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Hopfer H.,University of California at Davis | Jodari F.,California Cooperative Rice Research Foundation | Negre-Zakharov F.,University of California at Davis | Wylie P.L.,Agilent Technologies | Ebeler S.E.,University of California at Davis
Journal of Agricultural and Food Chemistry | Year: 2016

Demand for aromatic rice varieties (e.g., Basmati) is increasing in the US. Aromatic varieties typically have elevated levels of the aroma compound 2-acetyl-1-pyrroline (2AP). Due to its very low aroma threshold, analysis of 2AP provides a useful screening tool for rice breeders. Methods for 2AP analysis in rice should quantitate 2AP at or below sensory threshold level, avoid artifactual 2AP generation, and be able to analyze single rice kernels in cases where only small sample quantities are available (e.g., breeding trials). We combined headspace solid phase microextraction with gas chromatography tandem mass spectrometry (HS-SPME-GC-MS/MS) for analysis of 2AP, using an extraction temperature of 40 °C and a stable isotopologue as internal standard. 2AP calibrations were linear between the concentrations of 53 and 5380 pg/g, with detection limits below the sensory threshold of 2AP. Forty-eight aromatic and nonaromatic, milled rice samples from three harvest years were screened with the method for their 2AP content, and overall reproducibility, observed for all samples, ranged from 5% for experimental aromatic lines to 33% for nonaromatic lines. © 2016 American Chemical Society.

Nelson J.C.,Kansas State University | Jodari F.,California Cooperative Rice Research Foundation | Roughton A.I.,California Cooperative Rice Research Foundation | Mckenzie K.M.,California Cooperative Rice Research Foundation | And 3 more authors.
Crop Science | Year: 2012

Rice (Oryza sativa L.) milling yield is a key export and domestic grain quality trait whose genetic control is poorly understood. To identify genomic regions influencing grain quality, quantitative trait locus (QTL) mapping was performed for quality-related traits including head-rice yield (HR) in 205 recombinant inbred lines (RILs) derived from a cross of L-204, a high-HR longgrain cultivar, with 01Y110, a low-HR advanced breeding line with high yield potential in the temperate U.S. rice-growing region. In replicated trials planted in California during 2007-2008, four QTLs carrying the HR-increasing allele from L204 and three from 01Y110 were consistently expressed. Multi-QTL models accounted for 30% of genetic variation for HR and up to 58% for other quality-related traits. Measures of kernel damage, though correlated with HR, were poor predictors of HR. Heading time, kernel dimension, apparent amylose content, and other highly heritable traits showed no correlation with HR. Stable QTLs for HR are likely to be revealed best by multienvironment experiments employing larger population sizes or more direct measurement of kernel structure and development traits involved in kernel breakage. © Crop Science Society of America.

Sha X.Y.,Louisiana State University | Linscombe S.D.,Louisiana State University | Jodari F.,California Cooperative Rice Research Foundation | Chu Q.R.,Rice Tec Inc | And 8 more authors.
Journal of Plant Registrations | Year: 2011

'Jazzman' (Reg. No. CV-134, PI 658006) is th e first U.S.-bred jasmine-type, soft-cooking, aromatic, long-grain rice (Oryza sativa L.) with a glabrous leaf, sheath, and hull and no dormancy. It was developed from a single cross by the modified pedigree selection procedure at the Rice Research Station, Louisiana State University Agricultural Center, Crowley, LA, and officially released in December 2008. Jazzman was tested under the experimental designation RU0402125 in the Louisiana Commercial Advanced trial at either six or seven locations, as well as in the Uniform Regional Rice Nursery (URRN) in Arkansas, Louisiana, Missouri, Mississippi, and Texas during 2004-2008. Jazzman is a moderately early maturing and conventional-height cultivar with commercially acceptable grain and milling yields, translucent slender grains, and a strong aroma. In 34 replicated Louisiana statewide and multistate URRN trials, Jazzman had average mainand ratoon-crop yields of 7.8 and 1.5 t ha -1, respectively. When averaged across years and locations, Jazzman had a head rice yield of 63.6% and a total milled rice yield of 69.6%. Jazzman has the typical jasmine-type cooking quality: a low amylose content, low gelatinization temperature, and an average 2-acetyl-1-pyrroline content of 436 ng g -1. Under both artificial inoculation and natural infection, Jazzman was found to be moderately susceptible to sheath blight [caused by Thanatephorus cucumeris (A.B. Frank) Donk (anamorph Rhizoctonia solani Kühn)], bacterial panicle blight (caused by Burkholderia glumae), and the physiological disorder straighthead but moderately resistant to blast [caused by Magnaporthe grisea (Hebert) Barr (anamorph Pyricularia grisea Sacc.)]. Successful development of Jazzman rice, which is well-adapted to the Gulf- and Mid-South rice-growing regions, should enable the U.S. rice industry to compete with Asian exporters in high-value aromatic-rice niche markets. © Crop Science Society of America.

Nelson J.C.,Kansas State University | Mcclung A.M.,U.S. Department of Agriculture | Fjellstrom R.G.,U.S. Department of Agriculture | Moldenhauer K.A.K.,University of Arkansas | And 6 more authors.
Theoretical and Applied Genetics | Year: 2011

Rice (Oryza sativa L.) head-rice yield (HR) is a key export and domestic quality trait whose genetic control is poorly understood. With the goal of identifying genomic regions influencing HR, quantitative-trait-locus (QTL) mapping was carried out for quality-related traits in recombinant inbred lines (RILs) derived from crosses of common parent Cypress, a high-HR US japonica cultivar, with RT0034, a low-HR indica line (129 RILs) and LaGrue, a low-HR japonica cultivar (298 RILs), grown in two US locations in 2005-2007. Early heading increased HR in the Louisiana (LA) but not the Arkansas (AR) location. Fitting QTL-mapping models to separate QTL main and QTL 9 environment interaction (QEI) effects and identify epistatic interactions revealed six main-effect HR QTLs in the two crosses, at four of which Cypress contributed the increasing allele. Multi-QTL models accounted for 0.36 of genetic and 0.21 of genetic × environment interaction of HR in MY1, and corresponding proportions of 0.25 and 0.37 in MY2. The greater HR advantage of Cypress in LA than in AR corresponded to a genomewide pattern of opposition of HR-increasing QTL effects by AR-specific effects, suggesting a selection strategy for improving this cultivar for AR. Treating year-location combinations as independent environments resulted in underestimation of QEI effects, evidently owing to lower variation among years within location than between location. Identification of robust HR QTLs in elite long-grain germplasm is suggested to require more detailed attention to the interaction of plant and grain development parameters with environmental conditions than has been given to date. © 2010 Springer-Verlag.

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