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The undomesticated rice relative Oryza longistaminata is a valuable genetic resource for the improvement of the domesticated Asian rice, Oryza sativa. To facilitate the conservation, management, and use of O. longistaminata germplasm, we sought to quantify the population structure and diversity of this species across its geographic range, which includes most of sub-Saharan Africa, and to determine phylogenetic relationships to other AA-genome species of rice present in Africa, including the prevalence of interspecific hybridization between O. longistaminata and O. sativa. Though past plant breeding efforts to introgress genes from O. longistaminata have improved biotic stress resistance, ratooning ability, and yield in O. sativa, progress has been limited by substantial breeding barriers. Nevertheless, despite the strong breeding barriers observed by plant breeders who have attempted this interspecific cross, there have been multiple reports of spontaneous hybrids of O. sativa and O. longistaminata (aka "Obake") obtained from natural populations in Africa. However, the frequency and extent of such natural introgressions and their effect on the evolution of O. longistaminata had not been previously investigated. We studied 190 O. longistaminata accessions, primarily from the International Rice Research Institute genebank collection, along with 309 O. sativa, 25 Oryza barthii, and 83 Oryza glaberrima control outgroups, and 17 control interspecific O. sativa/O. longistaminata hybrids. We analyzed the materials using 178,651 single-nucleotide polymorphisms (SNPs) and seven plastid microsatellite markers. This study identified three genetic subpopulations of O. longistaminata, which correspond geographically to Northwestern Africa, Pan-Africa, and Southern Africa. We confirmed that O. longistaminata is, perhaps counterintuitively, more closely related to the Asian species, O. sativa, than the African species O. barthii and O. glaberrima. We identified 19 recent spontaneous interspecific hybrid individuals between O. sativa and O. longistaminata in the germplasm sampled. Notably, the recent introgression between O. sativa and O. longistaminata has been bidirectional. Moreover, low levels of O. sativa alleles admixed in many predominantly O. longistaminata accessions suggest that introgression also occurred in the distant past, but only in Southern Africa.

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Rising temperatures and extreme heat events threaten rice production. Half of the global population relies on rice for basic nutrition, and therefore developing heat-tolerant rice is essential. During vegetative development, reduced photosynthetic rates can limit growth and the capacity to store soluble carbohydrates. The photosystem II (PSII) complex is a particularly heat-labile component of photosynthesis. We have developed a high-throughput chlorophyll fluorescence-based screen for photosynthetic heat tolerance capable of screening hundreds of plants daily. Through measuring the response of maximum PSII efficiency to increasing temperature, this platform generates data for modelling the PSII-temperature relationship in large populations in a small amount of time. Coefficients from these models (photosynthetic heat tolerance traits) demonstrated high heritabilities across African (Oryza glaberrima) and Asian (Oryza sativa, Bengal Assam Aus Panel) rice diversity sets, highlighting valuable genetic variation accessible for breeding. Genome-wide association studies were performed across both species for these traits, representing the first documented attempt to characterize the genetic basis of photosynthetic heat tolerance in any species to date. A total of 133 candidate genes were highlighted. These were significantly enriched with genes whose predicted roles suggested influence on PSII activity and the response to stress. We discuss the most promising candidates for improving photosynthetic heat tolerance in rice.

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Two species of rice have been independently domesticated from different ancestral wild species in Asia and Africa. Comparison of mutations that underlie phenotypic and physiological alterations associated with domestication traits in these species gives insights into the domestication history of rice in both regions. Asian cultivated rice, Oryza sativa, and African cultivated rice, Oryza glaberrima, have been modified and improved for common traits beneficial for humans, including erect plant architecture, nonshattering seeds, nonpigmented pericarp, and lack of awns. Independent mutations in orthologous genes associated with these traits have been documented in the two cultivated species. Contrary to this prevailing model, selection for awnlessness targeted different genes in O. sativa and O. glaberrima. We identify Regulator of Awn Elongation 3 (RAE3) a gene that encodes an E3 ubiquitin ligase and is responsible for the awnless phenotype only in O. glaberrima. A 48-bp deletion may disrupt the substrate recognition domain in RAE3 and diminish awn elongation. Sequencing analysis demonstrated low nucleotide diversity in a ~600-kb region around the derived rae3 allele on chromosome 6 in O. glaberrima compared with its wild progenitor. Identification of RAE3 sheds light on the molecular mechanism underlying awn development and provides an example of how selection on different genes can confer the same domestication phenotype in Asian and African rice.

