Composition and Distribution of Xanthomonas Oryzae Pv. Oryzae Pathotypes, the Pathogen of Rice Bacterial Leaf Blight in Indonesia

This research aimed to determine the composition and pathotype distribution of Xanthomonas oryzae pv. oryzae (Xoo) in several rice producing centers in Indonesia during the growing season of 2010-2013. The studies were conducted into three phases of activities, namely: sampling and collection of infected leaves from the representative rice growing areas; isolation and purification of the Xoo isolates; and evaluation of composition and pathotype of Xoo on five rice differential varieties. Results indicated that a total of 2,658 isolates Xoo have been isolated from 10 provinces representing rice ecosystem in Indonesia during the growing season from 2010-2013. Evaluating these Xoo isolates against five differential varieties revealed that these Xoo isolates consisted of three pathotypes III, IV, and VIII with a total of 30, 36, and 34%, respectively. The data also indicated that two pathotypes III and IV were dominant in three provinces, while the pathotype VIII was dominant in four provinces. As mentioned previously, such information are useful in designing strategy of integrating components of technologies combined in the management of Bacterial leaf blight (BLB) occurrences in a particular endemic areas

Heritabilitas, Sumber Gen, dan Durabilitas Ketahanan Varietas Padi terhadap Penyakit Hawar Daun Bakteri

Bacterial leaf blight (BLB) disease is one of the obstacles in increasing of rice production. The use of resistant varieties is an effective and easy to implement for farmers. This paper discusses the heritability and source of resistance genes of rice varieties against the BLB disease and strategies to maintain the durability of resistant varieties as one of the control efforts through plant breeding to supports the increasing of rice production. Assembling and development of resistant varieties play an important role in controlling BLB disease because it has a genetic resistancemechanism that can be inherited to progeny level. Varieties with vertical resistance are easily broken by pathogens, so it is necessary to assembling of varieties with horizontal resistance. To obtain the resistant progeny to BLB disease in the assembly of varieties, the position of the resistant varieties should be played as a female parent that has a high specific joining power. The nature of resistance to BLB is from a population whose parent genes are derived from multiple cross results has higher heritability. The populations derived from a double-cross have multigenic resistance and have the potential to produce recombinant individuals resistant for prolonged periods (durable). The availability of durable resistant varieties become a key requirement in sustainable BLB disease control. This matter can be done by improving the resistance of varieties through the assembling of varieties with various sources of resistance such as wild rice, local rice, and introduced rice

Karakteristik Wereng Hijau dan Epidemi Tungro di Kabupaten Garut, Provinsi Jawa Barat

Characteristics of Green Leaf Hoppers and Tungro Epidemic in Garut District, West Java Province. Tungro disease is one of the biotic constraints that may reduce crop yield potential of rice. The disease is caused by tungro virus that is spread by green leafhopper (GLH) Nephotettix virescens. GLH N. virescens is the most efficient vector of tungro virus among the others GLH. GLH was found in lowland to highland. The experiment was conducted in Garut district in the dry season 2012 and wet season 2012/2013. This study aims to determine the characteristics of GLH and Tungro epidemic in Garut District, West Java Province. Observations in the field include tungro disease intensity, GLH population density, and natural enemies populations, and the abiotic environment. Activities in the green house including adaptation test of GLH colonies from field to differential varieties resistant against GLH and virulence test of tungro virus to differential varieties resistant against tungro. The results in the fields showed that the GLH population density in the highlands Garut was relatively low. Likewise with tungro disease intensity at Garut in two cropping seasons had low intensity. Tungro attack depends on the effectiveness of GLH to transmit the virus. Although the GLH population was low but could transmit tungro virus effectively in the field. Natural enemies were most commonly founds in the highlands Garut was long jawed spiders Tetragnatha sp. The test results to the differential varieties resistant against GLH in green house suggested that adaptation of GLH colony from Garut was low and have not been able to break the resistance of GLH resistant varieties. While the test results to the differential varieties resistant against tungro showed that tungro virus from Garut was variants 071. That variant was highly virulent because it can break tungro resistant differential varieties except Tukad Petanu

