Effectiveness of Rhizobacteria to Reduce Rice Blast Disease Intensity

Rice blast disease caused by Magnaporthe grisea Barr (anamorf Pyricularia grisea Sacc. synonym Pyricularia oryzae Cav.) is one of important diseases for rice cultivation in Indonesia. Five isolates of rhizobacteria isolated from the rhizospheres of rice in Bali were tested for their effectiveness to reduce the rice blast disease intensity on rice cultivar Ciherang under green house condition. All isolates were formulated in liquid formulas which were respectively contained bacterial suspension of Enterobacter agglomerans Ch2D, Xanthomonas luminescens Ch3D, Enterobacter agglomerans Ch4B, E. agglomerans Gg14D and  Serratia liquefaciens Gh13D.  Results of this study showed that all five formula of rhizobacteria effectively reduced the rice blast intensity on rice cultivar Ciherang. The rice blast intensity on plants treated with  rhizobacteria were varied from 13.96 to 19.44%, while the disease intensity on control was 33.56%. Formula containing bacterial suspension of E. Agglomerans Gg14D resulted in the lowest blast disease intensity and the highest yield per hill. The yield increment resulted from this treatment was 40% when compared to control. This result suggested that E. agglomerans Gg14D is one of promising candidate for bio-control agent to manage rice blast disease. However, the field trial is needed in order to evaluate the stability and effectiveness of the rhizobacteria formula under field condition at several localities. Keywords: rhizobacteria, rice blast disease, disease intensit

UPAYA MEMINIMALISIR DAMPAK LINGKUNGAN DARI PENGGUNAAN PESTISIDA DALAM PERTANIAN (DAMPAK LINGKUNGAN DAN PENANGGULANGANNYA)

Utilization of synthetic pesticide seems up to now remains to be one of the methods in controlling pest and plant disease because it plays a role in determining the quality and quantity of the crops. Improver of synthetic pesticide in agriculture can adversely affect the ecosystem such as water and soil pollution. The occurrence of pest resistance, the outbreak of secondary pest, the resurgence of pest, the death of predators, the residue of pesticide in food, and the pesticide residue that affects man's health. Although it has been widely known that pesticide has a bad impact on the environment, the use of pesticide is still needed in agricultural practice. Its use needs to pay attention to the concept of Integrated Pest Management in which the use of pesticide is only made when it is absolutely necessary, that is, when the population of pest increases and lies above one level of the pest population, the Economic Threshold (Untung, 1993). To know the safety level of pesticide, evaluation of toxicity of a pesticide is needed and it is commonly tested in the animal of high level. This is done in such a way that the toxicity and safety level of the pesticide can be known by farmers, users of pesticide, and the environment. Based on the information on the toxicity level, it is expected that the steps of environmental management can be taken to minimize the negative impact of pesticide. The effort of minimizing the negative impact of pesticide can be done in a variety of ways. For example, the direction was given to the users in terms of giving the dosage, application time, safe working procedure, choosing pesticide with the precise target, choosing a pesticide that can decompose easily, application target, a time before harvest, tool and exact application technique, keeping as small pollution as possible. In the future, it is hoped that the use of pesticide will decrease and will be more selective, and supported by new inventions in the technology of processing pesticide disposal and the technology of utilizing botanical pesticide which is all expected to be effective in overcoming the disturbance of pest and plant disease at the same time minimizing environmental degradation

Efficacy of Rhizobacteria to Promote the Growth and Increase the Yield of Several Rice Cultivars

