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Maneenuam T.,Kasetsart University | Wanchai C.,Kasetsart University | Ronnarit R.,Kasetsart University | Prasertsakc A.,Bureau of Rice Research and Development | Wongpiyachond S.,Pathum Thani Rice Research Center
Journal of Near Infrared Spectroscopy | Year: 2015

The analysis of 2-acetyl-1-pyrroline (2AP) content in Hom Mali rice by conventional method is time consuming, an experienced technician is needed and it is costly, therefore a reliable and rapid method for determining 2AP content in aromatic rice is required. The purpose of this study was to assess if the 2AP content in Hom Mali rice could be determined using near infrared (NIR) spectroscopy. A total of 205 ground samples with 2AP in the range 0.52-3.32 ppm were scanned by a Fourier-transform near infrared (FT-NIR) spectrometer in reflectance mode over the region 1100-2500 nm at room temperature (25-27°C). 2AP content was analysed by headspace-gas chromatography and used as the reference method. A model derived from this study was developed and the coefficient of determination (R2), root mean square error of prediction (RMSEP) and bias of the calibration equation were 0.79, 0.27 and 0.01 ppm, respectively. The calibration equation developed in this study could rapidly predict 2AP content and there was no significant difference between NIR-predicted values and actual values at a confidence interval of 95%. The calibration was based on ranges at 1409 nm and 1895 nm wavelengths which infer that the 2AP is linked to the lipid content of the samples. Therefore, it can be concluded that NIR spectroscopy can be used for the evaluation of 2AP content at the ppm level in Hom Mali rice. © IM Publications LLP 2015.

Win K.M.,Kasetsart University | Korinsak S.,Kasetsart University | Jantaboon J.,Kasetsart University | Siangliw M.,Kasetsart University | And 7 more authors.
Field Crops Research | Year: 2012

Bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae is one of the most devastating diseases of rainfed lowland rice in Thailand. The gene Xa21 shows broad-spectrum resistance and has been widely utilized to improve BB resistance in rice worldwide. However, Xa21 is not fully expressed in the early stages of development (seedling stage). In this study, we attempted to improve the Thai jasmine rice variety KDML105 to obtain non-age-related broad-spectrum resistance to BB. The Xa21 gene and seedling resistance genes from rice variety IR1188 (a variety with non-age-related broad-spectrum resistance to BB) were introgressed into KDML105 through three rounds of marker-assisted backcrossing (MAB) and phenotypic selection. Sixty KDML105 backcross introgression lines (KBILs) carrying the Xa21 gene were successfully developed. They were used to evaluate seedling resistance against thirteen Xoo strains. Three seedling resistance (SR) loci inherited from IR1188 were identified on rice chromosomes 1 (RM302-RM212), 8 (RM210-RM149) and 11 (RM287-RM224). The agronomic characters of the KBILs were assessed by planting these lines in the paddy field at Kasetsart University in 2003. Phenotypic variation was observed in the agronomic traits of these lines. Seven KBILs carrying the Xa21 and multiple SR loci and also having a similar plant type to the original KDML105 were chosen for testing in multi-location trials at research stations in rainfed lowland environments. The trials were conducted in 10 and 11 locations in the North and Northeast of Thailand, respectively, between 2005 and 2006. The yield, agronomic traits, cooking quality and important diseases were examined and compared with those of the original KML105. All of the 7 KBILs had a cooking quality profile (aroma, amylose content, gel consistency and alkaline spreading value) and agronomic performance similar to the original KDML105. In 2007, four KBILs were planted in farmers' fields at 5 locations. All BILs and the original KDML105 did not differ significantly in their agronomic performance. In this study, multiple loci for broad-spectrum seedling resistance were identified from the KBIL population developed by the integrated marker-assisted and phenotypic selection procedures (MAS and PS). These results facilitated the successful improvement of non-age-related broad-spectrum BB resistance in KDML105. The established non-age-related broad-spectrum BB-resistant KDML105 is currently recommended by Kasetsart University for planting in farmers' fields where the crop is vulnerable to BB. © 2012 Elsevier B.V.

