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

Papaya Ringspot Virus (PRSV) Causing Ringspot Disease on Papaya in Bali

In a survey of papaya plantation in Tabanan, Bali, some papaya cultivars were found showing papaya ringspot disease symptomps i.e. yelowing and mottle on leaves; and ring spot on fruits. The analysis of enzyme linked immunosorbent assay (ELISA) of symptom leaf with papaya ringspot virus (PRSV) antiserum shown the disease was corresponding to the PRSV. The test results showed that PRSV infected papaya in Bali and detected in Tabanan. Previously, there has been no reports of the existence of this disease in the area of ​​Bali. The objective of the study were to observe the variations of disease symptoms caused by PRSV, mapping the disease spread in Bali, and  determine the molecular character of  PRSV Bali isolate. Surveys were conducted to observe the variations of disease symptoms and mapping the disease spread. Molecular method was used to determine the coat protein (CP) sequence. Analysis of leaf samples from diseased plants by reverse transcription-polymerase chain reaction (RT-PCR) was conducted using a pair of primers specific to PRSV. Study result shown the disease was detected in Bangli village, Tabanan regency with the infection index 73,33% (11/15), whereas samples from other survey sites not found infected with PRSV.  On samples that infected with PRSV were found yelowing and stunting on leaves; and ring spot on fruits. Amplicons of 905 bp were successfully amplified. Result from BLAST and sequence alignments showed that Bali isolate had considerable homology to the China (Accession No. KF 033092.1) isolate (99.45% na-level). Results of phylogenetic analysis using Maximum Parsimony approaches with 1000 bootstrap replications indicates that Bali isolate is in a clade with the China  isolates (Accession No. KF 033092.1, KF 033089.1, KF 033078.1). Keywords: papaya , symptom, infection index, disease spread, molecular character

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

Pseudomonas alcaligenes, Potential Antagonist Against Fusarium oxysporum f.sp.lycopersicum the Cause of Fusarium Wilt Disease on Tomato

The research is financed by the Directorate General of Higher Education, Ministry of Education and Culture the Republic of Indonesia in fiscal year 2012. Abstract Fusarium wilt disease caused by Fusarium oxysporum f.sp. lycopersici is one of important diseases that potentially cause significant yield losses on tomato. There is no measure available to control the disease effectively.  This study was done to isolate the antagonistic Pseudomonas sp.  from rhizospeheres of plants of Leguminosae and Solanaceae and to determine their antagonistic activity against F.oxysporum f.sp.lycopersicum. Biochemical test and molecular analysis of the 16S rRNA gene were done  to determine the species of Pseudomonas sp. There are three isolates of Pseudomonas sp. were obtained in this study namely  isolates KtS1, TrN2, and TmA1. Results of 16S rRNA gene analysis showed that all three isolates had  more than 99% similarity to P. alcaligenes. These isolates showed strong antagonistic activity against F. oxysporum f.sp. lycopersici with inhibitory activity more than 80%.  Application of bacterial suspension of P. alcaligeneseffectively suppressed the disease incidence of Fusarium wilt on tomato. Keywords : antagonistic activity,  Pseudomonas alcaligenes, Fusarium wilt disease

First Report of Curvularia specifera the Cause of Leaf Spot Disease on Rice in Bali, Indonesia

Leaf spot disease was found to occur on rice grown in Badung Regency, Bali Indonesia at the end of 2016. A fungus was isolated from diseased-rice plant and was confirmed to cause inhibition to rice seed germination. More than 63% of the rice seed did not germinate after inoculated with the isolated fungus. Based on the Koch’s postulate test, the fungus caused of leaf spot disease symptom that appeared on the 3rd day with the disease intensity reached 34.26% on the 14th day. This fungus could also cause sheath spot disease on the 14th day. This study aimed to identify the species of fungus causing the leaf spot disease in rice plants. Based on macroscopic, microscopic and analysis of 18S rRNA gene, it was concluded that the fungus causing leaf spot disease in rice plant of Ciherang cultivar in Badung regency, Bali Indonesia is Curvularia spicifera.Keywords: leaf spot disease, rice plant, Curvularia spicifera

