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Exploring potential of pearl millet germplasm association panel for association mapping of drought tolerance traits.

Sehgal D, Skot L, Singh R, Srivastava RK, Das SP, Taunk J, Sharma PC, Pal R, Raj B, Hash CT, Yadav RS - PLoS ONE (2015)

Bottom Line: Most significantly, an important SNP in putative acetyl CoA carboxylase gene showed constitutive association with grain yield, grain harvest index and panicle yield under all treatments.An InDel in putative chlorophyll a/b binding protein gene was significantly associated with both stay-green and grain yield traits under drought stress.Expression patterns of genes also shed light on some physiological mechanisms underlying pearl millet drought tolerance.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological, Environmental and Biological Sciences (IBERS), Aberystwyth University, Gogerddan, Aberystwyth, Ceredigion, United Kingdom.

ABSTRACT
A pearl millet inbred germplasm association panel (PMiGAP) comprising 250 inbred lines, representative of cultivated germplasm from Africa and Asia, elite improved open-pollinated cultivars, hybrid parental inbreds and inbred mapping population parents, was recently established. This study presents the first report of genetic diversity in PMiGAP and its exploitation for association mapping of drought tolerance traits. For diversity and genetic structure analysis, PMiGAP was genotyped with 37 SSR and CISP markers representing all seven linkage groups. For association analysis, it was phenotyped for yield and yield components and morpho-physiological traits under both well-watered and drought conditions, and genotyped with SNPs and InDels from seventeen genes underlying a major validated drought tolerance (DT) QTL. The average gene diversity in PMiGAP was 0.54. The STRUCTURE analysis revealed six subpopulations within PMiGAP. Significant associations were obtained for 22 SNPs and 3 InDels from 13 genes under different treatments. Seven SNPs associations from 5 genes were common under irrigated and one of the drought stress treatments. Most significantly, an important SNP in putative acetyl CoA carboxylase gene showed constitutive association with grain yield, grain harvest index and panicle yield under all treatments. An InDel in putative chlorophyll a/b binding protein gene was significantly associated with both stay-green and grain yield traits under drought stress. This can be used as a functional marker for selecting high yielding genotypes with 'stay green' phenotype under drought stress. The present study identified useful marker-trait associations of important agronomics traits under irrigated and drought stress conditions with genes underlying a major validated DT-QTL in pearl millet. Results suggest that PMiGAP is a useful panel for association mapping. Expression patterns of genes also shed light on some physiological mechanisms underlying pearl millet drought tolerance.

No MeSH data available.


Related in: MedlinePlus

Contour plots of grain yield vs. leaf rolling and stay green (a) and grain yield vs leaf rolling and flowering time under drought stress (b).Effects of stay green (c) and leaf rolling (d) on grain yield under drought stress.
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pone.0122165.g003: Contour plots of grain yield vs. leaf rolling and stay green (a) and grain yield vs leaf rolling and flowering time under drought stress (b).Effects of stay green (c) and leaf rolling (d) on grain yield under drought stress.

Mentions: The heritability was generally high (>0.75) or moderately high (0.50–0.75) for all the traits under control conditions (S3 Table). The heritability estimates in early and late stress treatments ranged from 0.60 (BY) to 0.94 (FT) and 0.44 (BY) to 0.94 (FT), respectively. Across environments, heritability estimates for panicle and biomass yield were low (<0.50) and it was moderate for grain yield and panicle harvest index (≥0.50). For remaining traits, these estimates were fairly high (>0.70) (S3 Table). The correlation values among traits under control and drought stress conditions are provided in S5 and S6 Tables. In general, GY and FT were negatively correlated under both control and drought stress conditions but correlation was not significant under drought stress conditions. A significant negative correlation between GY and LR and positive correlation between GY and SG under drought stress conditions in both years (S6 Table) suggest that LR and SG have more effect on GY than FT under terminal drought stress in pearl millet The 3D contour plots confirm this (Fig 3A and 3B). The genotypes having stay green score more than 2.0 showed more grain yield than the genotypes having scores less than 2.0 (Fig 3C). An opposite trend was observed for leaf rolling and grain yield i.e. genotypes having leaf rolling scores more than 2.0 had significantly lesser yield than genotypes having scores less than 2.0 (Fig 3D).


