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Wheat Information Service
Number 93: 35-37 (2001)
Research information
New germplasm of durum wheat with stem rust
resistance
A. N. Mishra, H. N. Pandey, Kamini Kaushal, P. K. Varma and
R. S. Thakur
Indian Agricultural Research Institute, Regional Wheat Research
Station, Indore 452 001, India
Lack of stable resistance to stem rust is the major limiting factor
to develop durum wheat cultivars with high yielding potential in
India. One of the reasons for this instability seems to be resulted
from a narrow genetic base for stem rust resistance in CIMMYT
germplasm (Singh et al. 1992) used for durum wheat improvement in
India. There are relatively few reports on stem rust resistance in
durum wheats outside the CIMMYT germplasm (Mishra et al. 1989a, b;
Pandey and Rao 1989; Hare 1997). Hence, it is important to identify
new germplasm for breeding of durums with resistance to stem rust.
The present communication reports five new genetic stocks of durum
wheat with stem rust resistance; ED 2398-A, HG 110, B 662, IWP 5019
and Line 1172 (Table 1). These lines showed
high levels of field resistance to all of the important Indian stem
rust pathotypes at Indore during 1997-2000 with artificial
inoculation (Table 2). They also exhibit
good levels of leaf rust resistance as well, excepting Line 1172
(Table 2).
Seedling response to 16 important Indian stem rust pathotypes were
also evaluated along with suitable cheeks at 18-27C (temperatures
mostly ranging between 20-25C) using standard glasshouse procedures
(Stakman et al. 1962). While B 662 was resistant to all the test
pathotypes, others showed differential interaction (Table
3). Thus, the resistance of B 662 is effective throughout the
plant life, whereas part of the resistance component of the other
lines is expressed only in adult plants (Table
2 and Table 3). The stem rust
resistance base of Indian durum wheats comprises mostly of
Sr9e and few other genes like Sr11 or Sr7b
(Directorate of Wheat Research 1999). Presence of additional genes in
the germplasm under report is apparent from their resistance to stem
rust pathotypes 40A and 40-1, to which all the three aforesaid
Sr genes are susceptible. Furthermore, these pathotypes are
generally virulent to bread wheat cultivars too. Although nothing is
known of the occurrence of any of the designated Sr genes in
these lines, differences in their seedling response to various stem
rust pathotypes indicate that they carry different genes for stem
rust resistance (Table 4). Genetic studies
are in progress to determine the number and allelic relationship of
these genes.
Acknowledgments
We are grateful to the Head, Directorate of Wheat Research,
Regional Station, Flowerdale, Shimla, for supplying the nucleus
inoculum of rust pathotypes. Thanks are due to Mr. Jagdish for
helping with the glasshouse and field studies.
E-mail: iariindore@sancharnet.in
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