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

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 2.35

STUDY OVER THE TIME OF BIODIVERSITY OF ITALIAN RICE CULTIVARS

R. MANTEGAZZA*, S. GALLIANO*, A. PURICELLA*, M. BILONI**, A. SPADA*

*) Università degli Studi di Milano, Dip. Biol. Sez. Bot. Gen., Via Celoria 26, 20133 Milano, Italy

**) Sa.Pi.Se Soc. Coop., Via G. Mameli 7, 13100 Vercelli, Italy

biodiversity; SSR; rice; Italian cultivars

Rice (Oryza sativa L.) has a great importance for European economy and Italy is the main rice producing country in Europe with 218.675 ha of rice fields and 1.400.000 t of paddy production (data referred to 2002).

Rice was introduced in Italy in the XV century probably by Spanish or Arabs (Piacco 1959). However, little information is available on rice cultivation up to the beginning of the XIX century. At that time new varieties, like Originario Chinese, were introduced mainly from Asian. Moreover mass selection was the main breeding method till 1925 when the first cross was attempted to improve existing cultivars.

Thereafter breeding programs among ancient Italian varieties or with newly imported germoplasm were focused on three main objectives: resistance to fungal pathogens, productivity and quality. This led to a large number of varieties: 126 are listed in 2002 national register.

In this work microsatellite (SSR) markers were used to assess genetic diversity changes in Italian rice varieties over the time. One-hundred-twenty-three Italian varieties were chosen to represent the germoplasm in the years ranging from 1800 to 2001. A total of 11 microsatellite loci were analyzed, showing 68 polymorphic alleles: 24 alleles were found in the 1800 varieties, 64 in the 2001 ones.

The allelic frequencies and the analysis of polymorphism indicated an increased level of genetic diversity over the time. This is particularly due to the introduction of new varieties from abroad and to the intensive breeding programs of the last 80 years.

By means of microsatellite markers we were able to show how biodiversity is changed in the Italian rice history: although rice was selected for positive agronomic traits, the genetic pool is still large, and new alleles were introduced during breeding programs.