|Gulya Jr, Thomas|
Submitted to: Proceedings Sunflower Research Workshop
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2004
Publication Date: 4/1/2004
Citation: Rojas-Barros, P., Jan, C.C., Gulya Jr, T.J. 2004. Identification of powdery mildew resistance from wild sunflower species and transfer into cultivated sunflower. Proceedings Sunflower Research Workshop. Available: http://www.sunflowernsa.com/research/research-workshop/documents/176.pdf Interpretive Summary: Powdery mildew (Erysiphe cichoracearum D.C.) (PM) can cause serious economic loss in sunflower crop growing in warmer regions. Although PM resistances have been reported in sunflower, only a germplasm population with incomplete dominant genes for resistance, PM1, has been released. Wild annual Helianthus species had been reported to be tolerant and resistant to PM, and they can be readily hybridized with cultivated sunflower. Efforts to identify and transfer PM resistance found in wild annual populations during our investigations of interspecific crosses are reported here.
Technical Abstract: The PM disease reaction of 11 populations of wild annual Helianthus species and of the F1 derived from their interspecific hybridization with the susceptible line HA 89 were scored. Wild populations had a high variability in the disease reaction. H. debilis subsp. debilis and H. debilis subsp. vestitus were completely resistant to PM. This parental resistance was expressed to a high degree in the F1 plants of H. debilis subsp. debilis × HA 89, which suggests that there may be dominant or partial-dominant genes for resistance in H. debilis. subsp. debilis. PM resistant segregation observed in F1 generations evidences the heterozygosity for PM resistant genes in wild parents. The pollen viability and the F1 seed set were low, especially for the most resistance F1 plant. The low F1 pollen viability did not allow F2 seed production and also a low BC1F1 seed set. The 10-day-old embryo rescue technique aided to obtain F1 and BC1F1 plants from the most resistant F1 plants using HA 89 as the recurrent parent. The higher pollen viability observed in the BC1F1 generation suggests rapid fertility improvement with each backcross to the recurrent cultivated parent, and will allow us to self the BC1F1 plants to obtain the BC1F2 generation. BC1F2 families will be tested in the summer 2004 to determine the inheritance of PM resistance.