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Wheat Information Service
Number 93: 19-21 (200 1)
Research article
Effectiveness of Triticum tauschii
(Aegilops squarrosa) derived Lr genes in conferring
resistance to Indian on races of leaf rust (Puccinia
recondita tritici) of wheat
R K. Goel and R. G. Saini
Department of Genetics and Biotechnology, Punjab Agricultural
University, Ludhiana-141 004 (Punjab) India
Summary
Effectiveness of nine Triticum tauschii (syn. Aegilops
squarrosa) derived Lr genes in conferring resistance to
nine prevalent leaf rust (Puccinia recondita tritici) races at
the seedling stage in the glass-house and against the most virulent
Indian race 77-5 (known to attack all the Lr genes originating
from T. aestivum) at the adult stage in the field was studied.
Lr22b was ineffective while Lr41 was effective against
all the races tested at the seedling and adult stage. Lr38
behaved differentially while Lr42 showed susceptibility
against race 104-2 only. Lr21, Lr22a and Lr43 appeared
to confer adult plant resistance against race 77-5. Potential of
these alien genes in exploiting diverse resistance for strategic use
in wheat breeding is discussed.
Key words: Triticum, Aegilops, leaf rust, resistance,
Puccinia recondita
Introduction
Leaf rust caused by Puccinia recondita Rob . ex Desm. f .
sp.tritici Eriks and Henn. is a common disease of wheat,
Triticum aestivum L. in India. Breeding for disease resistance
in this crop is almost synonymous with breeding for leaf rust
resistance in all the regions in India. Genetic studies have led to
the naming of nearly 45 leaf rust resistance genes (Lr genes)
globally (McIntosh et al. 1995; Singh et al, 1998). The spread of
many leaf rust pathotypes showing combined virulence for the most
commonly occurring genes Lr23 and Lr26 in Indian
cultivars resulted in the susceptibility of several commercial wheat
cultivars (Nayar et al. 1994). This has necessitated search for new
sources of resistance to leaf rust effective against Indian
races.
According to Kerber and Dyck (1979), Aegilops squarrosa being
a donor of D genome to hexaploid wheat, the transfer of leaf rust
resistance from this diploid progenitor to hexaploid wheat is
relatively easier and also permits selection against deleterious
genes closely linked with the resistance genes. The present report
analyzes the effectiveness of several Lr genes transferred
from Asian goat grass, Triticum tauschii (syn. Aegilops
squarrosa) to common wheat (Cox et al. 1994) against the
pathotypes prevalent in different wheat growing regions in India.
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