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.
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 homozygous BC3F2 and BC4F2 plants harboring the rust resistance genes, R2, R4, and R5, respectively. These homozygous plants have been self-pollinated, and the harvested seeds were planted in the Fargo field for agronomic performance in 2012. We created F1 hybrids combining two rust resistance genes for rust R-gene pyramiding. HA-R6 is a confection line resistant to both rust races 336 and 777, the most predominant and virulent races in North America. Crosses have been made between HA-R6 and R2, R4 and R5, respectively. We have also developed DNA markers linked to rust resistance gene R11 and R12 to facilitate marker-assisted selection and R-gene pyramiding.