Rice is still play important role as staple food for most of Indonesian population; consequently  Indonesia is greatly relying on rice production to maintain food security. This plant is commonly cultivated with intensive use of synthetic agrochemicals such as synthetic chemical fertilizers and pesticides. However, the improper use of agrochemicals may result in adverse effects to the environment including biotic and abiotic components. This study was conducted to evaluate the efficacy of rhizobacteria formulation to promote the growth and increase the yield of four rice cultivars that commonly grown in Indonesia i.e. Ciherang, Cigeulis, Inpari 33, and IR64. Experiment was done in a green house with three concentrations of rhizobacteria formulation i.e. 0%, 1%, and 2% (v/v). Several parameters were observed in this study such as seedling height, leaf chlorophyll content of seedling, plant height at 50 days after transplanting (DAT), leaf chlorophyll content at 50 DAT, number of tillers per plant at 50 DAT, number of productive tillers per plant, and yield per plant. Results showed that significant interactions were observed between rice cultivar and concentration of rhizobacteria formulation in all parameters observed. Rice cultivar IR64 consistently showed superior growth and yield among four rice cultivars tested. Except for cultivar IR64, rhizobacteria concentration at 2% showed superior results compared to 1% and 0% for all parameters observed. This study proved that rhizobacteria formulation containing Stenotrophomonas maltophilia Sg3 and Enterobacter cloacae Al7Kla effectively promoted the growth and increase the yield of four rice cultivars that commonly cultivated in Indonesia, suggested that this rhizobacteria formulation is promising bio-agent to be used for rice production in Indonesia. Keywords: Rhizobacteria, plant growth promotion, rice yield DOI: 10.7176/JBAH/11-16-03 Publication date:August 31st 202

Effectiveness of Enterobacter cloacae to Promote the Growth and Increase the Yield of Rice

Rice productivity in Indonesia is relatively lower than the rice productivities in other rice growing countries. In order to increase the rice productivity, it is necessary to find agents that can improve and promote the rice growth. This study was done to determine potential use of Enterobacter cloacae isolated from rhizospheres of Imperata cylindrica to promote the growth and increase the yield of rice under green house experiment. Five isolates of E. cloacae namely Al2N, Al3Bt, Al9Sa, Al6G, Al7Kla were tested for their effectiveness to promote the growth and increase the yield of rice. Treatments with isolates of E. cloacae significantly improved the growth of rice seedlings, in which the plant height, root length and number of root significantly (p<0.05) higher on treated plants when compared to control. These treatments were also significantly increased the number of tillers, content of chlorophyll in the leaf, content of macro nutrients in the leaf, the dry weight of shoot and the dry weight of root, but did not significantly (p>0.05) affect the plant height. Number of panicles per hill and percentage of filled grain per hill of treated plants were significantly higher than that of control, but the weight of 1000 grains did not significantly different. Rizhobacteria treatment increased the rice yield ranged from 22.53% to 26.13% when compared to control. No significant different were observed on all parameters among treatments with isolates of E. cloacae suggested that all isolates resulted in similar level of effect to the growth and yield of rice.  These isolates may be further developed as plant growth promoting agents to increase the yield of rice in Indonesia. Keywords :  Enterobacter cloacae, plant growth promoting rhizobacteria, rice yield

Aqueous Extract of Purple Sweet Potato Tuber Increases Sod And Decreases VCAM-1 Expression By Increasing Nrf2 Expression In The Aortic Endothelia Of Hypercholesterolemic Rabbits

Aqueous extract of purple sweet potato tuber are supposed to prevent oxidative stress and protect endothelial function by unknown mechanisms. The purpose of this study was to prove the ability of purple sweet potato tuber aqueous extract in preventing oxidative stress through increasing superoxide dismutase (SOD) via Nrf2 upregulation and decreasing VCAM-1 expression in rabbit aortic endothelium. This study was experimental laboratoric study, with randomized post-test only control group design. The rabbits were randomized into 3 groups (6 rabbits per group). The control group was treated with standard diet, treatment 1 was treated with high-cholesterol diet, and treatment 2 was treated with high-cholesterol diet plus aqueous extract of purple sweet potato tuber with the dose of 4 mL/kg bw/day. After 12 weeks of treatment, blood samples were obtained for the examination of SOD, MDA and total cholesterol level. The expression of Nrf2, SOD-2 and VCAM-1 in aortic endothelium was evaluated based on immunohistochemical methods. One-way ANOVA  test were applied in data analysis, followed by path analysis. The results demonstrated significantly decreased MDA and increased blood SOD level, accompanied by statistically-significant increase in SOD-2 and Nrf2 expression, and decrease of VCAM-1 expression in the treatment group 2 compared to treatment group 1 (p <0.05). It can be concluded that the purple sweet potato tuber aqueous extract prevents oxidative stress by increasing the expression of SOD-2, via Nrf2 protein up-regulation, resulting in decreased VCAM-1 expression in the aortic endothelia of high-cholesterol diet-fed rabbits. Keywords: Purple sweet potato, oxidative stress, SOD-2, Nrf2, VCAM-1, rabbit aort

