Apple Orchard Rejuvenation Revisited

Introduction

In 2006, Harmony Hall Orchards – founded by Samuel Evans (Satyanand) Stokes in 1916 – initiated a rejuvenation of the old orchard, mainly having several old sports of Red Delicious – such as Red, Royal, and Rich-A-Red – with Golden Delicious as pollinizer. This effort evolved into an ambitious programme to establish a world-class, science-based orchard with modern cultivars on dwarf rootstocks. The early phases of this till 2010, together with summary history of apple growing in Himachal Pradesh, was reported in an article, “Apple Orchard Rejuvenation: Experiments at Harmony Hall Orchards,” which appeared in the June 2010 issue of Vidhanmala, a magazine published by the Himachal Pradesh Vidhan Sabha, which is not easily accessible because it is improperly indexed and therefore not available on the internet.

After a brief summary of how the rejuvenation was implemented, this article describes the post-2007, 15-year experience in bringing the trees to production. Some important lessons learned from this project: (1) In heavy clayey soils, legacy trees on seedling rootstock do not have tap roots, and the roots were no deeper than 1meter. (2) High-density plants on M-9 dwarf rootstock did not require irrigation over a 14-year period. (3) No incidence of replant disease in over 5,000 newly planted trees. And (4), thinned apples in all the new cultivars exhibit good size distributions.

Orchard Rejuvenation

The process of rejuvenation was started in the autumn of 2006: Old trees were cut (Figure 1), and after establishing that the old trees did not have tap roots (Figure 2) and no roots below 1 meter (Figure 3), the ground was levelled into fields (Figure 4), the entire mountainside terraced (Figure 5). Over a period of four years, old apple trees were cut from about 20 hectares (about 250 bighas) of orchard, and the mountainsides were re-terraced. This required the use of JCBs to form terraces on steep mountainsides that had to be reinforced through extensive use of stone walls (Figures 6, 7, 8). The positions of the future plants were marked (Figures 9, 10).

The first batch of apple trees from the Adams County Nursery in the US  – mainly comprising SuperChief (Red Delicious) on EMLA-111 rootstock, Crimson Gala on EMLA-7 rootstock, Fulford and Gale Gala on an M-9/EMLA-111 interstem (interstock), and Daybreak (early) Fuji and Autumn Rose (late) Fuji on EMLA-7 – arrived in Delhi in February 2007. They were planted in March 2007 in the form of whips in which the main stem was cut at the first bud at a height of about 1 m (about 38 in) with the bud facing into the main wind direction (Figure 11). Every three rows of SuperChiefs at 5.5-meter (18-feet intervals) were followed by a row of Gala as a pollinizer.

This first batch did not include plants on M-9 rootstock; because of its shallower roots, there was concern about drought resistance. However, together with some stone fruit and apple trees on semi-dwarf rootstock, about 300 plants (Crimson and Gale Gala, and Daybreak and Autumn Rose Fuji) on M-9 and Fulford Gala on Bud-9 rootstock were imported in February 2008, and planted in March 2008.

The medium density plants on EMLA-111, EMLA-7, and M-9/EMLA-111 interstem (interstock) rootstock were planted at a distance of 3 m (10 ft) to eventually form hedges, and the distance between tree-row hedges was set at 5.5 m (18 ft). All tree-rows were planted on a north-south axis; this way each side of each row is exposed to sunlight, which is important both for food production by the leaves and for colour development in the fruit.

Tree Pruning

An open spindle system with layered scaffolding was chosen to maximize solar exposure that is important both for food (starch) production and fruit colour. For this, lateral branches had to be trained to near horizontal configurations (Figures 12-14). Through careful pruning, scaffolds (layers) were created at approximately 1-meter intervals along the scaffold, and upper scaffolds were pruned to shorter diameters to maximize solar exposure on lower scaffolds. After pruning each plant, pruning knives were sterilized with alcohol wipes. Plant training is important. Flowering in such a feathered tree is shown in Figure 15.

