ARS | Publication request: Deployment of novel sources of Sclerotinia stalk rot resistance in sunflower

Submitted to: World Wide Web
Publication Type: Other
Publication Acceptance Date: January 12, 2011
Publication Date: January 14, 2011
Citation: Qi, L., Gulya, T.J., Block, C.C., Vick, B.A. 2011. Deployment of novel sources of Sclerotinia stalk rot resistance in sunflower. Presentation at the National Sunflower Association Research Forum, January 12-13, 2011, Fargo, ND. Available: http://www.sunflowernsa.com/research/research-forum-presentations/2011/

Interpretive Summary: Sclerotinia stalk rot, caused by Sclerotinia sclerotiorum, is a devastating disease in sunflower-growing areas worldwide. S. sclerotiorum attacks are difficult to control since there are no efficient chemical treatments for this pathogen. However, control of Sclerotinia by breeding resistant sunflower lines and hybrids now provides some relief. Sunflower wild species are an important source of genetic variation for Sclerotinia resistance. Greenhouse evaluations previously identified stalk rot resistance in wild annual species of Helianthus argophyllus, H. debilis, H. praecox, and H. petiolaris, providing us with a resource to attempt interspecific hybridization with annual species to find new QTL (quantitative trait locus). The data in this presentation include: 1) evaluation of F1 hybrids and BC1 progenies from the crosses of HA 89 with selected stalk rot resistant plants from the four wild species for their reaction to stalk rot in greenhouse trials; 2) optimization of the greenhouse method of stalk rot inoculation; and 3) investigation of the correlation between susceptibility assessed in the field and the greenhouse method. Both F1 and BC1 plants showed stalk rot resistance at a level higher than the recurrent parent and resistance check, indicating that stalk rot resistance from wild species could be readily transferred to cultivated sunflower to improve Sclerotinia resistance. The best differentiation of resistance was obtained in the soil temperature range of 21-24oC combined with 120 g of inoculated millet for one 54.6 × 34.3 × 10.2 cm tray. Positive correlations were observed in the data between the field tests and greenhouse trials. Reliable greenhouse screening techniques could make breeding and selection more efficient.

Technical Abstract: Sclerotinia stalk rot, caused by Sclerotinia sclerotiorum, is a devastating disease in sunflower-growing areas worldwide. The progress of traditional breeding for Sclerotinia resistance, which relies on incorporating genetic factors from various partially resistant breeding lines, has been very slow due to the lack of major gene resistance in germplasm sources. Sunflower wild species are an important source of genetic variation for Sclerotinia resistance. Greenhouse evaluations previously identified stalk rot resistance in wild annual species of Helianthus argophyllus, H. debilis, H. praecox, and H. petiolaris, providing us with a resource to attempt interspecific hybridization with annual species to find new QTL (quantitative trait locus). The data in this presentation include: 1) evaluation of F1 hybrids and BC1 progenies from the crosses of HA 89 with selected stalk rot resistant plants from the four wild species for their reaction to stalk rot in greenhouse.