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African cultivated rice (Oryza glaberrima Steud.) was domesticated from its wild progenitor species (Oryza barthii) about 3000 years ago. Seed shattering is one of the main constraints on grain production in African cultivated rice, which causes severe grain losses during harvest. By contrast, Asian cultivated rice (Oryza sativa) displays greater resistance to seed shattering, allowing higher grain production. A better understanding in regulation of seed shattering would help to improve harvesting efficiency in African cultivated rice. Here, we report the map-based cloning and characterization of OgSH11, a MYB transcription factor controlling seed shattering in O. glaberrima. OgSH11 represses the expression of lignin biosynthesis genes and lignin deposition by binding to the promoter of GH2. We successfully developed a new O. glaberrima material showing significantly reduced seed shattering by knockout of SH11 in O. glaberrima using CRISPR-Cas9 mediated approach. Identification of SH11 not only supplies a new target for seed shattering improvement in African cultivated rice, but also provides new insights into the molecular mechanism of abscission layer development.

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The evolutionary paths of humans and plants have crossed more than once throughout millennia. While agriculture contributed to the evolution of societies in prehistory, human selection of desirable traits contributed to the evolution of crops during centuries of cultivation. Among cereal crops, rice is currently grown around the globe and represents staple food for almost half of the world population. Over time, rice cultivation has expanded from subtropical to temperate regions thanks to artificial selection of mutants with impaired response to photoperiod. Additional regulatory mechanisms control flowering in response to diverse environmental cues, anticipating or delaying the floral transition to produce seeds in more favourable conditions. Nevertheless, the changing climate is threatening grain production because modern cultivars are sensitive to external fluctuations that go beyond their physiological range. One possibility to guarantee food production could be the exploitation of novel varieties obtained by crossing highly productive Asian rice with stress tolerant African rice. This review explores the genetic basis of the key traits that marked the long journey of rice cultivation from the end of the paleolithic to the anthropocene, with a focus on heading date. By 2050, will rice plants of the future flower in the outer space?

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African cultivated rice, Oryza glaberrima, is characterized by its glabrous glumes. During domestication, the pubescent glumes of its wild ancestor, Oryza barthii, lost their trichomes, and in this study, we show that glabrous glume 5 (GLAG5), a WUSCHEL-like homeobox transcription factor gene on chromosome 5, is required for trichome development. DNA methylation associated with an hAT transposable element inserted in the promoter region of GLAG5 is found to reduce its expression, leading to the formation of glabrous glumes and leaves in African cultivated rice. Among 82 African cultivated rice varieties investigated in this study, 59 (approximately 71%) lines exhibit glabrous glumes and harbor the hAT transposon; however, the other 23 varieties (approximately 29%), which exhibit pubescent glumes, lack the hAT transposon, indicating that glag5 had undergone strong artificial selection. The πw/πc ratios also show the hAT transposon insertions influence the genetic diversity of an approximately 150-kb interval encompassing the GLAG5 locus. The identification of the GLAG5 gene provides new insights into the domestication of cultivated rice in Africa. We speculate that the selection of varieties with mutations in their promoter regions is an important aspect of crop domestication.

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African rice (Oryza glaberrima) has adapted to challenging environments and is a promising source of genetic variation. We analysed dynamics of photosynthesis and morphology in a reference set of 155 O. glaberrima accessions. Plants were grown in an agronomy glasshouse to late tillering stage. Photosynthesis induction from darkness and the decrease in low light was measured by gas exchange and chlorophyll fluorescence along with root and shoot biomass, stomatal density, and leaf area. Steady-state and kinetic responses were modelled. We describe extensive natural variation in O. glaberrima for steady-state, induction, and reduction responses of photosynthesis that has value for gene discovery and crop improvement. Principal component analyses indicated key clusters of plant biomass, kinetics of photosynthesis (CO2 assimilation, A), and photoprotection induction and reduction (measured by non-photochemical quenching, NPQ), consistent with diverse adaptation. Accessions also clustered according to countries with differing water availability, stomatal conductance (gs), A, and NPQ, indicating that dynamic photosynthesis has adaptive value in O. glaberrima. Kinetics of NPQ, A, and gs showed high correlation with biomass and leaf area. We conclude that dynamic photosynthetic traits and NPQ are important within O. glaberrima, and we highlight NPQ kinetics and NPQ under low light.

