scholarly journals Association Mapping of Drought Avoidance and Agronomic Traits in Rice (Oryza Sativa L.) Landraces with SSR Markers and Genotyping-By-Sequencing Approach

Author(s):  
Beena R ◽  
Silvas Kirubakaran ◽  
Nithya N ◽  
Sah R.P ◽  
Abida P.S ◽  
...  

Abstract Development of rice varieties suited to varying drought stress level, and crop stages, relies mainly on identifying new genetic resources and genomic targets to improve whole plant physiological processes and productivity. This study with 99 rice germplasm adapted to Southwestern Indian peninsular region genotyped with 100 SSR markers evaluated over five different seasons/field trials to characterize plant physiological, root traits and yield related traits under different intensity and crop stage experienced water limitation. Traits like chlorophyll stability index, leaf rolling, days to 50% flowering, chlorophyll content, root volume and root biomass were identified as best predictors of grain yield under stress. Genome-Wide Association Study revealed genetic variation and genomic targets underlying major QTLs for different physiological, root and plant production traits. Combined analysis with trials 1-4 revealed 14 genomic regions governing multiple traits that contribute to plant performance and productivity under water stress. Genetic characterization of nine selected landraces and two elite cultivars using genotyping-by-sequencing (GBS) revealed haplotype variation within genomic targets on chromosome 1, 4, 6 and 11 for potential use as molecular markers. The genetic and genomic resources identified will enable combining traits with agronomic value to optimize yield under stress and hasten trait introgression into elite cultivars.

2019 ◽  
Vol 02 ◽  
pp. 39-48
Author(s):  
Toan D. Pham

Rice (Oryza sativa L.) is the most important food crop in Vietnam particularly in the Mekong Delta. Screening of good quality and high yield rice varieties are needed for rice production in Vietnam. The purpose of this study was to use molecular techniques to identify fgr gene and to evaluate preliminarily agronomic traits of pandan sticky rice variety. The results showed that this variety contained fgr gene. The fragrant allele was amplified by ESP - IFAP primers with a product of 255 bp in size. Similarly, evaluation of agronomic traits showed that the pandan sticky rice variety displayed many desirable characteristics such as plant height of 108 cm, panicle length of 25.6 cm, seed/panicle 135, 100-grain weight 2.07 g, pandan smell, level 2 of alkali digestion, gel consistency 93 mm. These results were useful information and could be applied for improving and providing pandan sticky rice variety for rice production.


2020 ◽  
Author(s):  
Aditi Bhandari ◽  
Nitika Sandhu ◽  
Jérôme Bartholome ◽  
Tuong-Vi Cao-Hamadoun ◽  
Nourollah Ahmadi ◽  
...  

Abstract Background Reproductive-stage drought stress is a major impediment to rice production in rainfed areas. Conventional and marker-assisted breeding strategies for developing drought-tolerant rice varieties are being optimized by mining and exploiting adaptive traits, genetic diversity; identifying the alleles, and understanding their interactions with genetic backgrounds for their increased contribution to drought tolerance. Field experiments were conducted in this study to identify marker-trait associations (MTAs) involved in response to yield under reproductive-stage (RS) drought. A diverse set of 280 indica-aus accessions was phenotyped for ten agronomic traits including yield and yield-related traits under normal irrigated condition and under two managed reproductive-stage drought environments. The accessions were genotyped with 215,250 single nucleotide polymorphism markers. Results The study identified a total of 219 significant MTAs for 10 traits and candidate gene analysis within a 200kb window centred from GWAS identified SNP peaks detected these MTAs within/ in close proximity to 38 genes, 4 earlier reported major grain yield QTLs and 6 novel QTLs for 7 traits out of the 10. The significant MTAs were mainly located on chromosomes 1, 2, 5, 6, 9, 11 and 12 and the percent phenotypic variance captured for these traits ranged from 5 to 88%. The significant positive correlation of grain yield with yield-related and other agronomic traits except for flowering time, observed under different environments point towards their contribution in improving rice yield under drought. Seven promising accessions were identified for use in future genomics-assisted breeding programs targeting grain yield improvement under drought. Conclusion These results provide a promising insight into the complex genetic architecture of grain yield under reproductive-stage drought in different environments. Validation of major genomic regions reported in the study will enable their effectiveness to develop drought-tolerant varieties following marker-assisted selection as well as to identify genes and understanding the associated physiological mechanisms.


