Grain physical characteristic of the Australian wild rices

2016 ◽  
Vol 15 (5) ◽  
pp. 409-420 ◽  
Author(s):  
Tiparat Tikapunya ◽  
Glen Fox ◽  
Agnelo Furtado ◽  
Robert Henry

AbstractRice yield improvement is required to support increasing global rice demand. However, the limited genetic diversity within the cultivated rice gene pool may be a major obstacle. Australian wild rice which has been largely genetically isolated from cultivated rice might be a new source of genetic variation for use in improving rice production. The physical properties of Oryza australiensis and of the two perennial Australian Wild rice taxa-belonging to the A genome wild rice were evaluated. Seeds collected from rice in the wild were generally smaller than those from domesticated rice. The wild rice A genome collections were classified as extra-long paddy rice with grains that were long or medium, while O. australiensis was categorized as long paddy rice with a short grain. However, these wild rices were slender compared with domesticated rice. The grain colour of these wild rices varied from light red brown to dark brown compared with domesticated rice which is brighter, with less redness and more yellowness than the wild rice. The physical characteristics of the grains of the Australian wild rice indicate that these rice grains may be successfully processed using current rice processing techniques and may be a useful novel food especially in the coloured rice market.

Author(s):  
Jyotirmaya Mathan ◽  
Anuradha Singh ◽  
Aashish Ranjan

Abstract The source-sink relationship is key to overall crop performance. Detailed understanding of the factors that determine source-sink dynamics is imperative for the balance of biomass and grain yield in crop plants. We investigated the differences in the source-sink relationship between a cultivated rice Oryza sativa cv. Nipponbare and a wild rice Oryza australiensis that show striking differences in biomass and grain yield. Oryza australiensis, accumulating higher biomass, not only showed higher photosynthesis per unit leaf area but also exported more sucrose from leaves than Nipponbare. However, grain features and sugar levels suggested limited sucrose mobilization to the grains in the wild rice due to vasculature and sucrose transporter functions. Low cell wall invertase activity and high sucrose synthase cleavage activity followed by higher expression of cellulose synthase genes in Oryza australiensis stem utilized photosynthates preferentially for the synthesis of structural carbohydrates, resulting in high biomass. In contrast, the source-sink relationship favored high grain yield in Nipponbare via accumulation of transitory starch in the stem, due to higher expression of starch biosynthetic genes, which is mobilized to panicles at the grain filling stage. Thus, vascular features, sucrose transport, and functions of sugar metabolic enzymes explained the differences in the source-sink relationship between Nipponbare and Oryza australiensis.


2009 ◽  
Vol 8 (1) ◽  
pp. 74-81 ◽  
Author(s):  
S. Kasem ◽  
D. L. E. Waters ◽  
N. Rice ◽  
F. M. Shapter ◽  
R. J. Henry

The grain morphology of 17 wild rice relatives were studied by light and scanning electron microscopy and compared to two cultivated rice varieties (Oryza sativa cv. Nipponbare and O. sativa cv. Teqing). Observations were made of the grain colour, size and shape. Grains from wild rice species exhibited a variety of colours that have potential aesthetic and nutritional value. The grains of these species exhibited a wide array of sizes and shapes, but still fell within the standard classification scale that rice breeders use for routine breeding evaluation. These results highlight the potential of these species as whole grain foods or as sources of novel alleles in conventional rice breeding programmes.


2020 ◽  
Author(s):  
Jyotirmaya Mathan ◽  
Anuradha Singh ◽  
Aashish Ranjan

AbstractThe source-sink relationship is key to overall crop performance. Detailed understanding of the factors that determine source-sink dynamics is imperative for the balance of biomass and grain yield in a crop plant. We investigated the differences in the source-sink relationship between a cultivated rice Oryza sativa cv. Nipponbare and a wild rice Oryza australiensis that show striking differences in biomass and grain yield. The wild rice, accumulating higher biomass, was not only photosynthetically efficient but also had efficient sucrose export from leaves. However, sucrose mobilization to the grains was limited due to impaired vasculature and sucrose transporter functions at the reproductive tissues of the wild rice. High cleavage activity of Sucrose Synthase followed by higher expression of Cellulose Synthase genes in the wild rice stem efficiently utilized photosynthates for the synthesis of structural carbohydrates, resulting in high biomass. In contrast, the source-sink relationship favored high grain yield in Nipponbare via accumulation of transitory starch in the stem, due to higher expression of starch biosynthetic genes, which is mobilized to panicles at the grain filling stage. Thus, sucrose transport along with functions of key sugar metabolic enzymes explained the differences in the source-sink relationship between the selected cultivated and wild rice.


