Article

Identification and validation of QTL for Sclerotinia midstalk rot resistance in sunflower by selective genotyping

State Plant Breeding Institute (720), University of Hohenheim, Stuttgart, Germany.
Theoretical and Applied Genetics (Impact Factor: 3.51). 08/2005; 111(2):233-42. DOI: 10.1007/s00122-005-2004-x
Source: PubMed

ABSTRACT Midstalk rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is an important cause of yield loss in sunflower (Helianthus annuus L.). Objectives of this study were to: (1) estimate the number, genomic positions and genetic effects of quantitative trait loci (QTL) for resistance to midstalk rot in line TUB-5-3234, derived from an interspecific cross; (2) determine congruency of QTL between this line and other sources of resistance; and (3) make inferences about the efficiency of selective genotyping (SG) in detecting QTL conferring midstalk rot resistance in sunflower. Phenotypic data for three resistance (stem lesion, leaf lesion and speed of fungal growth) and two morphological (leaf length and leaf length with petiole) traits were obtained from 434 F3 families from cross CM625 (susceptible) x TUB-5-3234 (resistant) under artificial infection in field experiments across two environments. The SG was applied by choosing the 60 most resistant and the 60 most susceptible F3 families for stem lesion. For genotyping of the respective F2 plants, 78 simple sequence repeat markers were used. Genotypic variances were highly significant for all traits. Heritabilities and genotypic correlations between reMidstalk rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is an important cause of yield loss in sunflower (Helianthus annuus L.). Objectives of this study were to: (1) estimate the number, genomic positions and genetic effects of quantitative trait loci (QTL) for resistance to midstalk rot in line TUB-5-3234, derived from an interspecific cross; (2) determine congruency of QTL between this line and other sources of resistance; and (3) make inferences about the efficiency of selective genotyping (SG) in detecting QTL conferring midstalk rot resistance in sunflower. Phenotypic data for three resistance (stem lesion, leaf lesion and speed of fungal growth) and two morphological (leaf length and leaf length with petiole) traits were obtained from 434 F3 families from cross CM625 (susceptible) x TUB-5-3234 (resistant) under artificial infection in field experiments across two environments. The SG was applied by choosing the 60 most resistant and the 60 most susceptible F3 families for stem lesion. For genotyping of the respective F2 plants, 78 simple sequence repeat markers were used. Genotypic variances were highly significant for all traits. Heritabilities and genotypic correlations between resistance traits were moderate to high. Three to four putative QTL were detected for each resistance trait explaining between 40.8% and 72.7% of the genotypic variance (PTS). Two QTL for stem lesion showed large genetic effects and corroborated earlier findings from the cross NDBLOSsel (resistant) x CM625 (susceptible). Our results suggest that SG can be efficiently used for QTL detection and the analysis of congruency for resistance genes across populations.

0 Bookmarks
 · 
101 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 2013): Genetic analysis of partial resistance to basal stem rot (Sclerotinia sclerotiorum) in sunflower Genetika, Vol 45, No. 3, 737-748. Basal stem rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is one of the major diseases of sunflower (Helianthus annuus L.) in the world. Quantitative trait loci (QTLs) implicated in partial resistance to basal stem rot disease were identified using 99 recombinant inbred lines (RILs) from the cross between sunflower parental lines PAC2 and RHA266. The study was undertaken in a completely randomized design with three replications under controlled conditions. The RILs and their parental lines were inoculated with a moderately aggressive isolate of S. sclerotiorum (SSKH41). Resistance to disease was evaluated by measuring the percentage of necrosis area three days after inoculation. QTLs were mapped using an updated high-density SSR and SNP linkage map. ANOVA showed significant differences among sunflower lines for resistance to basal stem rot (P≤0.05). The frequency distribution of lines for susceptibility to disease showed a continuous pattern. Composite interval mapping analysis revealed 5 QTLs for percentage of necrotic area, localized on linkage groups 1, 3, 8, 10 and 17. The sign of additive effect was positive in 5 QTLs, suggesting that the additive allele for partial resistance to basal stem rot came from the paternal line (RHA266). The phenotypic variance explained by QTLs (R 2) ranged from 0.5 to 3.16%. Identified genes (HUCL02246_1, GST and POD), and SSR markers (ORS338, and SSL3) encompassing the QTLs for partial resistance to basal stem rot could be good candidates for marker assisted selection.
    Genetika 01/2013; 45(3). · 0.49 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Basal stem rot caused by Sclerotinia sclerotiorum (Lib.) de Bary is one of the most important diseases of sunflower. Quantitative trait loci (QTL) implicated in partial resistance to two isolates of S. sclerotiorum (SSU107 and SSKH41) were investigated using F9 recombinant inbred lines (RILs) from the cross between sunflower parental lines PAC2 and RHA266. Experiments were conducted in completely randomized design with 3-6 replications under controlled conditions. The reaction of genotypes to basal stem rot disease was evaluated by measuring the percentage of necrosis area three days after inoculation. Combined analysis of experiments showed significant interactions between sunflower genotypes and S. sclerotiorum isolates suggesting that partial resistance to S. sclerotiorum should be isolate-specific in sunflower. QTLs were mapped using an updated high-density SSR and SNP linkage map. The map consisted of 210 SSRs and 11 genederived markers placed in 17 linkage groups (LGs). The total map length was 1,653.1 cM with a mean density of 1 marker per 7.44 cM. A total of 14 QTLs were detected for partial resistance to two isolates. The phenotypic variance explained by QTLs (R2) ranged from 0.10 to 9.85. The sign of additive gene effects showed that favorable alleles for partial resistance to isolates came from both parents. Six QTLs were common between two isolates on LGs 1, 8 and 17, whereas the others were specific for each isolate. Colocalized QTLs on LG 1 were linked to the glutathione S-transferase gene (GST). The colocalized QTLs for partial resistance to basal stem rot isolates could be good candidates for marker assisted selection (MAS).
    J. Agr. Sci. Tech. 01/2015;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Black stem, caused by Phoma macdonaldii, is one of the most important diseases of sunflower in the world. Quantitative trait loci (QTLs) implicated in partial resistance to three isolates of P. macdonaldii including MA6, MP6 and MP10 were investigated using F2/F3 population from the cross between sunflower resistant mutant line ‘M6-54-1’ and susceptible inbred line ‘ENSAT-B4’. A genetic linkage map was constructed with 88 amplified fragment length polymorphism (AFLP) and 44 simple sequence repeat (SSR) markers using 101 F2 individuals. The map comprises 17 linkage groups (LGs) with an overall length of 1,490 cM and mean density of one marker per 12.44 cM. Parental lines and their 101 F3 families were evaluated for their resistance to P. macdonalii isolates in controlled conditions in a randomized complete block design with three replications. High genetic variability and transgressive segregation were observed among F3 families for partial resistance to all of three P. macdonaldii isolates. Composite interval mapping analysis revealed 14 putative QTLs, localized on seven linkage groups, with phenotypic variance ranging from 4 to 42 %. The QTL bsrMP6.8.1 was detected as non isolate-specific QTL and the rest of them were ‘isolate-specific’ QTLs. The major QTL on LG8 which was involved in partial resistance to three isolates could be good candidate to introduce resistance to three P. macdonaldii isolates into elite sunflower breeding lines via marker assisted breeding program.
    Australasian Plant Pathology 01/2014; 43(2). · 1.04 Impact Factor

Full-text (2 Sources)

Download
57 Downloads
Available from
Jun 5, 2014