Seed abortion caused by the combination of two duplicate genes in the progeny from the cross between and .

Seed development is an essential phenomenon for all sexual propagative plant species. The functional allele at () or () loci is essential for seed development for and . In the present study, we performed fine mapping of , narrowing down the area of interest to 333kb on chromosome 6.

Chromosomal Location of , a Broad-Spectrum Rice Bacterial Blight Resistant Gene from XM5, a Mutant Line from IR24.

Bacterial blight is an important rice disease caused by bacteria named pv. (). XM5 is an resistant mutant line with the genetic background of IR24, an Indica susceptible cultivar, induced by a chemical mutagen N-methyl-N-nitrosourea (MNU).

QTL Analysis Revealed One Major Genetic Factor Inhibiting Lesion Elongation by Bacterial Blight ( pv. ) from a Cultivar Koshihikari in Rice.

pv. () is a pathogen that has ravaged the rice industry as the causal agent of bacterial blight (BB) diseases in rice. Koshihikari (KO), an elite cultivar, and ARC7013 (AR), an cultivar, are both susceptible to .

New Hybrid Spikelet Sterility Gene Found in Interspecific Cross between and .

Various kinds of reproductive barriers have been reported in intraspecific and interspecific crosses between the AA genome species, to which Asian rice () and African rice () belong. A hybrid seed sterility phenomenon was found in the progeny of the cross between and , which is found in Northern Australia and Indonesia and has diverged from the other AA genome species. This phenomenon could be explained by an egg-killer model.

Linkage analysis of rice bacterial blight resistance gene in XM6, a mutant line from IR24.

Bacterial blight caused by pv. () is an important disease constraining rice ( L.) production worldwide.

Phylogenetic analysis of the Si7PPO gene in foxtail millet, Setaria italica, provides further evidence for multiple origins of the negative phenol color reaction phenotype.

To elucidate the diversity and evolution of the Si7PPO gene that controls phenol color reaction (Phr) in foxtail millet, Setaria italica, we analyzed sequence polymorphisms of the Si7PPO gene in 39 accessions consisting of foxtail millet landraces (32 accessions) and their wild ancestor ssp. viridis (seven accessions) collected from various regions in Europe and Asia. The accessions included wild type (positive Phr) and three different types of loss-of-function phenotype (negative Phr), "stop codon type", "TE1-insertion type" and "6-bp duplication type", found in our previous study.

Molecular and Morphological Divergence of Australian Wild Rice.

Two types of perennial wild rice, Australian Oryza rufipogon and a new taxon Jpn2 have been observed in Australia in addition to the annual species Oryza meridionalis. Jpn2 is distinct owing to its larger spikelet size but shares O. meridionalis-like morphological features including a high density of bristle cells on the awn surface.

Detailed investigation of methylmercury accumulation in rice grain from Hg-spiked non-contaminated paddy field soils.

Total-Hg (T-Hg) and methylmercury (MeHg) concentrations in rice grains were measured to understand the MeHg accumulation process. Rice plants were cultivated in Hg-spiked non-contaminated soils in experimental pots at three different places. Although soil MeHg concentrations in the pots changed significantly and individually during the rice-growing season, T-Hg concentration of brown rice grain was high at high soil MeHg concentration.

- and -Mediated Hybrid Weakness in Rice Involves Cell Death, Reactive Oxygen Species Accumulation, and Disease Resistance-Related Gene Upregulation.

Hybrid weakness is a type of reproductive isolation in which F hybrids of normal parents exhibit weaker growth characteristics than their parents. F hybrid of the Indian cultivars 'P.T.

Segregation Distortion Observed in the Progeny of Crosses Between and . Caused by Abortion During Seed Development.

Wild rice relatives having the same AA genome as domesticated rice () comprise the primary gene pool for rice genetic improvement. Among them, and are found in the northern part of Australia. Three Australian wild rice strains, Jpn1 (), Jpn2, and W1297 (), and one cultivated rice cultivar Taichung 65 (T65) were used in this study.

High-resolution mapping and characterization of , a resistance gene against multiple pv. races in rice ( L.).

Improvement of resistance against rice bacterial blight (BB) disease is an important breeding strategy in breeding programs across the world, especially in Africa and southern Asia where BB is more prevalent. This report describes a high-resolution map and characterization of at locus, a rice BB resistance gene in XM14, a mutant line originating from IR24. The candidate gene region was narrowed down from 582 kb, which had been obtained in our previous study, to 57 kb.