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The ultraviolet B (UVB) sensitivity of rice cultivated in Asia and Africa varies greatly, with African rice cultivars (Oryza glaberrima Steud. and O. barthii A. Chev.) being more sensitive to UVB because of their low cyclobutane pyrimidine dimer (CPD) photolyase activity, which is a CPD repair enzyme, relative to Asian rice cultivars (O. sativa L.). Hence, the production of UVB-resistant African rice with augmented CPD photolyase activity is of great importance, although difficulty in transforming the African rice cultivars to this end has been reported. Here, we successfully produced overexpressing transgenic African rice with higher CPD photolyase activity by modifying media conditions for callus induction and regeneration using the parental line (PL), UVB-sensitive African rice TOG12380 (O. glaberrima). The overexpressing transgenic African rice carried a single copy of the CPD photolyase enzyme, with a 4.4-fold higher level of CPD photolyase transcripts and 2.6-fold higher activity than its PL counterpart. When the plants were grown for 21 days in a growth chamber under visible radiation or with supplementary various UVB radiation, the overexpressing transgenic plants have a significantly increased UVB resistance index compared to PL plants. These results strongly suggest that CPD photolyase remains an essential factor for tolerating UVB radiation stress in African rice. As a result, African rice cultivars with overexpressed CPD photolyase may survive better in tropical areas more prone to UVB radiation stress, including Africa. Collectively, our results provide strong evidence that CPD photolyase is a useful biotechnological tool for reducing UVB-induced growth inhibition in African rice crops of O. glaberrima.

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African rice (Oryza glaberrima Steud) is one of the two independently domesticated rice species, the other one being Asian rice (Oryza sativa L.). Despite major progress being made in understanding the evolutionary and domestication history of African rice, key outstanding issues remain controversial. There appears to be an underlying difficulty in identifying the domestication centre and number of times the crop has been domesticated. Advances in genomics have provided unprecedented opportunities for understanding the genetic architecture of domestication related traits. For most of the domestication traits, the underlying genes and mutations have been identified. Comparative analysis of domestication genes between Asian and African rice has revealed that the two species went through an independent but convergent evolution process. The genetic and developmental basis of some of the domestic traits are conserved not only between Asian and African rice but also with other domesticated crop species. Analysis of genome data and its interpretation is emerging as a major challenge facing studies of domestication in African rice as key studies continue giving contradictory findings and conclusions. Insights obtained on the domestication of this species are vital for guiding crop improvement efforts.

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BACKGROUND: African rice, Oryza glaberrima, is an invaluable resource for rice cultivation and for the improvement of biotic and abiotic resistance properties. Since its domestication in the inner Niger delta ca. 2500 years BP, African rice has colonized a variety of ecologically and climatically diverse regions. However, little is known about the genetic basis of quantitative traits and adaptive variation of agricultural interest for this species. RESULTS: Using a reference set of 163 fully re-sequenced accessions, we report the results of a Genome Wide Association Study carried out for African rice. We investigated a diverse panel of traits, including flowering date, panicle architecture and resistance to Rice yellow mottle virus. For this, we devised a pipeline using complementary statistical association methods. First, using flowering time as a target trait, we found several association peaks, one of which co-localised with a well described gene in the Asian rice flowering pathway, OsGi, and identified new genomic regions that would deserve more study. Then we applied our pipeline to panicle- and resistance-related traits, highlighting some interesting genomic regions and candidate genes. Lastly, using a high-resolution climate database, we performed an association analysis based on climatic variables, searching for genomic regions that might be involved in adaptation to climatic variations. CONCLUSION: Our results collectively provide insights into the extent to which adaptive variation is governed by sequence diversity within the O. glaberrima genome, paving the way for in-depth studies of the genetic basis of traits of interest that might be useful to the rice breeding community.

