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1.
Weedy rice is a complex of Oryza morphotypes widely distributed in commercial rice fields, which interfere with rice cultivation, seed production, industrial
processing and commercialization of this crop in several countries. The objective of this study was to characterize the weedy
rice complex of Costa Rica by comparing it with the cultivated and wild rice species found in the country. A collection of
weedy rice accessions, representative of the morphotypes found in the country, was established and characterized. Their morphometric
relationships were established by comparing 27 morphological traits with commercial rice cultivars, landraces and wild Oryza species and by performing a multivariate analysis. Twenty-one weedy rice morphotypes were identified among 735 weedy accessions
by using a three-digit code based on seed characters. Three principal components (PCs) explained 66.25% of the variation observed.
The first PC accounted for 36.21% of the variation and separated CCDD genome type Oryza latifolia and O. grandiglumis from AA genome species O. sativa, O. glumaepatula, O. rufipogon and O. glaberrima. The second (18.9%) and third (11.14%) PCs separated the weedy morphotype groups from the AA genome species O.sativa, O. glaberrima and O. rufipogon. The weedy morphotypes were scattered between the indica commercial rice varieties, the cluster landraces–glaberrima and O. rufipogon. Additionally, a group of morphotypes showed intermediate characteristics between O. sativa and O. rufipogon, suggesting that hybridization could have taken place in the past between these species. None of the morphotypes collected
in Costa Rica clustered with the allotetraploids CCDD species or O. glumaepatula. 相似文献
2.
Nonnatus S. Bautista Duncan Vaughan A. H. M. Jayasuriya A. S. U. Liyanage Akito Kaga Norihiko Tomooka 《Genetic Resources and Crop Evolution》2006,53(3):631-640
The CC genome of Oryza is found in nine species of Oryza that are distributed on all continents having a tropical climate. Three diploid Oryza species with CC genome are found in Africa and Asia to Papua New Guinea. In southern South Asia these three CC genome diploid
species can be found, O. eichingeri and O. rhizomatis in Sri Lanka and O. officinalis in India. AA genome wild relatives of rice are also found in the same geographic region. Germplasm of both diploid CC and
AA genome Oryza germplasm has recently been collected from Sri Lanka. AFLP analysis was used to compare the genetic diversity of the two
Oryza genomes from a similar geographic region in southern South Asia. In addition, the diploid CC Oryza germplasm was also analyzed by RAPD and SSR methodologies and the combined results were analyzed. The results show that in
southern South Asia the diploid CC genome species have a high level of genetic diversity compared to the diploid AA genome
species. Molecular marker analysis revealed that populations of O. rhizomatis from northern and southeastern Sri Lanka are genetically differentiated. One accession of O. rhizomatis was aligned with O. eichingeri. This accession was collected from the site of O. rhizomatis that is the closest to a population of O. eichingeri. O. eichingeri showed lower genetic diversity than the other two diploid Oryza CC genome species. O. officinalis accessions from Assam, India, and China were genetically less diverged from O. eichingeri and O. rhizomatis than two accessions of O. officinalis from Kerala state, India.
The first two authors contributed equally to this research 相似文献
3.
Wild relatives of rice (Oryza spp.) are an important source of novel resistance (R-)genes for rice improvement. Rice sheath blight, caused by Rhizotonia solani, and leaf blast, caused by Magnaportha oryzae, are major fungal diseases of rice worldwide. To identify novel R-genes, a group of Oryza spp. accessions represented by O. alta, O. australiensis, O. barthii, O. glaberrima, O. glumaepatula, O. latifolia, O. meridionolis, O. nivara, O. officinalis, and O. rufipogon, were evaluated for their reaction to leaf blast and sheath blight disease, and genotyped with 176 microsatellite (SSR) markers.
Selected rice (O. sativa) accessions were included as reference. Cluster analysis performed with PowerMarker software using Rogers genetic distance and UPGMA, revealed most Oryza spp. accessions clustered with the same species or a closely related Oryza spp. Only a few Oryza spp. accessions grouped with the O. sativa accessions included as a reference. Analysis of this genotypic data in the software Structure revealed that the Oryza spp. accessions were assigned into eight different subpopulations and fit well into eight different backgrounds. Marker-trait
associations between the SSR markers and disease reactions to blast and sheath blight were ascertained using the software
TASSEL. Associations with blast disease were identified in ten different chromosomal regions and five of the ten were not
located near known blast R-genes. Three associations were discovered with sheath blight disease and one was not near previously reported sheath blight
QTL. These newly identified regions may represent novel R-genes that will be the basis future fine mapping studies.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
4.
