Clonal Rootstocks: High Density Plantation

In my previous post on Apple Rootstocks I discussed about advantage of clonal rootstocks. These stocks though have genetic similarity is bound to react similarly to the scion wood. Thus we can visualize the final product and can make a blue print of our production unit. Most of us call horticulture an industry, but how many of us understand that in any of the industry we first calculate the production and then inputs and then we decide about whether to produce or not. Whereas in horticulture as an industry how many of us calculate our production, or visualize the quality or critically decide about critical inputs? Even then this industry is giving us lot of remuneration this means even we are doing horticulture without planning it is giving us the upward growth, what it can do if we plan it properly.

There are number of clonal rootstocks around the world. There are some popular rootstocks like M9, MM106, MM 111, 793, M7, M26, Bud -9, and so on.

M9

World over this rootstock having dwarfing effect is appropriate for dense planting methods. Its use is recommended with the varieties of vigorous development, Fuji, Gala etc. Around the world it has been proven to be the most stable in preciosity, performance and production rootstock with very satisfying tolerance to  Phytophthora disease.  This rootstock requires support for the development of plantation and it is the most widespread and popular rootstock worldwide. Its combination with the varieties of the Red Delicious is not advised.

M26

A very popular rootstock in Greece. It produces trees 65% more vigorous compared to seedling apple tree. It forms the perfect combination with the Red Delicious varieties in every type of orchard planting. It requires careful actions as to accomplish a successful production every year. The quality of the produced product is regarded very nice. Avoid combining it with varieties like Fuji, Gala, Johnagold etc. Along with the variety Granny Smith a good combination is achieved.

MM106

This rootstock is particularly sensitive towards the Phytophthora fungus. It should be avoided in  intensive planting . Its use in moist soil, watered with inclination and in soil which had been previously replanted with apple trees would not be wise. Its products are relatively small so the careful thinning down is demanded. It has a fairly developed rooting system, hence its trees do not require any support.

MM111

This rootstock coordinates very well with the Red Delicious varieties. Its basic characteristic and its advantage over the MM106, is the tolerance towards the soil borne fungus Phytophthora sp. This is the apparent reason why, the use of this rootstock, and not of the MM106, is recommended.

In coming posts I shall be discussing about Planting systems in apple.

Apple Tree Diseases: Monitored Sprays for Apple Scab

This post is in continuation to my previous post on Apple Diseases:Holistic Management of Apple Scab. Here we are going to discuss about Monitored spray control

There are two spray strategies for controlling the diseases i.e. preventive and curative. Since this disease is a polycyclic, the spray schedule should focus on reduction of inoculum and protective covering before the infection takes place based on the predictive models developed at RHRTS Mashobra.

Monitored Spray control:           
 Among two different monitored spray strategies (curative and eradicative) as developed and tried in the orchards, the curative sprays with well timed application of Ergosterol-biosynthesis-inhibiting (EBI) fungicides even after 72 and 96 hour of the predicted infection periods is not only more effective but also economical for control the disease with three lesser sprays.

Av Temp (oC)	Minimum wetness (hr)		Scab appear (days)
	Ascospores	Conidia
17.2-23.8	9.0	5.9	9
13.8-11.0	11.0	7.5	15
10.5-8.5	15.0	9.8	17

The monitored spray programme developed for Indian conditions at Regional Horticultural Research and Training Station, Mashobra, Shimla for the control of spring and summer scab conditions is described below. This strategy is recommended to orchard areas where scab is present.

First Spray:

At green tip stage if scab during last three years was present and temperature after rains remained above 10^oC. The spray strategy to control primary scab must include high residue fungicides for better protective action for longer duration. The strong bio-efficacy of dodine, mancozeb, dithianon, and captan is established on apple parts. The residues of these fungicides are persistent, stable and re-distributive on the foliage and remain effective against primary infection up to 36 days. Hence recommended at green tip stage as first spray under monitored control program in Himachal Pradesh.

Second Spray:

Second spray at pink bud stage is recommended to give protective coverage on plant parts to control primary scab infection during the long flowering session. However, according to monitored spray strategy, this spray is considered to be optional and should be given only if first spray is not given or continuous wet conditions prevailed after the first spray. The fungicides recommended at this stage are both protective as well as curative. However, it is also observed that at high altitude locations (above 6500 ft) where primary infection generally initiates after pink bud stage the first spray at green tip stage is inappropriate. Benzimidazole and EBI fungicides having protective/ curative and broad-spectrum mode of action is recommended for such locations at pink bud stage (as first spray) to control invisible infection caused by apple scab, canker fungi, powdery mildew, core rot and leaf blotch. However, the sensitive flowering stage is avoided for any spray as might obstruct the cross-pollination process.

