scholarly journals Characterization of Functional Genes GS3 and GW2 and their Effect on the Grain Size of Various Landraces of Rice

Author(s):  
Haroon Rasheed ◽  
Sajid Fiaz ◽  
Muhammad Abid Khan ◽  
Sultan Mehmood ◽  
Faizan Ullah ◽  
...  

Abstract Grain size is an essential factor in grain quality and yield. In the existing agricultural lands in Pakistan and even all over the world, genetics in rice works better for yield potential and quality improvement. GS3 and GW2 with functional mutation responsible for grain size in rice. In the current study, 17 different Pakistani landraces of various genetic and geographic backgrounds were evaluated for grain phenotypic traits (thousand-grain weight, length, width, and thickness) and characterized genotypes for GS3 gene (grain length) and GW2 (grain width). The two accessions JP5 and Bas370, were used as control. Phenotypic data revealed the range for grain weight from 16.86g (Lateefy) to 26.91g (PS2), grain length ranged from 7.27 mm (JP-5) to 12.18 mm (PS2), grain width ranged from 2.01 mm (Lateefy) to 3.51 mm (JP5), and grain thickness ranged from 1.79 mm to 2.19. Pearson correlation revealed a negative and significant correlation between grain width and length. There was no significant correlation between grain length and 1000-grain weight and grain width. LSD test displayed that the means of three variables grain length, grain width, and 1000-grain weight were statistically different from one another except grain width and grain breadth. GS3 is a negative regulator of grain length. Fifteen accessions GA-5015, PS-2, Swat-1, Swat-2, DR-2, Dilrosh, Malhar-346, Kashmir Basmati, Rachna Basmati, KS-282, Basmati-370, KSK-133, KSK-434, MG-Basmati, and Lateefy, carried the domesticated allele of GS3 while JP5 and Fakhr-e-Malakand carried the dominant allele. Similarly, the GW2 is a negative regulator of grain width. Fifteen accessions, i.e., Bas-370, GA-5015, PS-2, Swat-1, Swat-2, DR-2, Dilrosh, Malhar-346, Kashmir Basmati, Rachna Basmati, KS-282, KSK-133, KSK-434, MG-Basmati, and Lateefy carried the dominant allele while JP-5 and Fakhr-e-Malakand carried the mutant allele. The current phenotypic evaluation of the Germplasm revealed a diverse range of grain size of Pakistani landraces and also suggests that the selection of grain length in Pakistani landraces was independent of 1000-grain weight. The accessions with genotypic characterization will aid in marker-assisted breeding programs to break the stagnant yield prevail for the last few decades in Pakistan.

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yue Feng ◽  
Xiaoping Yuan ◽  
Yiping Wang ◽  
Yaolong Yang ◽  
Mengchen Zhang ◽  
...  

Abstract Background Grain size and weight are important target traits determining grain yield and quality in rice. Wild rice species possess substantial elite genes that can be served as an important resource for genetic improvement of rice. In this study, we identify and validate a novel QTL on chromosome 7 affecting the grain size and weight using introgression lines from cross of Oryza sativa and Oryza minuta. Results An introgression line ‘IL188’ has been achieved from a wild species Oryza minuta (2n = 48, BBCC, W303) into O. sativa japonica Nipponbare. The F2 and F2:3 populations derived from a cross between IL188 and Nipponbare were used to map QTLs for five grain size traits, including grain length (GL), grain width (GW), grain length to width ratio (LWR), grain thickness (GT) and thousand grain weight (TGW). A total of 12 QTLs for the five grain traits were identified on chromosomes 1, 2, 3, 6, 7, and 8. The QTL-qGL7 controlling GL on chromosome 7 was detected stably in the F2 and F2:3 populations, and explained 15.09–16.30% of the phenotypic variance. To validate the effect of qGL7, eight residual heterozygous line (RHL) populations were developed through selfing four F2:3 and four F2:4 plants with different heterozygous segments for the target region. By further developing SSR and Indel markers in the target interval, qGL7 was delimited to a ~ 261 kb region between Indel marker Y7–12 and SSR marker Y7–38, which also showed significant effects on grain width and thousand grain weight. Comparing with the reference genome of Nipponbare, stop or frameshift mutations in the exon of the three putative genes LOC_Os07g36830, LOC_Os07g36900 and LOC_Os07g36910 encoding F-box domain-containing proteins may be the candidate genes for qGL7. Scanning electron microscopy analysis of the glume’s epidermal cells showed that the cell length and width of NIL-qGL7IL188 was higher than NIL-qGL7Nip, indicating that qGL7 increases grain size and weight by regulating cell expansion. Conclusions In this study, we detected 12 QTLs regulating grain size and weight using an introgression line from a cross between Oryza sativa and Oryza minuta. Of these loci, we confirmed and delimited the qGL7 to a ~ 261 kb region. Three putative genes, LOC_Os07g36830, LOC_Os07g36900 and LOC_Os07g36910 encoding F-box domain-containing proteins may be the candidate genes for qGL7. These results provide a basis for map-based cloning of the qGL7 gene and useful information for marker assisted selection in rice grain quality improvement.