High-density plants on M-9 and BUD-9, were planted in 2008: Plant-to-plant distance in two different plots were 1.4 m (4.5 ft) and 1.5 m (5 ft). The distance between plant rows was 3.4 m (11 ft) in both plots. Each plant was loosely tethered to a metal pole by wire ties inside polyethylene tubes. The metal tubes were attached to horizontal, tensioned wires. Figures 16 and 17 show fruit on M-9 rootstock.

Fruit Thinning

Thinning of all the new cultivars is important for size development. With little or no thinning the plants can have excessive fruit loading: Even though it was thinned, Figure 18 shows excessive fruit loading on an Autumn Rose Fuji plant on EMLA-26 rootstock. Continuing experiments have shown that apples on medium density plants (on EMLA-26, EMLA-7, M-9/EMLA-111, and EMLA-111 rootstock) require well in excess of 50% thinning –  on the order of 80% – which is done while the fruit is between pea and walnut sizes. Currently, the plants are being manually thinned – this allows refining of the thinning algorithm: which apples should be thinned and why. Eventually, foliar sprays will have to be used  for chemical thinning. Figures 19 and 20 show the extent of thinning on a 15-year old Crimson Gala tree on EMLA-7 rootstock. High-density plants (on M-9 and Bud-9 rootstock) may require even more thinning.

Fruit Size Distribution

Fruit size distribution is important: Once  the fruit is well set, other than ‘June dropping’ caused by heat and lack of moisture, the number of apples on a tree should remain about the same, so that the larger the fruit size achieved, the higher the overall fruit weight will be. But, because of the ‘food’ available for fruit growth, excessive fruit loading results in smaller size distributions, which can be prevented by thinning (culling) the number of apples However, most growers are reluctant to thin fruit: “It’s with great difficulty that we have a good crop, and you recommend thinning,’’ which they do not do. Later in the season the refrain is, “The crop was good but the apple size was very small.”

The sequel addresses size-distributions in different cultivars. To study apple size distributions, apples were harvested from two adjacent, 15-year old SuperChief trees, from each of which about 80% of fruit had been thinned. The apples from the two trees were graded separately. The apples in each grade were weighed together and the number of apples counted. The size and weight distribution for these two trees (marked 9/1 and 9/2) are given in Table 1. The rows highlighted in yellow give the percent size distributions. Clearly, the apples from Tree 9/1 have more apples in the larger sizes than Tree 9/2. Note that while Tree 9/1 had fewer apples (430) than Tree 9/2 (507), the weight (85 kg) of all the apples from Tree 9/1 is significantly more than that (77 kg) of apples from Tree 9/2. This clearly shows that more apples do not result in higher apple weights. In this case, a 15% decrease in the number of apples resulted in a 10% increase in the apple weight. This points to the need for establishing the optimum thinning level for each cultivar. The fruit loading on Tree 9/1 is shown in Figure 17.

For trees that had undergone about 80% thinning, Table 2 shows the overall (orchard) percent size distributions (highlighted in light beige) in seven cultivars for the 2022-2023 apple season. The four Galas are listed in order of descending sweetness levels – Crimson Gala being the sweetest and Buckeye Gala being the tartest (sour): In the Gala family, the darker the colour, the tarter the apple. Clearly, the two Fuji sports have very large apples, and even SuperChief apples are markedly skewed towards larger sizes. The last three columns give the percent grades of apples: Grade A comprises ‘flawless,’ ‘full colour’ apples. Grade AA comprises ‘flawless,’ ‘less colour’ apples. And Grade AAA comprises ‘flawed’ apples – distorted apples, apples with insect damage, and apples with missing stems. AAA apples represent a small fraction which could be reduced through timely use of insecticides and better plucking practices. Grade AA apples could be moved to the A category by proper pruning to ensure that apples are exposed to sunlight, and by removing leaves covering mature apples.