Resistance of Several Local Rice Varieties to Isolate Tungro Virus from Muara

Resistance of Several Local Rice Varieties to Isolate Tungro Virus from Muara Tungro disease is one of the important diseases in rice because it causes stunted plants and may induce significant yield losses. Planting resistant varieties is a recommended control strategy to overcome tungro disease. The research was conducted to find sources of genetic resistance from local rice varieties that can be used in breeding of tungro disease resistant varieties. The experiment was arranged in a descriptive research design with observational techniques. Observations were made on 16 local rice varieties with each variety consisting of 30 sample plants so that the number of plants used was 480 plants. The isolate of tungro virus collected from rice field in Muara, Bogor was inoculated to the test plants through the insect vector, green leafhopper (Nepothettix virescens). The results showed that the resistance of local varieties varied based on the value of disease index, disease incidence and plant height reduction. ‘TN1’ was the check susceptible variety against tungro virus, while the local rice varieties were differentiated into resistant (‘Utri Merah’), moderate (‘Karau’, ‘Bekongan’, ‘Bujang Bernai’, ‘Srogel Abang’, ‘Pulut Garu’, ‘Randu Range’, ‘Siredep’, ‘Katimpung’, ‘Pulut Sawijan’, ‘Dube’), moderate tend to be susceptible (‘Blumbungan’, ‘Tjere bandung’, ‘Sempor’) and susceptible (‘Rumbai’). All varieties can be infected (disease incidence 27 – 76%), but disease severity varies greatly (3–7). The more severe the disease, the higher the plant height reduction. ‘Srogel Abang’ is a variety that is useful for breeding rice varieties resistant to tungro disease because it showed moderate response with a low percentage of plant height reduction (36%) so that plant productivity can still be maintained.Penyakit tungro merupakan salah satu penyakit penting pada tanaman padi karena menimbulkan gejala tanaman kerdil dan mampu menyebabkan kehilangan hasil yang nyata. Penanaman varietas tahan merupakan strategi pengendalian yang direkomendasikan untuk mengatasi penyakit tungro. Penelitian dilakukan untuk mencari sumber ketahanan genetik dari varietas padi lokal yang dapat digunakan dalam perakitan varietas tahan penyakit tungro. Percobaan disusun dalam rancangan penelitian deskriptif dengan teknik observasi. Observasi dilakukan terhadap 16 varietas padi lokal dengan setiap varietas terdiri atas 30 tanaman contoh sehingga jumlah keseluruhan tanaman yang digunakan sebanyak 480 tanaman. Isolat virus tungro dari pertanaman padi di Muara, Bogor diinokulasikan ke tanaman uji melalui serangga vektor wereng hijau (Nephotettix virescens). Hasil penelitian menunjukkan bahwa ketahanan varietas lokal bervariasi berdasarkan nilai indeks penyakit, insidensi penyakit dan penyusutan tinggi tanaman. Varietas TN1 merupakan varietas pembanding dengan reaksi rentan, sedangkan varietas padi lokal dibedakan atas tahan (‘Utri Merah’), moderat (‘Karau’, ‘Bekongan’, ‘Bujang Berinai’, ‘Srogel Abang’, ‘Pulut Garu’, ‘Randu Kisaran’, ‘Siredep’, ‘Katimpung’, ‘Pulut Sawijan’, ‘Dube’), moderat cenderung rentan (‘Blumbungan’, ‘Tjere bandung’, ‘Sempor’) dan rentan (‘Rumbai’). Semua varietas dapat terinfeksi (insidensi penyakit 27–76%), tetapi indeks keparahan penyakit sangat bervariasi (3–7). Semakin berat keparahan penyakit menyebabkan penyusutan tinggi tanaman semakin tinggi. ‘Srogel Abang’ merupakan varietas yang bermanfaat untuk perakitan varietas padi unggul tahan penyakit tungro karena bersifat moderat dengan persentase penyusutan tinggi tanaman yang rendah (36%) sehingga produktivitas tanaman masih dapat dipertahankan

Genetic Variation of Coconut Tall (Cocos nucifera L., Arecaceae) in Bali, Indonesia Based on Microsatellite DNA.

The coconut has  important roles for economics, traditional medicine and culture,  especially for Hindu’s ceremonial purpose in Bali Island (Indonesia). Each coconut cultivar  has unique characteristics.   The aimed of this research was to determine genetic variation of coconut tall (Cocos nucifera L., Arecaceae) in Bali, based on DNA microsatellite.  Six pairs microsatellite markers were used to determine heterozygosity. The results showed that total of 80 alleles  were detected by microsatellite with an average of 13.33 alleles per locus, there were 12 alleles on microsatellite locus CnCirA3, 12 alleles on locus CnCirC3, 16 alleles on locus CNZ05, 14 alleles on  CNZ09 , 17 alleles on CNZ21,  and 9 alleles  on microsatellite primer  pairs CNZ51. The mean values of gene diversity (He) and observed heterozygosity (Ho) were 0.8835 and 0.5421, respectively.  The highest heterozigosity  was on bulan tall coconuts cultivar (0.816), the lowest heterozygosity was on bluluk tall coconuts (0.35).   Keywords: unique characteristic, microsatellite, allele, heterozygosity, coconu