Criteria for sprays:

In addition to its anti-fungal properties it also help in improving fruit set and can be used safely during bloom.

Third Spray:

Third spray at petal fall stage is very essential to protect the newly emerged fruit-lets against primary scab and powdery mildew infections. Moreover, the earlier sprays given either through first spray or at pink bud stage are found ineffective all through the long flowering period of apple. The brands of benzimidazole and EBI are recommended at this stage also having both protective curative and anti-sporulant actions. This group of fungicides is effective to other summer diseases as well and also acts as anti-senescent and increased fruit set.

Fruit Development Spray:

At fruit development stage the actual monitored spray strategy implies where curative fungicide sprays are recommended after the infection period instead of routine sprays. There are three options of sprays and type of fungicides use according to the prevailing weather and scab conditions in the orchards.

Most effective option of curative (EBI) fungicides is to kill the fungus in host tissues after the infection has occurred. However, the fruit development sprays can be extended for longer duration or discontinue in case there is no visible scab on leaves and fruits out of primary infection. This can also be ascertained by the overall scab records in the last three years and no primary symptoms have appeared till date in the current period.

Dormant spray:

Dormant sprays of 5 per cent urea a foliar nitrogenous fertilizer at leaves shedding stage and followed by a spray of Bordeaux mixture (1%) are most effective IDM strategy used to eradicate the most overwintering pathogen/diseases on apples.

In coming posts I shall be discussing about the cankers.

Apple Tree Diseases: Holistic Management of Apple Scab

Reduction of Primary Inoculum:

The primary inoculum of the disease resides in the infected leaves fallen on the orchard floor. These lesions develop into pseudothecia that further develop ascospores that got released in coming spring season and cause primary infection. To reduce the primary infection primary inoculums should be reduced. Thus phytosanitation plays an important role in reducing the primary inoculum. During Oct Nov when 80 per cent leaves have fallen the leaves either should be collected with the help of rake or should be sprayed with 5 percent urea solution. The spray should be directed on orchard floor rather than on the trees. As the nitrogen concentration of 5 percent is required to decompose the fallen leaves that is containing the scab infection and harbouring the fungus for the development of pseudothecia. Since it will decompose faster than the pseudothecia development thereby reducing the primary inoculum of the disease.

Modification of environment:

The disease development requires leaf wetness. The wetness is always affected by relative humidity. Means more the relative humidity slower will be the drying time thus increasing the leaf wetness period. Longer will be the leaf wetness period more severe disease will appear in the orchard. This situation warrants for better sun penetration and air circulation. If we avoid dense canopy and follow proper training and pruning practices we can improve the air circulation and light penetration thereby reducing the chances of scab to appear in the orchard.

Monitored spray control:

             There are two different strategies (curative and eradicative) for monitored sprays, the curative sprays with well timed application of Ergosterol-biosynthesis-inhibiting (EBI) fungicides even after 72 and 96 hour of the predicted infection periods is not only more effective but also economical for control the disease with three lesser sprays.

In coming posts we shall be discussing about the monitored sprays....

Apple Tree: Training Systems in Intensive Apple Cultivation: Vertical Axis

This post is in continuation of the series on Training Systems in Intensive Apple Cultivation This post explains about the Vertical Axis or French Axis training system 

The vertical axis (VA) system

The vertical axis (VA) system has been touted by some growers as the next logical step from free standing central leader trees to high density supported systems. The main reason cited is the great similarities between the systems and the low emphasis on limb manipulation by tying. There are ladders used in picking, but with a flat tree wall at ladder height it is quite fast and simple to manage ladders.

Even though the VA system is one of the taller systems used in high density supported systems, there is still a critical need for lower limb development. These lower limbs will form a fruiting table yielding perhaps 60% of the crop and must be established before the trees should be allowed to grow taller. Proper development of the bottoms of the tree will allow 75% or more of the fruit to be picked from the ground. Cultivars that have a high requirement for light (e.g. McIntosh) are well suited to this system. Other cultivars like Gala, Goldrush, Golden Delicious and Empire have a growth habit highly suited to this system.

VA systems allow trees to grow taller than SS systems. The system basically consists of one or more high tensile steel wire(s) drawn tight and supported 2 - 3 m above the ground by a series of in-line posts spaced 9 to 15 m apart. The closer the spacing for the inline posts, the higher the degree of stability of the support system under strong wind or high cropload conditions. 

Individual trees in the row are supported by vertical leader supports that reach up to the top support wire. The tree consists of a conical, or "Christmas tree" shape and grown up to 3.5 - 4.0 m tall. The leader is not pruned until the tree reaches its full height. Shoots arising on the side of the axis or trunk close to and competing with the leader are removed as they arise or during the dormant pruning season. Side branches on the leader are renewed on a periodic basis.

