Peach is a temperate zone fruit tree but is possible to grow in the sub-tropical climate of Punjab plains because of availability of suitable low chilling cultivars. In Punjab about 300 chilling hours are available and the cultivars whose chilling requirement is more than 300 hours shall not grow successfully. Peach cultivation is distributed throughout the state.
Peaches are highly valued as a table fruit for their attractive color and palatability. Fruits contain about 8.0% sugar, 0.8 per cent minerals and 1.5 per cent proteins. Peaches can be processed as canned and dried products, frozen preserves, jam, nectar, juice,beverage and marmalade etc. Peaches are also good source of low calorific diet.
Climate and Soil
Sub-tropical climate of Punjab is ideally suited for the cultivation of low chilling peaches. Availability of chilling temperature up to 300 hours during winter months is enough to break the dormancy of low chilling cultivars. After fruit setting from March to June, the climate is warm to hot (35'-42'C). This is favorable for the development and maturity of fruits provided adequate water supply is available.Loamy sand or sandy loam, well drained, fertile soil with lime content less than 10% is suitable for peach cultivation. Heavy wet soils are unfit for peach growing. Soil with an electrical conductivity below 0.5 m mhos/cm, calcium carbonate less than 5%, lime less than 10%, absence of hard pan, up to a depth of 120 cm and pH between 6-8 is good for peach.
1. Partap (1990) : Its fruits mature in the third week of April.Tree is medium in vigor. Fruit weight is 65-70 g, almost round,yellow with red over color: Flesh is firm and free stone at full ripe stage. Average yield 70 kg per tree; The fruit contains TSS 12%and acidity 0.7% .
2. Florda Prince (1997) : Tree is vigorous and the fruits mature in the fourth week of April. Fruit size medium (65-70 g); yellow with 71 72 red blush at maturity, flesh firm and free stone at full ripe stage.Average yield 100 kg per tree; TSS 12% and acidity 0.5%.
3. Shan-i-Punjab (1979) : Tree is vigorous with fruits maturing in the first week of May. Fruit is large, turns yellow with red blush at maturity. Average yield 70 kg per tree, flesh firm and free stone at full ripe stage. It is good for canning. Its TSS is 12% and acidity is 0.74%.
4. Earli Grande (1997) : Tree is semi-vigorous, high yielding and fruit maturity occurs in the first week of May (4 days earlier than Shan-i-Punjab). Fruit is large (90 g) and firm fleshed, free stone at full ripe stage and of good keeping quality. Its TSS is 10.5% and acidity is 0.7%.
B. White Fleshed
1. Prabhat (2003) : Tree semi-vigorous. Fruits matures in the 3rd week of April. Fruits are medium round with an attractive red blush, flesh white, juicy, sweet and free stone when fully ripe. TSS 12% and acidity 0.37%. Average yield is 64 kg per tree.
2. Sharbati (1967): Tree is very vigorous. Fruit matures in the end of June to first week of July. Fruit medium in size (70 g), cling stone and turns greenish yellow on ripening with pink patches. Yield per tree is 100-120 kg. TSS 13% and acidity 0.33%.
Punjab Nectarine (2008): Tree is vigorous and spreading, fruits mature in 2nd week of May. Fruit large, fuzzless, weighing 90 g, round,attractive with 90-100% red blush over yellow ground color at maturity,flesh yellow, firm, melting and free stone at full ripe stage. TSS is11.5% and acidity is 0.8%. Average yield is about 40 kg/plant.
Flordaguard (2010): This rootstock is resistant to root knot nematodes.The trees are vigorous spreading, self fertile and precocious having red leaves. Flowers produced in abundance, deep pink and showy. Fruits pubescent with dull red color, yellow fleshed and free stone. Fruits ripen from end June to 1st week of July. On this rootstock the peach varieties give 17.3 kg yield per plant while on sharbati it gives 10.3 kg per plant only.
The peach is commonly propagated by budding or grafting on peach rootstock like Flordaguard and Sharbati.
Root Stock Raising : Procure ripe fruits of Sharbati/Flordaguardin June-July. Extract stones from pulp, wash and dry these unders hade for 4-5 days. Treat the stones with Ziram or Thiram or Captan@300g per quintal of stones. Pack the stones in dry gunny/plastic bags and store these under cool dry place till these are used for stratification from November-January.
Stratification is a low temperature treatment in which stones are placed in alternate layers of moist sand at or below 7.20 C for 100-120 days till the seed dormancy is broken and germination starts.Kernels/seeds can be used instead of stones for raising the seedlings.Wooden boxes or well drained trenches in open space can be used for stratification. When seed germination starts in upper layer it is considered that dormancy of seed is broken. Stones or seeds are removed carefully from each layer of sand without damage to radicleor plumule of germinating seeds. Separate the germinating stones from cracked stones and uncracked stones and sow these separately in well prepared nursery plots. These are sown 30 cm apart in rows at a distance of 15 cm. Normally sowing of seeds is done in the first fortnight of February.
