About Mango (Mangifera indica L.) Production technologies

Mango (Mangifera indica L.) considered as ‘King of fruits’, is the most important commercially grown fruit of India due to its wide range of adaptability, high nutritive value, richness in variety, delicious taste and excellent flavour.  It is a rich source of vitamin A and C. The fruit, utilized raw or ripe, is well-liked by the people and has great export potential. Raw fruits are used for preparing various products like raw slices in brine, amchur, pickle, murabba, chutney, sharbat etc. while ripe fruits are relished as table fruit and used for processing into a variety of juice preparations such as squashes, ready to serve beverages etc. Good mango varieties contain about 20% total soluble solids in their pulp. The acid content of ripe desert fruits varies from 0.2 to 0.5% and protein content is about 1%. Mango has medicinal uses also. Ripe fruit has fattening, diuretic and laxative properties. Mango kernel contains about 8 to10% good quality fat which can be used for saponification while its starch is used in confectionery industry. The wood of mango trees is used as timber, and dried twigs as firewood. Due to its importance, mango is grown widely in varying agro-climatic conditions ranging from tropical to sub-tropical and humid to semi-arid.

India ranks first among world’s mango producing countries with 2.50 million hectares cultivated area and 18.0 million tonnes production during 2012-13. Mango accounts for 35.8 and 22.1 per cent of the country’s fruit acreage and fruit production, respectively. Other major mango producing countries include China, Thailand, Mexico, Pakistan, Philippines, Indonesia, Brazil, Nigeria and Egypt. About 55,585 tonnes of fresh mangoes valued at Rs 2647 million were exported from India during 2012-13 with a share of 5.20 per cent in the global experts to countries like UAE, Bangladesh, UK, Saudi Arabia, Kuwait, Nepal, Bahrain, Oman, USA, Singapore, Switzerland, France and Japan. About 1,47,816 tonnes of mango pulp valued at Rs 6085.6 million was also exported to countries like Saudi Arabia, Yemen, The Netherlands, UAE, USA, Sudan, Kuwait, UK etc.Soil and climatic requirements.

Soil and climatic requirements

Mango is well adapted to tropical and sub-tropical climates. It thrives well in almost all the regions of the country from sea level to an altitude of about 1,400 m, provided there is no high humidity, rain or frost during flowering period.  It may not be desirable to grow mango commercially in areas above 600 m above MSL in subtropics. It cannot stand severe frost, especially when plants are young. Though the best mango growing regions of the world have the annual mean temperature ranging from 21 to 27 °C, it can tolerate a temperature range of 5 to 44°C. High temperature accompanied by low humidity and wind affects the trees adversely. Mango thrives well in places with annual rainfall in the range of 75 to 375 cm. It can also do well in areas having average annual rainfall of as low as 25 cm with irrigation during peak requirement of plant establishment and fruit development. Heavy rainfall prior to flowering induces excessive vegetative growth at the expense of flowering. Frequent rains and high humidity (about 80%) during flowering and fruit set are conducive to the incidence of pests and diseases and impair pollination and fruit set. In general, places with well distributed rainfall and dry summer are ideal for mango cultivation. Light rains during fruit development are good but heavy rains and hail cause damage to the fruits. It is better to avoid areas with heavy winds and cyclones, which may cause flower and fruit shedding and also breaking of branches.

            Mango comes up well on a wide range of soils which are deep (minimum 6 feet) and well drained except clay, extremely sandy, rocky, calcareous, alkaline and water logged soils.  Mango prefers slightly acidic soils though it can tolerate pH range of 5.5 to 7.5 and can also tolerate salinity up to 4.5 dSm-1. Slightly acidic to neutral, well drained and aerated loamy or alluvial deep soils rich in organic matter are ideal for mango cultivation

