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Wheat Information
Service
Number 73: 8-10 (1991)
Transfer
of leaf rust resistance from durum wheats CPAN 6051 and CPAN 6073 to
Triticum aestivum
Sanjiv Gupta, A. K. Gupta and R. G. Saini
Department of Genetics, Punjab Agricultural University,
Ludhiana-141004, India
Durum wheats are reported to carry leaf rust resistance genes which
are different from the Lr genes identified in Triticum
aestivum and very effective against highly virulent races
prevalent in the Indian sub-continent (Pasquini et al 1979; Sharma et
al 1986; Roelfs, personal communication). These genes can be used to
broaden the genetic base of leaf rust resistance in bread wheats.
Although successful transfer of genes from durum wheats have been
achieved earlier for the improvement of Triticum aestivum
(McIntosh et al 1967; McIntosh and Dyck 1975), an altered expression
of some genes due to change in ploidy level has also been reported
(Kerber 1983; Dyck 1987). We report here the transfer of resistance
from two highly resistant durums CPAN 6051 and CPAN 6073 to a
susceptible hexaploid wheat Agra Local and comparison of the
hexaploid derivatives with two commonly grown hexaploid wheats.
Cultivars CPAN 6051 and CPAN 6073 were crossed with Agra Local. The
F1s were selfed and the F2 seeds thus obtained
were sown in an open experimental area under artificial epiphytotic
of race 77A which is virulent on all the known genes from T.
aestivum. Resistant F2 plants were identified and
cytologically examined for chromosome number. A hexaploid derivative
D 525-2 was isolated from cross of cultivar CPAN 6051 with Agra Local
and D 3542-6 was from cross of CPAN 6073. The infection types on
seedlings were recorded according to the scale given by Stakman et al
(1962). The seedlings showing infection types 0;, ;, 1, 2, and X were
classified as resistant and those showing infection types 3 and 4
were considered as susceptible. The terminal disease severity was
recorded as percentage of leaf area covered with rust according to a
modification of Cobb's scale as given by Peterson et al. (1948).
The seedling reactions (infection types) of hexaploid derivatives,
the donor cultivars, susceptible parent Agra Local and two most
commonly grown cultivars HD 2329 and Sonalika against leaf rust
(Puccinia recondita Rob. ex Desm. f. sp. tritici) races 1, 108
and 77A and their field scores are given in Table1.
The infection types of hexaploid derivative D 525-2 and D 3542-6
against race 1 were ; and ; 1, respectively whereas those on CPAN
6051 and CPAN 6073 were ; 12+ and ; 1-,
respectively. The infection types against race 108 were very close to
those on durums and the derivatives. Against race 77A, the infection
type on D 3542-6 was 1-1 which was very close to its donor
parent CPAN 6073 (IT=11+) but that of D 525-2 varied from
2- to 3 which was different from that seen on its donor
parent CPAN 6051 (1+). This difference might have appeared
due to outcrossing of this derivative. Saini (1987) tested cultivar
CPAN 6051 and its derivative D 525-2 against 14 Australian leaf rust
races and identified Lr23 from D 525-2 as well as the donor
parent CPAN 6051. However, D 525-2 was segregating for Lr13.
These observation confirm outcrossing of D 525-2. Cultivar Agra
Local was susceptible to all the these races and disease severity on
Agra Local was 90S. The infection type on cultivars HD 2329 and
Sonalika against race 1 was ;1 and ;1+, respectively.
Against race 108 the infection type on seedlings of HD 2329 was ;1
but cultivar Sonalika was susceptible. Both these cultivars were
susceptible to race 77A at seedling stage.
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