Breeding tomorrow’s trees

May 30, 2013
The Arboretum’s new tree breeder has his eye on the landscapes of the future.
Joe Rothleutner, tree improvement specialist, is in his first full growing season at the Arboretum. Rothleutner arrived at The Morton Arboretum last July to reinvigorate the New Plant Development Program, with support from the Daniel P. Haerther Charitable Trust. His mission is to spot or breed beautiful and durable new varieties of landscape trees and shrubs that can meet the challenges of a changing climate and an increasingly urbanized world.
This summer, he is crossing species of hazelnuts and other trees. Seeds and cuttings he collected last year are growing in the greenhouses. And having caught Rothleutner’s eye, trees that have been growing at the Arboretum for decades have a date with a marketing plan. His work takes him from the woods to the laboratory to the Tree Breeding Nursery on the Arboretum’s East Side.
Some of Rothleutner’s methods are ancient: tramping the Arboretum, hoping to spot useful oddities in seedlings or sprouting twigs. Others are more finicky: choosing plants with distinctive characteristics and crossing them in hope of creating hybrids that combine the best of the parents. And some are high-tech: using chemicals to switch around the components of DNA or multiply the number of chromosome sets in a cell, all in the hope of increasing variety in the offspring.
Any plant that shows star qualities will be years away from going on the market. Multiple examples will be rigorously tested for disease resistance and other important qualities over the course of several years. Then the variety will be distributed for more testing to the Arboretum’s partners in the Chicagoland Grows® New Plant Introduction Program. “We only want to release the best,” Rothleutner says.
Rothleutner is young — just 25 — but he has his eye far in the future. In the long tradition of plant improvement at the Arboretum that included such introductions as the disease-resistant Accolade™ elm, he is opening a new chapter.