Final Report Summary - YIELD (Is there a limit to yield?) Is there a limit to yield?Plant breeders are challenged with sustaining global crop improvements. Is there a limit to crop yield? This project addressed this central question using tomato as a model crop. By integrating a broad germplasm base of wild species introgressions, mutants and a large tomato core collection combined with deep genotyping and phenotyping we identified genes and QTL that regulate crop productivity and quality. To implement these tools in the breeding of competitive F1 hybrids we developed new elite parental lines into which all discovered traits were introduced. Below are a few examples of our strategy: 1) We exploited tomato mutations of genes in the ‘florigen activation complex’ to modify plant architecture in the field and improve yield via single gene heterosis. 2) By accessing a collection of 350 sequenced cultivated genotypes it became possible to better understand the reasons for the poor flavor in modern commercial varieties and provide the information necessary for recovery of good flavor through molecular breeding. 3) We identified mutations in the strigolactone synthesis pathway, which confer resistance to tomatoes against the holo-parasitic plant Orobanche, or Broomrape. Hybrids grafted on these rootstocks are already grown in commercial fields in Israel and provide a healthy alternative to the cocktails of herbicides presently in use. The project was executed by a dedicated team of six graduate students who are finishing up their thesis work in 2017 - all are planning to find positions in breeding companies. We also conducted a 4-day international workshop that highlighted modern breeding concepts and methods that will hopefully lead the way to increased productivity of crops that are important for global food security.
