scholarly journals Genome-wide association study for yield and yield related traits under reproductive stage drought in a diverse indica-aus rice panel

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.

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 globally. 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 contributing to drought tolerance. Field experiments were conducted in this study to identify marker-trait associations (MTAs) involved in response to yield under reproductive-stage drought. A diverse set of 280 indica-aus accessions was phenotyped for grain yield and nine yield-related traits under normal condition and under two managed drought environments. The accessions were genotyped with 215,250 single nucleotide polymorphism markers. Results The study identified a total of 220 significant MTAs and candidate gene analysis within 200kb window centred from GWAS identified SNP peaks detected these MTAs within/ in close proximity to 47 genes, 4 earlier reported major grain yield QTLs and 8 novel QTLs for 10 traits. The significant MTAs were majorly located on chromosomes 1, 2, 5, 6, 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 traits, except 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 program 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 under different environments. Validation of major genomic regions reported in the study can be effectively used to develop drought tolerant varieties following marker-assisted selection as well as to identify genes and understanding the associated physiological mechanisms.


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 grain yield and nine 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 220 significant MTAs for 10 traits and candidate gene analysis within a 200kb window centered 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 traits, except 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.


BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Shamseldeen Eltaher ◽  
P. Stephen Baenziger ◽  
Vikas Belamkar ◽  
Hamdy A. Emara ◽  
Ahmed A. Nower ◽  
...  

Abstract Background Improving grain yield in cereals especially in wheat is a main objective for plant breeders. One of the main constrains for improving this trait is the G × E interaction (GEI) which affects the performance of wheat genotypes in different environments. Selecting high yielding genotypes that can be used for a target set of environments is needed. Phenotypic selection can be misleading due to the environmental conditions. Incorporating information from phenotypic and genomic analyses can be useful in selecting the higher yielding genotypes for a group of environments. Results A set of 270 F3:6 wheat genotypes in the Nebraska winter wheat breeding program was tested for grain yield in nine environments. High genetic variation for grain yield was found among the genotypes. G × E interaction was also highly significant. The highest yielding genotype differed in each environment. The correlation for grain yield among the nine environments was low (0 to 0.43). Genome-wide association study revealed 70 marker traits association (MTAs) associated with increased grain yield. The analysis of linkage disequilibrium revealed 16 genomic regions with a highly significant linkage disequilibrium (LD). The candidate parents’ genotypes for improving grain yield in a group of environments were selected based on three criteria; number of alleles associated with increased grain yield in each selected genotype, genetic distance among the selected genotypes, and number of different alleles between each two selected parents. Conclusion Although G × E interaction was present, the advances in DNA technology provided very useful tools and analyzes. Such features helped to genetically select the highest yielding genotypes that can be used to cross grain production in a group of environments.


2021 ◽  
Author(s):  
NITIKA SANDHU ◽  
Amandeep Kaur ◽  
Mehak Sethi ◽  
Satinder Kaur ◽  
Varinderpal Singh ◽  
...  

Abstract Nitrogen is one of the most important macronutrients for crop growth and metabolism. To identify marker-trait associations for complex NUE-related agronomic traits, field experiments were conducted on nested synthetic wheat introgression libraries at three nitrogen input levels across two seasons. The introgression libraries were genotyped using the 35K Axiom® Wheat Breeder’s Array and genetic diversity and population structure were examined. Significant phenotypic variation was observed across genotypes, treatments and their interactions across seasons for all the 22 traits measured. Significant positive correlations were observed among grain yield and yield attributing traits and root traits. Across seasons, a total of 233 marker-trait associations (MTAs) associated with fifteen traits of interest at differential levels of nitrogen (N0, N60 and N120) were detected using 9,474 genome-wide single nucleotide polymorphism (SNP) markers. Of these, 45 MTAs for 10 traits in the N0 treatment, 100 MTAs for 11 traits in the N60 treatment and 88 MTAs for 11 traits in the N120 treatment were detected. We identified putative candidate genes underlying the significant MTAs which were associated directly or indirectly with various biological processes, cellular component organization and molecular functions involving improved plant growth and grain yield. In addition, the top 10 lines based on N response and grain yield across seasons and treatments were identified. The identification and introgression of superior alleles/donors improving NUE while maintaining grain yield may open new avenues in designing next-generation nitrogen efficient high yielding wheat varieties.