J. Xie H. A. Agrama D. Kong J. Zhuang B. Hu Y. Wan W. Yan 《Genetic Resources and Crop Evolution》2010,57(4):597-609
The wild progenitor species (Oryza rufipogon) of Asian cultivated rice (O. sativa L.) is located in Dongxiang county, China which is considered its the northernmost range worldwide. Nine ex situ and three in situ populations of the Dongxiang wild rice (DXWR) and four groups of modern cultivars were genotyped using 21 SSR markers for
study of population structure, conservation efficiency and genetic relationship. We demonstrated that the ex situ conservation of the DXWR failed to maintain the genetic identity and reduced genetic diversity. Therefore, in situ conservation is absolutely necessary to maintain the genetic identity, diversity and heterozygosity. Also, in situ conservation is urgently needed because natural populations in DXWR have decreased from nine to three at present due to farming
activity and urban expansion. In DXWR, the three surviving in situ populations had greater expected heterozygosity than any cultivated rice, and were genetically closer to japonica than either the male-sterile maintainer or restorer lines, or indica. Japonica has the lowest genetic diversity of cultivated rice. As a result, DXWR is a rich gene pool and is especially valuable for
genetic improvement of japonica rice because these O. rufipogon accessions are most closely related to the japonica as compared to O. rufipogon collected anywhere else in the world. 相似文献
5.
Tonapha Pusadee Barbara A. Schaal Benjavan Rerkasem Sansanee Jamjod 《Genetic Resources and Crop Evolution》2013,60(1):335-353
The gene pool of cultivated Asian rice consists of wild rice (Oryza rufipogon Griff.), cultivated rice (O. sativa L.) and a weedy form (O. sativa f. spontanea). All three components are widespread in Thailand, frequently co-occurring within fields and providing the opportunity for gene flow and introgression. The purpose to this study is to understand the on-going evolutionary processes that affect the gene pool of rice by analysis of microsatellite variation. Results indicate that O. rufipogon, the wild ancestor of rice, has high levels of genetic variation both within and among populations. Moreover, the variation is structured predominantly by annual and perennial life history. High levels of variation are detected among cultivars indicating Thai cultivated rice has a broad genetic base with only a 20 % reduction in diversity from its wild ancestor. The weedy rice populations reveal varying levels of genetic variation, from nearly as high as wild rice to near zero. Weedy rice is genetically structured into 2 groups. Some populations of invasive weedy rice are the result of hybridization and gene flow between local wild rice and local cultivated rice in the regions of co-occurrence. Other populations of weedy rice are genetically nearly identical to the local cultivated rice. The diversity analysis indicates that the rice gene pool in Thailand is a dynamic genetic system. Gene flow is ongoing among its three main components, first between cultivated and wild rice resulting in weedy rice. Weedy rice in turn crosses with both cultivated varieties and wild rice. 相似文献
6.
Oryza granulata, an upland wild rice species, represents an unique germplasm for possessing abilities of tolerance to shade and drought,
immune to bacterial blight and resistance to brown planthopper. Although low degree of genetic variability has been revealed
within its populations, little genetic information at the species level is available in determining rational conservation
strategies. Here we used dominant DNA marker random amplified polymorphism DNA (RAPD) to assess the genetic variability among
23 accessions of O. granulata that collected from main distribution areas worldwide. Twenty decamer primers generated a total of 243 bands, with 83.5%
of them (203 bands) being polymorphic. Calculation of Shannon index of diversity revealed an average value of 0.42 ± 0.25,
indicating that O. granulata maintains a relatively high degree of genetic diversity on the species level. Analysis of genetic dissimilarity (GD) showed
that genetic differentiation occurred among studied accessions, which supports the feasibility of current ex situ conservation strategies. We also suggested that information based on population studies, which could be achieved by international
co-operation, is needed to conserve this widespread germplasm more effectively. 相似文献
7.
Preecha Prathepha 《Genetic Resources and Crop Evolution》2009,56(1):13-18
The Asian cultivated rice, Oryza sativa L. (spp. indica or japonica), is assumed to have originated from one or both of the two wild Asian species, O. rufipogon Griff. and O. nivara Sharma and Shastry. They occur throughout the monsoon Asia and west Oceania. Fragrance is the most important trait among
the domesticated characters of basmati and jasmine rice of Asia. The gene for fragrance in a scented rice shows the presence
of a mutated portion (i.e., an eight base pair deletion in exon 7) that result in its loss of fragrance. In the present study,
229 wild rice O. rufipogon accessions were genotyped for this locus using a PCR assay. The wild rice species contained the mutated allele of the fgr
gene at a low frequencies of 0.23. The surveyed populations were in Hardy–Weinberg equilibrium. This observation supports
the hypothesis that the allele for fragrance was already present in the wild rice, and that this trait appeared in scented
rice cultivars because of selection by the farmers of genotypes possessing this character during the process of domestication. 相似文献
8.
