Efektivitas Bacillus Subtilis QST713:109 CFU/ml sebagai Plant Growth Promoting Rhizobacteria pada Tanaman Kubis (Brassica oleracea)

Bacillus subtilis is a ubiquitous bacterium commonly found in various ecological niches and has potential as a plant growth promoting rhizobacterial (PGPR). This study aims to determine the effectiveness and determine the effective concentration of B. subtilis strain QST713:109 CFU/ml as PGPR in cabbage. Five treatment levels of B. subtilis QST713:109 CFU/ml concentration namely 0 ml L-1 as a control, 2.5 ml L-1, 5.0 ml L-1, 7.5 ml L-1, and 10.0 ml L-1 have been applied on cabbage plants. The solution with those concentrations was sprayed on cabbage plants aged 1, 2, 3, and 4 weeks after planting with a spray volume of 500 L ha-1. Plant height, number of roots, crop weight, yield per plot, and yield potential per hectare of cabbage treated with B. subtilis QST713:109 CFU/ml with a concentration of 2.5 and 5.0 ml L-1 was higher than the control. The concentration of 2.5 ml L-1 B. subtilis QST713:109 CFU/ml resulted in the highest relative agronomic effectiveness (RAE) value of 112.2%. This concentration is the most effective for increasing the growth and production of cabbage with a potential yield of 52.16 tonnes ha-1 without causing phytotoxicity. The yield potential of control treatment is 46.50 tons ha-1. Thus B. subtilis QST 713:109 CFU/ml is effective as a PGPR for cabbage. Keywords: efective, PGPR, phyotoxicity, relative agronomic efectiveness ; Bacillus subtilis adalah bakteri yang ada di mana-mana yang biasa ditemukan di berbagai relung (niche) ekologi dan berpotensi sebagai Plant Growth Promoting Rhizobacterial (PGPR). Penelitian ini bertujuan untuk mengetahui efektivitas dan menentukan konsentrasi efektif dari B. subtilis QST713:109 CFU/ml sebagai PGPR pada tanaman kubis. Perlakuan terdiri dari 5 taraf konsentrasi B. subtilis QST713:109 CFU/ml yaitu 0 ml L-1 sebagai kontrol, 2.5 ml L-1, 5 ml L-1, 7.5 ml L-1, dan 10 ml L-1. Larutan dengan konsentrasi tersebut disemprotkan pada tanaman kubis umur 1, 2, 3, dan 4 minggu setelah tanam dengan volume semprot 500 L ha-1. Pertumbuhan tinggi tanaman, jumlah ...