Genes ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 62
Author(s):  
Niranjan Baisakh ◽  
Jonalyn Yabes ◽  
Andres Gutierrez ◽  
Venkata Mangu ◽  
Peiyong Ma ◽  
...  

Improving drought resistance in crops is imperative under the prevailing erratic rainfall patterns. Drought affects the growth and yield of most modern rice varieties. Recent breeding efforts aim to incorporate drought resistance traits in rice varieties that can be suitable under alternative irrigation schemes, such as in a (semi)aerobic system, as row (furrow-irrigated) rice. The identification of quantitative trait loci (QTLs) controlling grain yield, the most important trait with high selection efficiency, can lead to the identification of markers to facilitate marker-assisted breeding of drought-resistant rice. Here, we report grain yield QTLs under greenhouse drought using an F2:3 population derived from Cocodrie (drought sensitive) × Nagina 22 (N22) (drought tolerant). Eight QTLs were identified for yield traits under drought. Grain yield QTL under drought on chromosome 1 (phenotypic variance explained (PVE) = 11.15%) co-localized with the only QTL for panicle number (PVE = 37.7%). The drought-tolerant parent N22 contributed the favorable alleles for all QTLs except qGN3.2 and qGN5.1 for grain number per panicle. Stress-responsive transcription factors, such as ethylene response factor, WD40 domain protein, zinc finger protein, and genes involved in lipid/sugar metabolism were linked to the QTLs, suggesting their possible role in drought tolerance mechanism of N22 in the background of Cocodrie, contributing to higher yield under drought.


2021 ◽  
Vol 12 ◽  
Author(s):  
Nitika Sandhu ◽  
Amandeep Kaur ◽  
Mehak Sethi ◽  
Satinder Kaur ◽  
Varinderpal-Singh ◽  
...  

Nitrogen is one of the most important macronutrients for crop growth and metabolism. To identify marker-trait associations for complex nitrogen use efficiency (NUE)-related agronomic traits, field experiments were conducted on nested synthetic wheat introgression libraries at three nitrogen input levels across two seasons. The introgression libraries were genotyped using the 35K Axiom® Wheat Breeder's Array and genetic diversity and population structure were examined. Significant phenotypic variation was observed across genotypes, treatments, and their interactions across seasons for all the 22 traits measured. Significant positive correlations were observed among grain yield and yield-attributing traits and root traits. Across seasons, a total of 233 marker-trait associations (MTAs) associated with fifteen traits of interest at different levels of nitrogen (N0, N60, and N120) were detected using 9,474 genome-wide single nucleotide polymorphism (SNP) markers. Of these, 45 MTAs for 10 traits in the N0 treatment, 100 MTAs for 11 traits in the N60 treatment, and 88 MTAs for 11 traits in the N120 treatment were detected. We identified putative candidate genes underlying the significant MTAs which were associated directly or indirectly with various biological processes, cellular component organization, and molecular functions involving improved plant growth and grain yield. In addition, the top 10 lines based on N response and grain yield across seasons and treatments were identified. The identification and introgression of superior alleles/donors improving the NUE while maintaining grain yield may open new avenues in designing next generation nitrogen-efficient high-yielding wheat varieties.


2020 ◽  
Vol 5 (2) ◽  
pp. 97-104
Author(s):  
M.M. Islam ◽  
M.I. Ali ◽  
M.S. Islam ◽  
A.B.M.S. Alam ◽  
M.H. Rahman ◽  
...  

