Glaberrima Steud Research Articles

The Mystery of Black Rice: Food, Medicinal, and Spiritual Uses of Oryza glaberrima by Maroon Communities in Suriname and French Guiana

AbstractDuring plantation slavery, African rice (Oryza glaberrima Steud.) was widely cultivated in the Americas but was soon replaced by Asian rice (Oryza sativa L.). Maroons, descendants of Africans who escaped slavery in Suriname and French Guiana, continue to cultivate African rice. Genomic research linked this rice to an O. glaberrima variety in the Ivory Coast. Based on interviews with 99 Maroon farmers, of whom 23 cultivate black rice, we describe its diverse uses as (ceremonial) food, offerings, spiritual medicine, and its role during funerals. Maroon oral history accounts on the origin of black rice differ among and within communities: enslaved women brought it from Africa or took it from the plantations where they worked; escaped slaves found it in the savanna; or ancestors encountered it in interior swamps. These multiple and sometimes contradictory accounts of the origins of black rice are related to the diverse ethnic and geographical backgrounds of the Africans brought as slaves to Suriname and their different histories with the crop after marronage. Various characteristics of black rice, including its ability to compete with weeds and grow on poor soils, its shattering seeds, and its visibility to birds explain how this African domesticate survived in the wild in the Amazonian forest. The migration of Maroons to cities, their engagement in gold mining, and their evangelization may lead to the loss of black rice knowledge and practices.

Native and modified starch nano-crystals loaded with doxorubicin mediated apoptosis in human breast cancer MCF7 cells

The present study was aimed at evaluating the effect of doxorubicin (Dox) loaded nanocrystals starch in human breast cancer MCF7 cells. A model for breast cancer, MCF7 cells, were treated with Dox loaded in S (native starch), NS (starch nanocrystal), ANS (acetylated starch nanocrystal) extracted from Oryza glaberrima Steud and compared with Dox (diluted in water). MTT assay, Hoechst33342, H2DCFDA, Live Death, and Rhodamine123 staining, and Western Blot were used to detect different signaling protein expressions and apoptosis. Hoechst33342 staining showed cellular apoptosis of MCF7 after treating with DOX loaded S, NS, ANS or Dox alone. Intracellular ROS levels, p53 and Bax/ Bcl2 expressions, and decrease in mitochondrial membrane potential were also higher in MCF7 cells treated with Dox loaded S, NS, ANS or Dox alone. To ensure Dox loaded S, NS or ANS did not cause any cellular damages to normal cells, HEK-293 kidney cells were used as control. Dox loaded S, NS, or ANS were as effective formulations as Dox alone to decrease progression and metastasis of breast cancer in MCF7 cells. This study provides a novel approach for further investigation since Dox loaded starch nanocrystals are effective and can prevent side effects of cardiotoxicity when using Dox alone.

Comparison between the impact of osmotic and NaCl treatments on the expression of genes coding for ion transporters in Oryza glaberrima Steud.

We analyzed the expression of genes coding for Na+ transporters (OsHKT1.5, OsHKT1.1, OsSOS1, OsSOS2, OsNHX1, OsNHX2), Cl- transporter (OsNRT1, OsCLC, OsCCC1) and gene coding for the transcription factor DREB (OsDREB2) involved in response to desiccation in two cultivars of O. glaberrrima differing in salt-resistance (salt-tolerant cultivar (TOG5307) and salt-sensitive (TOG 5949)) exposed to NaCl, PEG or both agents present simultaneously. Seedlings were grown in iso-osmotic nutrient solution (Ψs = -0.47±0.02 MPa) containing PEG 6,000 12.9% (water stress), NaCl 75 mM (salt stress) and PEG 6.4% + NaCl 37.5 mM (MIX-treatment) during 1 and 7 days. Plants were analyzed for gene expression, mineral nutrients, and photosynthetic-related parameters. Na+ and Cl- accumulations in salt-treated plants were lower in roots and shoots of TOG5307 comparatively to TOG5949 while water content decreased in TOG5307. TOG5307 exhibited tolerance to water stress and maintained higher net photosynthesis and water use efficiency than TOG5949 in response to all treatments, but was less efficient for osmotic adjustment. Dehydration tolerance of TOG5307 involves a higher OsDREB2 expression. TOG5307 also exhibited a higher OsSOS1, OsSOS2, OsNHX1 and OsNHX2 expression than TOG5949 in response to salinity. OsHKT1.5 was slightly induced in the shoot. OsHKT1.1 was recorded in the shoots but remained undetectable in the roots. Chloride and sodium accumulations were strongly reduced in the shoots when PEG was present. Salinity resistance in Oryza glaberrima implies tolerance to dehydration as well as complementary strategies of Na+ exclusion through the SOS system and Na+ tolerance through vacuolar sequestration.