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African rice (Oryza glaberrima) has a pool of genes for resistance to diverse biotic and abiotic stresses, making it an important genetic resource for rice improvement. African rice has potential for breeding for climate resilience and adapting rice cultivation to climate change. Over the last decade, there have been tremendous technological and analytical advances in genomics that have dramatically altered the landscape of rice research. Here we review the remarkable advances in knowledge that have been witnessed in the last few years in the area of genetics and genomics of African rice. Advances in cheap DNA sequencing technologies have fuelled development of numerous genomic and transcriptomic resources. Genomics has been pivotal in elucidating the genetic architecture of important traits thereby providing a basis for unlocking important trait variation. Whole genome re-sequencing studies have provided great insights on the domestication process, though key studies continue giving conflicting conclusions and theories. However, the genomic resources of African rice appear to be under-utilized as there seems to be little evidence that these vast resources are being productively exploited for example in practical rice improvement programmes. Challenges in deploying African rice genetic resources in rice improvement and the genomics efforts made in addressing them are highlighted.

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Species misclassification (misidentification) and handling errors have been frequently reported in various plant species conserved at diverse gene banks, which could restrict use of germplasm for correct purpose. The objectives of the present study were to (i) determine the extent of genotyping error (reproducibility) on DArTseq-based single-nucleotide polymorphisms (SNPs); (ii) determine the proportion of misclassified accessions across 3134 samples representing three African rice species complex (Oryza glaberrima, O. barthii, and O. longistaminata) and an Asian rice (O. sativa), which are conserved at the AfricaRice gene bank; and (iii) develop species- and sub-species (ecotype)-specific diagnostic SNP markers for rapid and low-cost quality control (QC) analysis. Genotyping error estimated from 15 accessions, each replicated from 2 to 16 times, varied from 0.2 to 3.1%, with an overall average of 0.8%. Using a total of 3134 accessions genotyped with 31,739 SNPs, the proportion of misclassified samples was 3.1% (97 of the 3134 accessions). Excluding the 97 misclassified accessions, we identified a total of 332 diagnostic SNPs that clearly discriminated the three indigenous African species complex from Asian rice (156 SNPs), O. longistaminata accessions from both O. barthii and O. glaberrima (131 SNPs), and O. sativa spp. indica from O. sativa spp. japonica (45 SNPs). Using chromosomal position, minor allele frequency, and polymorphic information content as selection criteria, we recommended a subset of 24 to 36 of the 332 diagnostic SNPs for routine QC genotyping, which would be highly useful in determining the genetic identity of each species and correct human errors during routine gene bank operations.

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Plant architecture is a key agronomical factor determining crop yield and has been a major target of cereal crop domestication. The transition of plant architecture from the prostrate tiller of typical African wild rice (Oryza barthii) to the erect tiller of African cultivated rice (Oryza glaberrima) was a key step during domestication of African rice. Here we show that PROG7 (PROSTRATE GROWTH 7), a zinc-finger transcription factor gene on chromosome 7, is required for the prostrate growth of African wild rice. Mutations in the promoter region of prog7 reduced the level of gene expression in the tiller base, leading to erect growth in African cultivated rice. Sequence comparison and haplotype analysis show that 90 varieties of cultivated rice from 11 countries carry the same mutations in the prog7 region. A strong signal in a 60-kb genomic region was detected around the prog7 gene, suggesting that the region was under strong positive selection during the domestication process. Identification of the PROG7 gene provides new insights into the molecular basis of plant architecture in crops and facilitates investigation of the history of domestication of African rice.

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Grain number per panicle is a major component of rice yield that is typically controlled by many quantitative trait loci (QTLs). The identification of genes controlling grain number per panicle in rice would be valuable for the breeding of high-yielding rice. The Oryza glaberrima chromosome segment substitution line 9IL188 had significantly smaller panicles compared with the recurrent parent 9311. QTL analysis in an F2 population derived from a cross between 9IL188 and 9311 revealed that qgnp7(t), a major QTL located on the short arm of chromosome 7, was responsible for this phenotypic variation. Fine mapping was conducted using a large F3 population containing 2250 individuals that were derived from the F2 heterozygous plants. Additionally, plant height, panicle length, and grain number per panicle of the key F4 recombinant families were examined. Through two-step substitution mapping, qgnp7(t) was finally localized to a 41 kb interval in which eight annotated genes were identified according to available sequence annotation databases. Phenotypic evaluation of near isogenic lines (NIL-qgnp7 and NIL-qGNP7) indicated that qgnp7(t) has pleiotropic effects on rice plant architecture and panicle structure. In addition, yield estimation of NILs indicated that qGNP7(t) derived from 9311 is the favorable allele. Our results provide a foundation for isolating qgnp7(t). Markers flanking this QTL will be a useful tool for the marker-assisted selection of favorable alleles in O. glaberrima improvement programs.