Budding/Grafting : About 40% seedlings from the nursery plots become fit for T-budding in first week of May. The successful buddedplants become ready for transplanting in December-January. The rest of the unbudded seedlings or the unsuccessful budded seedlings are used for grafting in December-January.
In the middle of February the scions produce new growth. Usually a scion may produce 3-4 shoots which may be allowed to grow up to April. In May, one of the vigorous shoots is retained and all others are removed. This practice produces vigorous nursery plants.Polythene tape around the graft union should be removed before it causes girdling. Staking of young grafts is necessary to prevent breakage.
Stenting Technique : Peach plant can be propagated by stentingtechnique (simultaneously grafting & rooting) in the first week of January by dipping the basal portion of cutting of Sharbati in 2000 ppm IBA solution for 2 minutes. This practice will cut short the period of one year for propagation.
Crown Gall Disease
The crown gall disease is caused by a bacterium Agrobacteriumtumefaciens and has been noticed in peach nurseries and orchards.The disease can be easily identified by the formation of tumours of 73 74 varying sizes especially at the crown portion and sometimes on roots and on the stem at the position of the graft union of the plant.For raising disease free plants in the orchards following points may be kept in view.(I) Procure disease free plant material from a reliable source.(II) Avoid injury to roots and crown portion of the plant at the time of uprooting from the nursery, replanting and performing other cultural practices in the orchard.(III) Keep the plants free from insects, nematodes and rodent injuries.(IV) Discourage the exchange of plant material without knowing its sanitary conditions.(V) Uproot and destroy the diseased plants from nursery or orchard whenever noticed.(VI) While planting, the diseased roots of the plant are pruned and remaining root system is dipped for one minute in 5% solution of bleaching powder and then planted in the orchard.
Peach should be planted in the orchard during winter when the plants are completely dormant. One year old healthy nursery plants which are free from the incidence of nematodes and crown gall disease should be planted in the orchard from the end of December to end January. The nematode infestation can be identified by the presence of small root nodules and soil also remain sticking to the roots.Plant to plant distance is kept at 6.5 x 6.5m in square system of planting. Peach can also be used as filler plant in pear and litchi orchards. Keep the bud/graft union of the plant about 10-15 cm above the ground. Always procure 1.0-1.2 m tall plants for planting an orchard.
High Density Planting
Peach trees should be planted at spacing of 6m x 1.5 m with ‘Y’system of training. This practice ensures higher yield and better fruit quality than the traditional planting system.Training and Pruning To control tree size and to ensure new growth annually for fruit bearing, training and pruning are important canopy management practices.
Training : Peach plants are trained according to the modified leader system. Various steps involved in training are as follows:i) At the time of planting one year old plants are headed-back to about 90 cm. Cut all side shoots to one or two bud stubs.ii) During spring and summer months many lateral branches are produced along the whole length of the plant. At the time of first pruning in January, select 4-5 healthy well placed spirally located branches in all directions on the axis of the plant and remove all others. The lowest branch on the trunk should be at 45 cm from the ground level. The top most central branch is called leader.iii) During the next growing season many new branches develop on the selected primary branches. The leader of the plant also grows in height and some side branches are developed on it. Select 3-4 more well placed branches on the central branch and remove all others if present. At this stage head-back the leader branch very close to some outward growing lateral. The leader is restricted in its vertical growth. Thus, a peach tree is trained to modified leader with a strong framework for future fruiting.
Pruning : In peach, fruit is borne on one year old branches.Pruning should be done by thinning out some one year old shoots expected to bear fruit. Some heading-back of old and unsuitably placed branches and sterile parts of flower bud bearing shoots should be done. About 40 per cent of one year old branches should be thinned out to ensure proper tree growth and improve fruit size and quality. Lengthy and hanging branches should also suitably be shortened by heading back.Best time of pruning peach is during January. Cuts thicker than 5 cm should be covered with Bordeaux paste followed by Bordeaux paint after 1 or 2 weeks.
Peach is a heavy fruit bearer. If all the fruits are allowed to matureon the trees, they remain small sized and of inferior quality with low marketable yield. Over bearing weakens the trees and causes short life of trees. To overcome these problems, fruits should be thinned annually. In Partap best time of fruit thinning is during second and third week of March while in Shan-i- Punjab it is third to fourth week of March. Girdling plus thinning done at full bloom or girdling alone done four weeks after full bloom advance fruit maturity by 7-12 days and improves fruit quality in Shan-i-Punjab. Fruit to fruit distance on the shoots should be 10-15 cm. Before starting fruit thinning, shake fruit bearing branches slightly. The weak stemmed fruits are likely to drop naturally. Then start thinning of fruits from base to top of branches. The operation must be completed before pit hardening of fruits. Proper pruning of trees also helps in thinning of fruits.
