Chemical and physical influence of sodic soils on the coleoptile length and root growth angle of wheat genotypes

Abstract Background and Aims High exchangeable sodium percentage (ESP) and bulk density of sodic soils can reduce seedling emergence. This study examined variation in seedling coleoptile length and seminal root angle of wheat (Triticum aestivum. L) genotypes to determine whether these traits vary between genotypes that differ in their tolerance to sodic soils. Methods Wheat genotypes were grown in three different experiments. First, four wheat genotypes were grown using soils of three ESPs (4, 10 and 17 %) and secondly in soils of three different bulk densities (1.2, 1.4 and 1.5 g cm–3) and ESP 10 %. Thirdly, seedling coleoptile length and seminal root angle were determined for 16 genotypes grown in a soil of ESP 10 % and bulk density 1.2 g cm–2. Seminal root angle and coleoptile length measurements from the current study were compared with seedling emergence rate and force measured previously. Key Results The seedling coleoptile length of all genotypes decreased with increasing soil ESP and bulk density, but with no significant differences between genotypes. In contrast, seminal root angles differed significantly between genotypes, but were not significantly affected by ESP or bulk density. There was an inverse relationship between the seminal root angle of the 16 genotypes and seedling emergence rate (R2 = 0.89) and also between seminal root angle and seedling emergence force (R2 = 0.61). Conclusions Lack of significant variation in coleoptile length between genotypes suggests that this may not be a suitable characteristic to identify wheat tolerance to sodic conditions. However, a narrower seminal root angle was correlated with rate and force of seedling emergence, traits likely to improve establishment. The mechanism underlying this correlation is not yet clear. Genotypes with a narrow root angle had greater root depth. One possible mechanism might be that genotypes with narrow root angles were able to take up more soil moisture at depth, leading to a higher proportion of seedling emergence.

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Genetic Mapping of Quantitative Trait Loci (QTLs) Associated with Seminal Root Angle and Number in Three Populations of Bread Wheat (Triticum aestivum L.) with Common Parents

Plant Molecular Biology Reporter ◽

10.1007/s11105-020-01214-1 ◽

2020 ◽

Vol 38 (4) ◽

pp. 572-585

Author(s):

Christopher E. Hohn ◽

Harun Bektas

Keyword(s):

Triticum Aestivum ◽

Quantitative Trait Loci ◽

Genetic Mapping ◽

Bread Wheat ◽

Quantitative Trait ◽

Triticum Aestivum L ◽

Seminal Root ◽

Root Angle ◽

Trait Loci ◽

Seminal Root Angle

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Selection in Early Generations to Shift Allele Frequency for Seminal Root Angle in Wheat

The Plant Genome ◽

10.3835/plantgenome2017.08.0071 ◽

2018 ◽

Vol 11 (2) ◽

pp. 170071 ◽

Cited By ~ 11

Author(s):

Cecile Richard ◽

Jack Christopher ◽

Karine Chenu ◽

Andrew Borrell ◽

Mandy Christopher ◽

...

Keyword(s):

Allele Frequency ◽

Seminal Root ◽

Root Angle ◽

Seminal Root Angle

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A toolkit to rapidly modify root systems through single plant selection

Plant Methods ◽

10.1186/s13007-021-00834-2 ◽

2022 ◽

Vol 18 (1) ◽

Author(s):

Charlotte Rambla ◽

Sarah Van Der Meer ◽

Kai P. Voss-Fels ◽

Manar Makhoul ◽

Christian Obermeier ◽

...

Keyword(s):

