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Vergara G.V.,International Rice Research Institute | Nugraha Y.,Indonesian Center for Rice Research | Esguerra M.Q.,International Rice Research Institute | Mackill D.J.,University of California at Davis | Ismail A.M.,International Rice Research Institute
AoB PLANTS | Year: 2014

Stagnant flooding (SF) is amajor problem in rainfed lowlands where floodwater of 25-50 cmstagnates in the field for most of the season.We aimed to establish a system for phenotyping SF tolerance and identifying tolerant germplasm through screening of landraces. A total of 626 rice accessions were evaluated over 3 years under control conditions and two levels of SF. Floodwater was raised to 20 cm at 25 or 30 days after transplanting (DAT). In one trial, the depth was increased subsequently by 5 cm a week and in another (severe stress), it was increased to 40 cm at 37 DAT and to 50 cm at 42 DAT. In both trials, water depth was maintained at 50-60 cm until maturity. In all cases, no plant was completely submerged. Plant height, elongation rate and yield were measured at maturity. Genotypes best suited to SF showed moderate elongation of 1.3-2.3 cm day-1 under SF. In contrast, semi-dwarf and fast-elongating types performed poorly. Subsequent trials using 18 genotypes, including six pairs of near isogenic lines (NILs) with or without SUB1 showed that all SUB1 NILs were sensitive to SF. Five of the other six genotypes contained SUB1 and were SF tolerant, suggesting the possibility of combining tolerances to complete submergence (SUB1) and SF. Stem starch and soluble sugar concentrations were similar under control conditions among the 18 genotypes, but starch was depleted by 37 %under SF, with less depletion in tolerant genotypes. SUB1 NILs contained similar concentrations of starch and sugars under SF.We conclude that survival and yield under SFare dependent onmoderate elongation, high tillering, lesser carbohydrate depletion and higher fertility. The tolerant genotypes identified here performed strongly in bothwet and dry seasons and will be used to identify tolerance mechanisms and alleles for use in marker-assisted breeding.


Jacob J.,CSIRO | Jacob J.,Institute for Plant Protection in Horticulture and Forestry | Sudarmaji,Indonesian Center for Rice Research | Singleton G.R.,CSIRO | And 4 more authors.
Wildlife Research | Year: 2010

Context. Overabundant rodents cause considerable crop damage and, in developing countries of South-east Asia, rodents can be an obstacle to attempts at alleviating poverty. Management is often based on the use of chemicals that can harm non-target species. Therefore, an effective and environmentally benign management approach such as ecologically based rodent management (EBRM) is desirable. Aims. We compared the effectiveness of EBRM to that of conventional management on populations of rice-field rats (Rattus argentiventer). Methods. The study was conducted as a large-scale replicated field trial in lowland irrigated rice fields in West Java, Indonesia. EBRM actions included habitat manipulations, removal of rats with trap barrier systems, coordinated rat-control campaigns and synchrony of cropping on the village level. We measured abundance, population structure, and breeding of rice-field rats as well as rice production and crop damage caused by rats. Key results.Although there was no overall effect of the EBRM treatment on rat abundance, we found decreasing rat abundance in rice-field habitats at the late cropping stage in treated villages and a decrease in body size of rats. In addition, we found fewer reproducing females when EBRM was applied than with the application of conventional methods, whereas male reproductive condition did not decrease. Overall, there was a reduction in mean crop damage when EBRM was applied (4.40.4% in treatments v. 2.50.4% in experimental controls), which translated into 6% higher rice production. Conclusions. The results demonstrated that EBRM is an appropriate approach to manage overabundant rodents in irrigated lowland rice-based agro-ecosystems and possibly in other agro-ecosystems. This will provide substantial benefits for smallholder farming communities in developing countries and most likely benefits for ecosystem health. Implications. The EBRM approach should be used routinely in irrigated lowland rice crops that are at risk of damage by rice-field rats. © 2010 CSIRO.


