Inheritance studies on the nonhost resistance of plants would normally require interspecific crosses that suffer from sterility and abnormal segregation. Therefore, we developed the barley-Puccinia rust model system to study, using forward genetics, the specificity, number, and diversity of genes involved in nonhost resistance. We developed two mapping populations by crossing the line SusPtrit, with exceptional susceptibility to heterologous rust species, with the immune barley cultivars Vada and Cebada Capa. These two mapping populations along with the Oregon Wolfe Barley population, which showed unexpected segregation for resistance to heterologous rusts, were phenotyped with four heterologous rust fungal species. Positions of QTL conferring nonhost resistance in the three mapping populations were compared using an integrated consensus map. The results confirmed that nonhost resistance in barley to heterologous rust species is controlled by QTL with different and overlapping specificities and by an occasional contribution of an R-gene for hypersensitivity. In each population, different sets of loci were implicated in resistance. Few genes were common between the populations, suggesting a high diversity of genes conferring nonhost resistance to heterologous pathogens. These loci were significantly associated with QTL for partial resistance to the pathogen Puccinia hordei and with defense-related genes.

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Gelatinization temperature and apparent amylose content are key parameters used to describe the eating and cooking qualities of rice. Sequence variants of SSIIa and Waxy genes are important determinants of gelatinization temperature and apparent amylose content, respectively. A collection of Italian non-glutinous japonica rice accessions was characterized for sequence polymorphisms in SSIIa and Waxy genes, in comparison with non-Italian japonica and indica genotypes. For SSIIa two markers, SNP3 and SNP4, were used. A PCR amplification of multiple specific alleles protocol was developed for the identification of G/T polymorphism in 5′ splice site of first intron and A/C polymorphism in exon 6 of the Waxy gene. Based on simple allele-specific PCR, it can be proposed as a user-friendly, cost-effective tool for marker-assisted selection of amylose content. The collection was characterized also for the (CT)n repeats in exon 1 of the Waxy gene. The results showed that while SSIIa haplotypes were rather similar between Italian and non-Italian japonica rice, the Waxy gene haplotype T/A/(CT)18 was largely predominant in Italian accessions, other haplotypes, well represented in non-Italian japonica [T/A/(CT)19] and indica [e.g. G/C/(CT)20] genotypes, were present at lower frequency. Grain starch quality traits as apparent amylose content and RVA profile were also analysed. The In1/Ex6 SNP haplotypes of Wx gene were found to explain 79 % of variation in apparent amylose content, and 36, 22 and 25 %, of variation in the RVA parameters peak viscosity, breakdown and setback, respectively. The additional use of (CT)n repeats marker further improved the association of haplotypes with RVA parameters