Variation for Salinity Tolerance During Seed Germination in Diverse Carrot [Daucus carota (L.)] Germplasm

in HortScience

Global carrot production is limited by the crop’s high susceptibility to salinity stress. Not much public research has been conducted to screen for genetic salinity stress tolerance in carrot, and few resources exist to aid plant breeders in improving salinity tolerance in carrot. The objectives of this study were to evaluate the response of diverse carrot germplasm to salinity stress, identify salt-tolerant carrot germplasm that may be used by breeders, and define appropriate screening criteria for assessing salt tolerance in germinating carrot seed. Carrot plant introductions (PIs) (n = 273) from the U.S. Department of Agriculture (USDA) National Plant Germplasm System representing 41 different countries, inbred lines from the USDA Agricultural Research Service (n = 16), and widely grown commercial hybrids (n = 5) were screened for salinity tolerance under salinity stress and nonstress conditions (150 and 0 mm NaCl, respectively) by measuring the absolute decrease (AD) in the percent of germination, inhibition index (II), relative salt tolerance (RST), and salt tolerance index (STI) of germinating seeds. All salt tolerance measurements differed significantly between accessions; AD ranged from −4.2% to 93.0%; II ranged from −8.0% to 100.0%; RST ranged from 0.0 to 1.08; and STI ranged from 0.0 to 1.38. Broad sense heritability calculations for these measurements were 0.87 or more, indicating a strong genetic contribution to the variation observed. Six accessions identified as salt-tolerant or salt-susceptible were evaluated in a subsequent experiment conducted at salt concentrations of 0, 50, 100, 150, 200, and 250 mm NaCl. Variations between mean AD, II, RST, and STI of tolerant and susceptible lines were greatest at 150 mm NaCl, validating the use of 150 mm NaCl concentrations during salt tolerance screening of carrot seed. Wild carrot accessions displayed little tolerance, and PI 256066, PI 652253, PI 652402, and PI 652405 from Turkey were most salt-tolerant.

Contributor Notes

We thank the Global Crop Diversity Trust Project GS14014 for providing financial support. We also thank Kathleen Reitsma and the USDA National Germplasm System for their capable assistance and for providing the plant introduction carrot collection accessions.

Corresponding author. E-mail:

Article Sections

Article Figures

  • View in gallery

    Distribution and mean (dotted line) percent of seed germination among 294 carrot accessions without salt stress (dark gray) and with salt stress (light gray).

  • View in gallery

    Distribution and mean (dotted line) percent of seed germination among 294 carrot accessions with four different measures of salt tolerance: (A) absolute decrease; (B) inhibition index; (C) relative salt tolerance; and (D) salt tolerance index.

  • View in gallery

    Pooled percent of seed germination for three sensitive (solid line) and three tolerant (dotted line) carrot accessions using six NaCl concentrations (0, 50, 100, 150, 200, and 250 mm).

Article References

AbelG.H.MacKenzieA.J.1964Salt tolerance of soybean varieties (Glycine max L. Merrill) during germination and later growthCrop Sci.4157161

BatesD.MaechlerM.BolkerB.WalkerS.ChristensenR.H.B.SingmannH.DaiB.ScheiplF.GrothendieckG.GreenP.2018Linear mixed-effects models using 'Eigen' and S4. R. package version 17 p. 42–44

BaxterI.BrazeltonJ.N.YuD.HuangY.S.LahnerB.YakubovaE.LiY.BergelsonJ.BorevitzJ.O.NordborgM.VitekO.SaltD.E.2010A coastal cline in sodium accumulation in Arabidopsis thaliana is driven by natural variation of the sodium transporter AtHKT1;1PLoS Genet.611e1001193

BernsteinL.AyersA.1953Salt tolerance of five varieties of carrotsJ. Amer. Soc. Hort. Sci.61360366

ChinnusamyV.JagendorfA.ZhuJ.K.2005Understanding and improving salt tolerance in plantsCrop Sci.452437448

CuarteroJ.Fernández-MuñozR.1998Tomato and salinityScientia Hort.781-483125

FalconerD.S.MackayT.F.C.1996Introduction to quantitative genetics. 4th ed. Pearson Essex England

De MendiburuF.2014Agricolae: Statistical procedures for agricultural research. R. package version 1 p. 1–6