Upland rice: A new high potential non-traditional cash crop for Africa

Rice is the main staple food for almost half of the world’s population and leading cereal in terms of production area and consumption. Rapid urbanization and changes in consumer preferences have led to a concomitant increase in consumption which so far exceeds any other crop in Africa. Therefore, upland rice cropping has become a common sight in Africa as farmers engage in diversification and respond to demand for the crop. Interspecific hybridization of African rice (Oryza glaberrima Steud.) and Asian rice (Oryza sativa L.) produced upland rice NERICA varieties that combine adaptability, tolerance to stresses and high production potential. Traditional African rice varieties though adapted to the continent are prone to lodging, shattering and comparatively low yielding which adversely affects production and consequently their adoption. Some of the poorest farmers are found in Africa where there is dependence on biomass cooking fuel and upland rice has greater significance. There is, therefore, need to re-evaluate the role played by the crop, identify gaps and proffer solutions that will make it productive and widely cultivated. Accordingly, this review intends to examine upland rice production patterns and strides which can be made to sustainably increase its productivity so that there is food and nutrition security. Some of the pertinent issues that need to be considered include prioritization of farmer preferences in quality and agronomic attributes to enhance adoption. Upland rice breeding programs can go beyond traditional breeding for stresses and yield but focus on genetic biofortification to use the crop as a conduit for vital nutrients. Ultimately, for sustainable rice productivity, there is need to have affordable infrastructure to lessen labor requirement particularly during production and post-harvest processing. Moreover, there is need to build institutional capacity to conduct more research and offer extension services to support production of the crop. A wider product portfolio for the crop will subsequently have a multiplier effect and enhance adoption of rice production by many farmers in Africa. The ultimate aim is to spread awareness of upland rice as an alternative cash crop that can be produced in suitable agroecologies in Africa. Key words: Crop diversification, NERICA, Oryza glaberrima, Oryza sativa, Upland rice

Genomic introgressions from African rice (Oryza glaberrima) in Asian rice (O. sativa) lead to the identification of key QTLs for panicle architecture

