Rootstock research at East Malling: a history

The very first work at East Malling Research looked at the relationship between tree anatomy and vigour, and its use as a screening tool in the early rootstock selection and breeding programmes. The growth and physiology of roots were studied extensively with below ground work being carried out in the underground root laboratory. The effect of soil type and management, planting density, irrigation, pruning methods and light interception on the final crop were all studied. Types of water supply and the use grass strips and herbicide use all helped lay the foundation for modern orchard systems we have today, and this knowledge has contributed to the increases in yields and quality of many different fruit crops over the last 100 years.

Apples must be propagated clonally by grafting and for many years East Malling produced large numbers of rootstocks for the industry (in 1921 = 15,000 and by 1936 = 500,000). Work looking at the biological processes associated with root development, cutting establishment and graft union formation was undertaken as well as looking at practical considerations such as optimal environmental conditions. New, more successful Double Shield and Chip budding techniques were developed. Robert Garner, in charge of rootstock propagation produced ‘The Grafter’s Handbook’. EMLA stock and micro-propagated material also provided a reliable source of virus free rootstocks for the growers.

The Malling (M) series and Malling/Merton (MM) series (with John Innes Inst.) of rootstocks are used in virtually every part of the world where apples are grown commercially and it is estimated that 90% of apple orchards in Western Europe are grafted onto M9.

Apple rootstocks M1-M16 were released between 1912-1914, and M17-M24 in 1924. In the 1920’s the quince rootstocks QA and QC were released and became very widely used for pears as did Myrobalan Brompton and St. Julian A for plum. In the 1950’s the MM series of apple rootstocks, selected for their resistance to woolly apple aphid, as well as M25 (1952) and the semi-dwarfing M26 (1959) were released. More recent releases include the dwarfing apple rootstock M27 (1975), the plum rootstock Pixy (1977) and cherry rootstocks Colt (1977), Cob (1980) and Charger (1986).

In 2001, East Malling’s most recent rootstock selections were released: for apple M116, and for pear the quince rootstock EMH.  The crosses that produced these rootstocks were both made in the 1960’s – an indication of just how long a process it is to produce a new improved rootstock.

The East Malling Rootstock Club (EMRC) was established in 2008 and aims to deliver improved rootstocks to UK growers, with support from the Horticultural Development Company (HDC), and to overseas producers with funding provided by the International New Varieties Network (INN). Click here to read more about the current rootstock breeding programme at EMR.

To learn more about the history of East Malling Research click here

Dwarfing effect of rootstocks