Identification of Morphological and Physiochemical Characteristics, Flowering Periods, and Genetic Relationship of Citrus Species

Abstract

Variety improvement program of citrus in Indonesia has still been prioritized, therefore, characterization and identification of varieties within and/or among citrus species are absolutely required in order to obtain desired varieties based on market demand needs. The aim of this research was to determine morphological characteristics, flowering periods, and the genetic relationship of four citrus species. This study was carried out at Indonesia Citrus and Subtropical Fruit Research Institute (ICISFRI). A total of 12 varieties derived from Citrus reticulata Blanco, Citrus sinensis L. Osbeck, Citrus aurantifolia (Christm.) Swingle), and Citrus lemon (L.) Burm. F was used for morphological description. The genetic relationship was evaluated by morphological and molecular analyses using Inter-simple Sequence Repeat (ISSR). The result showed that variations of morphological characters were identified either within or among four citrus species. Citrus reticulata Blanco had the highest physiochemical contents. In terms of flowering periods, varieties that belong to Citrus reticulata Blanco, and Ortaji (Citrus sinensis L. Osbeck) required 9 to 11 days for fully blooming after flower bud; whereas Montaji (Citrus limon (L.) Burm. F) and Nimas (Citrus aurantifolia (Christm.) Swingle) needed 16 days. In both morphological and molecular analyses, 12 varieties were classified into two main clusters, however, some differences were found between the two dendrograms. The genetic relationship of four citrus species based on similarity coefficient ranged from 1 to 25 (morphological analyses) and 0.62 to 0.90 (ISSR marker), respectively. The highest genetic relationship derived from both analyses was performed by Krisma versus Monita, and Krisma versus Orlinda Kuning, respectively. Morphological analyses are still needed to complement molecular analyses in citrus classification in order to produce desired new citrus varieties in order to create sustained citrus agribusiness in Indonesia.