2021 ◽  
Author(s):  
Yue Feng ◽  
Xiaoping Yuan ◽  
Yiping Wang ◽  
Yaolong Yang ◽  
Mengchen Zhang ◽  
...  

Abstract Background: Grain size and weight are important target traits determining grain yield and quality in rice. Wild rice species possess substantial elite genes that can be served as an important resource for genetic improvement of rice. In this study, we identify and validate a novel QTL on chromosome 7 affecting the grain size and weight using introgression lines from cross of Oryza sativa and Oryza minuta. Results: An introgression line ‘IL188’ has been achieved from a wild species Oryza minuta (2n = 48, BBCC, W303) into O. sativa japonica Nipponbare. The F2 and F2:3 populations derived from a cross between IL188 and Nipponbare were used to map QTLs for five grain size traits, including grain length (GL), grain width (GW), grain length to width ratio (LWR), grain thickness (GT) and thousand grain weight (TGW). A total of 12 QTLs for the five grain traits were identified on chromosomes 1, 2, 3, 6, 7, and 8. The QTL-qGL7 controlling GL on chromosome 7 was detected stably in the F2 and F2:3 populations, and explained 15.09-16.30% of the phenotypic variance. To validate the effect of qGL7, eight residual heterozygous line (RHL) populations were developed through selfing four F2:3 and four F2:4 plants with different heterozygous segments for the target region. By further developing SSR and Indel markers in the target interval, qGL7 was delimited to a ~261 kb region between Indel marker Y7-12 and SSR marker Y7-38, which also showed significant effects on grain width and thousand grain weight. Comparing with the reference genome of Nipponbare, stop or frameshift mutations in the exon of the three putative genes LOC_Os07g36830, LOC_Os07g36900 and LOC_Os07g36910 encoding F-box domain-containing proteins may be the candidate genes for qGL7. Scanning electron microscopy analysis of the glume's epidermal cells showed that the cell length and width of NIL-qGL7IL188 was higher than NIL-qGL7Nip, indicating that qGL7 increases grain size and weight by regulating cell expansion. Conclusions: In this study, we detected 12 QTLs regulating grain size and weight using an introgression line from a cross between an Oryza sativa and Oryza minuta. Of these loci, we confirmed and delimited the qGL7 to a ~261 kb region. Three putative genes, LOC_Os07g36830, LOC_Os07g36900 and LOC_Os07g36910 encoding F-box domain-containing proteins may be the candidate genes for qGL7. These results provide a basis for map-based cloning of the qGL7 gene and useful information for marker assisted selection in rice grain quality improvement.


2021 ◽  
Author(s):  
Pao Xue ◽  
Yu-yu Chen ◽  
Xiao-xia Wen ◽  
Bei-fang Wang ◽  
Qin-qin Yang ◽  
...  