CONTRIBUTION OF SUPPRESSIVE SOIL IN CONTROLLING PLANT DISEASES

Some soils have been observed to suppress diseases in crops grown upon them. Soils are a rich source of microbes that are thought to help plants suppress pathogens by improving the health of the plant, induce natural plant defense, produce antibiotics, compete against pathogens, or hyperparasitize the pathogen. Soil that suppresses crop disease due to the specific structure of its microbial community is known as disease-suppressive soil. Suppressive soil is an attractive method of biocontrol, because it has the potential to be sustainable over many seasons under favourable conditions.Suppressive soil is an example where the microflora in the soil is effective in protecting plants against soil-borne pathogens. The diversity and density of populations (bacteria, actinomycetes and fungi) is higher in suppressive soil than in conducive soil, including the diversity and population density of antagonistic microbes, for example in banana plant habitats without symptoms of Fusarium wilt (suppressive soil) is higher than the diversity of soil microbes in banana plant habitat with Fusarium wilt symptoms (conducive soil)

Potential of Acetoin-Producing Rizobacteria from Rhizospheres of Plants of Graminae Grown in Merauke Indonesia to Promote the Growth of Rice

Acetoin (3-hydroxybutan-2-butanone) is a volatile compound produced by bacteria that function as a plant growth promoting agent. Acetoin plays an important role in stimulating the process of plant organogenesis (morphogenesis) for faster formation of plant organs and faster plant growth. Besides being able to increase the growth,  acetoin  can also induce plant resistance, increase the formation of the number of branches, roots and flowers so that acetoin can increase crop productivity. This study aims to isolate and identify acetoin-producing rhizobacteria which can promote the growth of rice plants. Rhizobacteria isolation was carried out from the rhizospheres of plants of Graminae grown in Merauke, Indonesia. Identification was made molecularly through 16S rRNA gene analysis. This study obtained four rhizobacteria isolates that produce acetoin which act as a promoter for rice plant growth, namely isolates Pd13, Rg21, Pd7, and Bb7. These four rhizobacteria isolates can increase the number of lateral roots of rice seedlings aged 14 days after planting with percentage of increase by 60.68%; 40.24%: 32.61%, and 19.56% compared to controls. The identification results show that the species of isolates of rhizobacteria are Myroides odoratimimus Pd13 and Bb7, Providencia vermicola Rg21, and  Serratia marcescens Pd7. They have the potential to be developed as a promoter for plant growth and increase the yield of rice plants, especially in Marauke Papua, Indonesia. Keywords: Rizobacteria, acetoin, growth promotion, rice yiel

Exploring Antagonistic Candidate Fungi for Controling Pathogenic Fungi (Colletotricum gloeosporioides) Causing Anthracnose Disease in Kintamani Siam Orange Plants (Citrus Nobillis Lour Var. Hass)

Orange plantation center in Bali are located in Bangli Regency, Kintamani District. Kintamani orange plantations cultivated three types of oranges: tangerine, selayer, and mandarin oranges. The famous orange in Bali today is Kintamani orange,  tangerine type.  The typical flavor and aroma of Kintamani tangerine make it is favored by consumers from various regions. Based on the information from Bangli District Agriculture Office and the results of field surveys in the last two years (in 2013 and 2014), cultivation of orange in Kintamani has been infected with anthracnose disease. The disease is characterized by symptoms whereby brown twigs spread to the leaves and fruit, and the fruits which are about to be harvested rot simultaneously and eventually fall due to decay. This condition causes farmers to suffer significant losses. The cause of anthracnose on Kintamani orange is Colletotrichum gloeosporioides .  The Control of these diseases has been carried out by farmers with various synthetic fungicides but the disease is still widespread.   It is feared that the uncontrolled use of synthetic pesticides can harm the environment, cause resistance to C. gloeosporioides fungi, and kill non-target beneficial micro-organism. It is necessary to conduct research that aims to control anthracnose biologically to maintain the ecological balance and environmental safety. Based on the results of this research by exploring the fungi on healthy plants around orange trees infected with anthracnose diseases, nine isolates of antagonist candidate fungus were obtained based on colony color of fungal hyphae (IS1, IS2, IS3, IS4, IS5. IS6, IS7, IS8, IS9).   Based on the test results of the in vitro dual culture, two candidates of antagonistic fungal isolates were selected,  the isolates IS4 and IS7. It was because on day 7 after the second dual culture, these two isolates had the highest percentage of inhibition,  89.22% and 85.11 % respectively. Based on the conventional and molecular identifications, it is known that the two candidate isolates of antagonistic fungus (IS4 and IS7) belong to one species of the Aspergillus aculeatus