Propagation

Mango being highly heterozygous and cross pollinated, vegetative propagation is a must for getting true to type plant material. Only in the case of polyembryonic varieties, seed propagation can be adopted, but such trees will take longer period for bearing. Nucellar seedlings from polyembryonic varieties can be used to get clonal rootstocks, which impart uniformity. The polyembryonic variety Olour was found to be a dwarfing rootstock for Himsagar and Langra in North India and Vellaikulamban for Alphonso in South India. Bappakkai and Olour as rootstocks are moderately tolerant to salt (5.0 dSm-1) in irrigation water. Till a few years back, inarching was the most common method of propagation. However, veneer grafting has given good results both under North as well as South Indian conditions. More recently, epicotyl grafting and soft wood grafting by cleft and wedge method have become more popular being easier and economical. The latter three have the added advantage that grafts can be prepared at places away from the mother plant with transported scion sticks but the scion has to be pre-cured for good success. High humidity is essential for good success of epicotyl and soft wood grafting. In arid regions where field establishment of grafts is problematic, in situ soft wood or veneer grafting could be useful.

Spacing

The spacing varies according to fertility level of soil and prevailing growing conditions. Conventional spacing varies from 10m X 10m in the dry zones and poor soils where growth is less to 12m X 12m in heavy rainfall areas and rich soils where abundant vegetative growth occurs in case of vigorous varieties. New dwarf hybrids like Amrapali and Arka Aruna can be planted at closer spacing in the northern plains and the peninsular plateau, but not under humid tropical climate such as the coastal ecosystem where Amrapali tends to be vigorous.  High density planting is advocated for increasing the productivity per unit land area by use of dwarfing rootstock, application of growth retardants like paclobutrazol and pruning, apart from using low vigour scion varieties. Some recent trials have also indicated the suitability of rectangular and hedgerow planting for increasing planting density. Higher planting densities with spacing such as 6m X 4m or 4m X 3m could be attempted for higher productivity, especially during the early orchard years, which needs more intensive care and management practices compared to conventional spacing to contain the tree size within the restricted space without causing overcrowding or over-shading during the later years. 

Planting

Planting is usually done in the months of July - August in rain-fed areas and during February - March in irrigated areas.  In case of heavy rainfall zones, planting is taken up at the end of rainy season. Prior to planting, the land should be prepared by deep ploughing followed by harrowing and leveling with a gentle slope to facilitate good drainage. Pits of about one cubic meter size are dug at the desired spacing during dry summer months and after exposing them to sun for about 2 to 4 weeks, are refilled before rainy season with the original soil mixed with 20 - 25 kg well rotten FYM, 2.5 kg super phosphate and 1 kg muriate of potash.  In areas having termite problem, soil drenching with Chlorpyriphos (0.2%) can be done. The grafts for planting should be obtained from reliable sources and care should be taken that the polythene strip used for grafting is properly removed and that the plants have not become pot-bound. One-year-old healthy grafts are recommended for planting. The graft with its ball of earth intact is placed at the centre of the pit using a planting board by excavating as much soil as needed to accommodate the root-ball. Care should be taken that the roots are not exposed after planting and that the graft union is above the ground level. The moist soil of the pit is then pressed all round the ball of earth. Small basins should be formed around the plants and the plants should be irrigated immediately after panting.

Training and pruning

In the initial one or two years, provide stakes to make the plants grow straight. Training the plants in the initial stages is essential to give them proper shape. About 75 to 100 cm of the main stem from the base should be kept free from branching and the main branches can be allowed thereafter in such a way that they grow in different directions and are spaced at about 20 to 25 cm apart. The main stem may be headed back at a height of about 1.2 m to facilitate the development of scaffold branches in this manner. Any suckers coming from rootstock should be immediately clipped off. Branches which cross over and rub each other may be removed at pencil thickness and the centre of the trees may be kept open to facilitate infiltration of sunlight. Once proper frame work is thus established, minimal pruning may be needed for the removal of diseased, pest infested or dried shoots and overcrowding branches and those touching the ground annually, immediately after harvest of fruits. Occasional centre opening of the canopy once in three or four years, concurrently with the annual pruning, in overcrowded and old trees helps in getting good flowering and fewer incidences of pest and disease. Annual pruning assumes more importance under high density planting, to contain tree size and avoid overcrowding as well as to promote uniform vegetative growth soon after harvest, but this can vary with the variety, growing conditions and other vigour regulating practices followed. Tipping of primary, secondary and tertiary branches is also needed under high density planting during the initial years of orchard establishment to enhance branching and thereby fruiting terminals early and to give a compact shape to the trees

