Association of Fhb1 and Qfhs.ifa-5A in Spring versus Winter Growth Habits in Bread Wheat (Triticum aestivum L.)
Journal of Agricultural Science
Fusarium head blight (FHB) is a major disease that reduces grain yield and quality of winter and spring wheat in eastern South Dakota. This study was conducted to determine the association of FHB resistance QTLs (Fhb1 and Qfhs.ifa-5A) to spring and winter growth habits of bread wheat. Four genotypes consisting of susceptible winter wheats 'Nekota' and '2137' and moderately resistant spring wheats 'ND2710' and 'BacUp' were crossed and populations derived from the crosses were separated into
... separated into spring and winter types following cold treatment of seedlings at -7 0 C for 1 h. A total of six SSR markers (Fhb1 markers: Xgwm389, Xgwm493 and STS256; Qfhs.ifa-5A markers: Xgwm293, Xgwm304 and Barc186) were used to genotype the populations. A chi-square analysis deviating from a 1:1 ratio showed that there were significant differences in the percentage of genotypes containing homozygous marker alleles for Fhb1 and Qfhs.ifa-5A between spring and winter types in the population ND2710/2137, ND2710/Nekota and BacUp/2137. The percentage of genotypes with homozygous marker alleles for Fhb1 was lower in the spring types in the populations ND2710/2137 and ND2710/BacUp. In contrast, the spring types in the population ND2710/Nekota had a higher percentage of genotypes containing homozygous marker alleles for Qfhs.ifa-5A compared with the winter types. The results indicated that Fhb1 was not necessarily associated with the spring growth habit; whereas, Qfhs.ifa-5A was not necessarily associated with the winter growth habit. Three SSR primers Xgwm293, Xgwm304 (Roder et al. 1998) and Xbarc186 (Song et al. 2005) linked to Qfhs.ifa-5A were used. A 15 μL PCR mixture consisted of 0.2 μM of reverse primer, 0.2 μM of 6-FAM/VIC/NED/PET-labelled forward primer, 0.2 μM of deoxynucleotide, 1.5 mM MgCl 2 , 0.25 unit Taq polymerase (Invitrogen Corp., CA) and 200 ng of template DNA. After heating the mixture to 95 0 C for 3 min, 40 cycles consisted of 94 0 C for 30 sec, 60 0 C for 1 min, 72 0 C for 1 min and a final extension of 72 0 C for 10 min. PCR products were scanned with GeneScan-500 LIZ as an internal size standard (Applied Biosystems) in an Applied Biosystems 3130xl (ABI3130xl) DNA Analyzer (Applied Biosystems) and the results were analyzed with GeneMarker software (Softgenetics, LLC.). Statistical Analysis Proc FREQ of SAS (SAS Institute 2008) was used to analyze the data for chi-square test, Chi-square was tested for the equal proportions of resistant to susceptible alleles in spring and winter types. Results Polymorphic bands were observed for SSR markers Xgwm389, Xgwm493, Xgwm293 and Xgwm304 in the four parents. Polymorphic bands were also detected for the STS3B-256 marker between each of 2137 and Nekota with ND2710 but not with BacUp ( Figs. 1 and 2) . Similarly, polymorphisms were not detected between Nekota and ND2710 for Xbarc186.