Y. B. Sumardiyono

Pewarisan Ketahanan Penyakit Tungro pada Galur Padi OBSTG02-28

Seed of the rice hybrid generally is not fully filled, resulting in low seed quality. Study was conducted in 2009 at the Indonesian Centre for Rice Research, Sukamandi, aiming to determine the effect of seed invigoration methods on viability and vigor of hybrid rice seeds. The treatments consisted of two factors, namely: (A) initial quality of Hipa 5 seeds, i.e., low and moderate, and (B) 8 seed invigoration methods, i.e., no treatment (control); soaking in water for 48 hours; soaking in 1.0 Mpa PEG 6000 solution for 24 hours; soaking in 5 ppm GA3 solution for 24 hours; soaking in 10 ppm GA3 solution for 24 hours; 12 hours hardening, 24 hours hardening), and soaking in a solution mixture of GA3 10 ppm Kinetin + 15 ppm for 24 hours. The results showed that all seed invigoration treatments increased seed germinations by 1 to 8% and the seed growth rates by 0.7 to 4.3 %/24 hour in seeds of hybrid rice Hipa 5, either in the high initial quality seeds or in the low initial quality seeds. Soaking of the medium quality seeds in 10 ppm GA3 + 15 ppm kinetin solution resulted in the highest seed germination (89%). In the low quality seeds, treatments with GA3 and 15 ppm Kinetin also resulted in high seed germination (79%), equivalent to that of treatment with 24 hours hardening (78%). All seed invigoration treatments, except for soaking in water for 48 hours, increased length and dry weight of the seedling stem. The highest length of the stem was shown from seed soaked in 10 ppm GA3 solution (16.8 cm), whereas the highest stem dry weight was shown from seed soaked in a mixture of 10 ppm GA3 + kinetin 15 ppm solution (526 mg/seedling). Based on all variables evaluated, soaking seeds in 10 ppm GA3 solution or a mixed solution of 10 ppm GA3 + kinetin 15 ppm is considered effective invigoration treatment to improve vigor and growth of hybrid rice seeds.A research was conducted to determine the response of introduced hybrid rice varieties to bacterial leaf blight (BLB) disease caused by Xanthomonas oryzae pv. oryzae (Xoo) and its relationship to grain yields The trial was planted at the Sukamandi Experiment Station during the wet season (WS) 2008/09 and at Kuningan Experiment Station in the dry season (DS) of 2008 and WS 2008/09. Fourteen rice genotypes consisting of 9 introduced hybrid rice varieties from China, variety Code (resistant check), IR64 (susceptible check), and Intani-2 Batang Samo (hybrid checks), and Ciherang (inbred check) were evaluated. The experiment was laid out in a completely randomized block design with three replications. The trial at Kuningan, a BLB endemic area, was carried out with an assumption that grain yield performances of the 14 rice genotypes would be influenced by be severity of the BLB. Data from the greenhouse trial showed that reactions of the introduced hybrid rice to Xoo pathotype III varied from moderately resistant to resistant, moderately susceptible to susceptible to Xoo pathotype IV, and resistant to moderately Xoo pathotype VIII. In the field, the severity of the BLB disease ranged from 4.2% on Sembada B9 to 11.4% on WCR115 in the DS 2008, and from 4.9% on Sembada B9 to 30.4% on WCR073 in the WS 2008/09. In the DS 2008, the highest grain yield was obtained from Sembada B9 (9.79 t/ha) followed by Sembada B8 (9.6 t/ha), Sembada B3 (9.26 t/ha), and Sembada B5 (9.79 t/ha). In the WS 2008/2009, the highest grain yield was also obtained from Sembada B9 (8.85 t/ha) followed by Sembada B8 (8.80 t/ha), Sembada B3 8.63 t/ha), and Sembada B5 (7.77 t/ha). These four rice hybrids were resistant to Xoo pathotype III. The overall average rice yield in the DS, was higher than that in the WS 2008/2009, presumably as a result of the lower severity BLB disease.Tungro is the most important viral disease of rice plant, caused by two types of viruses, namely Rice Tungro Bacilliform Virus (RTBV) and Rice Tungro Spherical Virus (RTSV), transmitted by green leafhopper Nephotettix virescens. Planting resistant varieties proved effective in preventing the occurrence of tungro disease explosion, but the availability of tungro virus resistant varieties are still limited. To determine the best breeding strategy, genetic inheritance model for resistance to tungro disease needs to be studied especially the gene action and the number of genes controlling resistance. For this study, variety TN1 was crossed with OBSTG02-28 to produce F1, F1R, BC1-1, BC1-2, and F2. All crosses were inoculated with tungro virus and visual symptoms of the disease were observed, followed with the ELISA test. Scoring of the disease and ELISA test showed that the resistance of OBSTG02-28 was controlled by two complementary genes with a ratio of 9:7. The additive-dominant of gene action model fitted for the inheritance of resistant gene with additive gene action. The narrow sense heritability was considered high; therefore, selection for gene resistance to tungro disease could be conducted in the early generations.Aromatic rice such as Basmati and Jasmine has a high economic value in the world market. This study aimed to identify characteristics and grain quality of eight