Abstract Grain size is a key constituent of grain weight and appearance in rice. However, insufficient attention has been paid to the small-effect QTLs on grain size. In the present study, residual heterozygous populations were developed for mapping two genetically linked small-effect QTLs for grain size. After genotyping and phenotyping of five successive generations, qGS7.1 was dissected into three QTLs and two were selected for further analysis. qTGW7.2a was finally mapped into a 21.10-kb interval containing four annotated candidate genes. Transcript levels assay showed that the expression of candidates LOC_Os07g39490 and LOC_Os07g39500 were significantly reduced in the NIL- qTGW7.2a BG1 . Cytological observation indicated that qTGW7.2a regulated grain width through controlling cell expansion. Use the same strategy, qTGW7.2b was fine mapped into a 52.71-kb interval, showing a significant effect on grain length and width with opposite allelic directions but little on grain weight. Our study provides new genetic resources for yield improvement and fine-tunes of grain size in rice.


2020 ◽  
Vol 23 (2) ◽  
pp. 59-64
Author(s):  
F Akter ◽  
MZ Islam ◽  
A Akter ◽  
SK Debsharma ◽  
A Shama ◽  
...  

Genetic diversity of 65 rice genotypes was studied from IRBBN (International Rice Bacterial Blight Nursery) of INGER (International Network for Genetic Evaluation of Rice) materials through Mahalanobis D2 statistic for grain yield and yield contributing characters. The genotypes were grouped into five clusters. The inter-cluster distances were higher than intra-cluster distances indicating wider genetic diversity among the genotypes of different clusters. The intra-cluster distances were lower in all the cases reflecting homogeneity of the genotypes within the clusters. The cluster III contained the highest number of genotypes (23) and the clusterv contained the lowest (8). The highest intra-cluster distance was noticed for the cluster I and lowest for cluster III. The highest inter-cluster distance was observed between cluster I and V, followed by cluster IV and V, cluster II andV and the lowest between cluster I and IV. Regarding inter-cluster distance, the genotypes of cluster V showed high genetic distance from all other clusters. The genotypes from cluster V could be hybridized with the genotypes of other clusters for producing transgressive segregants. Based on canonical vector analysis, panicle number per plant had maximum contribution towards genetic divergence. The highest cluster means for yield, grain/panicle and spikelet fertility were obtained from cluster V. The highest means for 1000 grain weight, second higher yield and the lowest growth duration were found in cluster II, while the lowest mean value for yield and 1000 grain weight and higher mean value for growth duration were found in cluster IV. The crosses between the genotypes/parents of cluster V and cluster II, cluster V and cluster I would exhibit high heterosis as well as higher level of yield potential. Therefore, more emphasis should be given for selection of the genotypes from clusters II and V for future breeding programme. Bangladesh Rice j. 2019, 23(2): 59-64


2016 ◽  
Vol 16 (1) ◽  
pp. 74-81 ◽  
Author(s):  
Hongchun Xiong ◽  
Huijun Guo ◽  
Yongdun Xie ◽  
Linshu Zhao ◽  
Jiayu Gu ◽  
...  

AbstractThe dwarfing wheat (Triticum aestivum L.) breeding has promoted a dramatic increase in yields. Since the utilized dwarfing genes in wheat are very limited, identification of novel dwarfing genes is necessary for improving the genetic diversity of wheat. In this study, more than 300 dwarfing wheat lines from induced mutation were screened by kompetitive allele-specific PCR and gibberellin (GA) treatment. The 17.49% of Rht-D1b and 1.37% of Rht-B1b dwarfing mutants were identified in this mutant group. Additionally, Rht-D1b mutants showed more effective in reduction of plant height and higher 1000-grain weight comparing with that of Rht-B1b mutants. By combing with comparison of yield components and expression profile of GA biosynthetic genes with wild-type, the GA-responsive mutant dm15 without directly involvement in GA metabolism, significantly increased 1000-grain weight but no change of other yield components in two locations of field experiments. Meanwhile, another elite mutant dm11 with change of GA biosynthetic genes expression was also identified. These mutants will be promising candidates for dwarfing wheat breeding.


