The Origins of the Gisela Rootstocks
Howard Sringer provides the origins of the dwarfing, Gisela, cherry rootsotcks, which are transforming English cherry production; recently described here in an article by Don Vaughan. The difference in size of trees on dwarfng compared to old cherry rootstocks is easy to see in the pictures opposite, kindly supplied by Don Vaughan.
In the late 1950's the Justus Liebig University of the town of Giessen (north of Frankfurt in Germany) decided that they would create a department responsible for fruit breeding. Accordingly, in 1960, a Dr. Werner Gruppe was employed and it was left to him what project he should undertake.
So Dr. Gruppe sat in his office and thought about a worthwhile task. Looking out of his office window, he gazed upon the serried rows of closely spaced apple trees on M9 rootstock and he realised that his primary task was to breed a rootstock, which would enable sweet cherries to be grown in like manner. In those days, no-one had succeeded in breeding such a dwarfing rootstock. Accordingly he hired an assistant, Dr. Hanna Schmidt to help him think about the problems ahead. He decided to use the Prunus avium, the wild sweet cherry, as one partner, because that would make it easier to produce a compatible hybrid and to cross it with a whole range of dwarf Prunus species.
In all, 6000 crosses were made between various dwarf species and the resultant seedlings evaluated for graft compatibility, dwarfing ability and health status with a select group of cultivated sweet cherries.
The most promising of these was a cross with Prunus canescens and eventually one or two selections were chosen for extensive trial with several cultivars. Two of these proved the most worthy, these were the stocks labelled 248/1 and 248/2, which were named Gisela 6 and Gisela 5 respectively. Gisela 5 was the more dwarfing, about half the tree volume of Colt rootstock, which was, at that time, the standard, but cropped as heavily, and Gisela 6 was as vigorous as Colt but gave twice the crop and was more regular in bearing. Although Gisela is a girl's name in Germany, it actually stands for GIiessen's SELection for prunus Avium.
Oddly enough, when that research project was over, the university board decided that they no longer wanted to continue funding breeding projects, so Dr. Gruppe was given a pension and switched from talented scientist to business man. He made himself Head Licensee of the new rootstocks, founded a company, Gisela Inc in the USA to carry out more trials of his rootstocks and he now profits by getting royalties from all the nurserymen in many parts of the world who applied for propagation rights. Gisela 5 is now planted in large quantities in many countries, lately, one reads that growers in Turkey are planning to plant 40,000 trees on Gisela 5 this year!
Since his days at Giessen, other dwarfing cherry rootstocks have been bred, but Gisela 5 remains by far the most popular.
Howard Stringer
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