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

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Oral Communication Abstract - S2e

TWO ROWED AND SIX ROWED VARIETIES RESISTANT TO BARLEY LEAF STRIPE DEVELOPED USING CONVENTIONAL AND NON CONVENTIONAL (MAS) SELECTION METHODS

G. DELOGU, N. FACCINI, R. ALBERICI, GP. VALÉ

Istituto Sperimentale per la Cerealicoltura, Sezione di Fiorenzuola d’Arda, via S. Protaso 302, 29017 Fiorenzuola d’Arda (PC)

Pyrenophora graminea resistance, selection methods, new varieties

Pyrenophora graminea Ito and Kuribayashi (anamorph Drechslera graminea) is a seed-borne pathogen causing barley leaf stripe. The disease is widely distributed in most barley growing areas, where it causes serious damages and yield losses. At present disease control is focused mainly on seed dressing with a systemic fungicide, but the risk of naturally occurring resistance within the pathogen populations, together with increasing legal limitations to the use of fungicides and the development of organic farming, requires the development of new strategies for disease control. Several sources of resistance to P. graminea were reported in the literature and based on polygenic partial resistance genes or on single gene factors conferring complete resistance. To this aim we are currently applying breeding procedures to develop new varieties resistant to barley leaf stripe.

The programs started in 1987 using as source of complete resistance to P. graminea the cultivars Alpha, Tipper (two rowed type) (unknown gene) and Thibaut (six rowed type) and later the cultivar Rebelle (six rowed type). The last two genotypes both carrying Rdg2 gene. These cultivars have been crossed with susceptible advanced lines and high yielding varieties.

Since 1989 selection in F2 generation had been carried out using pedigree methods integrated by artificial infection in the field with spreader of natural population of P. graminea (cvs Perga and Express). After identifications of the ipervirulent isolate Dg2, the evaluation of resistance in the pedigree scheme, in 1990, has been modified introducing the screening in F3 generation with isolate Dg2 (Sandwich test). Recently the identification of a based marker linked the Rdg2 gene, called MWG2018, offer the possibility for the evaluation of the F2 plant visual selected in the field for agronomic characteristics. The use of different methodologies of selection applied starting from different F2 populations are presented. Practical results have been reached by integrating conventional and non conventional breeding procedure to incorporate single resistant gene as well as poligenic resistant genes.

Aiace, Auriga and Vela, are the varieties recently released for the seed companies.