Phenotypic Variation of Cultured Seaweed Gracilaria spp. in Brackishwater Pond at Desa Lengen Sari, Subang

Abstract

There are production constraints for seaweed processing industries in Indonesia because of Gracilaria inconsistent quality. Gracilaria quality determined by seed quality, and the quality of seed may influenced by phenotypic variation. This research collects information about phenotypic variation of seaweed in brackhishwater pond at Langen Sari Village, Subdistrict Blanakan, Subang, West Java as data base for seaweed production estimation and quality criteria. The Gracilaria phenotypic variation with the water quality of pond were analyzed. Sample Gracilaria spp. collected from 12 location in four brackhishwater pond, those are inlet, middle, outlet. Four brackhishwater pond distinguished by salinity level 4,0-4,4; 4,1-5,8; 6,5-7,4, and 11,7-11,9 ppt. The seaweed furthermore weighed, observed the colour, measured morphometric phenotype; thallus diameter, thallus length, thallus internode, and branching number. Water quality measured are salinity, water depth, temperature, water oxydation reduction potential (ORP), conductivity, turbidity, total dissolved sediment (TDS), pH, dissolved oxygen (DO), nitrate, and phosphate, and also measured the sludge ORP and sludge thickness. Relation between those parameters and the influence on seaweed phenotype were analized by MINITAB 14. Phenotype of Gracilaria spp. from salinity 6,5 ppt up to 11,9 ppt are more uniform, with thicker thallus diameter, less percentage of yellow colour, and less of tertiary thallus number than from lower salinity.

Terdapat kendala produksi bagi industri pengolahan rumput laut yang ada di Indonesia akibat kualitas Gracilaria yang tidak konsisten. Kualitas Gracilaria ditentukan, salah satunya oleh kualitas bibit, sementara itu terdapat beragam kualitas bibit yang dipengaruhi oleh keragaman fenotipe. Penelitian ini bertujuan mengumpulkan informasi mengenai keragaman fenotipe rumput laut pada tambak budidaya Gracilaria spp. di Desa Langensari, Kecamatan Blanakan, Subang, Jawa Barat sebagai data dasar pendugaan produksi dan kriteria mutu rumput laut. Kaitan antara keragaman fenotipe dan kondisi lingkungan perairan tambak di mana rumput laut dibudidayakan juga dianalisis. Sampel rumput laut Gracilaria spp. dikoleksi dari 12 lokasi pada empat tambak, yaitu di inlet, middle, dan outlet. Empat petak tambak yang dibedakan berdasarkan tingkat salinitas, yakni 4,0-4,4; 4,1-5,8; 6,5-7,4; dan 11,7-11,9 ppt. Sampel rumput laut selanjutnya diamati warnanya, ditimbang bobotnya, dan diukur diameter talus, panjang talus, internode talus, dan dihitung percabangannya.