|TALUKDER, ZAHIRUL - North Dakota State University|
|LONG, YUNMING - North Dakota State University|
Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2018
Publication Date: 6/21/2018
Citation: Qi, L.L., Talukder, Z.I., Long, Y.M., Seiler, G.J. 2018. Registration of oilseed sunflower germplasms HA-BSR2, HA-BSR3, HA-BSR4, and HA-BSR5 with resistance to sclerotinia basal stalk rot and downy mildew. Journal of Plant Registrations. https://doi.org/10.3198/jpr2017.11.0083crg.
Interpretive Summary: Basal stalk rot (BSR) and downy mildew (DM) are two fungal diseases that are major yield limiting factors in global sunflower production. The use of resistant hybrids, where available, is the most efficient and environmentally friendly means of controlling these diseases. Crop wild relatives of cultivated sunflower are highly resistant to BSR. Resistance to BSR was successfully transferred from two annual sunflower crop wild relatives into cultivated sunflower with four sunflower germplasms, HA-BSR2, HA-BSR3, HA-BSR4, and HA-BSR5 developed. These germplasm lines consistently showed high levels of BSR resistance in four years of field testing. HA-BSR2, HA-BSR3, and HA-BSR4 are also resistant to DM derived from one of the crossing parents, HA 458. These three lines represent the first germplasms to combine resistance to Sclerotinia BSR and downy mildew for sunflower breeders to develop durable resistant hybrids.
Technical Abstract: Basal stalk rot (BSR), caused by Sclerotinia Sclerotiorum (Lib.) de Bary, and downy mildew (DM), caused by Plasmopara halstedii (Farl.) Berl. & de Toni are two fungal diseases that are major yield limiting factors in global sunflower production. Four sunflower germplasms, HA-BSR2 (Reg. No. GP-346, PI 685015), HA-BSR3 (Reg. No. GP-347, PI 685016), HA-BSR4 (Reg. No. GP-348, PI 685017), and HA-BSR5 (Reg. No. GP-349, PI 685018), were developed to provide diversity for resistance to BSR and DM. HA-BSR2 is a BC2F5 derived BC2F6 oilseed sunflower maintainer line with its BSR resistance derived from the wild annual species, Helianthus petiolaris Nutt., PI 435843. HA-BSR3 to HA-BSR5 are BC2F5 derived BC2F6 oilseed sunflower maintainer lines with their BSR resistance derived from the wild annual species, H. argophyllus Torrey & Gray, PI 494573. HA-BSR2, HA-BSR3, HA-BSR4 and HA-BSR5 were tested for resistance to BSR in inoculated field nurseries across seven environments from 2012 to 2015 in North Dakota and Minnesota, and consistently showed high levels of BSR resistance across all environments. A four-year mean BSR disease incidence (DI) for HA-BSR2, HA-BSR3, HA-BSR4 and HA-BSR5 was 4.4, 3.0, 0.8, and 1.9%, respectively, compared to an average DI of 36.1% for Cargill 270 (susceptible hybrid check), 31.0% for HA 89 (recurrent parent), 19.5% for HA 441 (resistant check), and 11.6% for Croplan 305 (resistant hybrid check). Genetic analysis detected the presence of wild sunflower species chromosome segments in all four germplasm lines, which are presumably associated with BSR resistance. HA-BSR2, HA-BSR3, and HA-BSR4 are also homozygously resistant to DM that was derived from one of the parental lines HA 458. HA-BSR2, HA-BSR3, and HA-BSR4 represent the first sunflower germplasms to combine resistance against both Sclerotinia BSR and DM.