Location: Sunflower Research
Title: Sources of resistance to sunflower diseases in a global collection of domesticated USDA plant introductions Authors
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 2, 2013
Publication Date: February 27, 2014
Citation: Talukder, Z.I., Hulke, B.S., Marek, L.F., Gulya, T.J. 2014. Sources of resistance to sunflower diseases in a global collection of domesticated USDA plant introductions. Crop Science. 54:694-705. Interpretive Summary: This work uncovered sources of genetic resistance to three major diseases of sunflower by surveying the USDA Plant Introduction collection of sunflower lines. The three diseases were Sclerotinia stalk rot, Sclerotinia head rot, and Phomopsis stem canker. Resistance to each disease requires the simultaneous action of several genes, because no single gene resistance has been identified. Among the lines surveyed, several provided resistance to one or two of the diseases, but two lines provided resistance greater than that of check varieties to all three diseases simultaneously. This data uncovered sources of resistance that sunflower breeders can use right now to improve elite sunflower lines and varieties, but this data will also be used to further genetic mapping experiments for these three types of disease resistance.
Technical Abstract: Basal stalk rot (BSR) and head rot (HR) caused by Sclerotinia sclerotiorum (Lib.) de Bary are traditionally major diseases of sunflower (Helianthus annuus L.) in the United States, while Phomopsis stem canker (PSC) caused by Phomopsis helianthi Munt.-Cvet. et. al. has increasingly become damaging in recent years. Host resistance is the most effective approach to manage these diseases. Here, we report new sources of resistance to these diseases identified in USDA sunflower Plant Introduction (PI) collection. A total of 260 PIs including USDA-ARS inbred lines were tested in multiple years and locations of North Dakota, South Dakota and Minnesota. The effects of genotype (G), environment (E), and G×E interaction were significant. Broad sense heritability (H2) for BSR, HR and PSC were estimated as 0.70, 0.79 and 0.83, respectively, reflecting a large genetic variation in the panel for these diseases. A total of 6.2, 29.6 and 36.9% of the genotypes showed significantly higher resistance against BSR, HR and PSC, respectively, than the check cultivar. Two PIs, 531389 and 531366, were significantly more resistant against all three diseases. HR disease incidence (DI) was positively correlated with PSC (r = 0.52, p < 0.0001); while it was negatively correlated with BSR (r = -0.16, p < 0.05). A total of 13 PIs, mostly from Hungary, exhibited dual resistance against HR and PSC. Overall, sufficient variation exists among germplasm sources to warrant further breeding of sunflower against BSR, HR and PSC diseases.