Horgan F.G.,International Rice Research Institute | Naik B.S.,Directorate of Rice Research | Iswanto E.H.,Indonesian Center for Rice Research | Almazan M.L.P.,International Rice Research Institute | And 2 more authors.
Entomologia Experimentalis et Applicata | Year: 2016

This study examines the nature of intraspecific interactions among Nilaparvata lugens (Stål) (Hemiptera: Delphacidae) planthoppers feeding on resistant and susceptible rice varieties. Planthopper nymphs produced less honeydew and gained less weight when feeding on rice variety IR62 (resistant) compared to susceptible rice varieties. A series of bioassays was conducted that varied N. lugens nymph densities on IR62 and IR22 (susceptible). Increasing nymph density facilitated feeding by conspecifics; however, intraspecific competition increased mortality of nymphs on IR62 (but rarely on IR22). Furthermore, nymph weights declined with increasing conspecific density on IR22, and the effects were weak on IR62. More female nymphs than males survived on IR62 but this was not affected by density. Nitrogenous fertilizer increased competition among N. lugens on young plants of IR22, but not on IR62. Results indicate that nymphs have a low efficiency in accessing resources when feeding on IR62, even where the plants have received fertilizer. Female-biased survival and biomass compensation for mortality may promote population recovery after development on the resistant plant and accelerate adaptation to the resistant variety. Entomologia Experimentalis et Applicata © 2016 The Netherlands Entomological Society.


Safitri H.,Indonesian Center for Rice Research | Purwoko B.S.,Bogor Agricultural University | Dewi I.S.,Indonesian Center for Agricultural Biotechnology | Ardie S.W.,Bogor Agricultural University
Journal of the International Society for Southeast Asian Agricultural Sciences | Year: 2016

Salt accumulation in irrigated soil is one of the main factors limiting rice productivity. A greenhouse experiment was conducted at Cimanggu Experiment Station, Bogor, Indonesia from May to September 2014 using a completely randomized design in a factorial arrangement with three replications. Four salt tolerant and two salt sensitive genotypes of rice were used in this experiment. The treatments were five concentrations of NaCl (0, 20, 40, 60 and 80 mM) applied on 21 day-old seedlings and maintained until harvest time. The study sought to evaluate the response of several rice genotypes to various NaCl concentrations through observation of morphological and physiological characters. The study showed that the increase of NaCl concentrations in soil significantly reduced plant height, number of panicles plant-1, panicle length, leaf length, 1000 grain weight, and grain yield. On physiological characters, salinity increased [Na+], decreased [K+] and [Ca2+] concentrations, and reduced K+/Na+ and Ca2+/Na+ ratios in the leaf tissue. The addition of 40 mM NaCl can distinguish tolerant and sensitive genotypes. The grain yield of sensitive genotypes decreased 90-100% at 40 mM NaCl, while the tolerant genotypes showed <70% in grain yield reduction. © 2016, International Society for Southeast Asian Agricultural Sciences. All Rights Reserved.


Suwarto,Jenderal Soedirman University | Susanto U.,Indonesian Center for Rice Research | Nurchasanah S.,Jenderal Soedirman University
Research Journal of Pharmaceutical, Biological and Chemical Sciences | Year: 2015

Using the variability present in the F2 population originating from New Plant Type (NPT) rice population, selection was practiced for high grain yield. Expected response to selection was estimated in F3 generation and compared with F2 generation. The F3 generation showed significant positive selection response for plant height, number of grain per panicle, panicles length, and flowering (days to 50% flowering), thus indicating the effectiveness of selection for these characters. This indicates the effectiveness of selection for these characters in F2 generation. The correlation and regression coefficient between F2 and F3 generation was significant for these characters. But, grain yield per clump showed non significant response in F3 generation. The correlation and regression coefficient between F2 and F3 generation was non significant for grain yield per clump, which indicates straight selection for this character during early generation (F2) may not be effective. Selection for plant height, number of grain per panicle, panicles length, and flowering (days to 50% flowering) can be made in the early segregating generation. Grain yield per clump is not effective for selection in early generation.


Sudir,Indonesian Center for Rice Research | Yuliani D.,Indonesian Center for Rice Research
Agrivita | Year: 2016

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. © 2016, Agriculture Faculty Brawijaya University. All rights reserved.