Yao Zhao Chengbin Chen Jun Rong Shanshan Dong Hui Liao Fan Lu Baorong Lu Jiakuan Chen Zhiping Song 《Genetic Resources and Crop Evolution》2012,59(1):113-124
Population clonal diversity and fine-scale genetic structure of Oryza officinalis Wall. ex Watt, an endangered species in China recently experiencing habitat degradation, was estimated using inter simple
sequence repeat markers. We analyzed the genetic variations of 440 samples exhaustively collected from nine O. officinalis populations. Relatively rich clonal diversity and poor genetic variation were found in the extant populations. We found that
the number of genets, the percentage of polymorphic loci, and gene diversity decreased with population decline, suggesting
that habitat degradation will lead to further genetic depletion of O. officinalis populations. A pronounced spatial genetic structure occurs at both the ramet and genet levels in several larger populations,
which is the result of clonal growth and concomitant inbreeding. The in situ conserved population PS holds much more genotypes than other populations with the similar population size, which might have more seedling recruitments
from the soil seed bank due to habitat disturbance, suggesting a moderate disturbance combined with habitat degradation-avoiding
measures are effective for in situ conservation of this species. 相似文献
9.
10.
Gabriella Sonnante Anna Vittoria Carluccio Angelo De Paolis Domenico Pignone 《Genetic Resources and Crop Evolution》2008,55(7):1029-1046
A set of 24 microsatellite markers was identified in the artichoke genome, using various approaches. A genomic library allowed
the development of 14 SSR markers, whereas the other 10 were obtained from gene intron/UTR regions or from other species.
Allelic variation was scored in C. cardunculus (artichoke, cultivated cardoon, and wild cardoon) samples, and in other wild Cynara allies. For the 23 polymorphic loci, a total of 165 alleles were scored, 135 of which in the artichoke primary genepool,
and the remaining ones in the other Cynara species. Some allele combinations were able to identify artichoke varietal types, and some alleles were unique to specific
groups. This makes these markers potentially useful in product traceability and in contributing to the saturation of genetic
maps. The percentage of shared alleles between C. cardunculus taxonomic groups, and Nei’s genetic distances indicated that wild cardoons from the Eastern Mediterranean were more closely
related to artichoke and less to cultivated cardoon in comparison to wild cardoons from the Western Mediterranean, and the
genetic distance between the two wild cardoon genepools was rather high. The UPGMA dendrogram based on Nei’s genetic distances
revealed that artichokes formed a fairly defined cluster, whereas Eastern wild cardoons occupied another branch, and Western
wild cardoons were clustered together with cultivated cardoons. The transferability of microsatellite markers to other Cynara wild species was quite good. Sequencing alleles at three loci showed that, apart from microsatellite length variation, point
mutations and insertion/deletions were quite abundant especially when comparing C. cardunculus to the other Cynara species. In the sequenced regions, some SNPs were identified which distinguished artichoke on one side, and cultivated and
wild cardoon on the other, while other SNPs were apportioned according to the geographic distribution of Cynara wild species. 相似文献
11.
R. Shishido M. Kikuchi K. Nomura H. Ikehashi 《Genetic Resources and Crop Evolution》2006,53(1):179-186
As a part of an in situ survey of wild rice (Oryza rufipogon Griff.) in Myanmar (Burma), 16 strains of wild rice were collected, and analyzed for allelic diversity over 74 loci with
simple sequence repeat (SSR) markers to obtain a basic information for their conservation. Three each of indica and japonica cultivars were added for a comparison. In the six cultivars and 16 strains of wild rice, three to 15 alleles were detected
per locus with an average of 7.9. The wild rice revealed a large number of unique alleles throughout their chromosomes with
much wider ranges of variation than those detected in the six cultivars of O. sativa L.. The alleles found in the wild rice were classified into those specific to wild rice, common to wild rice and cultivars,
and those similar to indica or japonica cultivars. According to the classification, the genotype of each of the 16 strains of wild rice was schematically depicted.
