Approximately 800 homozygous resistant lines will be evaluated agromnomically in Abdereen in the summer of 1998. 17 BC3F1 populations were screened and 12 plants transplanted for increase in the greenhouse in the spring of 1998. These BC3F1 populations involved three cultivars and 16 resistant germplasm lines. Five previously increased BC3F2 populations were also screened and 100 resistant plants transplanted for increase in Stillwater in the spring of 1998. These 25 BC3F2 populations involved seven cultivars and 18 resistant lines.
Analysis is on going.
All 9 lines have shown multiple gene control for RWA resistance. Genetic diversity studies are planned for resistant lines to determine if these lines carry different genes for resistance. This type of analysis requires three years for development of seed necessary for each test. Field studies Previous field studies indicated that RWA feeding may have a negative effect on malting quality of RWA-resistant germplasm lines. Only agronomic data was collected because the aphids did not persist in the field at either location.