On the Apple Rootstock

On the Apple Rootstock
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Horticulture is the back bone of Jammu and Kashmir’s economy. It supports around 15 lakh families and provides direct and indirect employment to approximately 50 lakh people annually. This important sector of the economy needs to be promoted and developed scientifically, by way of tapping our resources in a proper and judicious manner.
Among the temperate fruits, the cultivation of apple forms the predominated part of horticulture activity in the valley, contributing to an annual return of around 3000 crores .The low productivity of apple continues to haunt stake holders. Increase in the population and the purchasing power of people has correspondingly increased the demand for fruits. To meet the requirement, the productivity per hectare/acre has to be increased through innovative and scientific methods. Use of high density plantation, modern technology in apple cultivation can achieve this objective to a large extent.
Fortunately, from last 3 years orchardists of the valley have begun to show a keen interest in early varieties of apple and many private firms are operating in valley for HD orchard installation. But orchardists who plan for HD orchards should have basic information about the important apple rootstocks used for better yields and infestation free.
The growers in the state continue to rely on seedling method to propagate new plants and new orchards. This method has proven to be poor practice as it results in high disease probability for plants and low survival rates and as such has been discarded in all apple producing countries. The new method has been adopted worldwide uses-rootstock. The changeover to adopting of rootstock for plantation was started by the growers in Kotgarh, where the growers Association first imported the latest EMLA rootstock from Oregon, USA. Since then attempts have been reported of additional imports. However, availability of large scale reliable material and plantation techniques is largely absent. For the growth of apple production , the availability of latest rootstock and new techniques is essential.
What is root stock?
A rootstock is a plant, which already has an established, healthy root system, used for grafting a cutting or budding from another plant. The part being grafted onto the rootstock is usually called the scion. Apple rootstocks-apple tree root stock is referred to by numbers prefixed by the letters indicating the developer of the rootstock.
M: designates Malling Series developed stocks. East Malling Research station in Kent, England collected clones of the paradise stocks from France in 1912 from which 24 M were designated with no particular order to the rootstock characteristics other than where assigned. In other words, M.2 is larger tree than M.9 while M.27 is smaller than M.26.
MM: designates Malling-Merton stocks developed from joint breeding program by John Innes Institute, in Merton, England, & East mailing Research Station in the early 1950s. The MM series was developed primarily to provide resistance to Woolly Apple Aphid (Eriosomatinae) infestation.
EMLA: designates East Mailing/Long Ashton research station which took the M stock and developed virus free versions. EMLA 7 is M7 with a guaranteed virus free stock. EMLA characteristics are often different from the parent M rootstock. Note that nearly all the apple rootstocks in the industry are now virus free.
CG or G:designates Cornel-Geneva stocks which are developed via the Cornell & USDA collaboration at the New York agricultural Experiment station in Geneva ,NY. The g is the old designation. All newer stocks are CG followed by numbers that actually provide some information about the stock.
M.27 Malling 27: very dwarfing rootstock. Unless the central leader is supported, the tree will be very small. Often used as an intermediate stem piece on MM.106 or MM.111
M.9: It is also very dwarfing rootstock. It reaches a height of 8 to 10 ft. (92.4-3.0m). It grows under average soil conditions, but needs a good rich soil to thrive and is good choice where space is limited and fertility is high. Permanent staking is required, as is routine feeding and watering. Trees on this rootstock always feeding require leader support. The rootstock is very susceptible to fire blight and can develop burr knots.
G.41 Geneva 41: Released in 2005, it produces trees of size of M.9. The rootstock was developed from a cross between M.27 and Robusta 5 made in 1975. It is resistant to crown/ collar/root and fire blight.
M.26 Dwarfing: Similar to M9 in effect, although somewhat more vigorous and generally stronger , with a height of 8 to 10 ft (2.4 to 3.0). A good choice where soil quality is average and compact growth is required. Comes into fruit after 3-4 years , reaching full cropping capacity after 5-6 years. It is susceptible to collar rot and fire blight and should not be planted in a wet site.
G.11 (Geneva 11):-it is the second release of the Cornell breeding program, similar in size to M.26 (class4) but more productive. It has the advantage of being resistant to fire blight and crown rot as well as only rarely producing suckers or burr knots.
G.202 Geneva 202 (CG5202):It is semi dwarfing rootstock that produces a tree in class 5 slightly larger than M.26 ( size class 4) and is more productive than M.26
M.7 Malling 7 Rootstock: It produces a semi -dwarf tree of class 6 that is free standing in deep well drained soils. The rootstock may profusely and is susceptible to collar rot.
MM.106:It is semi-dwarfing sometimes referred to as semi-vigorous. This is the most widely used of rootstocks. Trees on MM.106 are highly susceptible to collar rot especially when planted in soil that remains wet 9 poor percolations).
M.111:.It is vigorous –not generally suitable for garden scale growing, being both too large and spreading (18-25) and too slow to come into cropping. Planting depth of this rootstock is critical. The union should be no higher than 1 to 2 inches above the final soil line.
M.25:It is very vigorous-suitable for grassed orchard, and to grow on as a full standard. Plant 20 ft. (6.1 m) apart, makes a tree of 15 to 20 ft (4.6 to 6.1) or more height and spread.
So before planting an apple orchard, proper decisions should be made on selection of varieties, rootstock, tree size, spacing, placement of pollination and planting layout.
The planting distance varies accordingly to variety, vigour of rootstock, fertility of soil and climatic conditions. In flat and valley areas, the planting is done in square or hexagonal system of layout. However, on slopes, contour or terrace planting is preferred . Top soil must be filled first followed by sub soil on the top to improve fertility of lower soil of pit. While pit filling, 40-50 kg well rotten farmyard manure and 500g of super phosphate should be mixed in soil.
In short , it is better to consult an orchard architecture or specialised scientist for the laying an orchard. Further the companies working on contract basis for HD apple orchard planting should at least have a discussion with experts, Agronomists, Pathologists, Pollination specialists, Entomologists, Pomologists, land owners, financing agencies and marketing agencies so, that in future our orchardists shall not suffer any problem and such a prosperous industry of valley will contribute more to the economy.

—The author is a Researcher, Businessman and an Employee at SKUAST-Kashmir. He can be reached at: waseembhatspn@yahoo.com