Stock and scion relationship

Stock‑Scion Relationships in Roses

stock and scion relationship

M 7 rootstocks both as inter-stock and rootstock produced smaller trees with minimum tree volume and scion girth. Fig.1 shows the relative size of apple trees on. Results and Discussion. Stock-Scion Relationship in Connection With. Studies on reciprocal Grafts of Normal Plants and Plants Modified Through the Action. This varying aspect of rootstocks will influence the performance of a scion cultivar or vice versa is known as stock-scion relationship. A. Effect of.

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Troyer Citrange rootstock usually reduces fruit size in Kinnow but Karna Khatta and Sohsarkar improves it. Further, the fruits of Kinnow on Troyer Citrange are thin skinned with attractive bright orange colour having good TSS, compared to those obtained from Karna Khatta and Sohsarkar rootstocks.

stock and scion relationship

Rootstocks also affect the storage quality of the fruits. For example, the fruits produced on the dwarfing apple rootstocks have poor storage life as compared to those produced on standard rootstocks. Influence on insect-pests and disease resistance: Dwarfing apple rootstocks are susceptible to wooly apple aphid and crown gall but Malling-Merton MM series of rootstocks MM, MMMM, MMetc impart resistance against to the scion cultivar against woolly aphids.

French pear rootstock imparts resistance against fire blight disease to the scion cultivar. Old Home pear is resistant to pear decline.

Further, Mahaleb rootstock of cherry imparts resistance against buckskin virus. Similarly, a considerable variability exists in citrus rootstocks in their capacity to induce resistance against many diseases.

stock and scion relationship

For example, Sour orange is found to be highly susceptible to tristeza virus, whereas Rough lemon and Cleopatra imparts resistance against it. Citrus macrophylla is a very good rootstock for lemons because it is known to impart resistance against gummosis, the most serious disease of lemons. Poncirustrifoliata rootstock imparts resistance against trisreza virus and root rot disease.


Some rootstocks impart resistance to scion cultivar for cold tolerance. EM-IX is resistant to early winter frost, though susceptible to late winter frost. Among citrus rootstocks, trifoliate orange is considered as the hardiest rootstock to low temperature followed by sour orange and sweet orange.

Different rootstocks have been recommended for different fruit crops and even for different cultivars of the same species. Similarly, one rootstock recommended for one cultivar in a particular locality may not be suitable for same cultivar in the different locality.

Thus, selection of a proper rootstock as per scientific recommendation for different regions having different soil and climatic condition is very important, because the success or failure of a particular fruit crop in that particular locality would be decided by it. For example, Jatti khatti citrus rootstock performs well in semi-arid zones of Punjab and Rajasthan, whereas Karna khatta is suitable in Indo-Gangetic plains of Uttar Pradesh but not the others.

Myrobalam plum is highly suitable rootstock in regions of excessive soil moisture, whereas almond is most susceptible to wet conditions. Sour orange, Rangpur lime and Cleopatra mandarins are found to be resistant rootstocks for higher salt concentrations. In general, Rangpur lime has shown wider soil adaptability as compared to other citrus rootstocks. In mango, Kurukkan performs well in soils having higher salt concentrations. How does rootstock bring about dwarfing effects upon scion?

Dwarfed fruit trees have essentially the same structure and parts as do the standard trees. They carry on the same physiological processes and they respond to various stimuli similarly. The difference between a dwarfed and a standard tree lies in the manner in which various structures and, physiological processes are acted upon or manipulated.

The following mechanisms have been reported to be associated with dwarfing in different fruit crops: The dwarfing rootstocks have higher bark to wood ratio for stems and this character is used for screening dwarfing rootstocks in breeding trials.

stock and scion relationship

Further the dwarfing rootstocks had higher phloem to xylem ratio as compared to invigorating rootstocks. The roots of dwarfing rootstocks have smaller xylem vessels and lesser xylem fibers as compared to vigorous rootstocks. Limited ability to transport auxin: In dwarfing rootstocks, the basipetal transport of auxin from shoot tips toward the root system is slower as compared to vigorous rootstocks.

Higher amount of IAA indole acetic aid; a natural auxin was destroyed by shoot and root bark of various dwarfing apple rootstocks. Bark of more dwarf apple rootstocks caused higher rate of auxin destruction than bark of the less dwarf rootstock. The amount of auxin degrading depends on the amount of IAA oxidase, IAA peroxidase and phenols and perhaps some other compounds present in the phloem and cambial cells of dwarfing rootstocks.

The destruction of IAA in dwarfing rootstocks leads to limited transport of IAA to roots and this leads to poor vascular development since, auxin control cambial activity. This effects the transport of photosynthates, nutrients etc to and from roots. High auxin levels favour differentiation of xylem and low auxin levels favours differentiation of phloem.

This suggests the presence of low auxin in stems or roots of dwarfing rootstocks as the dwarfing rootstocks have thicker bark as compared to vigorous ones. The role of IAA in carbohydrate metabolism may be important in dwarfing mechanism as citrus and apple dwarfing rootstock contain more starch than vigorous ones.

