The CORETTE® series: the new early and dwarfing rootstocks from MSU

09 Jun 2023
2970

From the cherry breeding conducted by Amy Iezzoni, professor emeritus at Michigan State University, five new dwarfing and early rootstocks have recently been commercially released: the Corette® series. All five rootstocks significantly reduce the size of the tree compared to standard rootstocks and entry into production occurs within the third year, two years earlier than traditional planting systems. These rootstocks have completed the experimentation phase in the USA both for sweet cherry, in very high density wall planting systems, and for sour cherries, using a high density production system and mechanized harvesting above the row.

The main characteristics of the Corette® series rootstocks are reported below (Iezzoni, 2022).

Cass (Corette® 1)

Dwarfing, precocity-inducing, clonal rootstock for cherry.

Origin: Michigan State University, East Lansing, by A. Iezzoni. Hybrid of unknown complexity involving Prunus avium, P. cerasus, and P. fruticosa. USPP 30,553; 4 June 2019.

Plant: vigor weak; branching habit spreading.

Rootstock performance: induces reduced vigor and increased precocity compared to trees budded on mazzard seedling rootstocks; vigor lower than Gisela® 5; grafted plants tend to produce root suckers; exhibits moderate sensitivity to high soil pH.

Clare (Corette® 2)

Dwarfing, precocity-inducing, clonal rootstock for cherry.

Origin: Michigan State University, East Lansing, by A. Iezzoni. Hybrid of unknown complexity involving P. avium, P. cerasus, and P. fruticosa. USPP 32,852; 2 Mar. 2021.

Plant: vigor weak; branching habit spreading.

Rootstock performance: induces reduced vigor and increased precocity compared to trees budded on mazzard seedling rootstocks; vigor lower than Gisela® 5; grafted plants tend to produce root suckers.

Clinton (Corette® 3)

Dwarfing, precocity-inducing, clonal rootstock for cherry.

Origin: Michigan State University, East Lansing, by A. Iezzoni. (P. cerasus × P. canescens) O.P. USPP 30,538; 28 May 2019.

Plant: vigor weak; branching habit spreading.

Rootstock performance: induces reduced vigor and increased precocity compared to trees budded on mazzard seedling rootstocks; vigor similar to Gisela® 5; grafted plants produce no root suckers.

Crawford (Corette® 4)

Dwarfing, precocity-inducing, clonal rootstock for cherry.

Origin: Michigan State University, East Lansing, by A. Iezzoni. P. cerasus × (P. cerasus × P. canescens). USPP 30,473; 7 May 2019.

Plant: vigor weak; branching habit spreading.

Rootstock performance: induces reduced vigor and increased precocity compared to trees budded on mazzard seedling rootstocks; vigor similar to Gisela® 5; grafted plants produce no root suckers.

Lake (Corette® 5)

Clonal rootstock for cherry.

Origin: Michigan State University, East Lansing, by A. Iezzoni. Hybrid of unknown complexity including P. avium and P. fruticosa. USPP 32,813; 16 Feb. 2021.

Plant: vigor weak; branching habit spreading.

Rootstock performance: induces reduced vigor and increased precocity compared to trees budded on mazzard seedling rootstocks; vigor lower than Gisela® 5; grafted plants tend to produce root suckers; exhibits tolerance to water stress compared to Gisela® 5.

Learn more

Bibliography

L. Long, G. Lang, C. Kaiser (2020). Sweet Cherry. CABI Books

A. Iezzoni (2022). Cherry Rootstocks. Register of New Fruit and Nut Cultivars List 51. HORTSCIENCE


Cherry Times - All rights reserved

What to read next

MAP technology and refrigeration: how to preserve cherries after harvest

Post-harvest​

17 Jun 2025

Cherries stay fresher after harvest thanks to MAP technology and refrigeration. A study from Hunan University (China) highlights benefits for fruit quality, extended shelf life, reduced losses, and precise control of humidity, temperature, and microbial growth during storage.

Chile hit by bad weather, estimated 30% loss on early varieties

Press review

07 Nov 2023

In an interview with La Tribuna, Jorge Valenzuela, president of the fruit growers' federation Fedefruta, said that the rains caused losses in early varieties and left growers struggling with waterlogged soil.

In evidenza

How to prevent fruit cracking in Mediterranean orchards with advanced sensing

Tech management

01 Dec 2025

Fruit cracking leads to significant economic losses in Mediterranean orchards. Advanced sensing technologies and precision agriculture now allow growers to detect early stress signals, reduce fruit splitting, improve resource efficiency and enhance overall crop sustainability.

Self-care or failed responsibility? Cherry harvest reveals workplace safety gaps

Tech management

01 Dec 2025

Cherry season exposes the limits of self-care as a safety model. Is it a personal duty or a sign of poor risk management? When risks increase, only structured systems—not individual willpower—can ensure health and safety for all workers in the field.

Tag Popolari