The present study was initiated to determine whether isolates from soil and roots of soybean plants can express nitrogenase activity when grown in the absence of plant host. The study was conducted to answer the question “can benefit gained by” the interaction between Actinomycetes and Rhizobium symbiosis with legume. Thirty-five isolates identified as Rhizobium and twenty-one Actinomycetes were isolated from the rhizosphere of soybean plants and identified by morphological character, biochemical content identified. Fifty-six isolates were tested for their capabilities of N2 fixation and siderophore production. The isolated rhizobacteria were grown in N-free media, and twelve of them showed a good growth on the Burk’s N-free media. Almost all strains produced siderophores; however, the production level was very low, and only the strain AK 10 released considerable amounts of this metabolite. One strain of Actinomycetes was selected to test their interactions with Rhizobium. Coinoculation of Actinomycetes and Rhizobium produced synergic benefits on plant growth and get protection from the production of siderophore.

Blast disease caused by Pyricularia oryzae is one of the major rice diseases affecting rice output in Indonesia causing a 90% reduction in yield. This study aimed to determine the distribution of Pyricularia oryzae virulence pathotypes (races) in several South Sulawesi regencies. The P. oryzae races were determined in the Green House using 7 rice differential varieties: Asahan, Cisokan, IR 64, Krueng Aceh, Cisadane, Cisanggarung, and Kencana Bali. A total of 72 P. oryzae isolates from Maros, Gowa, Bone, and Pinrang Regencies were tested. The IRRI evaluation standard assessed the disease intensity seven days after inoculation. There were a total of 24 race compositions of P. oryzae were discovered based on the reactions of different rice varieties. However, only two races were dominant. Race 001 was dominant among Pinrang and Maros isolates, whereas race 020 was dominant in Bone and Gowa. Based on this result, monitoring of disease severity and the dynamics of P. oryzae population race structures is important for the breeding and rational distribution of resistant rice varieties.

Phosphate Solubilizing Bacteria (PSB) can be used to increase the efficiency and availability of P in the soil as it can help the process of releasing the bound of P elements so that they become available to the plants. This study aims to isolate and determine the morphological characteristics of the PSB colonies in the rhizosphere of the local aromatic rice plant, analyze the phosphate solubility of each isolate. A total of eleven rhizospheres bacterial were successfully isolated from the local aromatic rice rhizosphere. The morphological characteristics, including the size, edge, shape, elevation, and color of the colony, were obtained vary. The bacteria found were gram-positive and gram-negative, which are 81.81% and 18.18%, respectively. The result of the catalase reaction test showed 72.72% positive and 27.27% negative catalase. Furthermore, eight bacterial isolates formed a clear zone with an area of 0.84–2.66 cm. The Phosphate solubility was 116.67–133.00, and the Phosphate dissolving index was 2.17–2.33 at acidic pH between 4.27–5.67. The concentration of dissolved phosphate was 5.152 mg L−1 – 9.382 mg L−1. The results showed that the PSB has a potential being an alternative way to be developed as a biological fertilizer agent in supporting sustainable agriculture.

Chitin is the main component of fungal cell walls. The growth of fungi can be inhibited by chitinolytic bacteria because they can produce chitinase enzymes which play a role in degrading cell walls. The purpose of this study was to test the activity of bacteria isolated from the roots of Ipomea pes caprae in inhibiting the growth of the fungus Lasiodiplodia pseudothebromae. The research method was carried out by isolating as much as 5 g of I. pes caprae roots using specific media and testing for bacterial antagonism using a dual culture method. The results showed that there were four isolate codes obtained namely IPaR1, IPaR4, IPpA2, and IPpA3 and could inhibit the growth of Lasiodiplodia pseudtheobromae.

Tungro is one of the major diseases has ability reduce the yield potential of rice. The disease was caused by rice tungro baciliform virus (RTBV) and rice tungro spherical virus (RTSV). Both of virus only transmitted by green leafhoppers, Nephotettix virescens in a semi-persistent manner. The research purpose is to control tungro disease and its vectors as well as the diversity of natural enemies by applying the intercropping method of several rice plant varieties. The optimum of disease incidence in 11 weeks observation on the variety of Ciherang, Inpari 32, Inpari 36, and IR 64 planted in intercropping was 7.8%, 7.3%, 3,8%, and 6.3%. Whereas, the incidence on these respective variety planted in monoculture was 9.8%, 8,8%, 4.3%, and 8.5%. Then, the optimum of N. virescens population per clump on rice variety with intercropping in the same time of observation was 4.8, 2.3, 1.5, and 4, and on variety with monoculture was 6.5, 4.5, 3.3, and 4,5, respectively. Moreover, the population of insect predators tended to be higher on variety with intercropping than on rice variety with monoculture. These data indicated that rice planted with variety intercropping was related to the reduction of tungro incidence and its vector and also the increase of insect predators. Therefore, the intercropping of variety could used as one of control method against rice pests and diseases.