Addressing the molecular bases of heterosis in maize (Zea mays L.)

Heterosis is widely exploited in agriculture for the production of high-performing hybrid varieties. However, its genetic and molecular bases still remain unknown. In my PhD thesis I report the results of experiments carried out for contributing to a deeper understanding of the transcriptional mechanisms underlying heterosis in maize. Data are reported in the form of full paper manuscripts. The first manuscript deals with a genome-wide comparison of gene expression in immature ears carried out using cDNA microarray technology on two inbred lines and their heterotic hybrid. The second manuscript reports the expression analysis of intra-specific non-shared genes from large allelic genome segments between two different maize inbred lines, conducted during an 8-months stage in the lab of Antoni Rafalski at DuPont Experimental Station (Wilmington, DE, USA). Finally, results of allele specific expression analysis assessing the relative amount of parental-specific allele transcripts in different tissues within a heterotic maize hybrid are reported in the last manuscript.