Ketahanan Galur Isogenik IRBBN dan Galur Harapan Padi terhadap Patotipe Xanthomonas Oryzae Pv. Oryzae Dominan pada Tanaman Padi di Indonesia

Galur isogenik IRBB introduksi dari International Rice Research Institute (IRRI) telah diketahui gen ketahanannya dan dapat digunakan sebagai sumber ketahanan terhadap patotipe Xanthomonas oryzae pv. oryzae (Xoo) dominan di Indonesia. Kegiatan penelitian ini bertujuan untuk mengevaluasi ketahanan galur isogenik dan galur harapan terhadap patotipe Xoo dominan di Indonesia, yaitu patotipe III, IV, dan VIII. Penelitian dilaksanakan di Kebun Percobaan Sukamandi, Subang, Jawa Barat pada musim kemarau (MK) 2012 dan musim hujan (MH) 2012/2013. Penelitian dilakukan dengan Rancangan Faktorial Acak Kelompok dengan tiga ulangan. Faktor pertama adalah tiga patotipe Xoo, yaitu patotipe III, IV, dan VIII, sedangkan faktor kedua yaitu materi yang diuji sebanyak 20 galur IRBB, 6 galur harapan padi, dan 6 varietas pembanding, yaitu Conde, Lusi, Logawa, Java 14, Angke, dan Inpari 1. Hasil penelitian menunjukkan bahwa galur isogenik IRBB 21, IRBB 50, dan IRBB 52 bereaksi tahan terhadap Xoo patotipe III, IV, dan VIII pada MK 2012. Pada MH 2012/2013 diperoleh lima galur isogenik IRBB 52, IRBB 53, IRBB 54, IRBB 56, dan IRBB 57 bereaksi tahan terhadap Xoo patotipe III, IV, dan VIII. Galur isogenik IRBB 52 konsisten tahan terhadap Xoo patotipe III, IV, dan VIII pada dua musim tanam. Oleh karena itu, galur tersebut dapat direkomendasikan untuk dijadikan tetua tahan untuk perakitan varietas tahan HDB

Komposisi Dan Sebaran Patotipe Xanthomonas Oryzae Pv. Oryzae, Penyakit Pada Padi Di Nusa Tenggara Barat

A study was carried out to identify the composition and distribution of Xanthomonas oryzae pv. oryzae (Xoo) pathotypes on rice crop in West Nusa Tenggara, during the 2012 planting season. Three activities were conducted, namely collection of rice leaf samples from the fields, isolation of Xoo from the leaf samples at the laboratory, and testing pathotypes of Xoo at the screen house. Rice leaves showing typical bacterial leaf blight (BLB) symptom were collected from various farmers' fields. The samples were detached and put into paper envelopes, and were taken to the laboratory for isolation of Xoo, at the Laboratory of Pythopathology of Indonesian Center for Rice Research (ICRR), Sukamandi. Pathotype testing was done in the ICRR screen house by inoculating the leaves of five differential rice varieties using inocula of the Xoo isolates. Resistance of the rice differential varieties was determined based on the BLB disease severity. Inoculated plant with disease severity ≤11% was considered resistant (R) and disease severity >11% was susceptible (S). From the 240 samples of rice leaf infected with BLB collected from West Nusa Tenggara, 232 Xoo isolates were obtained. The Xoo pathotype identification showed that pathotype IV was the most dominant in West Nusa Tenggara during the 2012 planting season, numbering 118 isolates or 51.0% out of the total isolates, followed by pathotype VIII (67 isolates or 29.0%), and pathotype III (47 isolates or 20.0%)

Karakterisasi Sifat Morfologi Dan Ketahanan Terhadap Penyakit Hawar Daun Bakteri Pada Beberapa Varietas Padi