Phenols inhibit plant growth by affecting the levels of auxin in plant tissue. Phenols that inhibit growth enhance oxidative decarboxylation degradation of IAA, whereas the phenols that promote growth suppresses decarboxylation of IAA. Apple bark contains phenols that have reported to be synergistic or to antagonize IAA. Therefore, the phenols are the important growth controlling compounds in the bark of as they influence synthesis and translocation of auxin in the plant.

Cytokinin supply from roots to shoots: Cytokinins are synthesized primarily in roots and are translocated through the xylem to the shoot tip where they influence shoot growth. The differences in cytokinin production play a major role in causing the effects of rootstocks on scion growth. The level of auxin that reaches the roots of the plant influences the root growth and metabolism, including the synthesis of other hormones, such as cytokinins in the roots.

The cytokinin arriving at the shoot tip then influence shoot growth, stem elongation and leaf production i. The cytokinin arriving at the shoot tips would also influence the synthesis of auxin and the amount translocated in the roots. Abscisic acid is synthesized in leaves. ABA is involved in the growth inhibition and dormancy and also is known to have an adverse affects on auxin transport.

ABA inhibits stem elongation. ABA is moved by more than one transport system or mechanism and it occurs in both xylem and phloem depending upon the site of synthesis. Higher amount of ABA in the roots, shoots and leaves have been found in dwarfing rootstocks of apple as compared to vigorous roostocks, but in some other fruits like Prunus ABA had no role. Reduction in phloem transport: When scion is on a dwarfing rootstock, the phloem transport from the leaves to root is reduced.

In apple, the movement of sorbitol the predominant photo-assimilate in apple from mature leaves to roots was greater in vigorous rootstocks as compared to dwarfing rootstocks. This is because the i dwarfing rootstocks roots are a less strong sink for assimilates have a limited capacity to make use of assimilates or ii the transport is restricted by poorer transport system across the graft union or abstraction enroute. Experiments have indicated restriction of assimilate movement downwards at the upper graft unioin of a dwarfing interstock.

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Limited root system in dwarfing rootstocks: The root system of dwarfing rootstocks is small so they have limited growth potential and they control scion growth. It has been found that the rootstocks had larger root system with vigorous scion varieties as compared to dwarfing varieties. The main objective of this study is to know about the effects of rootstocks on the scions of commercially important varieties of major fruits so that they can be exploited to increase production of such fruits.

The study is solely based on the review of relevant available materials. In early days, French Crab seedlings M. Some of the Asiatic species of apples are apomictic and breed true from seeds even when pollinated by other species. These apomictic species have been used as rootstocks for commercial apple cultivars with the hope that they might be of value in controlling tree growth, age of fruiting.

Series of Clonal Rootstocks: Mitra, enumerated numerous series of clonal rootstocks, namely: These may be; a. M 12, M Malling Merton MM series: Developed in Poland e. P 18 have considerable resistant to collar rot disease but susceptible to fire blight, whereas P 22 has dwarfing effect on scion variety.

These selections have been developed with the primary objective of winter hardiness. All of them have been able to withstand the severe Russian winter. These are developed at the Michurin College of Horticulture. Some of the rootstocks are Bud 9, Bud and Bud These are the outcome of Canadian researchers and are cold hardy, e.

Scion-Stock Interactions in Fruit Crops

Originated in Sweden, well anchored and has a good tree form. Winter hardy and vigorous one. Cross rootstocks developed in Sweden. It is dwarfing as M 26 and has advantage of easy propagation.

Pollintz 80 Pi Cross between paradise and Doucin, highly productive and easily propagated. Jork 9 J 9: Developed in Germany, selected from open-pollinated M 9 seedlings.

It is resistant to wooly aphid and is traditional rootstocks of many countries. It is used in breeding programs. It is a Geneva selection from a set of open-pollinated seedling of Malus prunifolia from Japan. These are recently developed rootstocks. In Nepal, as stated by Ranjit and Shrestha, clonal rootstocks such as M, MM and Edi Mayal are not available in all the horticultural farms and private nurseries. They also reported that most of the horticultural farms have tried to maintain the collected apple rootstock germplasm of which some Prepared by: Seedling rootstocks are the major apple rootstocks used in Nepal.

Effects of Apple Rootstocks on Scion Cultivars 2. The built in size controlling mechanism of the rootstocks affords a relatively cheap and permanent method of controlling trees within a predetermined size Mitra, Ananda, have also stated that the stomata distribution as an index for predicting the growth potential of apple rootstock has revealed that it was high in the vigorous rootstocks like M 25, MM and MM and low in the dwarfing cultivars like M 9.

In general, the trees are more vigorous on MM series clones than on M clones. M 7 rootstocks both as inter-stock and rootstock produced smaller trees with minimum tree volume and scion girth. The rootstocks effects varied widely with different cultivars. The greater suitability of M 9 and M 26 for standard cultivars and of MM and MM for spur type cultivars was confirmed Strada and Fidegheli, Highest growth was observed on plants on MM rootstocks Cepoiu and Marval, Their poor anchorage was due to brittle nature of roots rather than being shallow rooted.