BackgroundDeveloping high yielding varieties is a major challenge for breeders tackling the challenges of climate change in agriculture. The panicle (inflorescence) architecture of rice is one of the key components of yield potential and displays high inter- and intra-specific variability. The genus Oryza features two different crop species: Asian rice (Oryza sativa L.) and the African rice (O. glaberrima Steud.). One of the main morphological differences between the two independently domesticated species is the structure (or complexity) of the panicle, with O. sativa displaying a highly branched panicle, which in turn produces a larger number of grains than that of O. glaberrima. The gene regulatory network that governs intra- and interspecific panicle diversity is still under-studied.ResultsTo identify genetic factors linked to panicle architecture diversity in the two species, we used a set of 60 Chromosome Segment Substitution Lines (CSSLs) issued from third generation backcross (BC3DH) and carrying genomic segments from O. glaberrima cv. MG12 in the genetic background of O. sativa Tropical Japonica cv. Caiapó. Phenotypic data were collected for rachis and primary branch length, primary, secondary and tertiary branch number and spikelet number. A total of 15 QTLs were localized on chromosomes 1, 2, 3, 7, 11 and 12, QTLs associated with enhanced secondary and tertiary branch numbers were detected in two CSSLs. Furthermore, BC4F3:5 lines carrying different combinations of substituted segments were produced to decipher the effects of the identified QTL regions on variations in panicle architecture. A detailed analysis of phenotypes versus genotypes was carried out between the two parental genomes within these regions in order to understand how O. glaberrima introgression events may lead to alterations in panicle traits.ConclusionOur analysis led to the detection of genomic variations between O. sativa cv. Caiapó and O. glaberrima cv. MG12 in regions associated with enhanced panicle traits in specific CSSLs. These regions contain a number of key genes that regulate panicle development in O. sativa and their interspecific genomic variations may explain the phenotypic effects observed.

Genome-wide association analysis identifies natural allelic variants associated with panicle architecture variation in African rice, Oryza glaberrima Steud.

African rice (Oryza glaberrima Steud), a short-day cereal crop closely related to Asian rice (Oryza sativa L.), has been cultivated in Sub-Saharan Africa for ∼ 3,000 years. Although less cultivated globally, it is a valuable genetic resource in creating high-yielding cultivars that are better adapted to diverse biotic and abiotic stresses. While inflorescence architecture, a key trait for rice grain yield improvement, has been extensively studied in Asian rice, the morphological and genetic determinants of this complex trait are less understood in African rice. In this study, using a previously developed association panel of 162 O. glaberrima accessions and new SNP variants characterized through mapping to a new version of the O. glaberrima reference genome, we conducted a genome-wide association study of four major morphological panicle traits. We have found a total of 41 stable genomic regions that are significantly associated with these traits, of which 13 co-localized with previously identified QTLs in O. sativa populations and 28 were unique for this association panel. Additionally, we found a genomic region of interest on chromosome 3 that was associated with the number of spikelets and primary and secondary branches. Within this region was localized the O. sativa ortholog of the PHYTOCHROME B gene (Oglab_006903/OgPHYB). Haplotype analysis revealed the occurrence of natural sequence variants at the OgPHYB locus associated with panicle architecture variation through modulation of the flowering time phenotype, whereas no equivalent alleles were found in O. sativa. The identification in this study of genomic regions specific to O. glaberrima indicates panicle-related intra-specific genetic variation in this species, increasing our understanding of the underlying molecular processes governing panicle architecture. Identified candidate genes and major haplotypes may facilitate the breeding of new African rice cultivars with preferred panicle traits.

Characterization of African Rice (Oryza glaberrima Steud.) Germplasm for Grain Iron and Zinc Content

Micronutrient deficiency is one of the major challenges for food security in developing nations. There is a need for the identification of micronutrient-rich genotypes for their direct use in the genetic enhancement of staple food crops using plant breeding strategies. In the present study, grain iron (Fe) and zinc (Zn) contents of 29 accessions of Oryza glaberrima along with check varieties were analyzed for three seasons. Grain Fe ranged from 6.40 ppm to 12.10 ppm with a mean of 8.57 ppm, while Zn content exhibited manifold variation by ranging from 7.30 ppm to 34.40 ppm in the brown rice. There was a two-fold variation in Fe and Zn concentrations between accessions indicating the potential to boost these micronutrients in rice grain. Fifteen African rice accessions were better than the checks for grain Fe content, while four accessions outperformed checks with higher Zn content. Altogether, one O. glaberrima accession, CG 239 was found to be having high Zn content (34.7 ppm) in the brown rice making it a valuable source for biofortification of popular rice varieties using conventional and molecular approaches.

Characterization and fine-mapping of a new Asian rice selfish genetic locus S58 in Asian-African rice hybrids.