2020 ◽  
Author(s):  
Subhas Chandra Roy ◽  
Pankaj Shil

AbstractRice (Oryza sativa L.) is a most important staple food grain consumed by more than half of the world’s population. Wild rice (O. rufipogon Griff.) is considered as the immediate ancestral progenitor of cultivated rice O. sativa, evolved through the process of domestication. Most of the cultivated rice produced grains with white pericarp, but can also produce grains with brown, red and black (or purple rice) pericarp. Red rice pericarp accumulates proanthocyanidin whereas black rice contains anthocyanin, both have antioxidant activity and health benefits. Black pericarp is predicted to be regulated by alleles of three genetic loci- Kala1, Kala3, and Kala4. Recombinational and insertional genetic rearrangement in the promoter region of Kala4 is crucial for the development of black pericarp in rice grain. In the present study, we report first time in the breeding history that aromatic black rice lines were developed through interspecific hybridization and introgression in the genetic background of O. sativacv. Badshabhog, Chenga and Ranjit. Badshabhog and Ranjit is white grain rice but Chenga is red rice category. Common Asian wild rice O. rufipogon is used as donor parent (red grain) and source of black rice gene. Several possible genetic explanations have come up for the creation of black rice pericarp in the progeny lines. Possible reason may be the rearrangement and insertion of LINE1 in the promoter region of Kala4 allele through recombination mechanism leading to ectopic expression of Kala4 gene for the accumulation of anthocyanin and resulted in black rice formation. Other genes and regulatory factors may be induced and become functional to produce black pericarp. Black pericarp colour appeared in F2 populations in the wide crosses (Badshabhog x O. rufipogon and Chenga x O. rufipogon) but not in the cross with (Ranjit x O. rufipogon). Black pericarp trait inherited in F4 and F5 population with segregation phenotypes.This is a first report in the history of rice genetics and pre-breeding research, that black rice has been created through wide crossing and introgression by combining wild rice O. rufipogon in the genetic background of O. sativa. Present experimental evidence provides a new model of black rice origin. Thus, black rice (indica type) of Indian subcontinent originated independently through natural out crossing and artificial selection in the course of domestication.


Author(s):  
Aaron L. Phillips ◽  
Andrew P. Scafaro ◽  
Brian J. Atwell

Abstract Key message A wild relative of rice from the Australian savannah was compared with cultivated rice, revealing thermotolerance in growth and photosynthetic processes and a more robust carbon economy in extreme heat. Abstract Above ~ 32 °C, impaired photosynthesis compromises the productivity of rice. We compared leaf tissues from heat-tolerant wild rice (Oryza australiensis) with temperate-adapted O. sativa after sustained exposure to heat, as well as diurnal heat shock. Leaf elongation and shoot biomass in O. australiensis were unimpaired at 45 °C, and soluble sugar concentrations trebled during 10 h of a 45 °C shock treatment. By contrast, 45 °C slowed growth strongly in O. sativa. Chloroplastic CO2 concentrations eliminated CO2 supply to chloroplasts as the basis of differential heat tolerance. This directed our attention to carboxylation and the abundance of the heat-sensitive chaperone Rubisco activase (Rca) in each species. Surprisingly, O. australiensis leaves at 45 °C had 50% less Rca per unit Rubisco, even though CO2 assimilation was faster than at 30 °C. By contrast, Rca per unit Rubisco doubled in O. sativa at 45 °C while CO2 assimilation was slower, reflecting its inferior Rca thermostability. Plants grown at 45 °C were simultaneously exposed to 700 ppm CO2 to enhance the CO2 supply to Rubisco. Growth at 45 °C responded to CO2 enrichment in O. australiensis but not O. sativa, reflecting more robust carboxylation capacity and thermal tolerance in the wild rice relative.


Genome ◽  
1997 ◽  
Vol 40 (1) ◽  
pp. 104-110 ◽  
Author(s):  
J. Provan ◽  
G. Corbett ◽  
W. Powell ◽  
J. W. McNicol

Short mononucleotide repeats analogous to nuclear microsatellites or simple sequence repeats (SSRs) have been identified in chloroplast genomes. Primers flanking mononucleotide repeats in the fully sequenced rice chloroplast genome have been used in conjunction with PCR to amplify genomic DNA from 42 wild rice accessions. The amplification products exhibited length polymorphism, which allowed the levels of chloroplast variability detected to be quantified. Seven primer pairs that amplified products from different regions of the rice chloroplast were used, five of which also amplified polymorphic products in cultivated rice (Oryza sativa). Diversity values ranged from 0.5224 ± 0.0845 (SE) to 0.8298 ± 0.0085 in the wild accessions, which was higher than that detected in the O. sativa accessions. Both intra- and inter-specific polymorphism was detected, and the extent of chloroplast genomic differentiation based on chloroplast simple sequence repeat (cpSSR) assays was quantified using the RST statistic. Primers designed to amplify cpSSRs in O. sativa can also be used to generate polymorphic chloroplast markers in related taxa. The potential of using cpSSR to trace the origin of rice polyploid species is discussed.Key words: rice, chloroplast, simple sequence repeat, microsatellites.


Genetics ◽  
2002 ◽  
Vol 162 (4) ◽  
pp. 1863-1873 ◽  
Author(s):  
J Slate ◽  
P M Visscher ◽  
S MacGregor ◽  
D Stevens ◽  
M L Tate ◽  
...  

Abstract Recent empirical evidence indicates that although fitness and fitness components tend to have low heritability in natural populations, they may nonetheless have relatively large components of additive genetic variance. The molecular basis of additive genetic variation has been investigated in model organisms but never in the wild. In this article we describe an attempt to map quantitative trait loci (QTL) for birth weight (a trait positively associated with overall fitness) in an unmanipulated, wild population of red deer (Cervus elaphus). Two approaches were used: interval mapping by linear regression within half-sib families and a variance components analysis of a six-generation pedigree of >350 animals. Evidence for segregating QTL was found on three linkage groups, one of which was significant at the genome-wide suggestive linkage threshold. To our knowledge this is the first time that a QTL for any trait has been mapped in a wild mammal population. It is hoped that this study will stimulate further investigations of the genetic architecture of fitness traits in the wild.


2013 ◽  
Vol 21 (8) ◽  
pp. 725-737 ◽  
Author(s):  
Chuandeng Yi ◽  
Wenli Zhang ◽  
Xibin Dai ◽  
Xing Li ◽  
Zhiyun Gong ◽  
...  

2015 ◽  
Vol 42 (12) ◽  
pp. 699-702 ◽  
Author(s):  
Chuandeng Yi ◽  
Mingsen Wang ◽  
Wei Jiang ◽  
Derong Wang ◽  
Yong Zhou ◽  
...  

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