2021 ◽  
Vol 58 (1) ◽  
pp. 1-7
Author(s):  
Vinod Kumar ◽  
Dhirendra Singh

Genetic diversity of 30 basmati rice genotypes was analysed based on nine agro-morphological and six quality traits. The results of the principal component analysis showed that the first six principal components explained 89.16% of the total variation in the experimental material. These 30 basmati genotypes were grouped into six clusters which indicated the presence of sufficient diversity among the tested genotypes. Cluster I and cluster III was found to be the largest comprising of 10 genotypes each followed by cluster II having seven genotypes. The highest average intra-cluster distance was observed in cluster III. Highest inter-cluster distance (D2) was observed between clusters III and VI followed by clusters III and V, III and IV & clusters II and III. Cluster II showed high mean value for grain yield per plant, 1000 grain weight, and grain length. The characters viz., amylose content, grain length after cooking, spikelet per panicle, grain width, grain length and 1000 grain weight contributed maximum towards total genetic divergence, suggest their suitability of selection.


Author(s):  
O. O. Skrypnyk ◽  
O. Yu. Leonov ◽  
T. P. Shyianova ◽  
K. Yu. Suvorova ◽  
Z. V. Usova

Purpose and objectives. To evaluate the effect of sorting seeds by size on their quality indicators: germination energy, laboratory germinability and 1000-grain weight. Materials and methods. The experiments were carried out in the experimental field of the Plant Production Institute named after V.Ya. Yuriev of NAAS in accordance with the field experimentation method in 2016–2018; 26 winter bread wheat lines and varieties were studied. The varieties and lines were grown in variety trial experiments; the plot area was 10 m2. Seeds were separated on sieves of a laboratory separator RLU-3; the 1000-grain weight was measured; the laboratory germinability and germination energy were determined. Results and discussion. When winter bread wheat seeds are sorted on sieves, they are separated into fractions with various 1000-grain weights. The separated fractions of winter wheat seeds have different sowing qualities. The 2.5 x 20 mm seeds and 2.8 x 20 mm seeds are of the best quality (germination energy, germinability). It was found that in 2016–2018, the germination energy, laboratory germinability and 1000-gain weight changed depending on the growing conditions. They were the highest in 2017. The varieties with a high 1000-grain weight have been identified: Doskonala, Pryvablyva, Smuhlianka, and Haiok. The highest germination energy and germinability were intrinsic to varieties Yednist, Harmonika and Bunchuk. Yednist (93.3%), Harmonika (94.3%), Metelytsia Kharkivska (94.5%), Bunchuk (94.7%), Alians (93.3%), Podolianka (92.5%), Patriotka (93.6%), Zapashna (93.3%), Dyvo (93.7%), Doskonala (93.6%), Krasa Laniv (94.0%), Smuhlianka (93.1%), and Erythrospermum 408-13 (93.7%) had a high germinability of small seeds (2.2 x 20 mm). To clean these varieties, especially in years with low seed yields, it is recommended to use seeds of the standard size (2.2–2.5 x 20 mm). Conclusions. The relationships between the grain size and sowing qualities of seeds have been established. Separation of seeds is an effective technological method allowing for selection of top-quality seeds


2021 ◽  
Vol 11 ◽  
Author(s):  
Ankit Verma ◽  
Geeta Prakash ◽  
Rajeev Ranjan ◽  
Akhilesh K. Tyagi ◽  
Pinky Agarwal