The VA support system is somewhat more complex than the SS to install. It does require a high level of skill to build the support system and be sure it is adequate to hold the trees and crop load. A post failure in this system can result in the loss of several trees. The standard anchoring system now in use is the "auger anchor" which is screwed into place. Posts are generally pounded or watered (water gun) into the ground.

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Apple Tree: Training Systems in Intensive Apple Cultivation: Slender Spindle

This post is in continuation of the previous post on Training Systems in Intensive Apple Cultivation: Trellis. This post explains about the Slender Spindle training system further modification of spindle bush training system.

Slender Spindle:

This is the system preferred by growers who wish to work exclusively from the ground and are not confident in building wire support systems. The slender spindle (SS) consists of an individual support post at every tree.

Slender Spindle Support System:

The post should be 2.4 - 3 m in length and of pressure-treated wood, concrete or metal to ensure it lasts the life of the orchard (perhaps 12 - 18 years). A diameter of 4 - 6 cm is preferred, since risk of frost heaving increases with larger diameters. The depth of the post in the ground should be 60 - 90 cm for stability leaving 1.5 to 2.5 m above ground. A common mistake is to have insufficient post height above ground.

Slender Spindle Training Pruning:

The tree is trained to a slender bell, or pear shape with the bottom whirl of branches acting as a permanent fruiting table. The leader and top of the tree is kept quite weak to contain height. Renewal pruning of mature trees consists mainly of removing 2 - 3 of the largest diameter branches on an annual basis during the dormant season.  Tree height does not exceed 2 - 2.5 m.

In the next post I shall be discussing about the Vertical Axis or French Axis training system. This system is followed mainly in France having average productivity of about 42 Tonnes per Ha.

Apple Tree:Training Systems in Intensive Apple Cultivation: Trellis

This is in continuation to my previous blog on Training Systems of Apple Trees in Intensive Orchards where I mentioned about three basic training systems of apple trees in intensive cropping i.e. high density apple plantations. Today I am going to discuss about trellis.

Trellis:

Why trellis or any other support system based training system should be adopted for the HDP on clonal rootstocks. As you are now aware of the fact that the production can be optimized by harvesting 70 per cent of available light. Further the wood produced and fruit produced ratios are to be optimized. Why we produce wood? Wood is produced for structural strength. This is the reason for growing larger trees on strong scaffolds. If we want to grow HDP we must understand that support system is necessary to reduce wood production. This helps us in growing the trees with more fruiting wood than the structural wood. Therefore the production can be started at early stage of the plant/ orchard life. If the production can be taken as early as two to three years of planting, the breakeven point of orchard establishment can be met earlier.

The system basically consists of one or more high tensile steel wire(s) drawn tight and supported 2 - 3 m above the ground by a series of in-line posts spaced 6 to 10 m apart. The closer the spacing for the inline posts, the higher the degree of stability of the support system under strong wind or high crop load conditions.

The trellis support system is somewhat more complex than the Slender spindle and vertical axis to install. It does require a high level of skill to build the support system and be sure it is adequate to hold the trees and crop load. A post failure in this system can result in the loss of several trees. The standard anchoring system now in use is the "auger anchor" which is screwed into place. Posts are generally pounded or watered (water gun) into the ground.

The key problems of trellis systems are varieties with excessive vigorous or strong rootstocks that result in excessive pruning to contain the tree. Also, trellis systems support the total weight of the crop load and, as a result, must be exceptionally sturdy with posts for wire support located every few trees in the row.

In coming posts I shall be discussing about Slender spindle, Vertical Axis and Super Spindle training systems.

Apple Tree: Training Systems of Apple Trees in Intensive Orchards

The number of apple trees per acre in new orchards has gradually been increasing. Orchard intensification is motivated by the desire to produce fruit early in the life of the orchard to rapidly recover establishment costs. Intensification is possible by using dwarfing rootstocks that control tree size, induce early cropping, and produce large quantities of fruit relative to the amount of wood produced.

Apple trees grown on dwarfing rootstocks have shallow or brittle roots systems and trees grew poorly and often leaned or fell over. Therefore these plants require support systems. However, Intensive orchard systems are more profitable than traditional low-density orchards on semi-dwarfing rootstocks. However, because the establishment costs for intensive orchards are high, trees must be trained and pruned properly to induce and maintain high yields.

Motivation for orchard intensification.

The primary reasons for orchard intensification include:

1.) early fruit production, and
2.) reduced pruning and harvest costs of mature orchards.