We identified and fine-mapped S58, a selfish genetic locus from Asian rice that confers hybrid male sterility in crosses between Asian and African cultivated rice, and found a natural neutral allele in Asian rice lines that will be useful for overcoming S58-mediated hybrid sterility. Hybrids between Asian cultivated rice (Oryza sativa L.) and African cultivated rice (Oryza glaberrima Steud) display severe hybrid sterility (HS), hindering the utilization of strong heterosis in hybrids between these species. Several African rice selfish loci causing HS in Asian-African cultivated rice hybrids have been identified, but few such Asian rice selfish loci have been found. In this study, we identified an Asian rice selfish locus, S58, which causes hybrid male sterility (HMS) in hybrids between the Asian rice variety 02428 and the African rice line CG14. Genetic analysis confirmed that S58 causes a transmission advantage for the Asian rice S58 allele in the hybrid offspring. Genetic mapping with near-isogenic lines and DNA markers delimited S58 to 186 kb and 131 kb regions of chromosome 1 in 02428 and CG14, respectively, and revealed complex genomic structural variation over these mapped regions. Gene annotation analysis and expression profiling analyses identified eight anther-expressed candidate genes potentially responsible for S58-mediated HMS. Comparative genomic analysis determined that some Asian cultivated rice varieties harbor a 140 kb fragment deletion in this region. Hybrid compatibility analysis showed that this large deletion allele in some Asian cultivated rice varieties can serve as a natural neutral allele, S58-n, that can overcome S58-mediated interspecific HMS. Our study demonstrates that this selfish genetic element from Asian rice is important for HMS between Asian and African cultivated rice, broadening our understanding of interspecific HS. This study also provides an effective strategy for overcoming HS in future interspecific rice breeding.

Genotypic data for association analysis in African rice, Oryza glaberrima Steud.

Genotypic data for association analysis in African rice, Oryza glaberrima Steud.

Effects of water use efficiency on plant dry matter in NERICA and Japanese rice cultivars under drought conditions

NERICA (New Rice for Africa) was produced by crossing Asian rice (Oryza sativa L.) and African rice (Oryza glaberrima Steud.) and recorded to be drought tolerance. This study aimed to examine the transpiration and water use efficiency affected plant aboveground dry matter in total 29 cultivars including 23 NERICA, 1 indica-type and 5 japonica-type cultivars. Seedlings were transplanted 2 plants per pot (1/5000 a Wagner pot) on June 14, 2021. When the flag leaf appeared, three water treatments with three replications were imposed for 14 days. The control plot (C) was watered daily to maintain the water content per pot at field capacity (SW). The water content of medium dry pots (MD) and hard dry pots (HD) were maintained at 40% and 10% of SW, respectively. Surface of the pots was covered to eliminate the evaporation. Samples for dry matter measurement were collected on the same day starting and ending water treatment. Water use efficiency (WUE) was significantly different among cultivars when soil moisture treatments were included, and the same observation on soil moisture treatments when included cultivars. NERICA 4 showed the lowest WUE while NERICA 9 and Hokuriku 193 had the highest WUE. Cultivars with higher transpiration rate (Tr) had higher dry matter production (ΔDW). Under high vapor pressure deficit, ΔDW was more correlated with transpiration corrected by vapor pressure deficit (Tr/VD) than with WUE.

