Philippine Rice Research Institute PhilRice

Marawi City, Philippines

Philippine Rice Research Institute PhilRice

Marawi City, Philippines

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Cumagun C.J.R.,University of the Philippines at Los Baños | Arcillas E.,University of the Philippines at Los Baños | Gergon E.,Philippine Rice Research Institute PhilRice
International Journal of Agriculture and Biology | Year: 2011

Twenty isolates of Fusarium fujikuroi from Nueva Ecija and Laguna provinces in the Philippines were characterized by Universally Primed Polymerase Chain Reaction (UP-PCR) using AA2M2 and L45 primer. Sixty-six unique banding patterns were generated and a dendrogram was created. High degree of variation was observed among the isolates. At 90% similarity, fifteen clusters were formed, suggesting that sexual reproduction plays a significant role in generating variation of F. fujikuroi populations in the field. © 2011 Friends Science Publishers.

Suralta R.R.,Nagoya University | Suralta R.R.,Philippine Rice Research Institute PhilRice | Kano-Nakata M.,Nagoya University | Niones J.M.,PhilRice | And 6 more authors.
Field Crops Research | Year: 2016

Roots play a number of important roles in crop adaptation to various abiotic stresses such as water stress. However, traits responsible for such adaptation may differ with environments. This paper reviews recent progress in our research on the functional roles of important root traits. We have been paying special attention to drought as well as to soil moisture fluctuations as prevailing water stresses, and the ability of the plant to change its development as environmental conditions change, which is known as phenotypic plasticity. We have been using various rice accessions/mapping populations such as the OryzaSNP panel, chromosome segment substitution lines (CSSL) derived from a Nipponbare and Kasalath cross, and IR64 introgression lines. The results consistently showed that, in addition to deep roots, the plasticity of root system development is a key trait for plant adaptation to water stress. We found that plasticity in the development of the entire root system as a function of the plasticity in lateral root development is important under progressive drought, while plasticity in lateral root development that is associated with aerenchyma formation is important under transient drought-to-waterlogged conditions. We quantitatively showed the contributions of root plasticity to dry matter production and yield through enhanced water uptake under such water stress. We also identified quantitative trait loci (QTLs) that are responsible for root plasticity. The importance of explicitly characterizing the nature of the stresses in the target areas is discussed in relation with designing an ideal root system, which is a primary requirement to define an actual breeding target for improving productivity in abiotic stress-prone soil environments. © 2016 Elsevier B.V.

Bautista E.G.,Philippine Rice Research Institute PhilRice | Saito M.,Tohoku University | Regalado M.J.C.,Philippine Rice Research Institute
Journal of Food, Agriculture and Environment | Year: 2014

In the Philippines, the tremendous quantity of rice husks (RH) produced by rice millers poses a variety of potentially harmful consequences to humans and the environment. We evaluated the burning of RH in updraft gasification systems to ameliorate the problem of RH disposal and reduce the use of other sources of energy that are usually purchased. In 2008, to assess the handling of rice by Philippine millers, we conducted a survey to determine the number and characteristics of rice milling factories in Central Luzon, specifically in Nueva Ecija, which is among the top rice-producing provinces. In this study, we focus on the most prevalent size of factory, which uses a single-pass mill with an average capacity of 1 t h-1 and requires roughly 30 kW of electric power, as the type of operation that would benefit by employing was targeted to be powered by a rice husk (RH) gasification system as a source of power. We evaluated the performance of such a system that is installed at the Philippine Rice Research Institute (PhilRice). This system comprises a gasifier reactor (internal volume, 1.44 m3), scrubber, condensers, filter, gas storage unit, and an internal combustion engine coupled to an electric generator. The gasification temperature ranged from 703 to 837°C, and the average temperature of the gas entering the engine was 39°C. The conversion rate from raw RH to carbonized rice husk was 18% by weight. On average, the system generated 10-18 kW at 173-240 V, based on a RH consumption rate of 78 kg h-1. Our results show that the generated power is insufficient to operate a rice mill processing 1 t h-1, but assessment of the operation indicates that this type of gasification system may be technically feasible if modified. The current size of the reactor and rate of RH consumption could produce 30 kW, if the efficiency of the engine and electric generator was improved. Given these improvements, RH updraft gasification systems might provide the electricity needed for local milling factories, using 40% of the RH material produced during milling operations.

