Evidence for enhanced resistance to diverse isolates of Pearl Millet Downy Mildew through gene pyramiding

Hash, C T and Thakur, R P and Rao, V P and Raj, A G B (2006) Evidence for enhanced resistance to diverse isolates of Pearl Millet Downy Mildew through gene pyramiding. International Sorghum and Millets Newsletter, 47. pp. 134-138.

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Breeding for downy mildew resistance in pearl millet [Pennisetum glaucum (L.) R. Br.] at ICRISAT-Patancheru in India, is currently focused on developing hybrid parental lines with resistance to one or more pathogenic variants of Sclerospora graminicola (Sacc.) Schroet. that exist in India. Resistance incorporation in inbred lines is done through conventional pedigree and bulk-pedigree selection, pure-line selection within elite inbreds originally developed by bulk-pedigree methods, backcrossing with conventional selection, and backcrossing with markerassisted selection (Hash et al. 1999). Stability of resistance to downy mildew in pearl millet inbred lines and hybrid cultivars has become elusive in India due to host-directed evolution of pathogenic variation in S. graminicola populations (Thakur et al. 1992). Average commercial life spans of popular hybrids have been reduced to only 3–5 years before they must be withdrawn due to pathogen virulence changes (Thakur et al. 2003). There are currently several pathogenic variants of S. graminicola prevalent in different parts of pearl millet growing regions of India, and new variants with higher virulence levels keep on appearing with deployment of new cultivars (Thakur et al. 2004; Pushpavathi et al. 2006). A number of quantitative trait loci (QTLs) for host plant resistance effective against one or more pathogen isolates of S. graminicola have been identified (Jones et al. 1995, Jones et al. 2002; Hash and Witcombe 2001), and resistance alleles for some of these QTLs have been transferred by marker-assisted backcrossing to elite parental lines of popular hybrids.

Item Type: Article
Subjects: Mandate crops > Millets
Depositing User: Library ICRISAT
Date Deposited: 11 Sep 2011 11:04
Last Modified: 11 Sep 2011 11:04
URI: http://oar.icrisat.org/id/eprint/1137
Official URL:
Funders: Department for International Development, United States Agency for International Development
Acknowledgement: UNSPECIFIED
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