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The sequence variation present in accessions conserved in genebanks can best be used in plant improvement when it is properly characterized and published. Using low cost and high density single nucleotide polymorphism (SNP) assays, the genetic diversity, population structure, and relatedness between pairs of accessions can be quickly assessed. This information is relevant for different purposes, including creating core and mini-core sets that represent the maximum possible genetic variation contained in the whole collection. Here, we studied the genetic variation and population structure of 2,179 Oryza glaberrima Steud. accessions conserved at the AfricaRice genebank using 27,560 DArTseq-based SNPs. Only 14% (3,834 of 27,560) of the SNPs were polymorphic across the 2,179 accessions, which is much lower than diversity reported in other Oryza species. Genetic distance between pairs of accessions varied from 0.005 to 0.306, with 1.5% of the pairs nearly identical, 8.0% of the pairs similar, 78.1% of the pairs moderately distant, and 12.4% of the pairs very distant. The number of redundant accessions that contribute little or no new genetic variation to the O. glaberrima collection was very low. Using the maximum length sub-tree method, we propose a subset of 1,330 and 350 accessions to represent a core and mini-core collection, respectively. The core and mini-core sets accounted for ~61 and 16%, respectively, of the whole collection, and captured 97-99% of the SNP polymorphism and nearly all allele and genotype frequencies observed in the whole O. glaberrima collection available at the AfricaRice genebank. Cluster, principal component and model-based population structure analyses all divided the 2,179 accessions into five groups, based roughly on country of origin but less so on ecology. The first, third and fourth groups consisted of accessions primarily from Liberia, Nigeria, and Mali, respectively; the second group consisted primarily of accessions from Togo and Nigeria; and the fifth and smallest group was a mixture of accessions from multiple countries. Analysis of molecular variance showed between 10.8 and 28.9% of the variation among groups with the remaining 71.1-89.2% attributable to differences within groups.

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Background: Availability of related rice species is critical for rice breeding and improvement. Two distinct species of domesticated rice exist in the genus Oryza: Oryza sativa (Asian rice) and Oryza glaberrima (African rice). New rice for Africa (NERICA) is derived from interspecific crosses between these two species. Molecular profiling of these germplasms is important for both genetics and breeding studies. We used 30 polymorphic SSR markers to assess the genetic diversity and molecular fingerprints of 53 rice genotypes of O. sativa, O. glaberrima, and NERICA. Results: In total, 180 alleles were detected. Average polymorphism information content and Shannon's information index were 0.638 and 1.390, respectively. Population structure and neighbor-joining phylogenetic tree revealed that 53 genotypes grouped into three distinct subpopulations conforming to the original three groups, except three varieties (IR66417, WAB450-4, MZCD74), and that NERICA showed a smaller genetic distance from O. sativa genotypes (0.774) than from O. glaberrima genotypes (0.889). A molecular fingerprint map of the 53 accessions was constructed with a novel encoding method based on the SSR polymorphic alleles. Ten specific SSR markers displayed different allelic profiles between the O. glaberrima and O. sativa genotypes. Conclusions: Genetic diversity studies revealed that 50 rice types were clustered into different subpopulations whereas three genotypes were admixtures. Molecular fingerprinting and 10 specific markers were obtained to identify the 53 rice genotypes. These results can facilitate the potential utilization of sibling species in rice breeding and molecular classification of O. sativa and O. glaberrima germplasms.

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BACKGROUND: The African rice Oryza glaberrima was domesticated from its wild relative Oryza barthii about 3000 years ago. During the domestication process, panicle complexity changed from a panicle with low complexity in O. barthii, to a highly branched panicle carrying more seeds in O. glaberrima. To understand the basis of this differential panicle development between the two species, we conducted morphological and molecular analyses of early panicle development. RESULTS: Using X-ray tomography, we analyzed the morphological basis of early developmental stages of panicle development. We uncovered evidence for a wider rachis meristem in O. glaberrima than in O. barthii. At the molecular level, spatial and temporal expression profiles of orthologs of O. sativa genes related to meristem activity and meristem fate control were obtained using in situ hybridization and qRT-PCR. Despite highly conserved spatial expression patterns between O. glaberrima and O. barthii, differences in the expression levels of these early acting genes were detected. CONCLUSION: The higher complexity of the O. glaberrima panicle compared to that of its wild relative O. barthii is associated with a wider rachis meristem and a modification of expression of branching-related genes. Our study indicates that the expression of genes in the miR156/miR529/SPL and TAW1 pathways, along with that of their target genes, is altered from the unbranched stage of development. This suggests that differences in panicle complexity between the two African rice species result from early alterations to gene expression during reproductive development.

