Location: Sunflower and Plant Biology Research2011 Annual Report
1a. Objectives (from AD-416)
The objective of the project is to transfer an identified gene for rust (Puccinia helianthi) resistance into an acceptable confectionery sunflower genetic background and make it available to the private seed industry for incorporation into finished commercial hybrids.
1b. Approach (from AD-416)
Three known rust resistance genes, R2, R5, and Radv, will be introduced into suitable confectionery sunflower inbred lines. Sunflower line CM29 containing the R2 gene will be crossed with inbred line CONFSCL B1; line HAR-2 containing the R5 gene will also be crossed with inbred line CONFSCL B1; and line RHA 340 containing the Radv gene will be crossed with line CONFSCL R5. Both the CONFSCL B1 and CONFSCL R5 lines are confectionery sunflower inbred lines with resistance to Sclerotinia disease. The progeny of these crosses will be planted for further backcrossing in the summer 2010 season. The goal for the first year of this projected three-year project is to have the BC1 (first backcross generation) available for planting in the greenhouse in the winter of 2010-11 for production of the BC2 (second backcross generation). At each generation, the progeny will be screened for rust resistance. This should allow the development of pure inbred lines with rust resistance after only a few generations, and the lines can be released to the sunflower seed industry by 2012.
3. Progress Report
The goal of the proposed project is to transfer rust resistant genes (R2, R4, and R5) into confection sunflower breeding material. To date we have obtained the BC3 seeds of three crosses of confection sunflower with oilseed sunflower lines containing rust resistance genes: 1) CONFSCL B1 x MC29 (which harbors the R2 gene), 2) CONFSCL B1 x HA-R2 (R5 gene), and 3) CONFSCL R5 x HA-R3 (R4 gene). We have also developed DNA markers linked to rust resistance gene R4 and R5 to facilitate marker-assisted selection. From our previous survey, four USDA-released lines, HA-R6, HA-R8, RHA 397, and RHA 464 are resistant to both rust races 336, the predominant race in North America, and 777, the most virulent race currently known. The resistance in these lines is from different origins, indicating diverse genetic sources. Four mapping populations were developed for molecular characterization of new rust resistance genes in lines HA-R6, HA-R8, RHA 397, and RHA 464. A total of 870 mapped SSR markers were screened for polymorphism between resistant lines, HA-R6, HA-R8, RHA 397, and RHA 464, and the susceptible line HA 89. The results showed that 45 to 53% of the markers were polymorphic among the parental lines. These polymorphic markers will be used in the bulk segregant analysis to identify markers closely linked to the new rust resistance genes. The ADODR monitors research progress by semiannual meetings with the Cooperator's personnel and by site visits to field plot locations.