Orge R.F.,Philippine Rice Research Institute PhilRice | McHenry M.P.,Murdoch University
International Journal of Innovation and Sustainable Development | Year: 2013

Successful long-term domestic rice research to feed the rapidly increasing population in the Philippines facilitated increased production of the nation's staple from 11.786 MT in 1999 to 16.258 MT in 2008. The additional rice production has correspondingly increased the annual milled rice husk waste resource to around 3.4 MT - currently, a disposal problem for millers who often dump the waste in open fields to slowly decompose. The waste represents approximately 42 million GJ of energy, equivalent to 7 million barrels of oil. This paper discusses the local development of an inexpensive, simple, fast, safe and versatile continuous rice husk carboniser which overcomes many limitations of existing batch carbonisers, including unacceptable operator emission exposures. The small-scale, portable, motor-less carboniser was designed to allow retrofitting of heat recovery components for alternative applications, including crop drying, and steam-driven systems, such as water pumps, as co-products to biochar used locally as a fertiliser. Copyright © 2013 Inderscience Enterprises Ltd.

Vu H.T.T.,Kobe University | Vu H.T.T.,Agricultural Genetics Institute AGI | Manangkil O.E.,Kobe University | Manangkil O.E.,Philippine Rice Research Institute PhilRice | And 3 more authors.
Biotechnology and Biotechnological Equipment | Year: 2012

Elongation escape mediated by seedling vigor with fast shoot elongation under submergence is considered to be an important strategy for rice particularly in direct seeding cultivation systems. We compared the expression profiles of two key genes in rice for ethylene biosynthesis - 1-aminocyclopropane-1-carboxylate synthase (OsACS) and oxidase (OsACO) genes, and five Na+/H+ exchanger (OsNHX) paralogs under normal and submerged conditions. The amount of transcripts was studied by RT-PCR using seedlings of one japonica and three indica cultivars with different levels of seedling vigor under submergence. In both types, submergence induced marked accumulation of transcripts of all paralogs of OsACS and OsACO except for OsACS1, which showed complete repression under the stress in non-vigorous indica cultivars suggesting its key role in seedling vigor under submergence. OsNHX expression was also enhanced under submergence, and the levels of OsNHX1 and OsNHX5 transcripts agreed well with those of seedling vigor under submergence. The observed mode of OsACS, OsACO and OsNHX expression under submergence suggests that these genes can be potential targets for understanding the mechanism regulating seedling vigor under submergence at the post-germination stage in rice. © 2012 American Scientific Publishers.

Beltran J.C.,University of Western Australia | Beltran J.C.,Philippine Rice Research Institute PhilRice | Pannell D.J.,University of Western Australia | Doole G.J.,University of Western Australia | Doole G.J.,University of Waikato
Crop Protection | Year: 2012

Implications of increasing labour costs and the development of herbicide resistance for profitable weed management in Philippine rice farming systems are investigated. The study employs RIMPhil (Resistance and Integrated Management in the Philippines), a bioeconomic simulation model developed to provide a comprehensive assessment of integrated weed management programmes for the control of annual barnyardgrass (Echinochloa crus-galli) in rice crops. Results indicate that herbicide application will become increasingly economically attractive, relative to manual weeding, as labour cost increases. This is important since urban migration in the Philippines continues to increase the scarcity of rural labour. Results also show that the onset of herbicide resistance results in substantial losses in farm profit. It is worthwhile for farmers to take management actions to prevent or delay the onset of herbicide resistance, provided that these changes are effective and not too costly. The study highlights the complexity of decision making about integrated weed management on rice farms in the Philippines. © 2011 Elsevier Ltd.

Beltran J.C.,Philippine Rice Research Institute PhilRice | Beltran J.C.,University of Western Australia | Pannell D.J.,University of Western Australia | Doole G.J.,University of Western Australia | And 2 more authors.
Agricultural Systems | Year: 2012

This paper describes a dynamic simulation model that allows for comprehensive assessment of integrated weed management programmes for the control of annual barnyardgrass (Echinochloa crus-galli complex) in Philippine rice farming systems. The main outputs of the model include weed seed and plant densities and seasonal and annualised profit over the simulated planning horizon. Results broadly indicate that a mixture of chemical and non-chemical treatments provides good weed control in rice crops, and maximises long-term profit for systems where the main weed is annual barnyardgrass. However, the performance of this strategy is heavily influenced by crop establishment method and labour cost. At current labour cost and low weed density, the regular use of manual weeding is the most valuable primary form of weed control in rice farming systems, relative to herbicide application. Herbicide application becomes more profitable than manual weeding when labour costs increase or the population of barnyardgrass plants is not maintained at its optimal level. These results illustrate the value of the model for guiding the efficient control of annual barnyardgrass in rice crops in the Philippines. © 2012 Elsevier Ltd.

