Colt has vigorous, sturdy, erect shoots with large leaves. Induces some dwarfing and higher fruit bud production. Colt performs well in replant situations where cherries follow cherries without fumigation. Shows some resistance to Phytophthora and gopher damage, but is susceptible to crown gall, also resists bacterial canker
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Gisela®3 (USPP 16,173)
The newest Gisela®rootstock that produces a tree 35 to 40% the size of Mazzard in the East and somewhat larger in the West. A good stock for high density plantings and high tunnels. Gisela®3 has flat branch angles and does not sucker. Very productive and precocious; support is recommended.
Gisela®5 is a very precocious stock that produces a tree about 45% the size of Mazzard. It is very productive and tolerant to virus infection. The tree is open and spreading with wide branch angles. Gisela®5 produces few if any suckers. This stock is the most heavily planted Gisela®stock in Europe and has been called the “most productive” on several NC-140 test sites in the U.S. This stock does well on heavy soils and adapts to all soil types. Gisela®5 has good anchorage but support is recommended.
Gisela®6 is a semi-dwarfing stock, producing a tree that is approximately 70%-80% the size of Mazzard. The tree structure is open and round. It is early blooming and very heavy bearing. Gisela®6 has a wide soil adaptability and does well on heavy soils. It has good virus resistance and no suckering problems. Gisela®6 needs a management system designed to maintain extension growth to balance its precocity and high bloom density. Gisela®6 is well anchored but support is recommended.
Gisela®12 is a precocious, semi-dwarfing stock that produces a tree about 60% of Mazzard. The tree structure is open, spreading and stocky. Gisela®12 has wide soil adaptability and does well on heavy soils. This stock is very precocious and productive. It has good virus resistance and no suckering problems. Gisela®12 is well anchored but support is recommended.
Sweet cherries planted on Krymsk®5 are a more precocious rootstock than Mazzard or Colt, yet not as precocious as the Gisela®series. Additionally, Krymsk®5 is very tolerant of stress conditions, such as high temperature and low soil moisture. The tree size is equivalent to Gisela®6 and has good anchorage and tolerance of heavy soils. In heavy soils, significant suckers may occur. Krymsk®5 is sensitive to the pollen borne ILAR viruses. Krymsk®5 appears to be less sensitive to Bacterial Canker than Gisela®6.
Krymsk®is a promising sweet cherry rootstock having more precocity than Mazzard or Colt, yet not as precocious as the Gisela®series. Krymsk®6 has more precocity and about 10% less vigor than Krymsk®5. Krymsk®6 has tolerance to stress conditions, such as hightemperatures and low soil moisture. Krymsk®6 is well suited to varieties needing improved precocity. Fruit maturity may be advanced by 1 to 3 days relative to Mazzard. Krymsk®6 is sensitive to the pollen spread ILAR viruses and can produce many suckers in heavy soils.
Krymsk®7 is a unique rootstock for sweet cherry, showing similar precocity and vigor to Mahaleb. Cherry trees on Krymsk®7 tolerate high temperatures. Compared with Mahaleb, Krymsk®7 is more tolerant of soil moisture extremes. Krymsk®7 is well suited to varieties needing improved precocity over Colt and Mazzard. Fruit maturity may be advanced by 1 to 3 days relative to Mazzard. Krymsk®7 is not sensitive to the pollen spread ILAR viruses. It is cold hardy and stress tolerant. Krymsk®7 is adapted to a wide range of soil and growing conditions.
It is more productive than Mazzard and similar in vigor, it is compatible to sweet and tart cherry varieties, compatible with a wide range of soils. The rootstock is cold hardy, drought tolerant and has excellent anchorage with a moderate resistance to phytophthora and crown gall, has some resistance to bacterial canker.
Michigan State University