Fig. 1.
Fig. 1.

Frequency distribution of Sclerotinia basal stalk rot (BSR) disease incidence (DI) among 106 sunflower recombinant inbred lines (RILs) screened in multienvironments during 2012 to 2014. The arrowheads indicate the DI levels of the parental lines, HA 441 (green) and RHA 439 (blue). The Shapiro–Wilk normality test statistic (W), the probability value (P), and the Pearson’s coefficient of skewness (Sk) of the data for each environments are shown inside the plots.

 


Fig. 2.
Fig. 2.

Genomic location of quantitative trait loci (QTL) associated with sunflower Sclerotinia basal stalk rot (BSR) resistance detected using HA 441 × RHA 439 recombinant inbred lines (RILs) mapping population screened in multienvironments during 2012 to 2014. Rectangles represent the one logarithm of odds (1-LOD) confidence interval of the QTL.

 


Fig. 3.
Fig. 3.

Analysis of means (ANOM) test shows the effects of allelic combinations of two major quantitative trait loci (QTL) associated with Sclerotinia basal stalk rot (BSR) resistance in sunflower recombinant inbred line (RIL) population derived from the cross, HA 441 × RHA 439 evaluated in five environments during 2012–2014 growing seasons. The first allele is from the QTL Qbsr-10.1 on LG10 contributing resistance from RHA 439 parent, while the second allele is from the QTL Qbsr-17.1 on LG17 contributing resistance from HA 441 parent. A light blue area inside each plot shows the upper and lower bounds of decision limits. Values outside decision limits are significantly different (P < 0.05) from the mean disease incidence (DI) of the RIL population. The dark blue columns represent the mean DI of the RILs possessing different allelic combinations of the two major QTL.

 


Fig. 4.
Fig. 4.

Polymerase chain reaction (PCR) amplification of two tightly linked single nucleotide polymorphism (SNP) markers (S10_288646223 and S17_228661362) associated with Sclerotinia basal stalk rot (BSR) resistance QTL Qbsr-10.1 and Qbsr-17.1 in sunflower. Allele-specific PCR primers designed for these SNP markers produced codominant polymorphic bands for the parents, HA 441 and RHA 439, and showed their segregation in the RIL population. The genotyping-by-sequencing (GBS) genotype data of the respective SNP markers (shown in the bottom rows) matches the band sizes produced by the allele-specific PCR primers.