Meeting the Challenge of Yellow Rust in Cereal Crops - ICARDA

Inqilab 91 at Nowshera, Swabi and Mardan in NWFP and caused 20–30%
losses.
It is evident from the results that the yellow rust problem has different
implications in different agro-climatic zones for wheat production. Similarly,
behaviour of different rust resistance genes was also different. Furthermore,
similar genes behaved differently in different backgrounds. This might be due
to some morphological or physiological characteristics regulated by some
other genes. Yellow rust-resistant genes Yr1, Yr4, Yr5, Yr8+, Yr10, Yr15 and
Yr17 still have the potential for utilization in wheat cultivars for rust
management in Pakistan.
The new yellow rust situation prompts the need for a suitable forecasting
system and strategy for incorporation and deployment of functional and
defeated yellow rust resistant genes singly or in combination. Keeping in view
the disease forecasting and management strategies recommended by
Nagarajan (1980), gene deployment for yellow rust should be carried out
keeping the regional situation in focus to avoid culture of single-gene-based or
single genetic background genotypes on a large scale, as in the case of Attila
(Yr27). Singh, Duveiller and Huerta-Espino (2004) suggested that wheat
breeders should take immediate action to identify and promote cultivars that
have resistance to the new Yr27-virulent race to avoid losses caused by yellow
rust. At present most of the wheat varieties being grown in the region,
including Pakistan, India, Iran and Kyrgyzstan, are protected by Yr27 located
on the 2BS chromosome, and are under threat. Similarly, Stubbs (1988)
suggested continuous monitoring of the virulence spectrum and breeding for
disease resistance and evaluation of host resistance in different agro-ecological
zones. Reddy and Rao (1979), while recommending the strategy for leaf rust
gene deployment, suggested the use of resistant genes in multigene cultivars
and gene rotation in different geographical regions to avoid monoculture on a
regional basis.
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References
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Anonymous. 2002b. Agricultural Statistics of Pakistan.
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