Modelling Distributions of Asian and African Rice Based on MaxEnt

Rice landraces, including Asian rice (Oryza sativa L.) and African rice (Oryza glaberrima Steud.), provide important genetic resources for rice breeding to address challenges related to food security. Due to climate change and farm destruction, rice landraces require urgent conservation action. Recognition of the geographical distributions of rice landraces will promote further collecting efforts. Here we modelled the potential distributions of eight rice landrace subgroups using 8351 occurrence records combined with environmental predictors with Maximum Entropy (MaxEnt) algorithm. The results showed they were predicted in eight sub-regions, including the Indus, Ganges, Meghna, Mekong, Yangtze, Pearl, Niger, and Senegal river basins. We then further revealed the changes in suitable areas of rice landraces under future climate change. Suitable areas showed an upward trend in most of study areas, while sub-regions of North and Central China and West Coast of West Africa displayed an unsuitable trend indicating rice landraces are more likely to disappear from fields in these areas. The above changes were mainly determined by changing global temperature and precipitation. Those increasingly unsuitable areas should receive high priority in further collections. Overall, these results provide valuable references for further collecting efforts of rice landraces, while shedding light on global biodiversity conservation.

The MYB transcription factor Seed Shattering 11 controls seed shattering by repressing lignin synthesis in African rice.

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.

Genetic analysis and identification of QTLs associated with yield-enhancing traits in Oryza sativa IR64 × Oryza glaberrima interspecific backcross populations

Context Broadening the gene pool of staple food crops by incorporating desirable genes from wild/relative species is way to achieve higher genetic gains. The African rice species Oryza glaberrima Steud. is a source of genes for genetic improvement of Oryza sativa L. to various biotic and abiotic stresses. Aim The study was undertaken to identify genomic regions associated with yield and yield-related traits in interspecific backcross mapping populations derived from variety IR64 (O. sativa indica) × O. glaberrima. Methods The BC1F2 and BC1F2:3 populations were phenotyped for days to 50% flowering, plant height, number of tillers, number of productive tillers, panicle length, spikelet fertility and grain yield under irrigated conditions. The BC1F2 population was genotyped with 99 genome-wide polymorphic SSR markers. Quantitative trait loci (QTLs) associated with yield-enhancing traits were identified through single marker analysis. Key results Significant genetic variability was observed with moderate to high heritability in mapping populations. Genotyping revealed the presence of segregation distortion and skewed genome composition. Single marker analysis identified 20 QTLs linked to the studied traits. A QTL linked to grain yield, qGY-4.1, derived from O. glaberrima was found in both populations with high phenotypic variance. The chromosome region around marker RM510 was identified as a QTL hotspot and putative candidate genes were identified. Conclusions Our study demonstrates that O. glaberrima can serve as a valuable genetic resource for genetic improvement of yield-enhancing traits in O. sativa cultivars. Implications The identified QTLs regions can be employed in molecular breeding. The promising introgression lines identified can be used as pre-breeding lines in future breeding programs.

Genetic characterization and fine mapping of qHMS4 responsible for pollen sterility in hybrids between Oryza sativa L. and Oryza glaberrima Steud.

The online version contains supplementary material available at 10.1007/s11032-022-01306-8.

Physiological and genetic control of transpiration efficiency in African rice, Oryza glaberrima Steud.

Improving crop water use efficiency, the amount of carbon assimilated as biomass per unit of water used by a plant, is of major importance as water for agriculture becomes scarcer. In rice, the genetic bases of transpiration efficiency, the derivation of water use efficiency at the whole-plant scale, and its putative component trait transpiration restriction under high evaporative demand remain unknown. These traits were measured in 2019 in a panel of 147 African rice (Oryza glaberrima) genotypes known to be potential sources of tolerance genes to biotic and abiotic stresses. Our results reveal that higher transpiration efficiency is associated with transpiration restriction in African rice. Detailed measurements in a subset of highly contrasted genotypes in terms of biomass accumulation and transpiration confirmed these associations and suggested that root to shoot ratio played an important role in transpiration restriction. Genome wide association studies identified marker-trait associations for transpiration response to evaporative demand, transpiration efficiency, and its residuals, with links to genes involved in water transport and cell wall patterning. Our data suggest that root-shoot partitioning is an important component of transpiration restriction that has a positive effect on transpiration efficiency in African rice. Both traits are heritable and define targets for breeding rice with improved water use strategies.

Distribution and accumulation of mercury in pot-grown African rice cultivars (Oryza glaberrima Steud. and Oryza sativa L.) determined via LA-ICP-MS.