Two field experiments were carried out at farmer’s field of Rajshahi and Chapainawabgonj under the Department of Agronomy, BINA during aman season of 2017 and 2018 consecutively to evaluate the drought tolerant rice varieties under different establishment methods in rain fed condition. First experiment (E1) was conducted to find out the performance of varieties and second experiment (E2) was to find out the suitability of method of transplanting/sowing in combination with short duration aman varieties. Different methods were as direct seeding, puddled and un-puddled transplanting and cultivars were used to cultivate BRRI dhan56, Binadhan-7, Binadhan-17 (except in second experiment) and Huttra (local cultivar). The experiment was laid out in a randomized complete block design with three replications. The recommended fertilizer doses applied for the experiment were 80 kg N ha-1, 15 kg P ha-1, 50 kg K ha-1, 20 kg S ha-1 and 2 kg Zn ha-1. Nitrogen, phosphorus, potassium, sulphur and zinc were supplied from urea, TSP, MoP, gypsum and zinc sulphate monohydrate respectively while urea was applied in three equal splits. Among the cultivar Binadhan-17 produced statistically higher grain yield (5.62 t ha-1) at Chapainawabgonj. Among methods Binadhan-7 statistically higher grain yield 5.32 t ha-1 and 5.21 t ha-1, respectively) in puddle transplanting method both Chapainawabgonj and Rajshahi region during 2017. Among the cultivar Huttra (local) produced statistically higher grain yield (5.43 t ha-1) at Chapainawabgonj. Among methods, BRRI dhan56 statistically higher grain yield 6.37 t ha-1 and 6.19 t ha-1, respectively) in puddle transplanting method bothat Rajshahi and Chapainawabgonj during 2018. Overall results indicates that BRRI dhan56, Binadhan-7, Binadhan-17 performed better in puddled transplanting, Huttra (local) in direct seeding method in drought prone region of Bangladesh.


2018 ◽  
Vol 19 (10) ◽  
pp. 3011 ◽  
Author(s):  
Madhav Bhatta ◽  
Alexey Morgounov ◽  
Vikas Belamkar ◽  
P. Baenziger

Synthetic hexaploid wheat (SHW; 2n = 6x = 42, AABBDD, Triticum aestivum L.) is produced from an interspecific cross between durum wheat (2n = 4x = 28, AABB, T. turgidum L.) and goat grass (2n = 2x = 14, DD, Aegilops tauschii Coss.) and is reported to have significant novel alleles-controlling biotic and abiotic stresses resistance. A genome-wide association study (GWAS) was conducted to unravel these loci [marker–trait associations (MTAs)] using 35,648 genotyping-by-sequencing-derived single nucleotide polymorphisms in 123 SHWs. We identified 90 novel MTAs (45, 11, and 34 on the A, B, and D genomes, respectively) and haplotype blocks associated with grain yield and yield-related traits including root traits under drought stress. The phenotypic variance explained by the MTAs ranged from 1.1% to 32.3%. Most of the MTAs (120 out of 194) identified were found in genes, and of these 45 MTAs were in genes annotated as having a potential role in drought stress. This result provides further evidence for the reliability of MTAs identified. The large number of MTAs (53) identified especially on the D-genome demonstrate the potential of SHWs for elucidating the genetic architecture of complex traits and provide an opportunity for further improvement of wheat under rapidly changing climatic conditions.


Agronomy ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 414 ◽  
Author(s):  
Khaoula El Hassouni ◽  
Bouchra Belkadi ◽  
Abdelkarim Filali-Maltouf ◽  
Amadou Tidiane-Sall ◽  
Ayed Al-Abdallat ◽  
...  

Heat stress occurring during the reproductive stage of wheat has a detrimental effect on productivity. A durum wheat core set was exposed to simulated terminal heat stress by applying plastic tunnels at the time of flowering over two seasons. Mean grain yield was reduced by 54% compared to control conditions, and grain number was the most critical trait for tolerance to this stress. The combined use of tolerance indices and grain yield identified five top performing elite lines: Kunmiki, Berghouata1, Margherita2, IDON37-141, and Ourgh. The core set was also subjected to genome wide association study using 7652 polymorphic single nucleotide polymorphism (SNPs) markers. The most significant genomic regions were identified in association with spike fertility and tolerance indices on chromosomes 1A, 5B, and 6B. Haplotype analysis on a set of 208 elite lines confirmed that lines that carried the positive allele at all three quantitative trait loci (QTLs) had a yield advantage of 8% when field tested under daily temperatures above 31° C. Three of the QTLs were successfully validated into Kompetitive Allele Specific PCR (KASP) markers and explained >10% of the phenotypic variation for an independent elite germplasm set. These genomic regions can now be readily deployed via breeding to improve resilience to climate change and increase productivity in heat-stressed areas.


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