Proceedings of the XLV Italian Society of Agricultural Genetics - SIGA Annual Congress

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Poster Abstract

GENETIC ENHANCEMENT OF PEARL MILLET FOR DOWNY MILDEW RESISTANCE

MALCEVSCHI A.*, BONAS CALÒ U.*, DEVOS K.**

* Sezione di Genetica e Biotecnologie Ambientali, Dipartimento di Scienze Ambientali, Università di Parma

** John Innes Centre, Norwich Research Park, Norwich (U.K.)

Pearl millet, Pennisetum glucu, downy mildew, single nucleotide polymorphism

Pearl millet (Pennisetum glucu (L.) R.Br.; 2n=2x=14) is an important crop providing the staple diet of people living in large areas of the semi-arid tropics of Africa and India, but despite its economic importance and amenability as a research organism, the genome of this crop has been little investigated. The research currently undergoing at the section of environmental genetics and biotecnologies of the Department od Environmental Sciences at the University of Parma aims at fine-mapping, isolating and characterising genes underlying downy mildew (Sclerospora graminicola) resistance, an agronomic trait affecting crop adaptability and yield.

In pearl millet two QTLs for resistance to downy mildew isolates from Niger are located on linkage groups 1 and 4. Two varieties PT 732B and P1449-2 were crossed for fine-mapping with the pathogen resistance carried by P1449-2. This population has also been screened in Ghana to assess the presence of QTL effective against Ghanaian Sclerospora graminicola isolates. The first step in fine-mapping is the identification of informative individuals, i.e.plants that carry a cross-over event in the target region. This can be done efficiently using PCR-based markers. Although RFLP markers could be identified that flanked the QTL on Lgs 1 and 4, no PCR-based markers could that displayed polymorphisms between PT 732B and P 1449-2. As far as the LG1 QTL is concerned, partial sequences corresponding to the RFLP markers were available in the pearl millet database, so efforts were focused on the development of allele-specific single nucleotide polymorphism (SNP) co-dominant markers in the mapping population. PCR products derived from the resistant and susceptible lines corresponding to the RFLP markers flanking the LG1 QTL were cloned and sequenced.The alignment of the amplified sequences allowed to identify a few SNPs between the lines allowing the identification of recombinants in the QTL region within the 800 F2 plants forming the mapping population. Seeds from informative plants have been collected and being planted for field screeening against downy mildew at the Savanna Agricultural Research Institute in Ghana, eventually QTL analysis and fine-mapping will be carried out in the last phase of the project.