Raya Cibodas - BRIN. Data morfologis diamati berdasarkan deskriptor genus Begonia dari Kementrian Pertanian Republik Indonesia yang dimodifikasi. Analisis hubungan kekerabatan fenetik secara morfologis dilakukan terhadap 15 sampel berdasarkan 56 karakter. Pendekatan fenetik dilakukan menggunakan analisis klaster dan analisis komponen utama. Kajian molekuler dilakukan dengan analisis sekuens ITS-rDNA dan atpB-rbcL IGS cpDNA terhadap 15 sampel Begonia seksi Sphenanthera. Pendekatan filogenetik berdasarkan sekuen DNA dilakukan menggunakan metode Neighbor-Joining dan Maximum Likelihood. Hasil analisis klaster terhadap data morfologis menunjukkan ada dua klaster utama dengan nilai koefisien kemiripan berada dalam kisaran 0,642-0,986. Berdasarkan analisis komponen utama diketahui terdapat 17 karakter morfologis berperan besar dalam pengelompokkan sampel ke dalam dua klaster. Variasi genetik Begonia seksi Sphenanthera di Pulau Jawa dan Bali berdasarkan karakter molekuler memperlihatkan polimorfisme genetik pada dengan jarak genetik berkisar 0-0,214 (sekuen ITS-rDNA) dan 0-0,0113 (sekuen atpB-rbcL IGS). Hasil analisis pola pengelompokan dan hubungan kekerabatan Begonia seksi Sphenanthera di Pulau Jawa dan Bali berdasarkan karakter morfologis dan molekuler cenderung terbagi menjadi dua klaster utama, yaitu kompleks Begonia multangula dan kompleks Begonia longifolia.

One of the most diverse plant in Indonesia is Begonia. The existence of variations found in nature indicates the presence of intermediate characters between species, the species boundaries between members of the Sphenanthera section are not yet clear, and the emergence of several new species of Begonia and natural hybrid influences the classification and systematics of Begonias of the Sphenanthera section in Java and Bali. This study aimed to determine the variability and relationship between species of Begonia sect. Sphenanthera in Java and Bali based on morphological and molecular characters. In this study, morphological and molecular character data collected from Begonia sect. Sphenanthera from "Eka Karya" Bali Botanic Garden and Cibodas Botanic Garden (BRIN) Collection. Morphological data was observed based on the Begonia descriptor from the Ministry of Agriculture of the Republic of Indonesia with modifications. Phenetic affinity based on morphology was conducted on 15 samples using 56 characters. Morphological data was subjected to cluster analysis and principal component. The molecular approach was conducted using DNA sequence analysis of ITS-rDNA and atpB-rbcl IGS on 15 samples. Phylogenetic relationships was examined using Neighbor-joining and Maximum Likelihood method. The cluster analysis of morphological data showed that there were two main clusters with similarity coefficient values in the range of 0.642-0.986. Based on the principal component analysis, it was found that 17 morphological characters played a major role in grouping the samples into two clusters. Based on molecular characters, the genetic variation of Begonia section Sphenanthera in Java and Bali showed genetic polymorphism in the ITS-rDNA sequence with a genetic distance ranging from 0-0.214 and in the atpB-rbcL IGS sequence with a genetic distance ranging from 0-0.0113. Based on morphological and molecular characteristics, the results of grouping patterns and relationships of Begonia section Sphenanthera in Java and Bali tend to be divided into two main clusters, namely the Begonia multangula complex and the Begonia longifolia complex.

Kata Kunci : atpB-rbcL IGS, fenetik, filogenetik, ITS rDNA, morfologis, Sphenanthera