A tree of fig
Fig is under cultivation since ancient times. Morphologically it is called as ‘syconium’, which is a vegetative, fleshy tissue, with tiny true fruits enclosed inside.
Fig is a gynodioecious species and some female type’s need pollination while others set fruits parthenocarpically. Pollination is effected by a wasp, which develops inside the syconium of male fig. This symbiotic relationship is a classical case of co-evolution between a plant and insect.
Fig fruits are often consumed as dried or canned. As a fresh fruit, it has a luscious taste. Fruits have been prized over centuries for the medicinal and dietary properties. In India, its cultivation is mostly confined to western parts of Maharashtra and Gujarat, Uttar Pradesh ( Lucknow and Saharanpur), Karanataka ( Bellary, Cnitradurga and Srirangapatna) and Tamil Nadu (Coimbatore).
Fig is a highly nutritious fruit. It is rich in calories (269), proteins, and calcium (higher than milk), iron and highest fibre content. Fig has nutritive index of 11, as against 9, 8 and 6 for apple, raisin and date respectively. The chemical composition and flavour of fig varies with the cultivar. The total sugar content of fresh fig is 16 % and of dried is 52%. The edible portion of dried fig (100g) supplies protein (4g), carbohydrate (69g), fat (1g), calcium (200mg), iron (4mg), vitamin A (100 iu) and thiamine (0.1 mg). Fig is valued for its laxative properties and is used in the treatment of skin infection. The fruits help to maintain acid alkali balance of the body. Latex is useful to coagulate milk.
Types of fig
Figs have been grouped into 4 types based on sex of the flower and pollination. The salient features of the fig types are given in Table 1. Only caprifig produces pollen, while other 3 pistillate types are dependent on pollen of caprifig or develop fruits parthenocarpically. Commercially grown Indian figs belong to ‘common’ fig group and set fruits parthenocarpically.
Climate and soil
Fig tree is a deciduous, and subtropical. It favours area having arid or semi arid environment, high summer temperature, plenty of sunshine and moderate winter. The plant has better threshold limit for temperature than for the lower. Although plants can survive temperature as high as 45`C, the fruit quality deteriorates beyond 39`C. Mature trees can withstand temperature up to 4`C, but young ones need protection. However, deciduous nature of fig allows the plant to resist temperature as low as- 10`C, when in dormancy. In mild climate, plants remain evergreen, lack well defined flowering and fruiting season, and sometimes produce long barren limbs.
Climate has an important bearing on size, shape and color of skin and pulp. A relatively cool climate stimulates production of larger and elongated fruits. Climatic
Table 1. Horticultural classification of fig
conditions during fruit development considerably influence the fruit quality. Very high temperatures (>39`C) induce premature fruit ripening. High humidity results in fruit splitting, while hot breeze during ripening leads to sweet but small fruits.
Medium to heavy, calcareous sell drained, deep (about 1m) soil having pH of 7-8 is ideally suited for fig cultivation. Although it does well even on light sandy, shallow soils, deep soils encourage better root establishment. The fruits produced on fertile, light soils are better suited for drying. The crop can tolerate drought, salts (chlorides and sulphates) but is sensitive to sodium carbonate and boron salts. In general, climate rather than soil is a limiting factor for its cultivation.
Nearly 700 varieties of fig have been listed in the world. The most popular varieties of fig are given in Table 1. Varieties vary for vegetative vigour, pollination requirement, yield, fruit size, shape, skin color, pulp quality and color. Large sized figs belong to ‘common fig ‘group.
Poona fig is most popular cultivar grown in India. Bangalore, Bellary, Coimbatore, Daulatahad, Dindigual, Ganjam, Hindupur, Lucknow and Saharanpur, have clearly acquired the name from the location in which they are cultivated. Most of them resemble in plant and fruit morphology to that of Poona fig. Possibly these are either clones or ecotypes and hardly they warrant varietal status. Black Ischia, Shahi, Maisram and Brown Turkey have not achieved prominence. Dinker, an improvement over Daultabad for yield and fruit quality, is gaining commercial significance.
Some well known fig hybrids from California have performed well in India in comparison to Poona fig under Bangalore conditions. They produce fruits parthenocarpically. Excel and Conardia figs that develop smaller canopies are suitable for high density planting. The fruits do not split like Poona and Conardia fig. Conardia, excel and Deanna are good for drying, canning and table purposes respectively.