Plant Protection

Early in the programme, Bayer CropScience (BCS) was consulted about plant diseases. This soon evolved into a long-standing, formal collaboration in which BCS took over the responsibility of managing the plant protection of two plots, each with both (about 130) medium-density (EMLA-7 and EMLA-111) and (about 190) high-density (M-9 and BUD-9) plants. Over a 15-year period many issues have been addressed: Beetles ‘overnight’ defoliating trees, insects such as thrips and mites attacking leaves, insect infestation in apple fruit – such as by codling moths causing interior rotting – and, of course, managing fungus attacks – such as by Powdery Mildew, Alternaria and Marssonina. BCS helped train the orchard staff to recognize the onset of several insect infestations – such as by thrips and mites – and trained them to regularly monitor plant leaves for insects and fungus infestation, a process that BCS refers as ‘scouting’; this makes possible the use of timely, ‘immediate’ sprays to control pathogen attacks.

While Harmony Hall Orchards has not had a single incidence of replant disease, root rot has been a problem. Although the incidences of root rot are small, they are worrisome because by the time root rot is discovered it is ‘too late’ to save the plant; losing a mature tree is a big loss. So, in collaboration with BCS, a plan was instituted to drench the affected trees several times a year with a ‘cocktail’ of insecticides for insects, several potent fungicides, and antibiotics for any bacterial infection. In 2018, a currently 15-year Golden Delicious (Gibson cultivar) tree on EMLA-7 rootstock was diagnosed as dying from root rot. The ‘cocktail’ described above was applied several times a year, and is still being applied to save the tree. Last year it had leaves but the plant did not grow much. This season, after six years of treatment, the tree had healthier leaves. During this treatment all apples on the tree were removed during thinning. HHO will continue this experiment to see whether trees with root rot can be saved.

HHO has instituted an aggressive programme to identify possible root rot cases: At the slightest suspicion of possible infection, the tree roots are bared to inspect for root rot; if found, results in the tree undergoing the cocktail treatment. As an extra precaution, all implements used on a plant are immediately cleaned (‘disinfected’) with alcohol.

Plant Nutrition

Soon after the plant-protection collaboration with BCS began, HHO initiated a plant-nutrition collaboration with YARA India, in which YARA took charge of managing the nutritional needs of the apple trees in the same two plots being used by BCS for plant-protection studies. HHO now regularly applies post-harvest fertilizers – consisting of two fertilizers: (1) NPK and (2) Boron, Calcium, Magnesium, etc. – on apple basins to store food in apple trees for use on bud break when the leaves are too small to produce food. Second and third doses of doses of this fertilizer combination are applied during the pink-bud and fruit-set stages. In addition several foliar sprays of Zinc, Boron, and Calcium are applied as needed. In particular, more than five sprays of Calcium are needed to prevent bitter pit in large apples, such as in the cultivars Cameo, Fuji, Honeycrisp, and Jonagold.

Apple Marketing

All legacy (Royal, Rich-A-Red, Red, and Golden) apples are currently sold through the Aarthi-Mandi system that evolved from the old Sabzi-Mandis created to sell highly perishable vegetables and fruits. The chain from the grower to the consumer is long: It starts with the grower selling his produce to an Aarthi, at which point, in addition to transportation charges, he incurs three costs – selling fee (aarath) to the Aarthi, labour charges for moving apple boxes from the vehicle to the auction station, and a government fee. Then the auctioned cases are moved to the truck of the intermediate trader (Ladani) which involves additional labour charges. It is not unusual for the apples to be resold several times to many intermediate Ladanis, each time adding the three costs outlined above. Thus, by the time the apples are sold to the final retailer, many additional costs accumulate. It is a cumbersome, inefficient system that cannot be reformed, especially by involving government agencies; it is on its way out. Royal apples in this mandi system fetch an orchard-averaged, wholesale price int the Rs. 40-45 per kg range.

