Assessment of designated series of genes for resistance against Indian pathogen
populations of all the three rusts and genetic basis for rust resistance in released
cultivars have revealed that several of the effective genes, mostly derived from
species related to T. aestivum, remained. unexploited. A number of these genes have
been successfully introgressed into formerly popular wheat cultivars that provided
easily usable diverse resistances for tailoring new generations of high yielding rust
resistant cultivars. Some of these stocks when employed as parents in several cross
combinations in a breeding programme have generated a number of promising
cultivars with diverse resistances. Deployment of diverse resistances in a crop
population has helped in suppressing the intensity, effectiveness and frequency of
rust epiphytotics and thus served as a buffer in checking disease spread.
It is well recognized that most resistances are eroded by the new pathogenic races
soon after the cultivar is extensively grown. Evolution of new virulences in each
of the pathogen populations as influenced by resistance genes deployed in the local
cultivars has been described.
Adult plant resistance (APR) is conferred by genes that are ineffective in seedlings
but becomes operative in adult plants. They are implicated in durability but usually
confer partial resistance. A number of cultivars both from national and international
programmes and certain near-isogenic lines carrying specific leaf-rust resistance genes
as possessing diverse sources of APR to leaf rust have been identified. A new
source Federation" 4/Kavkaz carrying novel complementry genes, seperately derived
from Federation and Kavkaz, determined adult plant resistance to leaf rust. Some
of these sources, besides Lr34/Yr18, Sr2, Sr26 and Sr31 that are recognized to confer
durable resistance, have potential to be durable. In certain cultivars Lr34 and Sr2
in combination with other specific genes have been successfully utilized for durable
resistance. A novel adult plant resistance gene associated with durability to leaf
rust in cv. Arjull has been identified.
Keywords: T. aestivum, Puccinia recondita, P. graminis, P. striiformis, Rust Genetics, Breeding durable resistance.
Article DOI: NA
Print ISSN: 0019-5200
Online ISSN: 0975-6906
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