FAO2017FAOSTAT production crops. 29 Nov. 2017. <>

FlowersT.J.GalalH.K.BromhamL.2010Evolution of halophytes: Multiple origins of salt tolerance in land plantsFunct. Plant Biol.377604612

FlowersT.J.YeoA.R.1995Breeding for salinity resistance in crop plants: Where next?Austral. J. Plant Physiol.22875884

FooladM.R.JonesR.A.1992Parent offspring regression estimates of heritability for salt tolerance during germination in tomatoCrop Sci.322439442

FooladM.R.LinG.Y.1997Genetic potential for salt tolerance during germination in lycopersicon speciesHortScience32296300

FrancoisL.E.DonovanT.MaasE.V.1984Salinity effects on seed yield, growth, and germination of grain sorghumAgron. J.765741744

IorizzoM.SenalikD.A.EllisonS.L.GrzebelusD.CavagnaroP.F.AllenderC.BrunetJ.SpoonerD.M.DeynzeA.V.SimonP.W.2013Genetic structure and domestication of carrot (Daucus carota subsp. sativus) (Apiaceae)Amer. J. Bot.1005930938

JamilM.LeeD.B.JungK.Y.AshrafM.LeeS.C.RhaE.S.2006Effect of salt (NaCl) stress on germination and early seedling growth of four vegetable speciesJ. Cent. Eur. Agr.7273281

KahouliB.BorgiZ.HannachiC.2014Effect of sodium chloride on the germination of the seeds of a collection of carrot accessions (Daucus carota L.) cultivated in the region of Sidi BouzidJ. Stress Physiol. Biochem.1032836

KhouryC.K.Castañeda-AlvarezN.P.AchicanoyH.A.SosaC.C.BernauV.KassaM.T.NortonS.L.van der MaesenL.J.G.UpadhyayaH.D.Ramírez-VillegasJ.JarvisA.StruikP.C.2015Crop wild relatives of pigeonpea [Cajanus cajan (L.) Millsp.]: Distributions, ex situ conservation status, and potential genetic resources for abiotic stress toleranceBiol. Conserv.184259270

MaasE.V.HoffmanG.J.1977Crop salt tolerance - current assessmentJ. Irrig. Drain. Div.103115134

MaasE.V.HoffmanG.J.ChabaG.D.PossJ.A.ShannonM.C.1983Salt sensitivity of corn at various growth stagesIrrig. Sci.414557

MunnsR.2005Genes and salt tolerance: Bringing them togetherNew Phytol.1673645663

QadirM.TubeilehA.AkhtarJ.LarbiA.MinhasP.S.KhanM.A.2008Productivity enhancement of salt-affected environments through crop diversificationLand Degrad. Dev.19429453

R Core Team2018R: A language and environment for statistical computing. R Foundation for Statistical Computing Vienna Austria

RavelombolaW.ShiA.WengY.MouB.MotesD.ClarkJ.ChenP.SrivastavaV.QinJ.DongL.YangW.BhattaraiG.SugiharaY.2018Association analysis of salt tolerance in cowpea (Vigna unguiculata (L.) Walp) at germination and seedling stagesTheor. Appl. Genet.13117991

RavelombolaW.S.ShiA.WengY.ClarkJ.MotesD.ChenP.SrivastavaV.2017Evaluation of salt tolerance at germination stage in cowpea [Vigna unguiculata (L.) Walp]HortScience5211681176

RodeA.NothnagelT.KampeE.2012Developing methods to evaluate salt stress tolerance in carrot cultivarsActa Hort.960393400

RozemaJ.FlowersT.2008Crops for a salinized worldScience32214781480

SaadF.F.El-MohsenA.A.A.El-ShafiM.A.A.Al-SoudanI.H.2013Effective selection criteria for evaluating some barley crosses for water stress toleranceEgypt. J. Plant Breed.1757998

SchmidhalterU.OertliJ.J.1991Germination and seedling growth of carrots under salinity and moisture stressPlant Soil132243251

SimonP.W.PollakL.M.ClevidenceB.A.HoldenJ.M.HaytowitzD.B.2009Plant breeding for human nutritional qualityPlant Breed. Rev.31325392

XuC.MouB.2015Evaluation of lettuce genotypes for salinity toleranceHortScience5014411446

Article Information

Google Scholar

Related Content

Article Metrics

All Time Past Year Past 30 Days
Abstract Views 508 508 329
Full Text Views 75 75 32
PDF Downloads 35 35 14