Changing Roles of Traditional Small Urban Green Spaces (Telajakan) in Bali, Indonesia

Bali Island, Indonesia is undergoing rapid land use changes due to heavy development pressure and its fast growing urban population. One such urbanization phenomenon is the shrinkage, deterioration, and disappearance of traditional small urban green spaces in Denpasar, Bali. Focusing on telajakan, a strip of traditional green space between the wall of a housing compound and a ditch/pedestrian path in a roadside, the study aims 1) to investigate and document the changes that are occurring with regards to telajakan and 2) to assess the functions (roles) of telajakan in Denpasar. The research methods include vegetation assessment at a lot scale and in-depth homeowner and village leader interviews with the help of local experts. The results show that telajakan space is often paved over to give way to more front space for the property owner and to ease maintenance. It is also minimized or destroyed as the owner builds a more “western” style house. Traditionally telajakan has multiple functions such as provision of plant and flower materials for Balinese daily rituals, regu-lation of stormwater from the property, and offering semi-public space for street vendors and neighbours. However, the results show that: diversity of planted species is decreasing; only a couple of functions such as aesthetics and economics are strongly favored; and the semi-public nature of telajakan is being lost. Since telajakan is as much traditional green open space as part of the aesthetics of the Balinese architecture, its loss, minimization, and degradation lead to the loss of Balinese culture and identity. On the other hand, new meaning is given to telajakan’s functions such as neighborhood beautification and exhibition of the owner’s pride in the modern context. Therefore, policy recommendations to conserve telajakan in the changing urban fabric need to balance these changing needs of telajakan for its use and conservation of traditional rituals and culture of Bali

The Use of Rhizobacteria to Promote Buds Formation of Bulbil of Elephant Foot Yam

Elephant foot yams (Amorphophallus muelleri Blume) is one of tuber crops becoming popular among farmers in Indonesia as the tubers of this plant rich in carbohydrates, fats, protein, minerals, vitamins and fiber. However, the propagation of this plant can not be done easily as the seedlings materials such as tubers, bulbils and seeds have dormancy periode after harvested. This study was done to evaluate the capability of rhizobacteria from rhizospheres of graminous plants to promote the buds formation of bulbil of elephant foot yams. A total of 76 isolates of rhizobacteria were tested for their capability to produce indole acetic acid (IAA), and for those capable of producing IAA were tested for their ability to promote buds formation of elephant foot yams bulbils. Results of this strudy showed that, nine isolates of rhizobacteria were proven to produce IAA, namely Sr3, Sr16, Sr17, Sr18, Sr19, Sr21, Jg8, Rg1 and Pb2. Treatments with rhizobacteria significantly (p<0.05) increased the percentage of bulbils produced buds. Treatment with three isolates namely Sr21, Jg8 and Rg1 resulted in percentage of buds formation more than 60%, in which treatment with isolate Rg1 showed the highest percentage of buds formation. This results suggested that isolate Rg1 potentially can be used as a bio-agent to promote buds formation in bulbils of elephant foot yams to produce uniform and vigorous seedlings of this plant. Keywords: elephant foot yams, rhizobacteria, buds formation, promotion, seedlings DOI: 10.7176/JBAH/13-12-03 Publication date:July 31st 202