Suralta R.R.,Philippine Rice Research Institute PhilRice
Philippine Agricultural Scientist | Year: 2010

In order to study the functional roles of plastic root system development (RSD) responses of rice to drought in terms of uptake of fertilizer nitrogen (N) applied prior to the onset of progressive drought, a root box experiment was conducted in a greenhouse. Two genotypes - drought-susceptible IR64 and drought-resistant strain DRS111 - were grown under two water conditions (continuously waterlogged, CWL, as control and droughted, DR) and two N treatments (without N, as control and with N at 120 kg ha-1). For the treatment with N fertilizer, half of the N rate was applied at basal prior to sowing while the remaining half was applied a day before withholding water for the DR treatment. Results showed that under progressive DR condition, plant growth, photosynthesis, transpiration, water use and relative chlorophyll content as indicated by soil and plant analysis development (SPAD) value were significantly higher with N applied during the onset of drought than without N in DRS111 only. This result was due to the greater ability of DRS111 than IR64 for plastic RSD through more initiation of L-type lateral root (LR) under progressive DR regardless of N treatment. Plastic RSD, in response to drought through greater promotion of L-type LR, can enhance not only the uptake of water but also of N if fertilizer N is applied during the onset of progressive drought stress in rice.

Regalado M.J.C.,Philippine Rice Research Institute PhilRice | Cruz R.T.,Philippine Rice Research Institute PhilRice
American Society of Agricultural and Biological Engineers Annual International Meeting 2010, ASABE 2010 | Year: 2010

Alternative tillage and crop establishment technologies were developed to provide options for Philippine rice farmers to improve productivity and efficiency, and reduce costs. Field experiments were conducted for six cropping seasons to test a reduced tillage (RT) system using an improved floating tiller and riding-type, 2-wheel tractor leveler versus conventional tillage (CT) which consisted of 4-wheel tractor rotary cultivation, and a series of pedestrian two-wheel tractor wet harrowing and leveling. For crop establishment of PSB Rc82 rice cultivar, a 4-row mechanical transplanter and a 12-row drum-seeder were comparatively tested with manual transplanting and broadcast seeding. In 2007 dry season (DS), drum-seeding with CT gave the highest yield at 7220 kg paddy ha-1 and highest labor productivity, 127.2 kg paddy per man-day. Drum-seeding with RT had the lowest production cost at P4.76 (USD 0.10) kg -1, and overall energy output-to-input ratio (OER) of 7.8. In 2008 DS, drum-seeding with RT had the highest yield at 7240 kg ha-1, productivity, 98.7 kg d-1, OER=7.7, and lowest cost, PHP 5.41 (USD 0.12) kg-1. In 2009 DS mechanical transplanting with RT gave the highest yields at 6600 kg ha-1. However, drum-seeding with RT had better labor productivity, 105.3 kg d-1, and lower cost, PHP 7.67 (USD 0.17) kg-1. Manual transplanting with RT was most energy-efficient (OER=9.6). Results implied that tillage operations could be reduced to lower unit cost, labor and energy inputs by 10%-24% without compromising yield. Drum-seeding with RT is most viable to increase labor productivity to the goal of 100 kg d-1.

Suralta R.R.,Philippine Rice Research Institute PhilRice | Inukai Y.,Nagoya University | Yamauchi A.,Nagoya University
Plant and Soil | Year: 2010

Drought and waterlogging are important abiotic stresses negatively affecting plant growth and development. They are transiently recurring in rainfed lowlands and in water-saving system practicing intermittent irrigation. This study aimed to determine the contribution of plastic development and associated physiological responses of roots to shoot dry matter production under transient soil moisture stresses. To minimize effect of genetic confounding, a selected line (CSSL47) drawn from 54 chromosome segment substitution lines (CSSL) of Nipponbare (japonica type) carrying an overlapping chromosome segments of Kasalath (indica type), was used and compared with the recurrent parent Nipponbare. Under transient droughted-to-waterlogged (D-W) conditions, CSSL47 showed greater shoot dry matter production than Nipponbare. This was due largely to its greater root system development through high induction of aerenchyma formation. Consequently, aerenchyma development effectively facilitated the internal diffusion of oxygen (O2) to the root tips under sudden waterlogged condition supporting rapid recovery of stomatal conductance, transpiration, and photosynthesis. Likewise, CSSL47 showed greater shoot dry matter production than Nipponbare under transient waterlogged-to-droughted (W-D) conditions. This was due to CSSL47's greater root system development through more initiation of L type lateral roots that effectively maintained soil water uptake. This in turn sustained higher stomatal conductance, transpiration, and photosynthesis. Results implied that utilization of CSSLs could precisely reveal that root plastic development in response to transient soil moisture stresses contributed to the maintenance of shoot dry matter production. © 2010 Springer Science+Business Media B.V.

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