There is limited information concerning the distribution of mercury in rice, particularly in African rice. The objective was to compare the distribution of total mercury (THg) and methylmercury (MeHg) in African rice (Oryza glaberrima Steud.) and Asian rice (O. sativa L.). It is hypothesized that increased mineral accumulation and greater stress tolerance in O. glaberrima will affect the uptake and distribution of THg and MeHg, compared to O. sativa. Rice varieties from the Republic of Mali, including O. glaberrima (n =1) and O. sativa (n = 2), were cultivated in a greenhouse, in mercury-spiked soil (50 mg/kg) (n =3 replicates/variety). THg and MeHg concentrations were analyzed in the grain (brown rice), and the THg distribution was analyzed using laser ablation inductively coupled-plasma mass spectrometry (LA-ICP-MS). THg and MeHg concentrations did not differ between O. glaberrima and O. sativa grain. However, in both O. sativa varieties, THg was highly concentrated in the scutellum, which surrounds the embryo and is removed during polishing. Conversely, in O. glaberrima grain, THg was widely distributed throughout the endosperm, the edible portion of the grain. Differences in the THg distribution in O. glaberrima grain, compared to O. sativa, may elevate the risk of mercury exposure through ingestion of polished rice. The novelty of this study includes the investigation of a less-studied rice species (O. glaberrima), the use of a highly sensitive elemental imaging technique (LA-ICP-MS), and its finding of a different grain THg distribution in O. glaberrima than has been observed in O. sativa.

Nutrient management for sustainable food crop intensification in African tropical savannas

AbstractIncreased fertilizer use is often an essential component of sustainable intensification for improved food security and economic growth in the upper elevation tropical savanna (UTS) and lower elevation tropical savanna (LTS) of Africa. The UTS and LTS are large “breadbasket” areas with little fertilizer use due to financial and other constraints. Farmers’ perceptions of high profit opportunity with low risk are often major drivers of adoption. Representative crop nutrient response functions are needed to maximize farm‐level profits from fertilizer use. Such functions were determined from results of past research, and profit potentials were evaluated. The mean yield increases due to fertilizer application at the economically optimum rate, relative to yield with no fertilizer applied, were as follows: 41% for cassava (Manihot esculenta Crantz), 18% for cowpea [Vigna unguiculata (L.) Walp.], 16% for groundnut (Arachis hypogaea L.), 67% for maize (Zea mays L.), 50% for lowland rice (Oryza sativa L.), and 39% for sorghum [Sorghum bicolor (L.) Moench] in LTS, and 46% for bean (Phaseolus vulgaris L.), 81% for groundnut, 58% for maize, 96% for upland rice (Oryza sativa L. or Oryza glaberrima Steud.), 32% for sorghum, and 48% for soybean [Glycine max (L.) Merr.] in UTS. The profit potential varied greatly across nutrient rates applied to individual crops making optimized crop–nutrient–rate choices especially important for cases of financially constrained fertilizer use. Considerations for achieving widespread adoption of increased fertilizer use are discussed. Increased fertilizer use needs to be complemented by mitigation of diverse yield and socioeconomic constraints to meet the growing demand for food.

Discriminating the impact of Na+ and Cl− in the deleterious effects of salt stress on the African rice species (Oryza glaberrima Steud.)