Root Biomass ◽

Root Traits ◽

Seminal Root ◽

Recurrent Parent ◽

Plant Selection ◽

Root Angle ◽

Single Plant Selection ◽

Non Destructive ◽

Elite Germplasm ◽

Seminal Root Angle

Abstract Background The incorporation of root traits into elite germplasm is typically a slow process. Thus, innovative approaches are required to accelerate research and pre-breeding programs targeting root traits to improve yield stability in different environments and soil types. Marker-assisted selection (MAS) can help to speed up the process by selecting key genes or quantitative trait loci (QTL) associated with root traits. However, this approach is limited due to the complex genetic control of root traits and the limited number of well-characterised large effect QTL. Coupling MAS with phenotyping could increase the reliability of selection. Here we present a useful framework to rapidly modify root traits in elite germplasm. In this wheat exemplar, a single plant selection (SPS) approach combined three main elements: phenotypic selection (in this case for seminal root angle); MAS using KASP markers (targeting a root biomass QTL); and speed breeding to accelerate each cycle. Results To develop a SPS approach that integrates non-destructive screening for seminal root angle and root biomass, two initial experiments were conducted. Firstly, we demonstrated that transplanting wheat seedlings from clear pots (for seminal root angle assessment) into sand pots (for root biomass assessment) did not impact the ability to differentiate genotypes with high and low root biomass. Secondly, we demonstrated that visual scores for root biomass were correlated with root dry weight (r = 0.72), indicating that single plants could be evaluated for root biomass in a non-destructive manner. To highlight the potential of the approach, we applied SPS in a backcrossing program which integrated MAS and speed breeding for the purpose of rapidly modifying the root system of elite bread wheat line Borlaug100. Bi-directional selection for root angle in segregating generations successfully shifted the mean root angle by 30° in the subsequent generation (P ≤ 0.05). Within 18 months, BC2F4:F5 introgression lines were developed that displayed a full range of root configurations, while retaining similar above-ground traits to the recurrent parent. Notably, the seminal root angle displayed by introgression lines varied more than 30° compared to the recurrent parent, resulting in lines with both narrow and wide root angles, and high and low root biomass phenotypes. Conclusion The SPS approach enables researchers and plant breeders to rapidly manipulate root traits of future crop varieties, which could help improve productivity in the face of increasing environmental fluctuations. The newly developed elite wheat lines with modified root traits provide valuable materials to study the value of different root systems to support yield in different environments and soil types.

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Seedling Emergence Rate of Fall‐sown Wheat and Its Association with Plant Height and Coleoptile Length 1

Agronomy Journal ◽

10.2134/agronj1962.00021962005400040022x ◽

1962 ◽

Vol 54 (4) ◽

pp. 347-350 ◽

Cited By ~ 32

Author(s):

R. E. Allan ◽

O. A. Vogel ◽

C. J. Peterson

Keyword(s):

Plant Height ◽

Seedling Emergence ◽

Coleoptile Length ◽

Emergence Rate

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A Toolkit to Rapidly Modify Root Systems Through Single Plant Selection

10.21203/rs.3.rs-882628/v1 ◽

2021 ◽

Author(s):

Charlotte Rambla ◽

Sarah Van Der Meer ◽

Kai P. Voss-Fels ◽

Manar Makhoul ◽

Christian Obermeier ◽

...

Keyword(s):

Root Biomass ◽

Root Traits ◽

Seminal Root ◽

Recurrent Parent ◽

Plant Selection ◽

Root Angle ◽

Single Plant Selection ◽

Non Destructive ◽

Elite Germplasm ◽

Seminal Root Angle

Abstract Background: The incorporation of root traits into elite germplasm is typically a slow process. Thus, innovative approaches are required to accelerate research and pre-breeding programs targeting root traits to improve yield stability in different environments and soil types. Marker-assisted selection (MAS) can help to speed up the process by selecting key genes or quantitative trait loci (QTL) associated with root traits. However, this approach is limited due to the complex genetic control of root traits and the limited number of well-characterised large effect QTL. Coupling MAS with phenotyping could increase the reliability of selection. Here we present a useful framework to rapidly modify root traits in elite germplasm. In this wheat exemplar, a single plant selection (SPS) approach combined three main elements: phenotypic selection (in this case for seminal root angle); MAS using KASP markers (targeting a root biomass QTL); and speed breeding to accelerate each cycle.Results: To develop a SPS approach that integrates non-destructive screening for seminal root angle and root biomass, two initial experiments were conducted. Firstly, we demonstrated that transplanting wheat seedlings from clear pots (for seminal root angle assessment) into sand pots (for root biomass assessment) did not impact the ability to differentiate genotypes with high and low root biomass. Secondly, we demonstrated that visual scores for root biomass were correlated with root dry weight (r = 0.73), indicating that single plants could be evaluated for root biomass in a non-destructive manner. To highlight the potential of the approach, we applied SPS in a backcrossing program which integrated MAS and speed breeding for the purpose of rapidly modifying the root system of elite bread wheat line Borlaug100. Bi-directional selection for root angle in segregating generations successfully shifted the mean root angle by 30o in the subsequent generation (P ≤ 0.05). Within 18 months, BC2F4:F5 introgression lines were developed that displayed a full range of root configurations, while retaining similar above-ground traits to the recurrent parent. Notably, the seminal root angle displayed by introgression lines varied more than 30° compared to the recurrent parent, resulting in lines with both narrow and wide root angles, and high and low root biomass phenotypes.Conclusion: The SPS approach enables researchers and plant breeders to rapidly manipulate root traits of future crop varieties, which could help improve productivity in the face of increasing environmental fluctuations. The newly developed elite wheat lines with modified root traits provide valuable materials to study the value of different root systems to support yield in different environments and soil types.

