ABSTRACT: Wild species of rice (genus Oryza) contain many useful genes but a vast majority of these genes remain untapped to date because it is often difficult to transfer
these genes into cultivated rice (Oryza sativa L.). Chromosome segment substitution lines (CSSLs) and backcross inbred lines (BILs) are powerful tools for identifying these
naturally occurring, favorable alleles in unadapted germplasm. In this paper, we present an overview of the research involving
CSSLs and BILs in the introgression of quantitative trait loci (QTLs) associated with the improved performance of rice including
resistance to various biotic and abiotic stresses, and even high yield from wild relatives of rice and other unadapted germplasm
into the genetic background of adapted rice cultivars. The CSSLs can be used to dissect quantitative traits into the component
genetic factors and evaluate gene action as single factors (monogenic loci). CSSLs have the potential to uncover new alleles
from the unadapted, non-productive wild rice accessions, develop genome-wide genetic stocks, and clone genes identified in
QTL studies for functional genomics research. Recent development of high-density single-nucleotide polymorphism (SNP) arrays
in rice and availability of custom-designed medium- and low-density SNP arrays will enhance the CSSL development process with
smaller marker-defined segment introgressions from unadapted germplasm.
Oryza species-Backcross inbred lines-Chromosome segment substitution lines-Introgression lines-Genome-wide genetic stocks-
Rice 04/2012; 3(4):218-234. · 3.11 Impact Factor
ABSTRACT: • Inorganic arsenic (As(i) ) in rice (Oryza sativa) grains is a possible threat to human health, with risk being strongly linked to total dietary rice consumption and consumed rice As(i) content. This study aimed to identify the range and stability of genetic variation in grain arsenic (As) in rice. • Six field trials were conducted (one each in Bangladesh and China, two in Arkansas, USA over 2 yr, and two in Texas, USA comparing flooded and nonflood treatments) on a large number of common rice cultivars (c. 300) representing genetic diversity among international rice cultivars. • Within each field there was a 3-34 fold range in grain As concentration which varied between rice subpopulations. Importantly, As(i) correlated strongly with total As among a subset of 40 cultivars harvested in Bangladesh and China. • Genetic variation at all field sites was a large determining factor for grain As concentration, indicating that cultivars low in grain As could be developed through breeding. The temperate japonicas exhibited lower grain As compared with other subpopulations. Effects for year, location and flooding management were also statistically significant, suggesting that breeding strategies must take into account environmental factors.
New Phytologist 12/2011; 193(3):650-64. · 6.64 Impact Factor
ABSTRACT: Asian rice, Oryza sativa is a cultivated, inbreeding species that feeds over half of the world's population. Understanding the genetic basis of diverse physiological, developmental, and morphological traits provides the basis for improving yield, quality and sustainability of rice. Here we show the results of a genome-wide association study based on genotyping 44,100 SNP variants across 413 diverse accessions of O. sativa collected from 82 countries that were systematically phenotyped for 34 traits. Using cross-population-based mapping strategies, we identified dozens of common variants influencing numerous complex traits. Significant heterogeneity was observed in the genetic architecture associated with subpopulation structure and response to environment. This work establishes an open-source translational research platform for genome-wide association studies in rice that directly links molecular variation in genes and metabolic pathways with the germplasm resources needed to accelerate varietal development and crop improvement.
Nature Communications 01/2011; 2:467. · 7.40 Impact Factor