Exploring potential of pearl millet germplasm association panel for association mapping of drought tolerance traits.

Sehgal D, Skot L, Singh R, Srivastava RK, Das SP, Taunk J, Sharma PC, Pal R, Raj B, Hash CT, Yadav RS - PLoS ONE (2015)

Contour plots of grain yield vs. leaf rolling and stay green (a) and grain yield vs leaf rolling and flowering time under drought stress (b).Effects of stay green (c) and leaf rolling (d) on grain yield under drought stress.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4430295&req=5

pone.0122165.g003: Contour plots of grain yield vs. leaf rolling and stay green (a) and grain yield vs leaf rolling and flowering time under drought stress (b).Effects of stay green (c) and leaf rolling (d) on grain yield under drought stress.
Mentions: The heritability was generally high (>0.75) or moderately high (0.50–0.75) for all the traits under control conditions (S3 Table). The heritability estimates in early and late stress treatments ranged from 0.60 (BY) to 0.94 (FT) and 0.44 (BY) to 0.94 (FT), respectively. Across environments, heritability estimates for panicle and biomass yield were low (<0.50) and it was moderate for grain yield and panicle harvest index (≥0.50). For remaining traits, these estimates were fairly high (>0.70) (S3 Table). The correlation values among traits under control and drought stress conditions are provided in S5 and S6 Tables. In general, GY and FT were negatively correlated under both control and drought stress conditions but correlation was not significant under drought stress conditions. A significant negative correlation between GY and LR and positive correlation between GY and SG under drought stress conditions in both years (S6 Table) suggest that LR and SG have more effect on GY than FT under terminal drought stress in pearl millet The 3D contour plots confirm this (Fig 3A and 3B). The genotypes having stay green score more than 2.0 showed more grain yield than the genotypes having scores less than 2.0 (Fig 3C). An opposite trend was observed for leaf rolling and grain yield i.e. genotypes having leaf rolling scores more than 2.0 had significantly lesser yield than genotypes having scores less than 2.0 (Fig 3D).

Bottom Line: Most significantly, an important SNP in putative acetyl CoA carboxylase gene showed constitutive association with grain yield, grain harvest index and panicle yield under all treatments.An InDel in putative chlorophyll a/b binding protein gene was significantly associated with both stay-green and grain yield traits under drought stress.Expression patterns of genes also shed light on some physiological mechanisms underlying pearl millet drought tolerance.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological, Environmental and Biological Sciences (IBERS), Aberystwyth University, Gogerddan, Aberystwyth, Ceredigion, United Kingdom.

ABSTRACT
A pearl millet inbred germplasm association panel (PMiGAP) comprising 250 inbred lines, representative of cultivated germplasm from Africa and Asia, elite improved open-pollinated cultivars, hybrid parental inbreds and inbred mapping population parents, was recently established. This study presents the first report of genetic diversity in PMiGAP and its exploitation for association mapping of drought tolerance traits. For diversity and genetic structure analysis, PMiGAP was genotyped with 37 SSR and CISP markers representing all seven linkage groups. For association analysis, it was phenotyped for yield and yield components and morpho-physiological traits under both well-watered and drought conditions, and genotyped with SNPs and InDels from seventeen genes underlying a major validated drought tolerance (DT) QTL. The average gene diversity in PMiGAP was 0.54. The STRUCTURE analysis revealed six subpopulations within PMiGAP. Significant associations were obtained for 22 SNPs and 3 InDels from 13 genes under different treatments. Seven SNPs associations from 5 genes were common under irrigated and one of the drought stress treatments. Most significantly, an important SNP in putative acetyl CoA carboxylase gene showed constitutive association with grain yield, grain harvest index and panicle yield under all treatments. An InDel in putative chlorophyll a/b binding protein gene was significantly associated with both stay-green and grain yield traits under drought stress. This can be used as a functional marker for selecting high yielding genotypes with 'stay green' phenotype under drought stress. The present study identified useful marker-trait associations of important agronomics traits under irrigated and drought stress conditions with genes underlying a major validated DT-QTL in pearl millet. Results suggest that PMiGAP is a useful panel for association mapping. Expression patterns of genes also shed light on some physiological mechanisms underlying pearl millet drought tolerance.

No MeSH data available.


Related in: MedlinePlus