aromatic rice varieties grown at locations with different altitudes. The aromatic rice varieties were Basmati 370, originated from the International Rice Research Institute (Basmati 370 IRRI), India (Basmati 370 India), collection of Indonesian Rice Research Institute Sukamandi (Basmati 370 Sukamandi), HSPR, Khao Dawk Mali (KDM/Jasmine), Milky rice, local variety Mentik Wangi, and Sintanur. The experiment was planted in 8 locations, namely in Klaten, Pasarmiring, and Bajeng (altitude 800 m asl). Results showed that the best quality of milled rice was obtained from aromatic rice grown at altitudes of 500 to 800 m asl., of which the introduced aromatic rice (Basmati, KDM/Jasmine, and HSPR) and the local aromatic rice varieties (Milky rice and Mentik wangi) yielded the highest, based on percentages of milled rice and head rice and the lowest percentages of broken and cracked rice grains. The best grain milling quality of Sintanur variety (percentage of milled rice and head rice yield) was obtained when it was planted at high altitude (>800 m asl).Fertilizers play important roles in increasing rice yield. Government policy in a form of determined Highest Retail Price (HRP) of urea and the Government Purchasing Price (GPP) of rice grains not always been effective, so that farmers might not rationally use the fertilizers. Assessment the effectiveness of policy on the implementation HRP and GPP was conducted in five provinces, with different agro-ecosystem. The assessment used primary data collected in 2008, with aim to analyze the effectiveness of the policy implementation on urea HRP and on rice grains GPP. Assessment locations at the provincial and regency levels were determined based on a purposive sampling technique, whereas assessment locations at the district to village levels were selected based on the production center, determined by the multistages random sampling. Data collection of input and output prices were done through surveys using structured questionnaires to kiosks of farm inputs at the village level, the Village Cooperative Units (KUD), and other relevant agencies. Results of the assessments indicated that policy on HRP of urea fertilizer was not effectively complied, especially in the irrigated land with a high-low tidal agro-ecosystem. The GPP policy implementation was quite effective; in the aggregate, the most effective implementation of the policy was on the irrigated lands. The highest level of farmers’ ability to buy urea fertilizer (IHKD) was on the irrigated land. The urea HRP policy is expected to go along with the increase of grain GPP.Rice as staple food is consumed as a source of energy and protein, but also contains minerals and vitamins. This study was aimed to obtain information on mineral contents of rice lines obtained from the bio-fortification program. The research was conducted at the Experiment Farm of the Rice Research Installation Sukamandi, during Wet Season of 2007/2008. A total of 26 rice varieties/lines with high yielding potential and high Fe and Zn contents in the grain were planted in 4 m x 5 m experimental plots with a spacing of 25 cm x 25 cm. The experiments were arranged in a randomized block design with three replications. Samples of grain harvested from each plot were milled using a Satake mini grinder that produces milled rice with an 80% milling degree. Analysis of the mineral content of rice from the varieties/lines was tested using an ICP (Inductivity Couple Plasma) at the Waite Analytical Service Laboratory, University of Adelaide, Australia. The results indicated a wide diversity in the mineral contents (Ca, P, Mg, Na, K, S, Fe, Zn, and Mn) of the milled rice of the tested rice varieties/lines. Six lines produced milled rice rich in macro minerals (Ca, P, and K) and have a potential to be released as varieties with high macro mineral contents. Seven other rice lines produced high levels of Fe and Zn and are recommended as candidate for high yielding rice varieties with high micro mineral contents.Pests and diseases cause significant rice yield losses every planting season. One of the important rice disease is tungro, a virus disease transmitted by green leafhoppers (Nephotettix virescens Distant), that can cause yield losses of up to 90%. This study was aimed to determine the effectiveness of entomopathogenic fungi Verticillium lecanii and Beauveria bassiana to control N. virescens as a vector of the tungro virus. The experiment was arranged in a randomized complete block design with two factors. The first factor was conidial density of the fungi and the second factor was period of food acquisition. The variables observed were mortality and the ability to fly of N. virescens at 3, 7, 10, and 14 days after application (DAA), tungro disease symptoms, virus incubation periods, disease incidences, plant heights, and number of tillers. The results showed that applications of B. bassiana (107 conidia/ml) and V. lecanii (108 conidia/ml) caused death of green leafhoppers within 3-14 DAA. Based on the virus incubation period and the incidence of the tungro disease, application of the entomopathogenic fungi did not affect the ability of N. virescens to transmit tungro virus.