Bacterial leaf blight, caused by Xanthomonas oryzae pv oryzae (Xoo) is common disease on rice crop in Indonesia. Resistance variety when available, would be a good control measure to the disease, which could be easily adopted by farmers. Source of gene for resistance needs to be identified among rice genotypes, to be used as parents in the breeding program. This research was aimed to characterize the morphological traits and the degree of resistance among rice genotypes against Xoo pathotype III, IV, and VIII. The experiment was conducted at Sukamandi experimental field of Indonesian Center for Rice Research, during the wet season of 2012/2013 and dry season of 2013, using a randomized factorial design. The first factor was three Xoo pathotypes i.e. pathotype III, IV, and VIII, the second factor was 20 rice genotypes including three check varieties, i.e. Ciherang, Inpari 13, and Angke. Observations of morphological and agronomic characters were done on rice plants started from primordial to grain ripening phase. Observations on BLB disease severity were done by measuring the longest symptoms on the leaves at two, three, and four weeks after inoculation. The morphological characters of the isogenic lines showed moderate leaf surface type with an open habitus (60o). Plant height ranged from 99 to 190 cm, maturity between 109 to 157 days after sowing, and the number of tillers was 9-23 tillers/hill. Against the Xoo pathotype III, IV, and VIII, three genotypes of near isogenic lines i.e. IRBB 60, IRBB 61, and IRBB 55 each was resistance, not significantly different from resistance check variety Angke, in two cropping seasons. All three isogenic lines can be used as parent to develop new resistant variety to bacterial leaf blight

Komposisi Dan Dominasi Patotipe Xanthomonas Oryzae Pv. Oryzae, Penyebab Penyakit Hawar Daun Bakteri Pada Tanaman Padi Dengan Sistem Pengairan Berbeda Di Kabupaten Karawang [the Composition and Domination of Xanthomonas Oryzae Pv. Oryzae Pathotype, the Cause of Bacterial Leaf Blight on Rice Plants in Different Irrigation System at Karawang District]

Bacterial leaf blight (BLB) is the major disease of rice caused by the bacteria Xanthomonas oryzae pv. oryzae (Xoo), that has various pathotypes making it difficult to control. This research was aimed to determine Xoo pathotype group in irrigated paddy fields with different of planting time based on differences of irrigation system in Jatiluhur Reservoir. The research was conducted in Karawang District the wet season (WS) of 2013/2014 and dry season (DS) of 2014 through survey and sampling of infected rice leaves of BLB. Isolation of Xoo bacte-ria was done in the laboratory by using dilution methods. Xoo pathotype test was carried out by inoculating Xoo isolate on five different varieties in Indonesian Center for Rice Research\u27s green house, West Java. Observation of disease severity was done by measuring symp-toms of the disease that appeared at two and four weeks after inoculation. The disease severity of ?11% was classified as resistant (R), and for the disease severity of >11% was classified as susceptible (S). The results obtained a total of 602 Xoo isolates from rice plant samplings of irrigated rice fields in Karawang with irrigation systems I, II, III, and IV. At WS 2013/2014 was obtained 448 Xoo isolates consists of 29.69% of pathotype III; 40.85% of pathotype IV, and 29.46% of pathotype VIII. While, at DS 2014 was obtained 154 Xoo isolates consists of 1.95% of pathotype III, 53.25% of pathotype IV, and 44.80% of pathotype VIII. The areas with Type I of irrigation systems were domi-nated by Xoo pathotype IV in two cropping seasons. The areas with Type II of irrigation system dominated by Xoo pathotype IV in the wet season, while the dry season was dominated by Xoo pathotype VIII. The areas with Type III of irrigation system were dominated by Xoo pathotype III in the wet season, whereas during dry season was dominated by Xoo pathotype IV. The areas with Type IV of irrigation sys-tem were dominated by Xoo pathotype IV during wet season. Over all, in the dry season, Xoo pathotype IV was the dominant pathotype especially in irrigation systems Type I and IV. The dominance of Xoo pathotype can determine the resistant varieties that grown in the areas with different planting times on different irrigation systems