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Variation in root system architecture among the founder parents of two 8-way MAGIC wheat populations for selection in breeding

10.1101/2021.07.12.451891 ◽

2021 ◽

Author(s):

Shree Pariyar ◽

Kerstin A Nagel ◽

Jonas Lentz ◽

Anna Galinski ◽

Jens Wilhelm ◽

...

Keyword(s):

Root System ◽

System Architecture ◽

Phenotypic Diversity ◽

Lateral Roots ◽

Crop Productivity ◽

Root System Architecture ◽

Seminal Root ◽

Wheat Crop ◽

Root Angle ◽

Seminal Root Angle

Root system architecture (RSA) is a target for breeding because of the interest to develop crops with roots that use nutrients and water more effectively. Breeding for RSA requires phenotypic diversity in populations amenable to QTL identification to provide markers for large breeding programs. This study examined the variation for root traits across the parents of two multi-parent advanced generation inter-cross (MAGIC) wheat populations from NIAB and CSIRO for 16 days in an upgraded version of the non-invasive, germination paper-based phenotyping platform, GrowScreen-PaGe. Across all parents, total root length varied up to 1.90 fold, root biomass 2.25 fold and seminal root angle 1.16 fold. The CSIRO parents grew faster, exhibited slightly wider seminal root angle and produced larger root systems compared to NIAB parents. Lateral root lengths, leaf lengths and biomass contrasted most between fastest (Robigus - NIAB and AC Barrie - CSIRO) and slowest growing parents (Rialto - NIAB and G204 Xiaoyan54 - CSIRO). Lengths of lateral and total root, and leaf number and length had moderate to high heritability (0.30-0.67) and repeatability. Lengths of lateral roots and leaves are good targets for enhancing wheat crop establishment, a critical stage for crop productivity.

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Varietal differences of seminal root angle among barley cultivars

Root Research ◽

10.3117/rootres.30.119 ◽

2021 ◽

Vol 30 (4) ◽

pp. 119-123

Author(s):

Junpei KONISHI ◽

Yuuki NAKANO ◽

Hirotake ITOH ◽

Takashi NAGAMINE

Keyword(s):

Seminal Root ◽

Varietal Differences ◽

Barley Cultivars ◽

Root Angle ◽

Seminal Root Angle

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Phenotypic Evaluation and Genetic Analysis of Seedling Emergence in a Global Collection of Wheat Genotypes (Triticum aestivum L.) Under Limited Water Availability

Frontiers in Plant Science ◽

10.3389/fpls.2021.796176 ◽

2021 ◽

Vol 12 ◽

Author(s):

Michael G. Francki ◽

Grantley S. Stainer ◽

Esther Walker ◽

Gregory J. Rebetzke ◽

Katia T. Stefanova ◽

...

Keyword(s):

Soil Water ◽

Water Availability ◽

Genome Wide Association Study ◽

Seedling Emergence ◽

Soil Water Availability ◽

Wheat Crop ◽

Coleoptile Length ◽

Wheat Genotypes ◽

A Genome ◽

Top Soil

The challenge in establishing an early-sown wheat crop in southern Australia is the need for consistently high seedling emergence when sowing deep in subsoil moisture (>10 cm) or into dry top-soil (4 cm). However, the latter is strongly reliant on a minimum soil water availability to ensure successful seedling emergence. This study aimed to: (1) evaluate 233 Australian and selected international wheat genotypes for consistently high seedling emergence under limited soil water availability when sown in 4 cm of top-soil in field and glasshouse (GH) studies; (2) ascertain genetic loci associated with phenotypic variation using a genome-wide association study (GWAS); and (3) compare across loci for traits controlling coleoptile characteristics, germination, dormancy, and pre-harvest sprouting. Despite significant (P < 0.001) environment and genotype-by-environment interactions within and between field and GH experiments, eight genotypes that included five cultivars, two landraces, and one inbred line had consistently high seedling emergence (mean value > 85%) across nine environments. Moreover, 21 environment-specific quantitative trait loci (QTL) were detected in GWAS analysis on chromosomes 1B, 1D, 2B, 3A, 3B, 4A, 4B, 5B, 5D, and 7D, indicating complex genetic inheritance controlling seedling emergence. We aligned QTL for known traits and individual genes onto the reference genome of wheat and identified 16 QTL for seedling emergence in linkage disequilibrium with coleoptile length, width, and cross-sectional area, pre-harvest sprouting and dormancy, germination, seed longevity, and anthocyanin development. Therefore, it appears that seedling emergence is controlled by multifaceted networks of interrelated genes and traits regulated by different environmental cues.

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