A parallel, more sophisticated, modern system is evolving rapidly that, in addition to selling most consumer items at attractive sites, also markets imported apples – which already have a larger volume than the apples grown in India. In contrast to the mandi system, these, and other rapidly evolving direct grower-to-retailer and grower-to-consumers companies – such as Reliance Retail and BigBasket – pay wholesale prices in the range Rs. 120-145 per kg for new cultivars such as Red Delicious (SuperChief), Gala, and Fuji.

Replacing Royal apples with modern cultivars and using the rapidly evolving modern marketing channels offers the best hope for the future of the Indian apple industry.

Rejuvenation Through Newer Cultivars

Although many younger growers have recognized the importance of planting newer cultivars on dwarf rootstocks – emphasizing high-density M-9 equivalent plants – their strategy is based on experience with the current, archaic mandi system: only elongated, deep red apples sell. This results in a mad rush for the ‘latest’ full-red coloured varieties from all over the world! When told that the green-coloured Granny Smith fetches better prices than red apples there is a pause – soon thereafter the thought process reverts to the ‘default’ mandi-system experience.

The ‘latest-variety’ craze appears to have infected many would-be progressive growers. But even if apples can be harvested from several types of fast-growing high-density plants, it takes many more years for the plants to produce commercially viable amounts of apples. And, of course, in the meanwhile many more ‘latest’ varieties would become available.

Already, over a three-year period, Gala has started fetching better prices than Red Delicious (SuperChief), and this season Fuji sold at even higher prices. What this shows is that in the evolving modern marketing system, which caters to more discerning customers, it is the taste that matters most. In the future, taste will drive more customers towards premium varieties such a Honeycrisp and Jonagold. And, as elsewhere in the world, colour will matter less.

Choice of Rootstock

Fruit production per unit area is known to be highest on M-9 and equivalent rootstocks, such as Bud-9 and the newer Geneva series equivalent. The use of interstem (interstock) technology is expected to enhance the productivity of larger rootstocks such as EMLA-111.

Harmony Hall Orchards is using EMALA-111 rootstock for SuperChief; this spur variety is known to shorten the overall tree height. All vigorous (non-spur) varieties are on EMLA-7 and M-9/EMLA-111 interstem rootstock. A direct assessment of the enhanced productivity of interstem-based trees will take time: The cultivars imported on interstem rootstock did not come on EMLA-7, and those on EMLA-7 did not come on interstem rootstock. HHO has been planting all new trees on interstock rootstock. So, as these plants mature, it should be possible to make a direct productivity comparison.

It is not just the productivity of a rootstock that determines the optimum choice, the topography of the terrain is important – high density plantations are more suited to relatively flat terrains.

Since the trees started bearing fruit in 2012, HHO has been recording the total number of apples harvested from each tree. A reduction and analysis of this data will provide information on the rate at which the productivity of newly planted trees increases.

Concluding Remarks

Experiments over fifteen years have generated a large amount of useful information: (1) In heavy clayey soils, legacy trees on seedling rootstock do not have tap roots, and the roots are no deeper than 1meter. Because of this, as a preventive against replant disease, during replanting the soil under old trees only needs to be removed to a depth of about 1 meter. (2) High-density plants on M-9 dwarf rootstock did not require irrigation over a 14-year period. So high-density, M-9 – based plantations may require far less irrigation than otherwise thought. (3) In over 5,000 planted trees, there was no incidence of replant disease. So, if the tree planting practice described in the Vidhanmala article is followed, the chance of developing replant disease is minimized. And (4), if about 80% apple thinning is practiced, all new apple cultivars on dwarf rootstocks exhibit good size distributions.

Vijay K Stokes

Vijay Kumar Stokes, PhD (Princeton, 1963), taught at IIT Kanpur (1964-1978), where he headed the Mechanical Engineering Department (1974-1977) and was the Convener of the Nuclear Engineering and Technology Program (1977-1978). He then worked at the GE Corporate R&D (1978-2002). Besides setting up a world-class, science-based apple orchard at his ancestral home in Ilaqa Kotgarh, for over 25 years he has been documenting the local language, culture, and music and dance.