Trabajo presentado en el International Wheat Innovation Workshop, celebrado en Clermont-Ferrand (France) el 16 y 17 de noviembre de 2015.The tetraploid wheat relative
Triticum turgidum
ssp.
dicoccum
shows particular promises as a
donor of useful genetic variation for several traits including disease resistances to be
introgressed in cultivated wheat.
The accession MG5323 of ssp.
dicoccum, which showed useful
level of resistance to leaf rust and powdery mildew diseases, was crossed with the susceptible
durum wheat cultivar Latino. A total of 110 recombinant inbred lines (RILs) were produced and a
high resolution linkage map was developed based
on the 90K Infinium (Illumina). The parents
and RIL population were phenotyped using two
Puccinia triticina
(VMC03 and 12766) and one
Blumeria graminis
(O2) isolates. Quantitative trait loci (QTL) analysis led to the identification of
one major resistance gene conferring resistance to
leaf rust on the short arm of chromosome 1B,
explaining a total phenotypic variation ranging from 41.4 to 49.5%. Two additional minor
resistance genes located on chromosome 7B explained a phenotypic variation ranging between
17.8 and 25.8%. For both QTLs the resistant allele was provided by MG5323. A significant
positive epistatic effect was detected between QTLs
, indicating that different QTLs contribute
different degrees of resistance. Moreover, analys
is of the leaf rust responses of the RILs
demonstrated complementary actions between genes on chromosomes 1B and 7B. Analysis of
powdery mildew resistance identified a single
dominant gene on the short arm of chromosome
2B explaining 78.7% of total phenotypic variation. MG5323 provided the resistant allele at the
QTL. A fine mapping approach of the major
genes for both diseases was undertaken by
developing a large F2-based high resolution mapping population and the flanking and peak
markers were used to select a number of recombinant lines that are currently under phenotypic
evaluation. The closest linked markers have been converted into PCR-based markers and are
suitable for marker assisted selection (MAS) in resistance breeding.N