Fegra fig (Ficus palmata): This is small fruited fig of excellent taste that grows wild in the mid-hill region of the Western Himalayas. This fig has been described in this website separately under the heading Fegra.
Although it is possible to propagate fig from seeds, cuttings, layers, grafts and by tissue culture, commercially cuttings are used for multiplication. About 25 cm long cuttings having 3-6 nodes are usually made from wood of previous season and planted in moist sand either in seed pans or in nursery beds. This can be taken up during pruning or just after the onset of monsoon. The cuttings are raised in shade with regular watering. After about 75 days, they are transplanted to polythene bags containing garden soil, sand farmyard manure (1:1:1), and field planted about 4-6 months later.
Higher success can be achieved by: (1) using cuttings with short internodes, collected from basal portion of the shoots located in the lower part of the crown; (2) storing of cuttings in moist sawdust or sphagnum moss for about 4 weeds at room temperature; (3) treating with growth regulators like IBA; (4) pre girdling at the base of canes ( removing 2.5 cm width bark) a month prior to taking cuttings; and (5) planting cuttings in a slightly slanting (80`) position.
Side grafting on Ficus glomerata and Ficus palmata may be adopted for circumventing nematode problem in the soil. Brown Trukey, as rootstock, imparts vegetative vigour in fig Excel, Conardia and Deanna. Shield or patch budding, cleft or bark grafting enables to top work a desirable genotype on established but inferior tree protocols are now available for micro propagation of fig shoot tips.
The best time for planting is the onset of the rainy season. The layout for planting can be either square or hexagonal system. The square system is more common and desirable. Spacing depends on variety and soil type. The recommended spacing for Poona fig is 5 m x 5 m(400 plants /ha). It is 2.5 m x 2.5 m (1,600 plants/ha) for Excel and Conardia. Pits of 60 cm x 60 cm x 60 cm size are dug and exposed to sun for about 15 days, and then filled with a mixture of compost, top soil and sand (1:1:1); 2 kg of neem or castor cake/ pit. Planting can preferably be taken up on an overcast day. When grafts are used the graft joint should remain above the ground level. Once the tree is planted the soil around the plant should be tamped firmly. Water is applied immediately after planting.
Training and pruning
Fig trees are trained initially to single stem to encourage a wide, symmetrical crown with a mechanically strong framework having evenly distributed laterals. The tree is allowed to grow for about a meter and then it is topped, which induces side branches all round the main stem. The interior of the bush should be maintained free of suckers, dry and sick branches.
Pruning in fig is practiced annually to stimulate production of new growth, and bearing fruits. The time and type of pruning vary with location, variety and number of crops harvested annually. The best time to secure a mature crop is hot, dry summer. Therefore, pruning may be done 4-5 months in advance. Generally, a single marketable crop is harvested yearly in our country. Either heavy or light pruning can be adopted in fig. When heavy running is practiced, trees are headed back severely every year, leaving about 2 buds on each one year old shoot. If light pruning is adopted, shoots which have yielded fruits are lightly headed back after harvesting. Copper fungicide should be used to protect the cut ends.
Notching is practiced sometimes in Poona fig for activating dormant buds before the start of vigorous growth. Usually 1-2 buds are selected for notching in the middle portion of about 8 month old canes. Notching involves removing of small slice of bark immediately above the dormant bud, giving 2 slanting cuts as deep as the bark. Notch should be about 2.5 cm long and the breadth depends on thickness of the shoot. The cut checks the free flow of sap and stimulates the bud just below it to throw out a fruiting shoot. The technique is useful for induction of fruiting laterals on vigorous upright braches and to increase the total bearing area of the plant.
Manuring and fertilizer
Nutrient requirements vary according to the variety and soil type. A general manure and fertilizer recommendation for fig is given in table 2. For young plants fertilizers can be applied with the onset of monsoon and, just after pruning for those which have commenced yielding. The annual requirement can be best divided into 2 applications, half after pruning and remaining 2 months later when the syconia are developing. Nitrogen is essential for rapid growth of foliage and development of syconia, fruit color and maturation and K for yield and quality. Better fruit quality can be achieved if N and K are applied in the form of ammonium sulphate and sulphate of potash respectively.