Nutrition and Integrated Nutrient Management

In general, 73g N (170g Urea), 18g P₂O₅ (112g single super phosphate) and 68g K₂O (114g muriate of potash) per plant per year of age from first to tenth years and thereafter 730g N, 180g P₂O₅ and 680g K₂O per plant per year can be applied in two splits – half N + full P₂O₅ and K₂O immediately after harvest of fruits in June - July and the other half of N in October, by broadcasting in the basins around the pants leaving about 30 cm from the tree trunk, followed by hoeing into a depth of 15 cm. Irrigation may be provided after fertilizer application if there are no rains. Well decomposed farm-yard manure may be applied every year. Application of FYM @ 25 t / ha is helpful in saline soils for mango plants to tolerate salt injury. Foliar spray of 3% urea is recommended before flowering in sandy soils. Precise fertilizer application has to be followed based on soil and leaf analysis. For nutritional diagnosis, 4 to 5 months old leaves from the middle of non-bearing shoots are used.

The optimum range of leaf nutrient concentration is tabulated below:

Nutrient	Optimum range
N	1.00 – 1.50%
P	0.08 – 0.25%
K	0.40 – 0.90%
Fe	50 – 250 ppm
Mn	50 – 250 ppm
Zn	20 – 200 ppm
Cu	7 – 50 ppm

Among the micronutrients, zinc deficiency is the predominant one, which can be corrected by three sprays of 0.3% zinc sulphate in February, March and May. Spraying 0.5% magnesium sulphate in February and April and 0.3% ferrous sulphate are helpful to correct magnesium and iron deficiencies. Spraying 0.5% Borax twice at monthly interval after fruit set and 0.5% manganese sulphate after blossom is useful to correct boron and manganese deficiencies respectively.

As a general practice, especially if multiple deficiencies limit fruit production, foliar spray with a mixture of micronutrients viz., zinc, iron, boron, copper, manganese and molybdenum and three secondary nutrients viz., calcium, magnesium and sulphur, which has been developed at ICAR-IIHR, can be sprayed @ 5g / L water once before flowering in October-November and once after flowering in February-March, which can solve most of the secondary and micronutrient deficiencies in mango

Nutrition (Alphonso) : Yield response surfaces of cv. ‘Alphonso' to major nutrients worked out based on sixteen years long field trial indicated that a combination of 100g N, 170g P₂O₅ and 80g K₂O/tree/year of age from 3^rd to 10^th orchard years and continuation of the 10^th year dose in subsequent years was optimum for maximizing the fruit yield under rain-fed cultivation. However, due to the marginal response to phosphorous nutrition, application of its high doses cannot be economical.

Nutrition (Totapuri) : For ‘Totapuri’ mango, application of nitrogen at 50g along with 20g P₂O₅ and 70g K₂O/ tree/ year of age, stabilized by the tenth year, is recommended for good growth and fruit yield under rain-fed cultivation

Canopy - Vigour management

Based on the performance of cv. Alphonso on eight polyembryonic rootstocks for twenty-two years, nucellar seedlings of Vellaikulumban and Olour varieties are identified as potential rootstocks for intensive cultivation of ‘Alphonso’ mango.

Annual application of paclobutrazol (0.25g ai/tree/year of age) as soil drench during October-November doubled fruit yield, suppressed excessive vegetative vigour and gave early crop harvest by a fortnight in cv. Alphonso.