The genetic variation among individual strains within a collection site was larger than the variation among the collection
sites. 相似文献
12.
The genus Oryza has given rise to rice (Oryza sativa L.), a major source of food for much of the human population. The Oryza genus is small, including only 23 species, but it is remarkably diverse in terms of its ecological adaptation. This diversity may not be only restricted to ecological characteristics but also to kernel end‐use quality characteristics. This study was undertaken to evaluate Oryza species as a gene pool for improving the properties of rice bran for human consumption. Several accessions of 13 Oryza species were grown in a greenhouse, along with eight rice (Oryza sativa L.) accessions displaying low and high bran oil content, as well as low and high palmitic acid content. The total lipid content of the Oryza species was within the range found for Oryza sativa accessions. However, the level of palmitic acid in the O. species was as high as that reported for soybean high‐palmitic acid mutants. Oryza species also contained higher levels of the γ‐oryzanol and phenolic fractions compared to cultivated rice. Low or not significant phenotypic correlations between lipid, palmitic acid, and γ‐oryzanol suggest that these fractions in cultivated rice could be increased simultaneously using several of the Oryza species accessions identified in this study. A cultivar with enhanced levels of these fractions would be suitable for use in the production of high γ‐oryzanol margarine, shortening, and frying oils. 相似文献
13.
Worapa Seehalak Norihiko Tomooka Aree Waranyuwat Piyada Thipyapong Paisan Laosuwan Akito Kaga Duncan A. Vaughan 《Genetic Resources and Crop Evolution》2006,53(5):1043-1059
Thailand is a center of diversity for section Angulares of the Asian Vigna (genus Vigna subgenus Ceratotropis) and 4 Vigna species are cultivated in Thailand. Using newly collected wild and cultivated germplasm of Vigna from Thailand and outgroup accessions AFLP analysis was conducted to clarify genetic diversity and relationships. The results
suggest that cultivated V. umbellata and V. mungo evolved from wild relatives in a single domestication event. Vigna umbellata is poorly differentiated from its wild and weedy relatives compared to V. mungo. Results suggest northern Thailand and the neighboring Shan state, Myanmar, is the probable center of domestication for V. umbellata as wild accessions from this area and cultivated rice bean from a wide area in Asia are not greatly diverged. Vigna minima, V. tenuicaulis and V. exilis accessions in Thailand are well differentiated with considerable intra-specific variation. Vigna hirtella consists of two well differentiated subgroups, suggesting taxonomic revision may be necessary. Close genetic relationships
between V. radiata and V. grandiflora, and between V. mungo and V. trinervia are confirmed. Naturally growing V. mungo populations in northern Thailand appear to be true wild species as they are well differentiated from Indian wild and Thai
cultivated populations. The origin of naturally growing cowpea in Thailand needs to be further studied using a more comprehensive
set of materials. This study clarifies inter and intra-specific genetic diversity and inter species relationships of Thai
Vigna species. 相似文献
14.
Masako Okoshi Tomotaro Nishikawa Hiromori Akagi Tatsuhito Fujimura 《Genetic Resources and Crop Evolution》2018,65(3):713-726
Asian rice (Oryza sativa L.) is widely cultivated in Asia, where it has been classified into Indica and Japonica Group, the latter is further classified into Tropical and Temperate Japonica Subgroup. O. rufipogon is believed to be the closest ancestor to O. sativa, but it remains unclear whether the two groups arose from a single ancestor or different ancestors. Therefore, here, we investigated the matrilineal ancestors of O. sativa using markers for organelle (chloroplast and mitochondrial) genomes, and 119 O. sativa landraces, 10 O. glaberrima Steud., 115 O. rufipogon Griff. from Asia, and 39 accessions from other wild rice species with AA genomes. We screened 18 organelle markers developed based on polymorphic loci in the organelle genomes. In addition, we used the open reading frame 100 of a chloroplast marker. The results indicated that O. rufipogon first differentiated into two lineages and then further differentiated into Indica and Japonica Group, respectively. Accessions of O. rufipogon (R-1f and R-2d types) from Myanmar appear to be the closest ancestors of Tropical Japonica Subgroup and Indica Group, respectively. Therefore, these wild strains may have made a strong contribution to the domestication of rice landraces in Myanmar. 相似文献
15.
