Mardhiana, Pradana AP, Adiwena M, Kartina, Santoso D, Wijaya R, Maliki A. 2017. Effects of pruning on growth and yield of cucumber (Cucumis sativus) Mercy variety in The acid soil of North Kalimantan, Indonesia. Cell Biol Dev 1: 13-17. In recent years, cucumber production in Tarakan, North Kalimantan only reaches 20 tons ha-1. In fact, cucumber production potential could reach 49 tons ha-1. Several factors that limit the low productivity of cucumbers in Tarakan are acid soil and cultivation techniques which are still limited. This study aimed to determine the effect of pruning on the growth and yield of cucumbers in acid soil in Tarakan. The study was conducted using Randomized Complete Block Design with the treatment of without pruning (P0), shoot of prunings on the main stem (P1), pruning of whole lateral branches above the third section (P2), and pruning of 2 lateral branches that emerged first above the third section (P4). The results showed that plant height was 16.17% (P1) and 2.26% (P2) lower also 0.13% higher (P3) than the control (P0). The highest number of leaves was found in treatment P1 (16.19%) compared to P0. The best fruit diameter was also found in P1 treatment with 4.93% difference compared to P0. Furthermore, a highly significant and the best result on weight per fruit were also obtained by P1 treatment. The results showed that the fruit weight of P1 treatment (11.39%) was higher than P0. This study provided new information that the pruning treatment of shoots on the main stem of cucumber variety Mercy in acid soil could increase the diameter and weight of cucumber.

Wiratno, Syakir M, Sucipto I, Pradana AP. 2019. Isolation and characterization of endophytic bacteria from roots of Piper nigrum and their activities against Fusarium oxysporum and Meloidogyne incognita. Biodiversitas 20: 682-687. The endophytic bacteria from spices plants have potential as biocontrol agents. Nevertheless, their potential has not been explored. Pepper plant (Piper nigrum L.) is linked with promising endophytic bacteria as biocontrol agents. This study aimed to obtain isolates of endophytic bacteria from root tissues of pepper plant. The isolation of endophytic bacteria was done using surface-sterilization method and using Tryptone Soya Agar (TSA) medium. The result showed that 10 endophytic bacteria were successfully isolated. We found that a total of 9 bacteria were safe for plants and mammals and used for subsequent steps. The selected bacteria showed inhibition activity of Fusarium oxysporum (18.6 to 43.7%). Furthermore, the secondary metabolites of the endophytic bacteria also promoted lethal effects on Meloidogyne incognita (16.6 to 65.8%). The physiological activity also showed that seven isolates were able to produce chitinase, and four (4) isolates were able to produce protease. Additionally, 55.6% of isolates were also able to dissolve phosphorus and fix nitrogen. This study provided fundamental information related to the biocontrol properties of endophytic bacteria isolated from pepper plant roots.

Mardhiana, Pradana AP, Adiwena M, Santoso D, Wijaya R, Murtilaksono A. 2017. Use of endophytic bacteria from roots of Cyperus rotundus for biocontrol of Meloidogyne incognita. Biodiversitas 18: 1308-1315. Yield loss due to M. incognita infection in tomato plants cultivation can reach 60%. The problem is able to be solved through the application of endophytic bacteria. In this study, endophytic bacteria from root Cyperus rotundus were isolated using Tryptic Soy Agar media. The bacteria isolates were then tested their safety against plants and mammals. The phenotypic and physiological properties of selected isolates were characterized and tested to know their resistance to antibiotics, and their ability in suppressing the infection rate of M. incognita on tomato. Eighteen bacterial isolates were obtained and 8 of them are categorized as safe bacteria for plants and mammals, which could be used in further tests. A result of the physiological test showed that bacterial isolates were able to produce protease enzyme (87.5%), chitinase enzyme (62.5%), and HCN (37.5%), having urease activity (75%) and could dissolve phosphate (87.5%). Based on the test results, all endophytic bacteria effectively increased tomato growth and suppressed the severity of M. incognita infection with the most stable isolate as a biocontrol agent of M. incognita was CRS16.

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic

Jagung merupakan komoditas unggulan Indonesia karena memiliki banyak manfaat dan bernilai ekonomi tinggi. Tanaman ini tumbuh optimal pada pH antara 5,6 – 6,2, dan akan mengalami penurunan produktivitas jika ditanam pada tanah dengan pH rendah. Salah satu tanah yang memiliki karakter pH rendah adalah tanah masam podsolik merah-kuning yang dapat ditemui di beberapa daerah di Indonesia. Berbagai upaya telah dilakukan untuk meningkatkan produktivitas jagung pada tanah masam. Namun demikian, hingga saat ini masalah tersebut belum dapat diatasi sepenuhnya. Salah satu solusi untuk masalah tersebut adalah aplikasi formula bakteri endofit. Penelitian ini bertujuan untuk menguji efektivitas formula cair bakteri endofit terhadap pertumbuhan tanaman jagung di tanah masam podsolik merah-kuning, dan menguji daya simpannya pada formula tersebut. Isolat bakteri yang digunakan adalah Pseudomonas sp. strain A175, Pseudomonas sp. strain F23, dan Micrococcus sp. strain S54. Ketiga isolat tersebut diformulasi dalam bahan pembawa ekstrak tauge, air kelapa, air beras, dan ekstrak ayam yang difortifikasi menggunakan 5g glukosa, 1 g urea, dan 10 g terasi. Pengujian di rumah kaca dilakukan menggunakan benih jagung varietas Bonanza F1 menggunakan tanah podsolik merah-kuning dengan pH 4,2. Pengujian dilakukan di rumah kaca mengikuti pola rancangan acak lengkap (RAL) dengan 29 perlakuan, 3 ulangan, dan setiap ulangan terdiri atas 3 unit percobaan. Uji viabilitas sel dilakukan mengikuti standar SNI 01-2897-1992. Hasil penelitian menunjukkan Seluruh formula bakteri endofit mampu memacu pertumbuhan tanaman jagung pada tanah masam podsolik merah-kuning. Formula bakteri endofit Pseudomonas sp. dan Micrococcus sp. yang konsisten dalam meningkatkan pertumbuhan tanaman jagung adalah formulasi bakteri endofit berbahan dasar ekstrak tauge dengan perlakuan ETA, ETBC dan ETAB. formula yang memiliki kemampuan daya simpan paling baik formula EKAC dengan total sel bakteri 5,7 Log CFU mL-1 pada penyimpanan minggu ke-10.

This study aimed to explore the potential of phyllosphere bacterial isolates as biological control agents against Xanthomonas oryzae pv. oryzae (Xoo). We isolated a strain exhibiting typical morphological and biochemical characteristics of Xoo, such as a yellowish, spherical colony, Gram-negative, and starch hydrolyzing ability. This isolate was shown to cause necrotic lesions on rice leaves, corroborating its pathogenic nature. Subsequently, we isolated ten diverse phyllosphere bacteria from rice plants. These isolates were characterized based on various morphological and biochemical attributes including colony shape, margin appearance, color, growth time, and the ability to fluoresce under UV light when cultivated on King's B medium. Crucially, none of these isolates induced a hypersensitive response in tobacco leaves, an initial indicator of their potential as safe biological control agents. In an antagonistic assay against Xoo, all the phyllosphere isolates demonstrated varying levels of inhibition, suggesting their potential role in biological control. Two isolates, PGM1 and PGM4, exhibited the highest antagonistic effects against Xoo. These findings provide preliminary evidence for the potential use of these phyllosphere isolates in managing bacterial leaf blight in rice, warranting further research to confirm their efficacy and safety under field conditions.