2010 Annual Report
Misting systems will be established and managed to create contrasting micro-climates that will be assessed to determine their ability to create conditions favorable for sclerotinia head rot infections and thus the evaluation of sunflower resistance. The contrasting micro-climates will be developed by utilizing different misting timings, misting durations, and mist intensities. The misting systems will be equipped with different emitters, spacing, and risers along with timers to achieve the different environments. Climate and plant canopy sensors tied to data loggers will be used to record the micro-climate variables. A series of known sunflowers hybrids will be planted and inoculated with ascospores in accordance with proven procedures. Assessments of head rot infection will be recorded and compared across the different misting system regimes. The different climatic data that is associated with each misting regime will evaluated to identify those conditions that best promote sclerotinia head rot infections.
Developing rapid screening field techniques for developing Sclerotinia resistance in sunflower: Incidence of Sclerotinia sclerotiorum in commercial sunflower production is a common occurrence that often results in serious loss in crop yield and quality. These disease outbreaks have resulted in frequent economic losses to both the producers and processors. The impact of Sclerotinia on the supply and quality of sunflower seed has on occasion compromised the viability of the sunflower industry. The overall objective of this project is to identify and determine resistance to Sclerotinia among commercial sunflower hybrids and germplasm used in public and private breeding programs. Achieving reliable identification of resistance or good tolerance among commercial sunflower hybrids will result in an effective tool for sunflower producers to lower their risk of infection and the associated yield and quality losses. An additional aspect of this project is to develop and refine misting systems that create the environment conducive for Sclerotinia development. This aspect will generate reproducible and reliable data that identifies genetic resistance. The experiences and data collected will also create a better understanding of the epidemiology of head rot form of Sclerotinia. The specific objectives of this project are: Evaluate commercial sunflower hybrids and experimental lines for improved resistance to Sclerotinia head rot; Implement and manage germplasm screening nurseries for USDA-ARS breeders and geneticists to evaluate sunflower germplasm and breeding lines for improved resistance to Sclerotinia head rot and stalk rot; and Refine management of Sclerotinia misting systems to improve their effectiveness in creating a micro-climate favorable for Sclerotinia infections and thereby the knowledge of Sclerotinia epidemiology. The project objectives are designed to generate new knowledge that will directly benefit sunflower producers, seed companies, and processors. In addition, information will be gained that will be useful to researchers as they work to better understand the biology of this pathogen and the environmental conditions that promote serious infections.