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Quantitative Trait Locus Analysis of Seed Germination and Seedling Vigor in Brassica rapa Reveals QTL Hotspots and Epistatic Interactions.

Basnet RK, Duwal A, Tiwari DN, Xiao D, Monakhos S, Bucher J, Visser RG, Groot SP, Bonnema G, Maliepaard C - Front Plant Sci (2015)

Bottom Line: The genetic basis of seed germination and seedling vigor is largely unknown in Brassica species.We identified 26 QTL regions across all 10 linkage groups for traits related to seed weight, seed germination and seedling vigor under non-stress and salt stress conditions illustrating the polygenic nature of these traits.These results contribute to the understanding of the genetics of seed quality and seeding vigor in B. rapa and can offer tools for Brassica breeding.

View Article: PubMed Central - PubMed

Affiliation: Wageningen UR Plant Breeding, Wageningen University and Research Center, Wageningen University Wageningen, Netherlands ; Centre for BioSystems Genomics Wageningen, Netherlands.

ABSTRACT
The genetic basis of seed germination and seedling vigor is largely unknown in Brassica species. We performed a study to evaluate the genetic basis of these important traits in a B. rapa doubled haploid population from a cross of a yellow-seeded oil-type yellow sarson and a black-seeded vegetable-type pak choi. We identified 26 QTL regions across all 10 linkage groups for traits related to seed weight, seed germination and seedling vigor under non-stress and salt stress conditions illustrating the polygenic nature of these traits. QTLs for multiple traits co-localized and we identified eight hotspots for quantitative trait loci (QTL) of seed weight, seed germination, and root and shoot lengths. A QTL hotspot for seed germination on A02 mapped at the B. rapa Flowering Locus C (BrFLC2). Another hotspot on A05 with salt stress specific QTLs co-located with the B. rapa Fatty acid desaturase 2 (BrFAD2) locus. Epistatic interactions were observed between QTL hotspots for seed germination on A02 and A10 and with a salt tolerance QTL on A05. These results contribute to the understanding of the genetics of seed quality and seeding vigor in B. rapa and can offer tools for Brassica breeding.

No MeSH data available.


Related in: MedlinePlus

Box plots showing the distributions of root length (RL) and shoot length (SL) at different days after germination (DAG) under non-stress (0 mM NaCl) and salt stress (50 mM NaCl) for the 2011 seed batch. The shaded color of the boxes indicates the treatments: white for non-stress and gray for salt stress. The y-axis indicates root and shoot length (in cm). The x-axis label is the combination of RL or SL at 3, 5, 7, and 9 DAG at non-stress and salt stress conditions. Box plots showing the distributions of RL and SL for the 2010 seed batch are shown in Supplementary Figure S2.
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Figure 1: Box plots showing the distributions of root length (RL) and shoot length (SL) at different days after germination (DAG) under non-stress (0 mM NaCl) and salt stress (50 mM NaCl) for the 2011 seed batch. The shaded color of the boxes indicates the treatments: white for non-stress and gray for salt stress. The y-axis indicates root and shoot length (in cm). The x-axis label is the combination of RL or SL at 3, 5, 7, and 9 DAG at non-stress and salt stress conditions. Box plots showing the distributions of RL and SL for the 2010 seed batch are shown in Supplementary Figure S2.

Mentions: The roots of yellow sarson were longer than roots of pak choi (p = 0.05) on all DAGs and the differences in root length between the parents increased over time. The variance of root- and shoot- length over the DH lines also increased with time (Figure 1; Supplementary Figure S2). Under salt stress root length was reduced (Figure 1; Supplementary Figure S2); yellow sarson had longer roots than pak choi until 7 DAGs, however at 9 DAG root lengths of the parental genotypes were similar. Similar to root length, also shoot length was larger in yellow sarson than pak choi and the difference between the two parents was smaller under salt stress than under non-stress conditions. Large variation in shoot length was observed across the DH lines. In both conditions in both years, a large number of transgressive segregants were observed across the DH population for all the seedling traits (Figure 1; Supplementary Figure S2).


