8th INTERNATIONAL WHEAT CONFERENCE

markers indicates the absence of the gene). Twenty-one accessions (1.2%) showed moderate
resistance (MR) in Kenya and another 52 accessions (3.2%) showed a discernable
level of resistance (“M”, lower infection type, lower severity) compared to susceptible
checks. Based on the amplification of DNA marker for Sr2 eighteen of theses accessions
may carry the S2 gene. Overall, there was a tendency for a higher proportion of accessions
with some resistance (R, MR, M) originating from Ethiopia (7.2%) and Iran (4.6%)
and from some countries in Southern Europe (7.5%) (Bosnia and Herzegovina, Greece,
Macedonia, Montenegro, Serbia, Portugal) compared to accessions from South America
(1.1%) and Western Asia (2.4%). However, these differences were non-significant based
on overlap of the 95% binomial confidence intervals due to the relatively small sample
sizes.
Work continues to screen the remainder of the NSGC spring landrace accessions. Since
many landrace accessions are heterogeneous, single plant selections have been derived
from resistant accessions and are being re-tested for resistance. Resistant selections, including
PI 436493, are being used in bi-parental crosses to establish the inheritance of
the resistance.
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