Punyawattoe P.,Nanjing Agricultural University | Punyawattoe P.,Entomology and Zoology Group | Han Z.,Nanjing Agricultural University | Sriratanasak W.,Bureau of Rice Research and Development | And 3 more authors.
Applied Entomology and Zoology | Year: 2013

This article reports the current status of ethiprole resistance in Nilaparvata lugens Stål in the central region of Thailand, together with the associated resistance mechanisms. A resistance survey found that a field population had developed 308. 5-fold resistance to ethiprole. Further selection with ethiprole for nine generations in the laboratory led to 453. 1-fold ethiprole resistance. However, following this selection procedure, the resistance of N. lugens to other insecticides decreased to about one-third of its original resistance. This result implies that there is no cross-resistance between ethiprole and other kinds of insecticides in this pest. In an in vivo study of synergisms, triphenyl phosphate (TPP) exhibited a strong synergism (SR 4. 2) with ethiprole in the resistant hoppers, piperonyl butoxide (PBO) also showed significant synergistic effects with ethiprole (1. 6), but diethyl maleate (DEM) did not show any obvious synergism with ethiprole (1. 2). An in vitro biochemical study indicated that esterase activity increased with ethiprole resistance in N. lugens, that P450 monooxygenase activity also increased significantly with high resistance, but that glutathione S-transferase activity did not. These results reveal that increases in esterase activity and P450 monooxygenase activity cause the ethiprole resistance observed in the field populations of N. lugens. Whether the mechanisms for ethiprole resistance involve target-site sensitivity is not yet known; further molecular analysis is required. However, an analysis of insecticide cross-resistance and the insecticide application history of the resistant populations indicated that target resistance was present and that rotation between insecticides with different modes of action will provide a key countermeasure to maintain the efficacy of ethiprole. © 2013 The Japanese Society of Applied Entomology and Zoology.

Xangsayasane P.,National Agricultural and Forestry Research Institute NAFRI | Xangsayasane P.,Khon Kaen University | Fukai S.,University of Queensland | Mitchell J.H.,University of Queensland | And 4 more authors.
Field Crops Research | Year: 2014

Drought is a major problem for rainfed lowland rice in Laos as well as for other countries in the Mekong region, and different drought screening methods under managed environments have been used to develop varieties adapted to drought prone environments. This paper evaluates the appropriateness of on-research station screening methods conducted under intermittent and terminal drought conditions, using the yield results of 12 on-farm multi-location trials with 25 genotypes some of which had been selected for drought tolerance. In these multi-location trials drought stress was rather mild, even in the intermittent or terminal drought trials which tended to develop in the higher fields of the rainfed lowlands. The high position generally produced low yielding crops but no significant interaction between position and genotypes were found for grain yield of 25 genotypes grown at 4 pairs of high and low field positions. Genotypes that performed well under higher yielding conditions in the on-(research) station experiments also performed well in on-farm multi-location trials. Genotypes that were identified as drought tolerant using drought response index as a criterion in the on-station experiments generally performed well in the on-farm multi-location trials (r= 0.49**), particularly in high yielding environments, but not under low yielding environments where low soil fertility appeared to be a major limitation for high yield. Similarly, genotypes that were identified to have high potential yield in flooded conditions in the on-station experiments also performed well in on-farm multi-location trials (r= 0.43*). Drought tolerance determined on-station either intermittent or terminal drought was similarly effective and was at least as effective as potential yield determined on-station in predicting on-farm yield. On-farm multi-location trials in combination with on-station experiments identified several promising lines that were well adapted to rainfed lowland conditions. It is concluded that genotypes selected for high yield potential under favorable conditions and for high drought tolerance determined in the on-station experiments would result in the development of well adapted cultivars suitable for drought-prone rainfed lowlands, and that either intermittent or terminal drought conditions developed at a research station is suitable for this purpose. The intermittent drought condition had the added advantage that genotypes selected directly for high yield, performed well in farmer's fields in the rainfed lowlands. © 2014.

Intaravanne Y.,Intelligent Systems Technology, Inc. | Sumriddetchkajorn S.,National Science and Technology Development Agency | Chaitavon K.,Intelligent Systems Technology, Inc. | Chanhorm S.,Intelligent Systems Technology, Inc. | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

The embryo or germ of a rice seed is growing to the shoot and the root parts of a seedling. In the early stage, the germinated embryo directly receives food from the endosperm. How healthy of the seedling can be physically predicted by measuring the areas of the embryo and endosperm. In this work, we show for the first time how the embryo and endosperm areas of a brown rice can be spatially measured. Our key design is based on the utilization of a tablet equipped with our lens module for capturing the rice seed image under white light illumination. Our Windows-based program is developed to analyze and separate the image of the whole brown rice into the embryo and endosperm parts within 2 seconds per seed. Our tablet-based system is just 30×30×6 cm3 with 1 kilogram in weight, capable to easily carry to perform in the field. © 2014 SPIE.

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