Screening and Evaluation of New Rootstocks with Resistance to Phytophthora cinnamomi

Ultimately, the control of Phytophthora root rot (PRR) of avocado will be accomplished with resistant rootstocks. Our goal is to find rootstocks that will eliminate Phytophthora cinnamomi as a serious pathogen on avocado. Our ability to find such rootstocks has been enhanced as a result of our breeding blocks where we focus on crossing already resistant rootstocks. Our objectives over the life of this project have been to collect, select, breed and develop avocado germplasm that exhibits resistance to Phytophthora root rot of avocado. This project has already produced several new tolerant rootstocks (Zentmyer, Uzi, and Steddom), which are greatly improving the yields of avocado on land infested with Phytophthora cinnamomi. The Office of Research is currently processing these rootstocks for release.