2021 ◽  
Author(s):  
Dong Cao ◽  
Dongxia Wang ◽  
Shiming Li ◽  
Yun Li ◽  
Ming Hao ◽  
...  

Abstract Key message The genetic diversity and loci underlying agronomic traits were analysed by the reads coverage and genome-wide association study based genotyping-by-sequencing in a diverse population consisting of 199 accessions.Abstract Triticale (×Triticosecale Wittmack) is an economically important grain-forage and energy crop planted worldwide for its high biomass. Little is known about the genetic diversity and loci underlying agronomic traits in triticale. We performed genotyping-by-sequencing of 199 cultivars and mapped reads to the A, B, D, and R genomes for karyotype analysis. These cultivars could mostly be grouped into five types. Some chromosome abnormalities occurred with high frequency, such as 2D (2R) substitution, deletion of the long arm of chromosome 2D or the short arm of 5R, and translocation of the long arms of 7D/7A, the short arms of 6D/6A, or the long arms of 1D/1A. We chose only widely planted hexaploid triticale cultivars (153) for genome-wide association study. These cultivars could be divided into nine distinct groups, and the linkage disequilibrium decay was 25.4 kb in this population. We identified 253 significant marker-trait associations (MTAs) on 20 chromosomes, except 7R. Twenty-one reliable MTAs were identified repeatedly over two environments. We predicted 16 putative candidate genes involved in plant growth and development using the genome sequences of wheat and rye. These results provide a basis for understanding the genetic mechanisms of agronomic traits and will benefit the breeding of improved hexaploid triticale.


Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 410 ◽  
Author(s):  
Fengling Wu ◽  
Jun Yang ◽  
Diqiu Yu ◽  
Peng Xu

Saline stress severely affects rice (Oryza sativa L.) growth and development and reduces crop yield. Therefore, developing salt-tolerant and high-yielding rice using quantitative trait loci (QTLs) and linkage markers is a priority for molecular breeding. Here, the indica rice Sea Rice 86 (SR86) seedlings showed higher tolerance than ordinary rice varieties in saline soil, and a dominant effect on salinity sensitivity was demonstrated by genetic analysis. We constructed bulked segregant analysis pools using F2 populations from parents Dianjingyou 1 as the recipient and SR86 as the donor. We identified a 2.78 Mb region on chromosome 1 as the candidate region. Using simple sequence repeat markers and substitution analysis, we mapped the target region within 5.49 cM in the vicinity of markers RM8904–RM493. We speculated that this QTL, named qST1.1, might contribute significantly to the salt tolerance of SR86. The high salt tolerance of introgression lines obtained by marker assistant selection (MAS) confirmed that the qST1.1 region was associated with salinity tolerance. This newly-discovered QTL will be helpful for the analysis of the salt-tolerant mechanism of rice and breeding high-quality rice varieties using MAS.