Leaf Extract of Cinnamomum burmanni Blume Effectively suppress the growth of Fusarium oxysporum f.sp. lycopersici the cause of Fusarium wilt disease On tomato

Productivity of tomato in Indonesia is still relatively lower than the productivity of tomato in other countries. One of the factors for the low productivity is occurrences of Fusarium wilt disease caused by Fusarium oxysporum f.sp. lycopersici. To find an alternative method to control the disease, in this study the antifungal activity of Cinnamomum burmanni was tested against the growth of F. oxysporum f.sp. lycopersici under in vitro condition on potato dextrose agar (PDA) and potato dextrose broth (PDB) media. Extraction was done using pro analysis (PA) grade of acetone. Results of this study showed that the leaf extract of C. burmanni effectively suppressed the radial growth, biomass formation and spores formation of F. oxysporum f.sp. lycopersici, with the minimum inhibitory concentration (MIC) by 1% (w/v). The inhibitory activities of this extract at concentration of 1% (w/v) against fungal radial growth, biomass formation and spores formation were respectively 41.66%, 43.68%, and 48.43% when compared to control. This leaf extract containing steroid, flavonoid, phenolate and tannin   which  probably responsible for the antifungal activity against F. oxysporum f.sp. lycopersici. Further study is still necessary to be done in order to identify the main substance that responsible for the antifungal activity as well as the effectiveness of the leaf extract to control Fusarium wilt disease on tomato plant. Keywords: leaf extract, Cinnamomum burmanni, inhibitory activity, Fusarium wilt diseas

Molecular Identification of Mushroom Causing Wilt Disease in Clove Plants (Syzygium aromaticum L.)

Wilt disease in clove plants (Syzygium aromaticum L.) becomes one of the main factors inhibiting the production of cloves in Buleleng Regency Bali. This study aims to identify the pathogen causing wilt disease in clove plants in Buleleng Regency Bali. The identification of the pathogen causing wilt disease in clove plants was done macroscopically, microscopically, and molecularly. The macroscopic characteristic were that the color of the mushroom was shiny white when seen from the surface and the base of a Petri dish, colonies of fungi grew in a Petri dish walls, fungi formed aerial hyphae and fruit bodies. The microscopic characteristic was that the hyphae formed clamp connection. The molecular identification of the pathogen causing wilt disease was performed using PCR (Polymerase Chain Reaction) with primers internal transcribed spacer (ITS) to produce DNA fragment size of about 580 bp. The phylogenetic tree wilt disease-causing pathogen isolates was based on the method Neighbor Joining Tree with bootstrap values of 1000 was in a clade with Schizophyllum commune. Conclusion of the study results showed that the pathogen isolated at the clove root having a wilt disease symptom in Bali was Schizophyllum commune Fr. (Schizophyllaceae, Basidiomycota)

Synergistic Activity of Leaves Extracts of Mansoa alliacea L. and Allamanda cathartica L. to Inhibit Athelia rolfsii, the Cause of Stem Rot Disease in Peanut Plants

Stem rot disease in peanut plants caused by Athelia rolfsii is an important disease because it can reduce peanut yield up to 13-59%. The study aimed to evaluate the synergistic activity of the leaves extracts of Mansoa alliacea L. and  Allamanda cathartica as an alternative control of stem rot disease in peanut plants. Testing of Antifungal activity was carried out  in the laboratory included: diameter of inhibition zone test with diffusion well method; colony growth test, sclerotia germination test, fungal biomass test, and ultrastructure observation using scanning electron microscope (SEM). The results showed that the crude extracts of the leaves of M. alliacea and  A. cathartica were able synergistically to inhibit the growth of the fungus A. rolfsii with diameter of inhibition by 42 mm, while the diameter of inhibition zones for leaf extract of M. alliacea L. was only 30 mm and as for  A. cathartica L. was only 9 mm. Minimum inhibitory concentration (MIC) of the mixture of leaves extracts of Mansoa alliacea L. and A. cathartica L. was 0.8% (w/v). Treatment with the extract’s mixture  significantly (P≤0,05) inhibited colony growth, germination rate of sclerotia, and fungal biomass of A. rolfsii. The result of mycelial observation of A. rolfsii by using SEM  showed that surface of fungal mycelia treated with extract looked smaller in size and shrunk, and leakage of cell wall became visible; while at the control, the surface of mycelia remained intact and thrived perfectly. Keywords: synergistic activity, leaves extract, stem rot diseas