Quantitative Trait Locus Analysis of Seed Germination and Seedling Vigor in Brassica rapa Reveals QTL Hotspots and Epistatic Interactions.

Basnet RK, Duwal A, Tiwari DN, Xiao D, Monakhos S, Bucher J, Visser RG, Groot SP, Bonnema G, Maliepaard C - Front Plant Sci (2015)

Box plots showing the distributions of root length (RL) and shoot length (SL) at different days after germination (DAG) under non-stress (0 mM NaCl) and salt stress (50 mM NaCl) for the 2011 seed batch. The shaded color of the boxes indicates the treatments: white for non-stress and gray for salt stress. The y-axis indicates root and shoot length (in cm). The x-axis label is the combination of RL or SL at 3, 5, 7, and 9 DAG at non-stress and salt stress conditions. Box plots showing the distributions of RL and SL for the 2010 seed batch are shown in Supplementary Figure S2.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664704&req=5

Figure 1: Box plots showing the distributions of root length (RL) and shoot length (SL) at different days after germination (DAG) under non-stress (0 mM NaCl) and salt stress (50 mM NaCl) for the 2011 seed batch. The shaded color of the boxes indicates the treatments: white for non-stress and gray for salt stress. The y-axis indicates root and shoot length (in cm). The x-axis label is the combination of RL or SL at 3, 5, 7, and 9 DAG at non-stress and salt stress conditions. Box plots showing the distributions of RL and SL for the 2010 seed batch are shown in Supplementary Figure S2.
Mentions: The roots of yellow sarson were longer than roots of pak choi (p = 0.05) on all DAGs and the differences in root length between the parents increased over time. The variance of root- and shoot- length over the DH lines also increased with time (Figure 1; Supplementary Figure S2). Under salt stress root length was reduced (Figure 1; Supplementary Figure S2); yellow sarson had longer roots than pak choi until 7 DAGs, however at 9 DAG root lengths of the parental genotypes were similar. Similar to root length, also shoot length was larger in yellow sarson than pak choi and the difference between the two parents was smaller under salt stress than under non-stress conditions. Large variation in shoot length was observed across the DH lines. In both conditions in both years, a large number of transgressive segregants were observed across the DH population for all the seedling traits (Figure 1; Supplementary Figure S2).

Bottom Line: The genetic basis of seed germination and seedling vigor is largely unknown in Brassica species.We identified 26 QTL regions across all 10 linkage groups for traits related to seed weight, seed germination and seedling vigor under non-stress and salt stress conditions illustrating the polygenic nature of these traits.These results contribute to the understanding of the genetics of seed quality and seeding vigor in B. rapa and can offer tools for Brassica breeding.

View Article: PubMed Central - PubMed

Affiliation: Wageningen UR Plant Breeding, Wageningen University and Research Center, Wageningen University Wageningen, Netherlands ; Centre for BioSystems Genomics Wageningen, Netherlands.

ABSTRACT
The genetic basis of seed germination and seedling vigor is largely unknown in Brassica species. We performed a study to evaluate the genetic basis of these important traits in a B. rapa doubled haploid population from a cross of a yellow-seeded oil-type yellow sarson and a black-seeded vegetable-type pak choi. We identified 26 QTL regions across all 10 linkage groups for traits related to seed weight, seed germination and seedling vigor under non-stress and salt stress conditions illustrating the polygenic nature of these traits. QTLs for multiple traits co-localized and we identified eight hotspots for quantitative trait loci (QTL) of seed weight, seed germination, and root and shoot lengths. A QTL hotspot for seed germination on A02 mapped at the B. rapa Flowering Locus C (BrFLC2). Another hotspot on A05 with salt stress specific QTLs co-located with the B. rapa Fatty acid desaturase 2 (BrFAD2) locus. Epistatic interactions were observed between QTL hotspots for seed germination on A02 and A10 and with a salt tolerance QTL on A05. These results contribute to the understanding of the genetics of seed quality and seeding vigor in B. rapa and can offer tools for Brassica breeding.

No MeSH data available.


Related in: MedlinePlus