Post Genome Era: New Insights in Peach Genetic Improvement

Peach (Prunus persica [L.] Batsch) is the most studied stone fruit species. Large amounts of genetic and genomic resources have been developed for peach, including a high quality annotated genome sequence. With the availability of the completed DNA sequence of peach, classical genetic analyses can more accurately answer fundamental and applied questions of interest to researchers, growers and consumers. New hypotheses of disease resistance and new approaches to determining qualitative and quantitative traits can be tested. In this poster, we summarize recent research conducted by the UC Davis group concerning fruit characteristics (freestone, clingstone, yellow flesh, etc.), chilling injury symptoms (mealiness, flesh browning, flesh bleeding, etc.) and disease resistance to the brown rot pathogen, Monilinia fructicola.  These fruit quality traits were partially characterized at the molecular level. For example, these approaches associated a zinc finger (C3HC4-type RING finger) family protein, the AOX1A (alternative oxidase 1a), and two novel proteins (the TIR domain-containing ppa011763m and ppa026453m) with mealiness, flesh browning and brown rot resistance, respectively. In addition, a quantitative genomic study was conducted to determine the relationship of specific genomic variants to specific phenotypes. The effect of artificial selection on peach breeding was studied and breeding strategies were developed to take advantage of molecular genetic information for peach cultivar improvement.