Manures and Fertilizers
Fruiting is an exhaustive process for the tree. This removeslarge amount of nutrients from the soil. To prevent the adverse effects of nutrient deficiency in the plant these are applied annually according to the tree age. Age Farm yard Dose per tree (g) (Years) manure Urea Superphosphate Muriate (kg) of Potash1-2 10-15 180-360 190-380 150-303-4 20-25 540-1000 570-760 450-8305 & above 25 1000 760 830 Apply FYM, superphosphate and muriate of potash in December.Split urea in two doses. Apply half of urea in January after pruning and the remaining second half after fruit set in March.
Iron deficiency: Peach trees planted on light textured and high pH soils often exhibit iron deficiency symptoms during summer and rainy season. Interveinal chlorosis (yellowing in between veins) of developing new leaves on the terminal part of shoots are the clearsymptoms of deficiency. In severe case the new leaves may unfold without any green color (Ivory color) and later veins may turn green.Typical symptoms appear by the second fortnight of March and with the passage of time these progress and accentuate. Iron deficiency can be corrected by spraying peach trees with 0.3 per cent ferroussulphate solution (3g ferrous sulphate in one liter of water) on spring flush in April, on summer flush in June and late summer flush in August-September.
In peach, fruit development period starts after fruit set in March and continues during April to June till maturity depending upon the variety. This is the critical period of irrigation for the trees. Trees should not suffer from any moisture stress particularly 25-30 days before maturity of fruit, because the maximum weight gain is during these days.
Critical period of irrigation for peach varieties:
Variety Critical periodPartap, Florda Prince End March to third week of April Shan-i- Punjab, Earli Grande Mid April to first week of May Sharbati End May to end June The irrigation frequency depends upon the type of soil and the source of irrigation. In early maturing varieties like Partap, FlordaPrince,Earli-Grande and Shan-i-Punjab, irrigation should be given during the first 3-4 weeks after fruit set at weekly intervals. Thereafter,from the second week of April to the start of harvesting, the trees may be irrigated at 3-4 days interval.
Weeds are common in peach orchards during spring and therainy season. They can be kept under control by using the following doses of herbicides.herbicides. Diuron 2 kg/acre or Glyphosate or Gramaxone at 1.5-2.0 liters/acre are very effective in controlling the broad spectrum weeds inpeach orchards. Diuron should be used at the pre-emergence stage of weeds in the first week of March, whereas Glyphosate or Gramoxone should be used at the post emergence stage of weed when the weeds are 15-20 cm tall. Dissolve the required quantity of weedicide in 200 liters of water per acre and spray during calm hours. The spray of post-emergence weedicides may be repeated as and when required particularly during the rainy season when the weeds are abundant.
Maturity and Harvesting
Peach fruits should be harvested at the right stage of maturity depending upon their market destination. For distant market the fruit should be picked at firm mature stage i.e. when the ground color of fruit begins to change from green to yellow in yellow fleshed varieties and fruits yield to pressure very slightly in between cupped hands.For the local market, however, the fruit may be picked when nearly ripe.In white fleshed varieties color of the fruit changes from green o straw (dry grass) with pink blush on the sides. Fruits harvested at this stage take 3-4 days to ripe.All the fruits do not ripen at the same time on the tree. Earlier set fruits mature first and later set fruits mature later. Generally 3-4 pickings are done to complete the harvesting. During picking collect the fruits in baskets/plastic cartons after putting some dry grass or paper strips in it as a cushion to prevent injury or bruises to fruits.Drop bottom picking bags are now available or can be made to order for picking peaches. Transfer the fruits to some shady place with good aeration to make them cool down. Field heat of the fruits can be effectively removed by giving them 10-15 minutes quick dip in cold water followed by surface drying of the fruits in shed. This process slows down the ripening process of fruits and is helpful in extending the shelf life.
Before packaging, remove the injured, damaged and undersized fruits from the lot and grade the fruits according to size and stage of maturity. Different grades of fruits are packed separately for better marketing. The commercially accepted fruit grades in peach and packaging size are given following:Fruit Grade Fruit size (cm) Inner size of box No.of layers No.of fruits per(cm) layer Special 5.5-6.3 and above 37x16.5x16.5 3 28-32 Grade-I 4.6-5.5 -do- 4 35-38Grade-II Below 4.6 -do- 4 38-generally 2 and 4 kg corrugated fiber board boxes (CFB) are used for packaging of fruits. These are better than wooden boxes.Shelf life of the peach fruits is very short after harvesting. This can be increased by storing the fruit in commercial cold stores where temperature varies between 0o-3.3'C with relative humidity 85-90%.Fruits at this low temperature can be stored for 25 days without affecting their palatability. Pack the peach fruits in paper moulded trays and wrap with heat shrinkable or cling film. It improves the shelf life and maintains the quality for 9 days in super market (18-20'C) and 4 days in ordinary market ((28-30 'C) conditions.