Oryza officinalis complex is the largest and the most complicated group in the genus Oryza L., consisting of about ten species with the B, C, BC, CD, and E genomes. Taxonomy and identification of the species, particularly those with the B, C and BC genomes, are difficult due to the similar morphology and overlapping distribution of some species. The difference in ploidy levels of some species adds more complexity. In the present study, we surveyed 64 accessions of rice germplasm in the O. officinalis complex using RFLP analysis of PCR-amplified Adh genes in addition to chromosome counting. The results confirmed that all O. rhizomatis accessions are diploids with the C genome, whereas all O. minuta accessions are tetraploids having the BC genome. However, both diploid and tetraploid forms were found for the accessions identified in the genebank as O. officinalis, O. punctata and O. eichingeri. The tetraploid form of O. officinalis with the BC genome is exclusively distributed in India and has been described as O. malampuzhaensis. The tetraploid form of O. punctata which has been called O. schweinfurthiana by some workers was found to be as widely distributed as its diploid form in Africa. It is noteworthy that two accessions that had been determined as tetraploid O. officinalis were actually belonging to a species with the CD genome (O. latifolia). Our results promote a better understanding of the genomic constitutions of many accessions in the O. officinalis complex and correct determination of the genebank material, which serves as an important basis of germplasm cataloguing for further research and utilization. 相似文献
16.
S. Al Khanjari K. Hammer A. Buerkert M. S. Röder 《Genetic Resources and Crop Evolution》2007,54(6):1291-1300
Results of archaeological studies indicate a millennia-old cultivation history for wheat (Triticum spp.) in Oman. However, in spite of numerous collection surveys and efforts for phenotypic characterization of Omani wheat
landraces, no attempts have been made using molecular tools to characterize this germplasm. To fill this gap, 29 microsatellite
markers revealing 30 loci were used to study the genetic diversity of 38 tetraploid wheat landrace accessions comprising the
species T. dicoccon, T. durum and T. aethiopicum. A total of 219 alleles were detected whereby the number of alleles per locus ranged from 2 to 16 with an average number
of 7.1 alleles per locus. The highest number of alleles occurred in the B genome with on average 7.9 alleles per locus as
compared to the A genome with 6.5 alleles per locus. Heterogeneity was detected for all microsatellites except for GWM 312, GWM 601 and GWM 192B with an average heterogeneity over all primers and lines of 14.4%. Approximately 10% of the accessions contained rare alleles
with an average allele frequency <4%. Gene diversity across microsatellite loci ranged from 0.26 to 0.85. The pairwise comparison
of genetic similarity ranged from 0.03 to 0.91 with an average of 0.2. Cluster analysis revealed a clear separation of the
two species groups T. dicoccon versus T. durum and T. aethiopicum. Within the species clusters regional patterns of subclustering were observed. Overall, this study confirmed the existence
of a surprisingly high amount of genetic diversity in Omani wheat landraces as already concluded from previous morphological
analyses and showed that SSR markers can be used for landraces’ analysis and a more detailed diversity evaluation. 相似文献
17.
Genetic variation and relationships among members of the azuki bean complex (Vigna angularis) including wild (V. angularis var. nipponensis), weedy, and cultivated types (V. angularis var. angularis), V. nakashimae, and rice bean (V. umbellata) from Korea were examined using the Amplified fragment length polymorphism (AFLP) method. AFLP analysis of 50 accessions
revealed 333 (72.1%) polymorphic fragments out of 462 fragments amplified using seven primer combinations. The number of polymorphic
fragments within each species was 70 in the azuki bean complex and 41 in V. nakashimae, but there was no polymorphism in rice bean. The number of shared fragments among species ranges from 142 between the azuki
bean complex and V. nakashimae to 166 between the azuki bean complex and rice bean. Within the azuki bean complex, the range of shared bands was from 231
between cultivated and weedy types to 238 between cultivated and wild types. A dendrogram generated from Jaccard’s similarity
matrix was divided into three groups, which correspond to V. nakashimae, azuki bean complex, and rice bean. The relationship between azuki bean and rice bean is closer than between azuki bean and
V. nakashimae. Phenetic distances averaged 0.502 between the azuki bean complex and V. nakashimae and 0.467 between the azuki bean complex and rice bean. Within the azuki bean complex, the weedy type was more closely related
to wild than cultivated types. But UPGMA dendrogram of the azuki bean complex reveals that each type is not clearly isolated.
These results will help to understand genetic diversity and evolutionary dynamics of Vigna in Korea. 相似文献
18.
