Genetic characterization and preliminary fusarium resistance evaluation in historical Italian rice germplasm

The conservation of traditional rice cultivars plays a crucial role in preserving agrobiodiversity and enhancing breeding programs aimed at improving resilience to climate change and disease resistance. This study presents the preliminary molecular, and phytopathological characterization of 22 historical rice accessions traditionally cultivated in the Lombardy region (Italy), now preserved in gene banks. Genetic diversity was assessed using 20 simple sequence repeats (SSR) markers, analyzed through Principal Coordinates Analysis and the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) clustering. Results highlighted the presence of genetically distinct subpopulations and confirmed the uniqueness of traditional landraces compared to modern control cultivars. To support their sustainable reintroduction into cultivation, protocols for seed sanitation and quality control were also implemented. In addition, the study provides a preliminary evaluation of the susceptibility of nine of these accessions to Fusarium fujikuroi, one of the most harmful seed-borne fungal pathogens affecting rice, associated with bakanae disease. The subset of accessions used in susceptibility assays was dictated by seed availability and infestation by nematodes that could alter the results. Pathogenicity tests revealed significant variability in susceptibility among the cultivars. Some landraces exhibited promising tolerance to Fusarium-induced bakanae, making them valuable candidates for organic and low-input farming systems. This integrated approach enhances the valorization and conservation of Italian rice germplasm and provides a foundation for breeding programs aiming at disease resistance and sustainable agriculture.