Many quantitative trait loci (QTLs) have been identified by molecular genetic studies which control grain size by regulating grain width, length, and/or thickness. Grain width 2 (GW2) is one such QTL that codes for a RING-type E3 ubiquitin ligase and increases grain size by regulating grain width through ubiquitin-mediated degradation of unknown substrates. A natural variation (single-nucleotide polymorphism at the 346th position) in the functional domain-coding region of OsGW2 in japonica rice genotypes has been shown to cause an increase in grain width/weight in rice. However, this variation is absent in indica rice genotypes. In this study, we report that reduced expression of OsGW2 can alter grain size, even though natural sequence variation is not responsible for increased grain size in indica rice genotypes. OsGW2 shows high expression in seed development stages and the protein localizes to the nucleus and cytoplasm. Downregulation of OsGW2 by RNAi technology results in wider and heavier grains. Microscopic observation of grain morphology suggests that OsGW2 determines grain size by influencing both cell expansion and cell proliferation in spikelet hull. Using transcriptome analysis, upregulated genes related to grain size regulation have been identified among 1,426 differentially expressed genes in an OsGW2_RNAi transgenic line. These results reveal that OsGW2 is a negative regulator of grain size in indica rice and affects both cell number and cell size in spikelet hull.


2011 ◽  
Vol 24 (2) ◽  
pp. 19-24
Author(s):  
Kaniz Fatema ◽  
M. G. Rasul ◽  
M. A. K. Mian ◽  
M. M. Rahman

Forty five aromatic rice genotypes were evaluated to assess the genetic variability and diversity on the basis of nine characters. Significant variations were observed among the genotypes for all the characters (grain breadth (mm), grain length (mm), grain L/B ratio, gelatinization temperature (score), gel consistency (mm), amylose content (%), protein content (%), 1000 grain weight (g) and grain yield per plant (g)) studied. High GCV, PCV, heritability and GA as observed in amylose content, grain length average and L/B ratio suggested that these three characters could be transmitted to the progeny. Multivariate analysis revealed that 45 genotypes were grouped into six clusters. There were marked variations in intra-cluster distances, which ranged from 0.482 to 7.851. The highest intra cluster mean for five traits (amylose content, width average, L/B ratio, length average, 1000 grain weight) was obtained from cluster I constituted 10 genotypes. Thousand grain weight and amylose content have been found to contribute maximum towards genetic diversity in 45 genotypes of aromatic rice.DOI: http://dx.doi.org/10.3329/bjpbg.v24i2.17002


2014 ◽  
Vol 12 (1) ◽  
pp. 26-32 ◽  
Author(s):  
MZ Islam ◽  
MA Siddique ◽  
ESMH Rashid ◽  
MS Ahmed ◽  
M Khalequzzaman

Genetic diversity of 40 traditional Bangladeshi rice genotypes was studied under rainfed condition through Mahalanobis D2 statistic for grain yield and yield contributing characters. The genotypes were grouped into six clusters. The inter-cluster distances were higher than intra-cluster distances indicating wider genetic diversity among the genotypes of different clusters. The intra-cluster distances were lower in all the cases reflecting homogeneity of the genotypes within the clusters. The cluster VI contained the highest number of genotypes (18) and the clusters I and II contained the lowest (1). The highest intra-cluster distance was noticed for the cluster IV and lowest for cluster VI. The highest inter-cluster distance was observed between cluster I and IV, followed by cluster I and II, cluster I and III and the lowest between cluster III and IV. Regarding inter-cluster distance, the genotypes of cluster IV showed high genetic distance from all other clusters. The genotypes from cluster IV could be hybridized with the genotypes of other clusters for producing transgressive segregants. Based on canonical vector analysis, panicle number per plant and 1000 grain weight had maximum contribution towards genetic divergence. The highest cluster means for yield, filled grains panicle-1 and grain breadth were obtained from cluster VI. The highest means for plant height, flag leaf area, unfilled grains panicle-1, harvest index and the lowest growth duration were found in cluster I, while the lowest mean value for yield, grain length, 1000 grain weight, plant height and highest mean value for days to flowering and maturity were found in cluster II. The crosses between the genotypes/parents of cluster VI and cluster II, cluster VI and cluster V would exhibit high heterosis as well as higher level of yield potential. Therefore, more emphasis should be given for selection of the genotypes from clusters I, VI and V for future breeding program.  DOI: http://dx.doi.org/10.3329/agric.v12i1.19576The Agriculturists 2014; 12(1) 26-32


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