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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Publications at this Location » Publication #390719

Research Project: Genetic Enhancement of Sunflower Yield and Tolerance to Biotic Stress

Location: Sunflower and Plant Biology Research

Title: QTL mapping of Sclerotinia head rot resistance introgressed from the wild perennial Helianthus maximiliani species into cultivated sunflower

item TALUKDER, ZAHIRUL - North Dakota State University
item Underwood, William
item Misar, Christopher
item Seiler, Gerald
item Cai, Xiwen
item LI, XUEHUI - North Dakota State University
item Qi, Lili

Submitted to: ARS Sclerotinia Initiative Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 1/20/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Sclerotinia head rot (HR), caused by the fungal pathogen Sclerotinia sclerotiorum, is one of the most devastating diseases of sunflower worldwide. The use of host resistance is the most economical and effective method of controlling the disease. The objective of this study was to dissect the quantitative trait loci (QTL) associated with Sclerotinia HR resistance introgressed from a wild perennial sunflower species, Helianthus maximiliani, into cultivated sunflower. A population of 188 F3:4 progeny lines was developed from a cross of HR 21, a HR resistant line with HA 234, a HR susceptible line. The population was evaluated for HR resistance in inoculated field trials at two locations with three replications during 2019-2020 seasons. A clear separation of the parents HR 21 and HA 234 for the HR disease incidence (DI) and disease severity (DS) was observed in all environments with a mean DI of 32.3% and 94.7%, and mean DS of 1.12 and 4.38, respectively. The distribution of HR DI and DS in the population was continuous, confirming a polygenic inheritance of the trait. Transgressive segregation was observed for both the traits in the population where some progenies showed more extreme phenotypes than either of the parents. Analysis of variance of the DI and DS data revealed highly significant variation (p <0.001) for genotype (G), genotype × year (G×Y), and genotype × year × location (G×Y×L) interactions effect in the population. However, Spearman's rank correlations for HR DI and DS measured across years and locations were highly significant (p <0.001), suggesting a high degree of collinearity of the field trials. The moderately high broad sense heritability (H2) estimates (~0.70) across environments for both the traits indicates that there is ample opportunity for improving HR resistance through breeding. QTL analyses were performed for HR DI and DS using both individual and combined environments data. Preliminary analyses identified 19 QTL on ten sunflower chromosomes associated with Sclerotinia HR resistance in this population. Fourteen of the QTL had HR resistance alleles contributed by the resistant HR 21 parent, while the remaining five QTL had resistance alleles derived from the susceptible parent HA 234.