Table 2. Recommended dose of manures and fertilizers for fig
*Neem, Pongamia or castor
Some soils are may be deficient in micronutrients. General guidelines for correcting micronutrient deficiencies are given in Table3. However, a grower should get the soil tested and consult the soil specialist for specific advice. Application of compost, which is done mostly in the beginning of monsoon also supplies micronutrients to some extent.
Table 3. Micronutrients to be applied for correcting deficiencies
*Either soil or foliar application can be done. Foliar spray is applied when the plants are flushing.
After the plants are set in the field, regular watering is essential until they are well established. A basin of 60 cm diameter should be prepared around the plant and is widened as the canopy size increases. Basin cleaning is taken up regularly to keep it weed free. The side shoots and suckers should be removed as and when they emerge.
Maintenance of weed free orchard is very important. During early years of orchard, raising green manure or intercrop is recommended. Green manure sun hemp suppresses the weed growth and augments the supply of organic matter in the soil. Intercropping vegetables and legumes is beneficial.
Fig plants can sustain heat and drought. But commercial fig production is possible if plants are timely irrigated. Such plants produce greater shoot growth and higher yield s of superior quality fruits. Loose and sandy soils require larger quantities of water than heavy soil. Either drip or flood irrigation can be practiced. The drip irrigation minimizes water requirement and allows fertilizer application through irrigation water.
Flood irrigation may be repeated every 10 days in summer. The frequency may be adjusted depending on the soil type and weather. Excessive irrigation during fruit development causes the terminal buds to initiate growth at the expense of fruit development. Also excessive irrigation or heavy rains during ripening result in fruit cracking and production of insipid fruits. In the absence of adequate and regular irrigation the fruit development is affected, resulting in small and hard fruits. Once harvesting of fruits is completed, irrigation may be reduced regular schedule is resumed after pruning. If drip irrigation is adopted, 15-20 liters of water/ day/ plant may be supplied. The thumb rule is to replenish 50% of pan evaporation losses.
Harvesting and postharvest management
Harvesting of figs depends on their use. About 90% of the figs produced in the world are dried. But figs produced in India are mostly sold as fresh. Fresh figs should be harvested when they are soft and slightly wilted at the neck and droop and little or no milky latex flow at the cut end of the stalk. Sudden increase in fruit size and opening of ostiole are other maturity indices. Harvesting process is mechanized in some parts of the world. But in our country, figs are hand picked from the trees by cutting or twisting the neck at the stem end. The fruits are collected and spread in shallow trays. Since flesh figs are very delicate, extra care is required in handling.
When figs are grown for drying, they are allowed to ripen and to dry partially on the tree and fall naturally to the ground. Hence, during this period, area beneath the canopy should be maintained clean and dry. Once in 2-3 days, the figs are gathered for further processing.
Bearing in fig commences a year after planting, the life span of the tree being 35 year. The harvesting season varies with region and the yield depends on variety and cultivation practices. The second crop is mostly of poor quality fruits.
Fig is classified as a climacteric fruit, and to a little extent ripening continues once the fruit is harvested. After picking, figs are carefully sorted. The diseased and damaged ones are culled. Fruits are grader for size as 50 kg, 40-50g and 30-40g. They are packed in a corrugated box carton of 3 ply having 12 holes for ventilation. They are arranged in the carton in2 layers, each of 28 (4 rows of 7 figs in a line). Fig leaves are used for cushioning. Owing to perishable nature of fruits, growers prefer to sell their produce to some extent in local or nearby markets. Figs can be held for a short period (7-10 days), at 0`C and 85-90 % relative humidity.
Figs are one of the first fruits to be preserved by drying. Apart from drying and canning, figs are processed into paste and jelly.
Fig is susceptible to sun burn, fruit splitting and fruit drop. Sun born is noticed mostly in young plants and those subjected to excessive pruning. The trunk and shoots that are exposed to direct sun are prone to sun burn. The affected parts crack and the bark peels off, providing easy access for fungi and other infection. Developing a good canopy by proper pruning and coating the exposed limbs with lime protect the plants from sunburn. Fruit splitting is attributed to sudden change in atmospheric humidity during ripening. This makes the fruit unfit fro consumption as the pulp is exposed to insect and microbial infection. Fruit drop may result from excessive drought and heat, cold nights or light frost. Lack of pollination also causes fruit drop in figs.