Yield is positively related to the amount of sunlight intercepted per acre. Profit, which is influenced by yield as well as fruit size and quality, is probably at an optimum when an orchard intercepts about 70% of the available light. Traditional orchards, using vigorous rootstocks, were typically planted at a spacing of about 22 feet x 16 feet with 132 trees per acre. For the first five or six years after planting, fruiting was discouraged to promote vegetative growth so trees would fill their space as rapidly as possible. The first crop was usually harvested four or five years after planting, but high yields were not obtained until trees finally occupied their allotted space. Maximum yields did not occur until about 12 to 14 years after planting.

Intensive orchards are typically planted at narrow spacing depending upon the training system adopted but one thing is very clear that a small crop is often harvested the year after planting, because trees have so little space to fill, peak production is usually achieved during the 6th or 7th year after planting. Once trees fill their allotted space, maximum yields are similar for all types of orchard systems. Because the primary advantage of intensive orchards is early fruit production, these orchards should be planted only on excellent sites with a low probability of crop loss due to frost or hail.

Intensive orchard training systems.

The three basic types of training systems used for intensive orchards are

1. "Trellis,"
2."Slender Spindle," and
3."Vertical axis or French Axis."

There are many modifications of each system, and orchardists will need to adapt a system to suit their own particular situation. The basic systems will be discussed in coming posts

Apple Tree: High Density Plantation: Apple Rootstock

This post is in continuation to my previous post on High Density Plantation: Advantages of smaller trees.

What is rootstock?

Rootstock is the root system and a small proportion of the lower trunk of most apple trees. Grafting the genetically distinct fruiting part of the tree, the scion, on the rootstock forms whole tree. Occasionally a third genetically distinct component, an interstock or interstem, is grafted between rootstock and scion.

Why rootstocks are used?

Its really difficult to propagate the scions directly, but the rootstocks can be propagated easily that’s why rootstocks are used in apple propagation whether seedling or clonal rootstocks. Next question comes to the mind that why clonal rootstocks when seedling rootstocks are available and are propagated easily. Its true that seedling rootstocks can be propagated easily but these vary in genetic make up because its a sexual propagule, therefore it is bound to produce a different reaction to the scion. This means that you can not expect the plant to produce the same quality as of the parent. Whereas the clonal rootstock is produced through vegetative means thus have same genetic print that gives assurance that reaction to the scion will be the same that means there is most likely same quality of the plants and fruits can be produced.

In coming post I shall be discussing about Advantages of clonal rootstocks

Apple Tree: High Density Plantation: Advantages of smaller trees

I discussed about Trichoderma with respect to its role in plant health management. In my previous posts I have discussed about low productivity in apple especially in our perspective. This low productivity in Himachal is because of many reasons discussed in previous posts that are to be dealt with technological back up. This requires lot of motivation of the farmers to adopt high density plantation on clonal rootstock but with this there is a great need for the technologocal backstoping. My core feeling is that what ever we are producing is not enough since if we check out the production data of our state it is hardly touching 11 T per hectare that too once or twice in the histroy of apple production but if we check out the average then it is hardly 4.5 T per hectare. Whereas countries like NewZea Land and Italy producing fruit to a tune of 40 T per hectare this makes us to review our strategies and to findout the way to increase our production. There are some farmers who are doing a very good Job in this regard they are trying to develop there own system to keep pace with the industry of apple production among these I must mention here that Mr. Vikram Singh Rawat in Karsog Valley is putting all his efforts to produce the trees on clonal rootstocks further he is putting lot of efforts in bringing the farmers under the umbrella of organic farming and high density plantation. In this series I feel that it is important to mention the name of Mr. Rajesh Thakur of Mahog, Mr. Rajender Kaushal of Chamanpur, Mr. Arun Bansal of Ruhni, Mr. Diljeet Singh Ghumman of Bakhrot, besides Mr. Dinesh Primta of Chaupal area, Mr. Neetu Dharma of Kotgarh and Rajender Chauhan of Kotkhai are the one those are working hard to make this high density apple plantation a reallity. This is a list where I know these farmers either personnaly or through my close connections. Many other farmers involved in the high density plantation this situation warrents us that we must put our steps forward to support these farmers in achieving their endeavours. That was the reason to bring out this topic ahead of disease and pest management in apple that was in planning well before persuing this blog.

In this blog I shall first cover the advantages of small trees these are as follows:

1.    Reduce pruning costs

2.    Less spray per unit fruit

3.    Better spray coverage

4.    Smaller, less expensive equipment

5.    Quicker fruiting

6.    Lower harvesting costs (no ladders)

7.    Labour prefers smaller trees

8.    Easier to mechanize

After looking on these let us see how many of farmers are getting motivation...............
In coming posts I shall be dealing with the Various rootstocks and scions that can be used in high density apple plantations