PLoS ONE ◽  
2014 ◽  
Vol 9 (10) ◽  
pp. e111508 ◽  
Author(s):  
Peng Zhang ◽  
Xiangdong Liu ◽  
Hanhua Tong ◽  
Yonggen Lu ◽  
Jinquan Li

1994 ◽  
Vol 34 (7) ◽  
pp. 911 ◽  
Author(s):  
AM Callegarin ◽  
K Perfanov ◽  
G Dorotea ◽  
G Baldi

Increasing market demand has led to efforts to select for non-sticky, long-grain rice varieties suited to the Italian environment. The variability of recombinant populations derived from crosses between Italian and USA genotypes was exploited. Together with the conventional breeding methods, in vitro anther culture was used to obtain homozygous lines from crosses more quickly. Moreover, hybrid lines were obtained from crosses otherwise impossible to exploit owing to sterility in the F, generation (namely those resulting from crosses involving semi-dwarf USA varieties). Plant regeneration was obtained from 6 F, hybrids whose parents were chosen for their grain quality or their suitability to the Italian environment. About 5500 plantlets were regenerated. Of these, 1000 were albino, and about 50% of the green ones died after transplanting into soil; 65% of the surviving plants were sterile, so about 1000 progeny were obtained (30-445 for each cross). Progeny with desirable characteristics were evaluated for agronomic traits. On the basis of these results, limits and possibilities of anther-culture breeding in rice are discussed.


2021 ◽  
pp. 52-59
Author(s):  
Khaled F.M. Salem ◽  
Maysoun M Saleh ◽  
Laila Aldahak ◽  
Abdelmoaty B. Elabd

An efficient way to achieve superior productivity is to determine the genetic variation of the various rice genotypes. This research was aimed at estimating potential variations between rice genotypes and identifying each trait contribution in total variation and classifying superior genotypes. The experiment was performed at the Rice Research and Training Centre, Sakha, Kafr El-Sheik, Egypt. Twenty-two genotypes of rice were analyzed using seven agronomic traits. Multivariate approaches were utilized including principal components and cluster analysis. Results showed that PC1 and PC2 represented 66.1% of the variation between studied genotypes, mainly 48% because of grain yield per plant variation in PC1 followed by the characteristics of its components i.e., number of panicles per plant, number of filled grains per panicle, and 1000-grain weight. The three Egyptian rice genotypes Giza 181, Giza 178, and Giza 177 were the best genotypes for grain yield. Cluster results revealed that the majority of genotypes originated from one source (except for Indian variety IET1444) or belonged to one classification were clustered together. Multivariate analytical approaches are ideal instruments for providing information on agronomic character variations. Consequently, the results of the current study should be taken into account when developing new rice varieties.   


2021 ◽  
Author(s):  
BOLLINENI SAIMOHAN ◽  
N. Chamundeswari ◽  
T. Haritha ◽  
N. Veronica

Abstract Background: Anaerobic germination is an important trait in particular for cultivation under direct seeding method in kharif season, as well as during nursery rising for transplant rice, as sometimes unexpected rains immediately after sowing will drastically reduce the plant population.Methods and Results: In the present investigation phenotypic screening for Anaerobic germination (AG) was carried out using 188 F2:3 population of Swarna Sub1/AC39416A at RARS (APRRI), Maruteru. The mean anaerobic germination per cent recorded after the two weeks of submergence ranged from 0% to 95% with overall mean of 47.51% whereas, for three weeks of submergence, the mean anaerobic germination per cent recorded between 0 and 95%, with overall mean of 37.66%. 134 (19.42%) out of 687 Simple Sequence Repeats (SSR) markers surveyed were polymorphic between the parents. Linkage analysis was done with 83 SSR markers showing polymorphism clearly using the integrated software called QTL IciMapping software version 4.1.0. The length of linkage map constructed across whole genome was 3600.8 cM and identified seven QTLs viz., qAG2, qAG3, qAG7-1, qAG7-2, qAG9, qAG10 and qAG12. All these seven QTLs explained phenotypic variance of about 37.47% collectively for AG trait, with their individual contributions ranging from 3.5% to 8.67% of phenotypic variation and LOD scores of 2.6 to 5.86. The LOD score and phenotypic variance is 5.86 and 8.67% respectively for qAG10 a novel QTL identified in the present study using ICIM method. Conclusion: QTL “qAG12-1” identified in this study may be considered for introgression into popular elite rice varieties otherwise susceptible for anaerobic germination after fine mapping studies.


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