Identifikasi dan Karakterisasi Penyakit Bintik Batang dan buah pada Tanaman Buah Naga (Hylocereus spp.) di Indonesia I

[Identification and Characterization of Stem and Fruit Canker Diseases on Dragon Fruit (Hylocereus spp.) in Indonesia]Kendala utama budidaya tanaman buah naga di Indonesia adalah masalah penyakit. Ada beberapa jenis patogen yang menyerang tanaman buah naga, namun penyakit yang paling berbahaya dan sangat merugikan adalah penyakit bintik batang. Penelitian ini bertujuan  mengkarakterisasi gejala serangan dan mengidentifikasi penyebab penyakit bintik batang pada tanaman buah naga. Penelitian dilakukan di kebun petani di area endemik Padang Pariaman dan Solok serta laboratorium penyakit dan molekular Balitbu Tropika sejak tahun 2014 sampai 2016. Penelitian dilakukan dengan metode deskriptif dan pengujian laboratorium. Karakterisasi gejala serangan penyakit diamati  terhadap bagian tanaman yang terserang. Identifikasi dilakukan dengan pengamatan cendawan penyebab penyakit secara mikroskopis, uji postulat Koch dan uji DNA. Hasil penelitian menunjukkan bahwa gejala awal penyakit ditandai dengan adanya bintik kecil berwarna putih pada tunas muda dan buah  tanaman buah naga, ditengah bintik ditemukan lubang halus seperti tusukan jarum. Gejala lebih lanjut berupa bercak-bercak yang sedikit membesar, menyatu dan bagian batang yang lunak berlubang dan hancur. Berdasarkan ciri-ciri mikroskopis dan hasil amplifikasi region ITS DNA isolat cendawan asal buah naga teramplifikasi pada 580 bp dan berdasarkan identifikasi bank gen (BLAST), sekuen nukleotida isolat cendawan menunjukkan 99% kesamaan dengan Neoscytalidium dimidiatum. Hasil penelitian ini selanjutnya dapat menjadi dasar/rujukan dalam melakukan penelitian untuk mencari teknik pengendalian di lapangan nantinya.KeywordsHylocereus spp.; Penyakit; Identifikasi; Karakterisasi gejalaAbstractDiseases are the main obstacles in the cultivation of dragon fruit plants in Indonesia. Several types of pathogens attack dragon fruit plants, but the most dangerous and detrimental disease is the stem canker. This study aimed to characterize disease symptoms and identify the causes of stem canker disease in dragon fruit plants. The research was carried out at the farmer’s farms in the endemic areas of Padang Pariaman and Solok as well as the Laboratory of Disease and Molecular Balitbu Tropika from 2014 to 2016. The study was conducted using descriptive methods and laboratory testing. Characterization of symptoms of disease was observed in the affected part of the plant. Identification is done by observing the fungus that causes disease microscopically, Koch's postulate test and DNA test. The results showed that the initial symptoms of the disease were characterized by the presence of small white spots on young shoots and fruit of dragon fruit plants, in the middle of the spots found a fine hole like a needle puncture. Further symptoms include patches that are slightly enlarged, fused and the soft part of the stem is hollow and broken. Based on microscopic characteristics and the results of amplification of the ITS region the fungus isolates DNA from dragon fruit amplified at 580 bp and based on gene bank identification (BLAST), nucleotide sequences of fungal isolates showed 99% similarity with Neoscytalidium dimidiatum. Further research is needed on the ecobiology of pathogen and effective control techniques

PENGELOMPOKAN PLASMA NUTFAH RAMBUTAN BERDASARKAN KARAKTER MORFOLOGI

Rambutan is a fruit native to Indonesia, which has a high diversity. Indonesian Tropical Fruit Research Institute has a rambutan germplasm collection. The objectives of the research were to identify and classify rambutan germplasm accessions based on morphological characteristics, in order to identify the specific characteristics important for the development of future varieties of rambutan. Collecting data on the 32 accession was conducted in Aripan Experimental Field, Indonesian Tropical Fruit Research Institute from September 2014 to February 2015. Characterization of morphology characters referred to as the Descriptor for Rambutan was published by IPGRI. Cluster analysis based on morphological characteristics successfully separated the accession of rambutan R7 and R11 with 30 other rambutan accessions with the dissimilarity coefficient of 45%. Accession R4 was similar to Sitangkue, R14 was similar to Korong Gadang, and R15 was similar to Sinyonya. Characteristics that can be used to distinguish each of the accession of rambutan were the width of seed, seed thickness, total soluble solids (TSS), fruit diameter, spintern texture and the spintern color. Accession R15 can be developed as a commercial variety, because it has a high yield, and shelf life associated with high fruit weight characteristics and thick rind