Distribution of , a causal gene of a hybrid weakness, in the World Rice Core collection and the Japanese Rice mini Core collection: its implications for varietal differentiation and artificial selection.

A pair of complementary genes, at locus and at locus, cause a weakness phenomenon in rice. For this study, we performed haplotype analysis around the locus in two core collections comprising 119 accessions. We also examined reactions to phenol and pv.

Identification and linkage analysis of a new rice bacterial blight resistance gene from XM14, a mutant line from IR24.

Bacterial blight caused by pv. () is a chief factor limiting rice productivity worldwide. XM14, a rice mutant line resistant to , has been obtained by treating IR24, which is susceptible to six Philippine races and six Japanese races, with N-methyl-N-nitrosourea.

Multiple origins of the phenol reaction negative phenotype in foxtail millet, Setaria italica (L.) P. Beauv., were caused by independent loss-of-function mutations of the polyphenol oxidase (Si7PPO) gene during domestication.

Foxtail millet shows variation in positive phenol color reaction (Phr) and negative Phr in grains, but predominant accessions of this crop are negative reaction type, and the molecular genetic basis of the Phr reaction remains unresolved. In this article, we isolated polyphenol oxidase (PPO) gene responsible for Phr using genome sequence information and investigated molecular genetic basis of negative Phr and crop evolution of foxtail millet. First of all, we searched for PPO gene homologs in a foxtail millet genome database using a rice PPO gene as a query and successfully found three copies of the PPO gene.

Genetic analysis of ion-beam induced extremely late heading mutants in rice.

Two extremely late heading mutants were induced by ion beam irradiation in rice cultivar 'Taichung 65': KGM26 and KGM27. The F2 populations from the cross between the two mutants and Taichung 65 showed clear 3 early: 1 late segregation, suggesting control of late heading by a recessive gene. The genes identified in KGM26 and KGM27 were respectively designated as FLT1 and FLT2.

Molecular relationships between Australian annual wild rice, Oryza meridionalis, and two related perennial forms.

Background: The perennial, Oryza rufipogon distributed from Asia to Australia and the annual O. meridionalis indigenous to Australia are AA genome species in the Oryza. However, recent research has demonstrated that the Australian AA genome perennial populations have maternal genomes more closely related to those of O.

Chromosomal Location of HCA1 and HCA2, Hybrid Chlorosis Genes in Rice.

MANY POSTZYGOTIC REPRODUCTIVE BARRIER FORMS HAVE BEEN REPORTED IN PLANTS: hybrid weakness, hybrid necrosis, and hybrid chlorosis. In this study, linkage analysis of the genes causing hybrid chlorosis in F(2) generation in rice, HCA1 and HCA2, was performed. HCA1 and HCA2 are located respectively on the distal regions of the short arms of chromosomes 12 and 11.

Fine mapping and allelic dosage effect of Hwc1, a complementary hybrid weakness gene in rice.

Hybrid weakness is a reproductive barrier that is found in many plant species. In rice, the hybrid weakness caused by two complementary genes, Hwc1 and Hwc2, has been surveyed intensively. However, their gene products and the molecular mechanism that causes hybrid weakness have remained unknown.

Ribosomal DNA intergenic spacer sequence in foxtail millet, Setaria italica (L.) P. Beauv. and its characterization and application to typing of foxtail millet landraces.

We determined the sequence of ribosomal DNA (rDNA) intergenic spacer (IGS) of foxtail millet isolated in our previous study, and identified subrepeats in the polymorphic region. We also developed a PCR-based method for identifying rDNA types based on sequence information and assessed 153 accessions of foxtail millet. Results were congruent with our previous works.

Phylogenetic analysis of the rDNA intergenic spacer subrepeats and its implication for the domestication history of foxtail millet, Setaria italica.

We sequenced ribosomal DNA intergenic spacer subrepeats and their flanking regions of foxtail millet landraces from various regions in Europe and Asia and its wild ancestor to elucidate phylogenetic differentiation within each of types I-III found in our previous work and to elucidate relationships among these three types. Type I was classified into seven subtypes designated as Ia-Ig based on subrepeat sequences; C repeats downstream of those subrepeats are also polymorphic. Of these, subtypes Ia-Id and Ig were found in foxtail millet landraces.