Salinity resistance of the African rice species (Oryza glaberrima) is poorly documented and the specific responses of the plant to Na+ and Cl− toxic ions remain unknown. Cultivars TOG5307 and TOG5949 were maintained for 15 days on iso-osmotic nutrient solutions containing 50 mM NaCl, or a combination of Cl− salts (Cl−-dominant) or Na+ salts (Na+-dominant). Plant water status, ion accumulation, gas exchange, fluorescence related parameters, carbon (δ13C) and nitrogen (δ15N) isotope ratios were analyzed. TOG5307 accumulated lower amounts of Na+ and Cl− in the shoot (1.63 and 1.49 µmol g−1 DW, respectively) than TOG 5949 (2.5 and 2.2 µmol g−1 DW). At 50 mM NaCl, TOG5307 also exhibited a higher net carbon assimilation rate (2.51 µmol CO2 m−2 s−1) than TOG5949 (1.51 µmol m−2 s−1) and a higher water use efficiency. Most recorded physiological parameters were affected by both Na+ and Cl−. The pattern of modification induced by both types of toxicities was similar in the two studied cultivars which thus mainly differ for the quantitative aspects of the response rather than for the qualitative nature of the response. NaCl was the most detrimental treatment, followed by Na+-dominant treatment while Cl−-treatment had the lowest effect. The two considered cultivars mainly differ for their response to the ionic component of salt stress but not for their osmotic behaviour. The impact of Na+ and Cl− on considered parameters are additive, except for mineral nutrition where synergistic interactions were recorded for Na+ and S accumulation.

Native and Modified Oryza glaberrima Steud Starch Nanocrystals: Solid-state characterization and Anti-tumour drug release studies

In a bid to explore new biodegradable sourced materials for drug delivery, Oryza glaberrima starch was extracted, modified, and characterized. Nanocrystalstarch (NS) and acetylated nanocrystal starch (ANS) were produced from the native starch (S). The physicochemical properties, scanning electron microscopy(SEM), X-ray diffraction (XRD), Differential scanning calorimetry (DSC) and Fourier Transform Infra-red spectroscopy (FTIR) were done. The loading and release studies of Doxorubicin-loaded starches were carried out. The density, solubility, swelling capacity, and hydration capacity of the starch increased after modification whereas the amylose content was reduced. SEM revealed no change in morphology with sizes of the starch granules to be 5-15µm and the shape to be polyhedral. Modification of the starch increased the percentage drug loading capacity (DLC) and loading efficiency (LE). The drug release kinetics of the Dox-loaded S and ANS was the first-order release, while Dox-loaded NS was Korsemeyer-Peppas model. Improvement in the physicochemical properties of the NS and ANS made them useful carriers to sustain and control drug release.

Weedy rice (Oryza spp.): what’s in a name?

AbstractThere are two species of cultivated rice in the world—Oryza sativa L. from Asia and Oryza glaberrima Steud. from Africa. The former was domesticated from the wild progenitor Oryza rufipogon Griff. and the latter from the African wild rice species Oryza barthii A. Shiv. The first known center of rice cultivation in China generated the O. sativa subspecies japonica. The indica subspecies arose from the second center of domestication in the Ganges River plains of India. Variants of domesticated lines and the continuous hybridization between cultivated varieties and the wild progenitor(s) resulted in weedy rice types. Some weedy types resemble the wild ancestor, but the majority of weedy rices today bear close resemblance to cultivated rice. Weedy rice accompanies rice culture and has increased in occurrence with the global shift in rice establishment from transplanting to direct-seeded or dry-drill-seeded rice. Weedy rice (Oryza spp.) is the most difficult weed to control in rice, causing as much as 90% yield loss or abandonment of severely infested fields. The gene flow continuum between cultivar and weedy rice or wild relative, crop de-domestication, and regionalized adaptation have resulted in a myriad of weedy rice types. The complex lineage of weedy rice has resulted in confusion of weedy rice nomenclature. Two names are generally used for weedy rice—Oryza sativa L. and Oryza sativa f. spontanea. Genomic data show that O. sativa L. applies to weedy rice populations derived from cultivated O. sativa, whereas O. sativa f. spontanea applies only to weedy types that primarily descended from O. rufipogon. Neither of these names applies to African weedy rice, which is of African wild rice or O. glaberrima lineage. Therefore, unless the lineage of the weedy population in question is known, the proper name to use is the generalized name Oryza spp.