Submitted to: American Oat Workers Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 7/27/1998
Publication Date: N/A
Technical Abstract: The overall objective of this research is to identify molecular (RFLP, AFLP) markers associated with genes for crown rust partial resistance in oat to be able to transfer these genes to elite germplasm using marker assisted selection. A population of 158 F6:8 recombinant inbred lines (RILs) derived from a cross between MN841801, a partially resistant line, and Noble, a susceptible cultivar, were evaluated for their resistance to oat crown rust in 1997 and 1998 in both greenhouse and field tests. In the greenhouse experiments, a single rust isolate MNB236 was chosen based on its virulence to the parents in the seedling stage and used to inoculate the flag leaf at the floret emergence stage. The pustule numbers per leaf area were hand-counted every 2 days for 5 dates starting from 12 days after inoculation. Digital pictures of the inoculated leaves were taken for image analysis of pustule numbers per leaf area, percentage of diseased area vs. total leaf area, and pustule size. For the field experiments, a natural crown rust population was used to inoculate adult plants at floret emergence and a computer simulated scale was used as a reference to read the percentage of diseased area vs. total leaf area. The number of pustules per leaf area obtained by digital image analysis and by hand counting matched well, the correlation coefficient was 0.91. The values for the different progeny lines for the area under the disease progress curve (AUDPC) from the greenhouse test had the same patterns as those from the field. Tests of selected RILs with four other isolates gave no indication of race specificity in the resistance responses. Restriction enzymes BamHI,DraI,EcoRI,EcoRV and HindIII are being used to survey parents and progeny for RFLP polymorphisms for marker analysis.