Resistance of Three Superior New Banana Varieties on Several Vegetative Compatibility Groups Fusarium oxysporum f. sp. cubense

Resistance of Three Superior New Banana Varieties on Several Vegetative Compatibility Groups Fusarium oxysporum f. sp. cubense    Indonesian Tropical Fruits Research Institute (ITFRI) has released three New Superior Varieties of bananas. In supporting the successful of new banana variety development is necessary to know information of the response of resistance variety to Fusarium oxysporum f. sp. cubense (Foc) in several VCGs. The aim of this research was to determine the three bananas new superior varieties resistance response against VCGs of Foc in screen house test. The experiment was conducted in plant protection laboratory and screen house of ITFRI, from September 2016 to December 2017. The design used was randomized block, 21 treatments and 3 replications; each treatment consisted of 10 plants. The treaments were Ketan 01 (AA), Kepok Tanjung (ABB/BBB) and Raja Kinalun (ABB), each was inoculated with 7 VCGs of Foc (VCG 0120/15, 0123, 0124/5, 0126, 01218, 01213/16 dan 01219). The results revealed that the three new superior banana varieties showed varying resistance responses (highly resistant-highly susceptible) to VCGs of Foc isolates in race 1 and race 4. Resistance of three new superior quality varieties of bananas was not associated with a group of pathogenic Foc in race, but was influenced by compatibility each of the VCGs of Foc isolates and banana variety. Kepok Tanjung (ABB/BBB) variety was susceptible and highly susceptible to all VCGs of Foc isolates tested, Ketan 01 (AA) variety was resistant to all VCGs of Foc isolates tested, except Foc VCGs 0124/5 (race 1) and VCGs 01213/16 (Tropical race 4). Raja Kinalun (ABB) variety was resistant and highly resistant to all used fungal isolates, except Foc VCGs 0124/5 (race 1), the response of it was highly susceptible. This information is expected to support the development of new superior quality varieties of bananas in Indonesia.Balai Penelitian Tanaman Buah (Balitbu) Tropika telah melepas tiga varietas unggul baru (VUB) pisang dengan keunggulan masing-masing. Dalam menunjang keberhasilan pengembangan varietas unggul baru tersebut perlu diketahui informasi tentang ketahanannya terhadap beberapa Vegetative Compatibility Groups (VCGs) Fusarium oxysporum f. sp. cubense (Foc). Tujuan penelitian ini ialah menentukan ketahanan tiga VUB pisang terhadap beberapa VCGs Foc di rumah kasa. Penelitian dilakukan di laboratorium proteksi tumbuhan dan rumah kasa Balitbu Tropika di Solok, dari bulan September 2016 sampai bulan Desember 2017. Rancangan yang digunakan ialah acak kelompok 21 perlakuan dan 3 ulangan, masing-masing perlakuan terdiri atas 10 tanaman. Sebanyak 3 VUB pisang (Ketan 01, Kepok Tanjung dan Raja Kinalun) masing-masing diinokulasi dengan 7 VCGs Foc: yaitu VCG 0120/15, 0123, 0124/5, 0126, 01218, 01213/16 dan 01219. Hasil penelitian menunjukkan bahwa tiga VUB pisang menunjukkan respons ketahanan yang bervariasi terhadap isolat Foc dari berbagai VCGs dalam ras 1 dan ras 4. Ketahanan dipengaruhi oleh kompatibilitas masing-masing VCGs dari isolat Foc dengan varietas pisang. Varietas Ketan 01 (AA) mempunyai respons agak tahan dan tahan terhadap semua VCGs Foc yang diuji kecuali dengan VCG 0124/5 (ras 1) dan VCG 01213/16 (ras 4 tropis). Kepok Tanjung (ABB/BBB) rentan dan sangat rentan terhadap semua VCGs Foc, Raja Kinalun (ABB) memberikan respons tahan dan sangat tahan terhadap semua isolat VCGs Foc kecuali dengan isolat Foc VCG 0124/5 (ras 1) responsnya sangat rentan. Hasil penelitian ini bermanfaat sebagai informasi awal pengembangan varietas unggul baru pisang di Indonesia

Karakter Virulensi Beberapa Isolat Fausarium oxysporum f. sp cubunse VCG 01213/16 Dari Lokasi dan Varietes Pisang yang Berbeda Terhadap Pisang Barangan.

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