Résumé
Soil salinization represents a threat for rice cultivation. The H2020 project NEURICE (New Commercial EUropean Rice) aimed at identifying and introducing genetic variation for salt tolerance in European rice germplasm, mainly by exploiting the positive effect of the Saltol QTL in maintaining the Na/K homeostasis. The Saltol QTL from the indica rice donor IR64-Saltol (located on chromosome 1) was introgressed into two japonica Italian varieties, Onice and Vialone Nano following a marker-assisted backcross (MABC) scheme, through three backcrosses and two selfing to achieve the BC3F4 generation. During the backcrosses, the scheme was coupled to an embryo rescue technique to fasten the process. At each backcross cycle, the foreground and background selections relied on SNP-based KASP markers. The BC3F1 selected lines showed a 91-98 and 93-98 recovery percentage for Onice and Vialone Nano backcrosses, respectively. BC3F2 lines were genotyped to identify homozygous lines at Saltol locus and the best BC3F3 lines (10 in Vialone Nano and 12 in Onice) were subjected to genotyping by sequencing (GBS) to allow a more precise screening of the recurrent parent genome. Finally, the best BC3F4 lines were subjected to field phenotyping in salinized fields on delta Po river, to in vivo assess their salt tolerance.