Rizobakteria Pseudomonas sp. dan Bacillus sp. Toleran Asam Aluminium sebagai Pemacu Pertumbuhan Tanaman dan Pengendali Fungi Patogen Akar Tanaman Kedelai

Abstract

Kedelai merupakan salah satu sumber protein nabati yang banyak dikonsumsi oleh masyarakat Indonesia sehingga produksinya perlu terus ditingkatkan. Kendala yang dihadapi dalam peningkatan produksi adalah sempitnya lahan yang subur dan serangan patogen termasuk fungi, sehingga perlu diarahkan pengembangannya ke lahan marginal dan memanfaatkan rizobakteria simbion sebagai altematif pengendalian serangan fungi patogen.

Soybean is one of protein source that is consumed by many Indonesian people, therefore it is needed to increas its production. One of the problems faced in increasing the production is the less of fertile soil, in this case acid aluminium soils. In this condition, symbiotic rhizobacteria that might give contribution to the increasing of production is not endured toward this condition. However, there are some strains of rhizobacteria that are endured, so it is needed selection of the potential rhizobacteria This research aimed to study rhizobacteria Pseudomonas sp. and Bacillus sp. Acid Al tolerant to promote plant growth and control the soybean root phytopathogenic fungi. Of 16 Pseudomonas sp. isolates and 15 Bacillus sp. isolates that were selected in pH 4.5+AI 50 IJM media, 10 Pseudomonas sp. isolates and 6 Bacillus sp. isolates were able to grow on media pH 4.5 + AlSO IJM. Combination treatment of Bacillus sp. Cr 76 with Bradyrhizobium japonicum increase dry weight of root 0.0505 g, dry weight of shoot 0.2768 g and nodule number 19 nodule. While Pseudomonas sp. Crbl7, Bacillus sp. Cr 24 and B. japonicum combination could disease suppression 66.66 % caused by Fusarium oxysporum. At the same time Bacillus sp. Cr 55 and Pseudomonas sp. Crb 64 with B. japonicum combination could disease suppression 55.56 % caused by Sclerotium rolftii. The other way, it was not found the optimum treatment in disease suppression caused by Rizoctonia solani with inoculated Pseudomonas sp. Crb 86, Bacillus sp. Cr 76 and B. japonicum agens. Peroxidase test, agens Pseudomonas sp. Crb 17, Bacillus sp. Cr 24 and B. japonicum combination, Pseudomonas sp. Crb 64, Bacillus sp. Cr 55 and B. japonicum combination, Pseudomonas sp. Crb 86, Bacillus sp. Cr 76 and B. japonicum combination could increase two times over activity of peroxidase than control.