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Detection of nitrogen deficiency QTL in juvenile wild barley introgression lines growing in a hydroponic system.

Hoffmann A, Maurer A, Pillen K - BMC Genet. (2012)

Bottom Line: The post-hoc Dunnett test identified 28 S42ILs that revealed significant (P < 0.01) effects for at least one trait.Forty-three, 41 and 42 S42ILs revealed effects across both N treatments, under low N and under high N treatment, respectively.Due to this finding, screening of plants in early developmental stages grown in a hydroponic system may be a fast and cost effective method for early QTL detection and marker-assisted allelic selection, potentially speeding up elite barley breeding programs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Agricultural and Nutritional Sciences, Chair of Plant Breeding, Martin-Luther-University Halle-Wittenberg, Betty-Heimann-Str, 3, Halle, 06120, Germany.

ABSTRACT

Background: In this report we studied the genetic regulation of juvenile development of wild barley introgression lines (S42ILs) under two contrasting hydroponic nitrogen (N) supplies. Ten shoot and root related traits were examined among 42 S42ILs and the recurrent parent 'Scarlett'. The traits included tiller number, leaf number, plant height, leaf and root length, leaf to root length ratio, shoots and root dry weight, shoot to root weight ratio, and chlorophyll content. Our aims were (1) to test the suitability of a hydroponic system for early detection of favourable S42ILs, (2) to locate quantitative trait loci (QTL) that control the examined traits, (3) to identify favourable wild barley alleles that improve trait performances in regard to N treatment and, finally, (4) to validate the identified QTL through comparison with previously reported QTL originating from the same parental cross.

Results: The phenotypic data were analysed in a mixed model association study to detect QTL. The post-hoc Dunnett test identified 28 S42ILs that revealed significant (P < 0.01) effects for at least one trait. Forty-three, 41 and 42 S42ILs revealed effects across both N treatments, under low N and under high N treatment, respectively. Due to overlapping or flanking wild barley introgressions of the S42ILs, these associations were summarised to 58 QTL. In total, 12 QTL of the hydroponic N study corresponded to QTL that were also detected in field trials with adult plants of a similar S42IL set or of the original S42 population. For instance, S42IL-135, -136 and -137, revealed increasing Hsp effects for tiller number, leaf number, leaf length, plant height and leaf to root ratio on the long arm of chromosome 7H. These QTL correspond to QTL for ears per plant and plant height that were previously detected in field trials conducted with the same S42ILs or with the S42 population.

Conclusion: Our results suggest that the QTL we identified under hydroponic N cultivation partly correspond to QTL detected in field experiments. Due to this finding, screening of plants in early developmental stages grown in a hydroponic system may be a fast and cost effective method for early QTL detection and marker-assisted allelic selection, potentially speeding up elite barley breeding programs.

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Related in: MedlinePlus

Seed germination and plant cultivation. A. Barley seeds were germinated in the dark at room temperature. B. After 72 h, seedlings that had three to five roots of 1.5 to 2.0 cm length and that had not yet started to extend the shoot were selected. Each seedling was inserted into a 1.5 ml reaction tube (Eppendorf, Hamburg) that was cropped at the bottom. C. The tubes with the seedlings were subsequently plugged into the perforated trays and placed on top of the boxes. D. Throughout the experiments the roots plunged into the nutrient solution whereas plant shoots grew on top of the tray.
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Figure 3: Seed germination and plant cultivation. A. Barley seeds were germinated in the dark at room temperature. B. After 72 h, seedlings that had three to five roots of 1.5 to 2.0 cm length and that had not yet started to extend the shoot were selected. Each seedling was inserted into a 1.5 ml reaction tube (Eppendorf, Hamburg) that was cropped at the bottom. C. The tubes with the seedlings were subsequently plugged into the perforated trays and placed on top of the boxes. D. Throughout the experiments the roots plunged into the nutrient solution whereas plant shoots grew on top of the tray.

Mentions: For each experiment, seeds of ‘Scarlett’, ‘Barke’ and the S42ILs were coated with the fungicide Abavit UF® (BASF, Ludwigshafen). Seed germination and plant cultivation is shown in detail in Figure3. To study the plant growth and responses to N deficiency on juvenile barley plants, ten traits were investigated. The methods of trait measurements and trait abbreviations are given in Table2.