Thitaporn Sukhotu Osamu Kamijima Kazuyoshi Hosaka 《Genetic Resources and Crop Evolution》2006,53(1):53-63
Solanum stenotomum Juz. et Buk. (2n = 2x = 24) is considered to be the most primitive diploid cultivated species from which all the other Andean cultivated potatoes
were originated (Hawkes 1990). To disclose chloroplast DNA (ctDNA) variability and the maternal origin of S. stenotomum, 36 accessions of S. stenotomum and 86 accessions of putative wild ancestral species were determined for ctDNA types and analyzed by high-resolution markers
(seven ctDNA microsatellites and an H3 marker). High-resolution markers discriminated 57 different ctDNAs (haplotypes), which
were classified into the W-type ctDNA group and C-, S- and A-type ctDNA group, and within the latter group S- and A-type ctDNAs
were distinct from each other among many different haplotypes mostly having C-type ctDNA. This ctDNA relationship supported
our previous findings obtained for mostly Andean cultivated species (Sukhotu et al. 2004). Compared with other putative ancestral
wild species, S. stenotomum showed somewhat limited ctDNA diversity, having two major haplotypes 1 and 2 also found in different wild species in different
places. Therefore, the ctDNA in S. stenotomum was of at least dual origins either by successive domestication from different species or else by introgression after initial
S. stenotomum arose. 相似文献
19.
Tatjana Gavrilenko Olga Antonova Anna Shuvalova Ekaterina Krylova Natalia Alpatyeva David M. Spooner Lubov Novikova 《Genetic Resources and Crop Evolution》2013,60(7):1997-2015
The origin of cultivated potatoes has remaining questions. In this study, 237 accessions of all cultivated species and 155 accessions of wild species closely related to cultivated potatoes, including their putative ancestors, were analyzed using 15 plastid microsatellites (SSRs) to investigate genetic diversity and their relationships with the wild species. We here used polymorphic plastid SSRs we developed from potato plastid genome sequences as well as already known plastid SSR markers. All 15 loci were polymorphic and identified a total of 127 haplotypes. Dramatic decreases in levels of genetic diversity were revealed in landraces in comparison with wild ancestor species. The plastid SSR results showed a decrease in haplotype number and diversity from Peru to both north and south. Phylogenetic analysis revealed two distinct groups. One of them, group A, contained the majority of accessions of cultivated species of the Solanum tuberosum Andigenum group including all accessions of cultivated diploid and triploid cytotypes of this group (S. chaucha, S. phureja, and S. stenotomum by a former taxonomic system) and most of tetraploid accessions of the S. tuberosum Andigenum group (S. tuberosum subsp. andigenum), and the majority of accessions of wild ancestors from the northern members of the S. brevicaule complex. Another group B comprised most of the wild species accessions and almost exclusively hybrid cultivated species which have introgressed plastid genomes from the other wild gene pools. Lack of clustering of traditional cultivated species (as used above) support a revised group classification of S. tuberosum. 相似文献
20.
Maria Celeste N. Banaticla-Hilario Kenneth L. McNally Ronald G. van den Berg Nigel Ruaraidh Sackville Hamilton 《Genetic Resources and Crop Evolution》2013,60(6):1899-1914
Reproductive barriers are thought to intensify with increasing genetic distance between species. To assess the extent of post-pollination reproductive isolation within and among the Asia Pacific species of Oryza series Sativae, crossing experiments using 15 accessions of O. meridionalis Ng, O. nivara Sharma et Shastry, and O. rufipogon Griff. were conducted. Intra- and interspecific crosses of the selfing species O. meridionalis and O. nivara had very low seed set and produced inviable F1 seeds indicative of strong pre- and post-zygotic barriers. Contrastingly, the outcrossing O. rufipogon exhibited high intraspecific crossability and modest compatibility with O. nivara and O. meridionalis in terms of seed set suggesting substantial pre-zygotic reproductive isolation of the species. O. rufipogon was asymmetrically compatible with O. meridionalis and symmetrically with O. nivara. The two inbreeding species manifested comparable degrees of isolation from O. rufipogon despite differences in strength of several post-zygotic barriers. Mating compatibility within and between the Asia Pacific species of Oryza series Sativae is not strongly spatially influenced, but some resistance to gene flow under sympatric conditions was observed. Intraspecific O. rufipogon F1s were more vegetatively robust and more late-flowering than their parents. Intra- and interspecific hybrids of Australasian O. rufipogon differed phenotypically from crosses with non-Australasian populations. Interspecific hybrids displayed both intermediate and parental character traits. O. nivara and O. rufipogon generated early-flowering F1s that are more similar to the former. O. meridionalis and O. rufipogon produced F1s that varied in phenology and morphology depending on the maternal and paternal species. 相似文献