Foto del docente

Elisabetta Frascaroli

Associate Professor

Department of Agricultural and Food Sciences

Academic discipline: AGR/07 Agricultural Genetics


Keywords: plant breeding methods maize and field crops tolerance abiotic stress phenotypic plasticity genetic resources

I am involved in studies regarding Agricultural Genetics. The purpose of these studies is to determine genetic bases of traits which can be useful in the frame of a sustainable agriculture. These studies presently address mainly the understanding and the exploitation of heterosis and of tolerance to stress.

My researches concern mainly one species, i.e., maize, which I have chosen both because of its great economic importance and because it is a well known model species for heterogamous crops.

Methods utilized in my research are those of classical quantitative genetics, combined with information coming from molecular genetics and genomics by means of advanced statistical tools.

Themes recently considered:
- Quantitative genetics
- Detection of loci controlling heterosis in maize
- Location of quantitative trait loci (QTL) in complex mapping populations
- Characterization of isogenic lines for heterotic QTL in maize
- Analysis of cold tolerance at germination in maize


- Genetic markers for the identification of QTL (quantitative trait loci) by means of the combination of phenotypic traits marker data in segregating populations.
- Production of ad hoc genetic materials (i.e., segreagating populations, cross of different stocks showing variability for different traits).
- Development of Near Isogenic Lines (NILs) differing for a particular genomic region of intertest.


- Heterosis, or hybrid vigour, refers to the superiority, in biomass and fertility of a hybrid compared to its inbred parents. Despite a century of investigations the genetic and the molecular bases of heterosis are still unclear. In a recently published research (Frascaroli et al. 2007), we addressed the genetic basis of heterosis in the material developed from the cross between B73 and H99 maize inbred lines. This study revealed appreciable heterosis for plant height and even a more marked heterosis for early vigour, grain yield and its component number of kernels per plant. The utilization of a suitable genetic design (a triple test cross), together with QTL detection procedures, allowed us to identify several QTL contributing to heterosis and to estimate their principal mode of action. In our material, heterosis was mainly due to allelic interaction (dominance at various levels), with non-allelic interactions (epistasis) playing a less important role. In a following research, we also studied stability of heterotic QTL when crossed with related and unrelated tester lines (Frascaroli et al., 2009). This study showed that, while QTL additive effects are quite stable with different testers, non additive QTL effects and especially overdominance can vary substantially with different testers.


An important step to identify the relevant genes underlying a QTL is the separation of the individual QTL from other segregating loci. Such a Mendelization of a QTL can be achieved by constructing near-isogenic lines (NILs), which can be characterized genetically. For some of the detected heterotic QTL, we developed NILs pairs, homozygous for contrasting alleles (Pea et al., 2009). NILs can be replicated extensively to detect small effects and can be tested in heterozygous combination by mating members of NIL pairs to each other, to the related or to unrelated inbred lines. In particular, crosses made among each couple of NILs and with the two parental lines will provide unbiased estimates of both the additive and dominance effects associated with the QTL. In case of crosses with unrelated inbred lines it is possible to assess if QTL effects are consistent in different genetic backgrounds. This information will be of a great value for marker assisted selection (MAS), which is efficient in case of QTL with stable effects. We already preliminarily evaluated these materials in order to plan their further extensive evaluation.