Keragaman Virulensi dan Konstruksi Molekuler Virus Tungro pada Padi dari Daerah Endemis

Tungro is an important disease of rice, constraining to the rice production in Indonesia. Tungro is caused by the infection of two different viruses namely tungro bacilliform virus (RTBV) and tungro spherical virus (RTSV). Both viruses are only transmitted by green leafhoppers, especially Nephotettix virescens in a semipersistent manner. The variation of tungro viruses from different areas had been reported, and there is a specific relationship between resistance variety and tungro virus isolate. It is important therefore, to study the virulences and the genetic diversities of tungro viruses derived from the endemic areas in Indonesia. This study was aimed to identify the virulence and the molecular diversity of tungro viruses from endemic areas in Indonesia. Susceptible variety TN1 was used in the study. Surveys and collection of the infected plants and green leafhoppers were conducted in some tungro endemic areas, including: West Java, Central Java, Yogyakarta, Central Sulawesi, West Sulawesi, South Sulawesi, Bali and West Nusa Tenggara. Artificial virus transmission using test tube method was used in the virulence test. Green leafhoppers caught from the field were used as vector transmitters. The virulence of tungro viruses was determined based on diseases indexes (DI). Results showed that the virulence of tungro viruses varied among region in the endemic areas in Indonesia. The Central Java virus isolate was the most virulence; however, not all isolates from endemic areas in the island of Java were more virulent than those from outside of Java. The presence of RTBV and RTSV was detected in the infected TN1 plants. The existences of molecular diversities of tungro viruses from the endemic areas were observed. The relationship between combination of DNA bands of RTBV and RTSV with the virulence in endemic areas outside of Java was more complex than it was in West Java and Central Java. The molecular diversities of tungro viruses were not correlated with the geographic difference of the endemic areas, nor with the virulences.

Kendali Ketahanan Genetik Padi terhadap Penyakit Tungro

Genetic study of resistant to rice tungro disease was carried out in Indonesian Agricultural Biotechnology and Plant Genetic Resources Institute, Bogor. TN1 rice variety was used as susceptible parent and OBSTG02-124 line as resistant parent. Cross combinations between resistant vs susceptible parents obtained 6 crosses. The study materials consisted of 55 plants of susceptible parent (P1) and 35 plants of resistant parents (P2), 70 F1 plants, 70 F1R plants, 100 BC1-1 plants, 100-BC1-2 plants, and 300 F2 plants. The probable maternal effect was identified by comparing resistant to tungro disease of F1 plants vs. the F1 of their reciprocal crosses, using the t-test. Each population was planted in pot containing 5 kg of soil. Plants were inoculated at 7-10 days old with virus tungro isolate Subang, using 4-5 green leafhoppers for 5 hours. Visual symptoms were observed based on the Standard Evaluation System for Rice. ELISA test (non Precoated I-ELISA) was performed at 21 days after inoculation, using polyclonal antibodies RTSV (S) and the combined RTBV and RTSV (BS). The results showed that there was no maternal effect on the inheritance of tungro disease resistance. The resistant to tungro in OBSTG02-124 was controlled by two complementary recessive genes. The moderate heritability indicated that the environment play role in determining the degree of resistant to tungro desease.

Seleksi, Karakterisasi, dan Reaktivitas Antibodi Monoklonal Virus Kerdil Kedelai

Soybean Stunt Virus (SSV) is a member of Cucumber mosaic virus group that caused soybean stunt disease. The disease is the most important viral disease of soybean in Indonesia. The objective of the study was to obtain SSV monoclonal antibody for detection SSV in both infected seed and plant. Six hybridoma clones were obtained from fusion between spleen cells of BALB/c immunized with Soybean stunt virus and mouse myelome cell lines (NS-1); they were IgG3 type antibodies, and its titres were varied between 1: 1O to 1: 1OO. Using non-recoated I-ELISA method, the homolog antigen (SSV) was well detected but not the heterolog antigens (CMV isolated from banana, tobacco).