Penanda Karakter dan Hubungan Kekerabatan Kultivar Kopi Robusta (Coffea canephora) di Jember Berdasarkan Karakter Morfologi

Character Marker and Kinship of Accession of Robusta Coffee (Coffea canephora) in Jember Based on Morphological Characters

Kopi Robusta merupakan salah satu varietas kopi yang mengalami penyerbukan silang sehingga kopi dengan karakter baru muncul akibat kawin silang ini. Karakter baru ini sulit untuk dibedakan. Penelitian ini bertujuan menentukan penanda karakter dan menganalisis hubungan kekerabatan berdasarkan karakter morfologi  dari 19 kultivar kopi Robusta di Jember sehingga memudahkan dalam membedakan, mendeskrispsikan, dan mengidentifikasikan. Penelitian ini merupakan penelitian deskriptif.   Prosedur penelitian meliputi tahap tiga tahap yaitu  eksplorasi dan koleksi serta dokumentasi,  pengamatan dan pengukuran, serta penanda karakter dan menganalisis hubungan kekerabatan. Eksplorasi dilakukan di lima kecamatan pada dataran sedang (350–700 mdpl), memperoleh 19 kultivar kopi Robusta. Kriteria sampel koleksi adalah tanaman kopi dengan tinggi ±2 meter, pernah berbuah, berdiameter batang ±10 cm. Karakter morfologi yang diamati merupakan karakter baik  sebanyak 15 karakter kuantitatif dan 15 karakter kualitatif. Tiga puluh karakter tersebut digunakan Principal Component Analysis (PCA) untuk menentukan penanda karakter dan menentukan hubungan kekerabatan dalam bentuk fenogram. Hasil analisis menunjukkan karakter diagnostik yaitu: bentuk stipula, bentuk daun, bentuk ujung daun, warna buah, bentuk buah, bentuk piringan buah, ketebalan pulp, ketebalan biji HS, warna biji HS, bentuk biji HS. Hasil analisis PAST4 kultivar-kultivar kopi Robusta terbagi dalam 4 kelompok dan fenogram terbagi dalam dua kelompok utama pada nilai ambang 42%.

Robusta coffee is one of the coffee varieties that undergoes cross-pollination so that coffee with new characters appears as a result of this cross-breeding. These new characters are hard to tell apart. This study aims to determine character markers and analyze kinship relationships based on the morphological characters of 19 Robusta coffee cultivars in Jember, making it easier to distinguish, describe, and identify. This research is a descriptive research. The research procedure includes three stages, namely exploration and collection as well as documentation, observation and measurement, as well as character markers and analyzing kinship relationships. Exploration was carried out in five sub-districts in the temperate plains (350–700 masl), obtaining 19 Robusta coffee cultivars. The criteria for the sample collection were coffee plants with a height of ±2 meters, ever bearing fruit, and a stem diameter of ±10 cm. The observed morphological characters were 15 quantitative characters and 15 qualitative characters. The thirty characters are used by Principal Component Analysis (PCA) to determine character markers and determine kinship in the form of a phenogram. The results of the analysis showed diagnostic characters, namely: stipule shape, leaf shape, leaf tip shape, fruit color, fruit shape, fruit disk shape, pulp thickness, HS seed thickness, HS seed color, HS seed shape. The results of the PAST4 analysis of Robusta coffee cultivars were divided into 4 groups and the phenogram was divided into two main groups at a threshold value of 42%.