One important benefit of using dwarfing rootstock is its utilization in high density planting HDP. Red Delicious Jonathan and Rymer when grafted on M 13 attend maximum girth, highest plant height, larger spread and higher plant volume. Chandal and Chauhan, reported that Starking Delicious on MM rootstock had higher stomata resistance and maximum transpiration rate whereas the minimum stomata resistance and maximum transpiration rate was recorded on M 25 rootstocks.

Similarly, the trees on Bud were larger than on Ottawa 8 and smaller than on Ottawa 11 but were less efficient than those on Ottawa 8 and on other dwarfing rootstocks like M 8, M 9, M 26, and Ottawa 3 Mitra, Precocity and flowering If the tree can be dwarfed by artificial means of an rootstock, the size of the trees can be controlled and they can be forced to be early, producing better crops Kanwar, M.

Flowering of the seedlings was hastened on M 9 and retarded on M 16 rootstock, irrespective of the influence of rootstock or interstock growth. Even the very unprecocious Northern Spy begins flowering by the fourth year on M9, when properly trained Mitra et al. Visser reported that M. One of the most striking attributes of M 9 is its capacity to induce early fruiting precocity in scion cultivars Mitra et al.

Spur leaf number and spur leaf area were both high with vigorous rootstocks, whereas, spur density was low. Golden Delicious was precocious and productive on all rootstocks with fairly uniform performance on M 7 and M 26, but was extremely variable on M 9. Spartan trees were precocious, productive and Prepared by: McIntosh performed best on M 7, being variable on M 26 and M 9. Fruit yield and Quality In a fourteen year test, the dwarfing stocks generally were more efficient than seedling in a number of cases; the more vigorous clonal rootstocks M 5, M 2, M 1, and M 16 also were more efficient than seedlings during the last five years Westwood, The spur type delicious strain produced more fruit per tree than non-spur strain like Red King Delicious with M 7 and MM but not with M 26 rootstocks.

Golden Delicious produced more fruit per tree than gold spur on all three stocks. Highest yield of spurred strains by 16 years data assessment were with MM stocks. It is generally accepted that clonal stocks are efficient producers than seedlings stocks. For this reason, more problems of graft incompatibility and fruit quality exist with pear.

In the past, the propagation by cuttings in majority of fruit trees was not successful making it imperative to resort to grafting and budding and in that case, the seed of commercial cultivars was used for raising the rootstock. Since such seedling rootstock does not impart any specific capability to the scion and efficient techniques of propagation through cuttings have developed, there is general trend in modern fruit culture toward growing cultivars on their own roots Rathore, A perusal of the available literature shows that rootstocks for pear have been used in Nepal without assessing their performances except for Quince Pyrus collerana for crown gall.

There is also little evidence to support the use of quince as an important rootstock in Nepal. Despite the lack of research findings, experience has shown that Mayal pear is extensively used as rootstocks for the oriental pear Asia Sand Pear in Nepal Khatiwada and Ghale, The recommended pear rootstocks in Nepal are Mayal seedlings and Quince Shrestha, Major effects of pear rootstocks on the scion cultivars: Tree vigor The need of dwarfing rootstocks for high density planting in pear is realized by commercial fruit growers, but satisfaction has not been achieved yet.

Approximate relative size of pear cultivars on a number of clonal and seedling rootstocks. Yields and quality In a number of rootstock trials, high yield, efficiency has been obtained in various cultivars: The fruits of both Bartlett and Anjou were higher in soluble solids than ever all others rootstocks among various quince rootstocks, EMA induced the lowest fruit acidity.

Generally, high soluble solids and acidity increase the fruit quality. Rootstocks exert more influence on acidity and firmness than on soluble solids Westwood, Yield efficiency is good on quince rootstock and on OH X F51 in high- density hedgerows. The use of Old Home as a compatible interstem for quince has consistently resulted in higher yield than when Hardy is used Westwood, Of the vigorous rootstock, P. Clonal OH X F rootstocks, however, were selected for their high-yielding potential, so they are better than unselected seedlings of the species.

Two fruit disorders related to rootstocks are hard end, caused by P. Fruit quality is generally good on quince, P.

In 6-year-old trees, the yields of Cv. Westwood reported that in general, Pyrus ussuriensis, P. Pest and disease resistant The new disease called pear decline has eliminate susceptible P. The pathogen migrates through the phloem downwards to the union.

If the rootstock is susceptible, the phloem just below the union is killed effectively girdling the trunk. Compatibility Quince and pear often are incompatible and must be double worked with a compatible interstem.

Old Home is better as an interstem than Hardy, which was used for many years. The following list of cultivars indicates compatibility with quince. Trees on quince roots need support for best performance. The root system is much branched and fibrous, but large roots are brittle and tend to break under the weight of crop and wind.

Similarly, in suckering ability, many good pear stocks tend to sucker profusely and they include Old Home, some clonal OH X F, quince, imported French, P. An ideal rootstock should be of fast growing in the nursery, having higher compatibility, long living, bearing numerous seeds in the fruits and having higher percentage of nucellar seedling Paudyal,