Identification of Sources of Resistance to Common Root Rot in Wheat-Alien Amphiploid and Chromosome Substitution Lines
- Robert L. Conner ,
- D. P. Whelan and
- Malcolm MacDonald
Current hard red spring wheat (Triticum aestivum L. em Thell.) cultivars have only a moderate level of resistance to common root rot caused by Cochliobolus sativus (Ito and Knrib.) Dreschl. ex Dastar. The objective of this study was to determine if wheat-alien amphiploid and chromosome substitution lines derived from Aegilops squarrosa L. and Agropyron species could be used as new sources of root rot resistance. A series of greenhouse studies established that Agrotana, a wheat-A. trichophorum amphiploid, carried resistance to common root rot. Tests of the chromosome substitution series for the D genome in the winter wheat cultivar Winalta by chromosomes 1 to 7 of Ae. squarrosa demonstrated that the substitutions had no consistent effect on disease severity. Similarly, substitutions of chromosomes 4D, 5D, and 6D of Winalta by homoeologons chromosomes from A. elongatum and chromosome 4B for chromosome 4 from A. intermedium had no effect on root rot severity. Isolations from the subcrown internodeshowed that Agrotana had a significantly lower percentage of plants infected with C. sativus than did other exotic lines and common wheat cultivars, suggesting that it might have a different resistance mechanism against common root rot.
Copyright © 1989.