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BACKGROUND: Chloroplast genome variations have been detected, despite its overall conserved structure, which has been valuable for plant population genetics and evolutionary studies. Here, we described chloroplast variation architecture of 383 rice accessions from diverse regions and different ecotypes, in order to mine the rice chloroplast genome variation architecture and phylogenetic. RESULTS: A total of 3677 variations across the chloroplast genome were identified with an average density of 27.33 per kb, in which wild rice showing a higher variation density than cultivated groups. Chloroplast genome nucleotide diversity investigation indicated a high degree of diversity in wild rice than in cultivated rice. Genetic distance estimation revealed that African rice showed a low level of breeding and connectivity with the Asian rice, suggesting the big distinction of them. Population structure and principal component analysis revealed the existence of clear clustering of African and Asian rice, as well as the indica and japonica in Asian cultivated rice. Phylogenetic analysis based on maximum likelihood and Bayesian inference methods and the population splits test suggested and supported the independent origins of indica and japonica within Asian cultivated rice. In addition, the African cultivated rice was thought to be domesticated differently from Asian cultivated rice. CONCLUSIONS: The chloroplast genome variation architecture in Asian and African rice are different, as well as within Asian or African rice. Wild rice and cultivated rice also have distinct nucleotide diversity or genetic distance. In chloroplast level, the independent origins of indica and japonica within Asian cultivated rice were suggested and the African cultivated rice was thought to be domesticated differently from Asian cultivated rice. These results will provide more candidate evidence for the further rice chloroplast genomic and evolution studies.

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Enzymatic hydrolysis in combination with gel-permeation and anion-exchange chromatography techniques were employed to characterise the composition of clusters and building blocks of amylopectin from two African rice (Oryza glaberrima) accessions-IRGC 103759 and TOG 12440. The samples were compared with one Asian rice (Oryza sativa) sample (cv WITA 4) and one O. sativa×O. glaberrima cross (NERICA 4). The average DP of clusters from the African rice accessions (ARAs) was marginally larger (DP=83) than in WITA 4 (DP=81). However, regarding average number of chains, clusters from the ARAs represented both the smallest and largest clusters. Overall, the result suggested that the structure of clusters in TOG 12440 was dense with short chains and high degree of branching, whereas the situation was the opposite in NERICA 4. IRGC 103759 and WITA 4 possessed clusters with intermediate characteristics. The commonest type of building blocks in all samples was group 2 (single branched dextrins) representing 40.3-49.4% of the blocks, while groups 3-6 were found in successively lower numbers. The average number of building blocks in the clusters was significantly larger in NERICA 4 (5.8) and WITA 4 (5.7) than in IRGC 103759 and TOG 12440 (5.1 and 5.3, respectively).

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High-performance anion-exchange chromatography was used to study the unit chain profiles of amylopectins and their φ,ß-limit dextrins from two African rice (Oryza glaberrima) accessions-TOG 12440 and IRGC 103759. The samples were compared with two Asian rice (Oryza sativa) samples (cv Koshihikari and cv WITA 4) and one O. sativa × O. glaberrima cross (NERICA 4). The ratio of short:long chains ranged between 12.1 and 13.8, and the ratio of A:B-chains was ∼ 1.0 in all samples. A significant difference was observed in the distribution of internal chains with regards to the proportion of short "fingerprint" B-chains (Bfp-chains), which in the φ,ß-limit dextrins have a degree of polymerization (DP) 3-7. The African rice starches and NERICA 4 had higher levels of Bfp-chains, but the major group of short B-chains (DP 8-25) was similar to that of the Asian rice samples. The average chain length (CL), internal chain length (ICL), and total internal chain length (TICL) were similar in all samples. However, the external chain length (ECL) was longer in the African rice samples and NERICA 4. ECL correlated positively and significantly (p<0.05) with gelatinization transition temperatures and enthalpy suggesting differences between the two rice types in cooking properties.

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