Detection of nitrogen deficiency QTL in juvenile wild barley introgression lines growing in a hydroponic system.

Hoffmann A, Maurer A, Pillen K - BMC Genet. (2012)

Seed germination and plant cultivation. A. Barley seeds were germinated in the dark at room temperature. B. After 72 h, seedlings that had three to five roots of 1.5 to 2.0 cm length and that had not yet started to extend the shoot were selected. Each seedling was inserted into a 1.5 ml reaction tube (Eppendorf, Hamburg) that was cropped at the bottom. C. The tubes with the seedlings were subsequently plugged into the perforated trays and placed on top of the boxes. D. Throughout the experiments the roots plunged into the nutrient solution whereas plant shoots grew on top of the tray.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3584942&req=5

Figure 3: Seed germination and plant cultivation. A. Barley seeds were germinated in the dark at room temperature. B. After 72 h, seedlings that had three to five roots of 1.5 to 2.0 cm length and that had not yet started to extend the shoot were selected. Each seedling was inserted into a 1.5 ml reaction tube (Eppendorf, Hamburg) that was cropped at the bottom. C. The tubes with the seedlings were subsequently plugged into the perforated trays and placed on top of the boxes. D. Throughout the experiments the roots plunged into the nutrient solution whereas plant shoots grew on top of the tray.
Mentions: For each experiment, seeds of ‘Scarlett’, ‘Barke’ and the S42ILs were coated with the fungicide Abavit UF® (BASF, Ludwigshafen). Seed germination and plant cultivation is shown in detail in Figure3. To study the plant growth and responses to N deficiency on juvenile barley plants, ten traits were investigated. The methods of trait measurements and trait abbreviations are given in Table2.

Bottom Line: The post-hoc Dunnett test identified 28 S42ILs that revealed significant (P < 0.01) effects for at least one trait.Forty-three, 41 and 42 S42ILs revealed effects across both N treatments, under low N and under high N treatment, respectively.Due to this finding, screening of plants in early developmental stages grown in a hydroponic system may be a fast and cost effective method for early QTL detection and marker-assisted allelic selection, potentially speeding up elite barley breeding programs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Agricultural and Nutritional Sciences, Chair of Plant Breeding, Martin-Luther-University Halle-Wittenberg, Betty-Heimann-Str, 3, Halle, 06120, Germany.

ABSTRACT

Background: In this report we studied the genetic regulation of juvenile development of wild barley introgression lines (S42ILs) under two contrasting hydroponic nitrogen (N) supplies. Ten shoot and root related traits were examined among 42 S42ILs and the recurrent parent 'Scarlett'. The traits included tiller number, leaf number, plant height, leaf and root length, leaf to root length ratio, shoots and root dry weight, shoot to root weight ratio, and chlorophyll content. Our aims were (1) to test the suitability of a hydroponic system for early detection of favourable S42ILs, (2) to locate quantitative trait loci (QTL) that control the examined traits, (3) to identify favourable wild barley alleles that improve trait performances in regard to N treatment and, finally, (4) to validate the identified QTL through comparison with previously reported QTL originating from the same parental cross.

Results: The phenotypic data were analysed in a mixed model association study to detect QTL. The post-hoc Dunnett test identified 28 S42ILs that revealed significant (P < 0.01) effects for at least one trait. Forty-three, 41 and 42 S42ILs revealed effects across both N treatments, under low N and under high N treatment, respectively. Due to overlapping or flanking wild barley introgressions of the S42ILs, these associations were summarised to 58 QTL. In total, 12 QTL of the hydroponic N study corresponded to QTL that were also detected in field trials with adult plants of a similar S42IL set or of the original S42 population. For instance, S42IL-135, -136 and -137, revealed increasing Hsp effects for tiller number, leaf number, leaf length, plant height and leaf to root ratio on the long arm of chromosome 7H. These QTL correspond to QTL for ears per plant and plant height that were previously detected in field trials conducted with the same S42ILs or with the S42 population.

Conclusion: Our results suggest that the QTL we identified under hydroponic N cultivation partly correspond to QTL detected in field experiments. Due to this finding, screening of plants in early developmental stages grown in a hydroponic system may be a fast and cost effective method for early QTL detection and marker-assisted allelic selection, potentially speeding up elite barley breeding programs.

Show MeSH
Related in: MedlinePlus