Searching for indigenous rhizobacteria from Solok Radjo coffee orchard at Aie Dingin, West Sumatera

Abstract

The coffee plant has been cultivated for a hundred years and is known for its use as a beverage that is widely accepted around the globe. Most of the coffee orchard in Indonesia has been managed conventionally and need to be improved to get a better quality of growth and yield. This experiment was conducted from July to November 2020 and aimed at identifying rhizobacteria associated with coffee plant rhizosphere that later can be applied to stimulate the early growth of coffee seedlings. The soil sample was collected from the Solok Radjo coffee orchard [var. Sigagar Utang] of Nagari Aie Dingin, Alahan Panjang, Municipality of Solok, the Province of West Sumatera Four different conditions of coffee orchard were chosen for this experiment according to plant ages and soil fertility. They were 2-year-old and 6-year-old coffee plants with health and less healthy plant growth. One gram of soil was mixed with distilled water and was diluted prior to being cultured in Nutrient Agar media for 48 hours at ambient temperature. Bacterial colonies went through series of re-culture until pure isolate was obtained and were observed for their morphological and physiological characters. Most of the isolates responded negatively to a hypersensitive reaction test that brings about their potential to promote the growth of coffee plants. In contrast, phytotoxic activity was observed in 2 isolates of rhizobacteria collected from the 6-year-old coffee orchard with less healthy plant growth. This experiment found 46 isolates of rhizobacteria indigenous to coffee orchard var. Sigagar UtangFuture research needs to be directed to investigate the physiological characters of the rhizobacteria before application to the coffee plants.