Ochoa, V., Madrid, E., Said, M., Rubiales, D., Cabrera, A.
EUPHYTICA
201:
89-95,
2015
Keywords:
Common wheat, Agropyron cristatum, Introgression, Leaf rust, FISH, GISH, SSR markers
Abstract:
Crested wheatgrass (Agropyron cristatum
L. Gaertn.) is a perennial species of economic importance
as forage that also displays potentially valuable
traits for wheat improvement trough intergeneric
hybridization. In order to incorporate resistance genes
from A. cristatum against wheat leaf rust (Puccinia
triticina Erikss.) into common wheat (Triticum aestivum
L.) a breeding programme was carried out by
crossing and backcrossing the self-fertile amphiploid
AABBDDPP (2n = 8x = 56) with T. aestivum
(2n = 6x = 42; AABBDD). The AABBDDPP
amphiploid was previously obtained by crossing
tetraploid wheat (Triticum turgidum L. conv. durum
Desf. 2n = 4x = 28; AABB) with a self-fertile
allotetraploid (2n = 4x = 28;DDPP) between diploid
wheat (Aegilops tauschii Coss.) and crested wheatgrass
(A. cristatum). After three backcrosses a fertile stable
line (named TH4) was obtained with 42 chromosomes.
The fluorescence in situ hybridization and GISH
analysis confirmed that TH4 carries a compensating
robertsonian translocation involving the long arm of
wheat chromosome 1B and the short arm of an
unidentified A. cristatum chromosome. Specific
molecular markers from A. cristatum also demonstrated
the presence of chromatin from this species in
the TH4 line. Macroscopic and microscopic observations
indicated that the A. cristatum fragment that has
been transferred to common wheat contributed a
substantial level of partial resistance to leaf rust. The
A. cristatum translocation line in bread wheat makes
the disease resistance gene(s) from A. cristatum
accessible for wheat breeding programmes.
Fulltext: contact IEB authors
IEB authors: Mahmoud Said