Lestari A.P.,Bogor Agricultural University | Suwarno,Indonesian Center for Rice Research | Trikoesoemaningtyas,Bogor Agricultural University | Sopandie D.,Bogor Agricultural University | Aswidinnoor H.,Bogor Agricultural University
Indian Journal of Genetics and Plant Breeding | Year: 2016

A study was conducted on the materials derived from the crosses, Gampai/IR77674 and Progol/Asahan to evaluate the performance of lines selected through pedigree method of selection under adequate nitrogen (138 kg/ha) and low nitrogen (34.5 kg/ha) conditions. Similar doses of nitrogen were taken for evaluating (cultural environment) the selected lines. Selection was made from F3 to F5 generations under adequate and low nitrogen environments, then F6 was evaluated at Muara Experimental Farm in dry season 2014, using augmented design, with checks replicated thrice. Results showed higher values of panicle weight, panicle length and plant height. The method followed under selection environment, similar to target environment was suitable enough to obtain adapted rice lines for the target environment. It is suggested that to obtain low nitrogen adapted rice lines, selection in breeding program should be conducted under sub-adequate nitrogen conditions in field. © 2016, Indian Society of Genetics and Plant Breeding. All rights reserved.


Satoto,Indonesian Center for Rice Research | Rumanti I.A.,Indonesian Center for Rice Research | Widyastuti Y.,Indonesian Center for Rice Research
Agrivita | Year: 2016

The adaptation of hybrid rice varieties mostly are in specific location and season, but there are some of the varieties have a wide adaptation then adopted by the farmer in the large area. Replicated yield trials were conducted to study the stability of hybrid rice yield and identify the best location to optimize their yield per ha. We have conducted the trials in three location such as Sukamandi, Salatiga and Malang during two seasons in 2011. We are analyzing data across location and season using AMMI and Eberhart Russel methods. The AMMI analysis showed that the IR79156A/PK88 was adaptable to favorable environments but unstable. This hybrid is always performing well and produce the higher yield compare to check variety. Some of other hybrids were good only in specific location, i.e. IR62829A/BP2280-1E-12-22 and IR58029A/BP2 280-1E-12-22. Those hybrids produced higher yield in Salatiga and Malang, respectively. Seem to AMMI analysis, the result of Eberhart and Russells method also showed that IR79156A/PK81 was the best hybrid with regression slope (b) around 1 with the yield average higher than average of all hybrids. It indicated that this hybrid has a wide adaptation and probably can be cultivated in the wider ecosystem. © 2016, Agriculture Faculty Brawijaya University. All rights reserved.


Blyton M.D.J.,Australian National University | Herawati N.'A.,Australian National University | Herawati N.'A.,Indonesian Center for Rice Research | O'Brien C.L.,The Canberra Hospital | And 2 more authors.
Environmental Microbiology Reports | Year: 2015

The probability of detecting Escherichia coli varies between host species with different diets and body sizes. An experimental study that mimicked the effect of different carnivore body masses found that digesta transit times influence E.coli abundance. In this study, we investigated how the host's gastrointestinal dynamics affected E.coli abundance and genotype in a system that reflected an herbivorous host. Forty rats from nine litters were fed a diet high in fermentable fibre. We found a small effect of fibre concentration on the difference between the liquid and particle digesta retention times. However, the rats' litter membership explained the majority of the retention time differences (79%). In turn, we found that as the difference between liquid and particle retention times increased, E.coli faecal cell densities decreased, while the likelihood that an animal's dominant E.coli strain possessed a gene involved in adhesion (agn43) increased. Thus, this experiment revealed an unanticipated high degree of association between the hosts' litter, their gastrointestinal dynamics and the E.coli genotypes. Furthermore, by comparing our findings to previous work, we show that the presence of fermentable fibre in the diet appears to change the relationship between the host's phenotype and E.coli. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.


Widyastuti Y.,Indonesian Center for Rice Research | Rumanti I.A.,Indonesian Center for Rice Research
Agrivita | Year: 2015

The hybrid rice program has been established since early 1990’s at the Indonesia Center for Rice Research (ICRR). Twenty-four experimental hybrid rice varieties which have been developed were tested in lowland rice fields in Sukamandi (West Java) and Batang (Central Java) during the dry season and the rainy season of 2012. Randomized complete block design (RCBD) with three replications was used in each location. The results showed that grains yields were affected by locations, seasons, and genotypes. The genotypes x locations x seasons interaction effect was significant; therefore, the best hybrid was different for each location and season. A7/PK36 hybrid has the best performance in Batang during the dry season, while A7/PK40 and A7/PK32 are the best hybrids in the rainy season. In Sukamandi, nine hybrids were identified as better yielder than that of the check cultivar in the dry season, but not so in the rainy season. Using the correlation and path analysis, we found that the number of panicles per hill and the number of filled grains per panicle could be used as selection criteria for yield in hybrid rice. © 2015, Agriculture Faculty Brawijaya University. All rights reserved.

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