Inheritance of Crown Rust Resistance in Tall Fescue1
- D. S. Wofford and
- C. E. Watson2
Crown rust caused by Puccinia coronataCordn. is a major disease of tall fescue (Festuca arundinacea Schreb.) in the southern United States. The objectives of this study were to examine the inheritance of crown rust resistance in tall fescue and to determine if it is possible to select for crown rust resistance using a greenhouse seedling technique.
In the first experiment a six parent diallel cross was evaluated for crown rust resistance. General (GCA) and specific combining ability (SCA) were both significant sources of variation for rust resistance. Significant SCA effects indicated that there was some nonadditive gene action for rust resistance among these six parents. In most cases, resistant ✕ resistant crosses had high levels of resistance, susceptible ✕ susceptible crosses had no resistance, and resistant ✕ susceptible crosses had intermediate levels of resistance.
In the second experiment, eight cultivars of tall fescue were subjected to a single cycle of mass selection for crown rust resistance. All eight cultivars were found to have some resistance to crown rust with the Mediterranean cultivars having the highest levels of resistance. There was a wide range of variation in the realized heritabilities (0.07 to 0.52) for crown rust resistance in these cultivars. Cultivars of related origin exhibited similar heritabilities and it appeared that different populations had different gene systems controlling crown rust resistance. It appears that mass selection is an efiicient means of improving the level of rust resistance in some cultivars.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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