Further, continuous application of paclobutrazol for three years was found to build up residual influence so that the dose could be tapered down or discontinued for one or two years without compromising the beneficial effects

Irrigation

Irrigation has to be scheduled depending on the soil and climatic conditions prevailing and age of trees. For young plants frequent watering is needed for proper establishment. During initial couple of years, protective irrigation is to be provided to the newly planted grafts at an interval of about 2-3 days while trees of 3-4 years can be irrigated at 4-5 days interval in summer. No irrigation is needed in rainy season unless there are long spells of drought and frequency can be reduced during winter months. In the case of grown up trees, irrigation at 10 to 15 days interval from fruit set to full maturity of fruits is beneficial for improving fruit size and reducing fruit drop. Irrigation is not advisable for 2 to 3 months prior to flowering, as it is likely to promote vegetative growth. Although basin irrigation was generally followed in mango orchards, drip irrigation is recommended for economizing the water use and the quantity of water to be given depends on tree age, canopy coverage, rainfall, evapo-transpiration etc. About 50% replenishment of evaporation losses is generally recommended under drip irrigation and 75% of recommended dose of fertilizers can be supplied through drip irrigation using soluble fertilizers. 

Inter-cultivation and Intercropping

In case of mono-cropping, the area between the basins should be ploughed thrice a year, mainly to control weeds. First ploughing is done just before the onset of monsoon to check run-off losses and facilitate proper in situ percolation of rainwater; second towards the end of rainy season to suppress the weeds and to break soil capillaries; and the third during last week of November, to check mealy bug population. Sod culture with regular weeding and earthing-up of the tree basins could be an alternative practice in mango orchards.

 Till mango attains 8 to 10 years age, a lot of inter-space remains unoccupied when planted at conventional spacing, which can be used to raise intercrops. Selection of intercrops depends on agro-climatic and socio-economic factors, but tall growing and exhaustive crops like maize, bajra, sugarcane etc., are to be avoided. Fertility restoring crops like legumes may be included in the intercropping pattern. Some dwarf, short duration fruit crops like papaya, guava and pineapple can also be grown in the interspaces. The water and nutrient requirement of the intercrops must be met separately. Besides intercrop, one may also grow some cover crops like sunhemp, daincha, cowpea etc., which can be sown with the onset of monsoon and ploughed into the soil towards the end of monsoon.

Rejuvenation

The old and senile orchards which have turned low yielding or unproductive may be rejuvenated by moderate to severe pruning of the tree canopy followed by intensive nutrition and plant protection measures with paclobutrazol application to promote flowering. Pruning 30 cm from point of origin of third order branches increase fruit yield during subsequent years. Mechanization of the pruning with appropriate machinery could be helpful in reducing the labour cost involved. Top working with improved varieties / hybrids can also be an option for inferior varieties and seedling trees. Top working may be done in pencil size healthy shoots emerged after heading back of tree to scaffold branches at a height of about 3 to 4 feet from the ground, after harvest of fruits.. Growing some intercrops in the interspaces facilitated by the reduction of canopy size following pruning or top working could be considered for additional income till the canopy coverage completes in such orchards.

High density planting of Alphonso at 1111 trees per hectare on Olour rootstock with annual paclobutrazol application from fourth year at 0.125g / tree/ year of age, stabilized by the tenth year gave fivefold increase in productivity of fruits during the initial fifteen orchard years, over the conventional planting at 100 trees per hectare on random rootstock.

Medium density planting of ‘Alphonso’ at 400 trees per hectare on ‘Vellaikulumban’ rootstock without paclobutrazol application gave 3.5 times increase in productivity of fruits during the initial fifteen orchard years, over the conventional planting at 100 trees per hectare on random rootstock.

Pruning the trees at 5m height followed by application of 800g N + 300g P₂O5 + 1000g K₂O + 50 Kg FYM + 4.0g paclobutrazol / tree identified as rejuvenation package for old and unproductive ‘Alphonso’ mango trees.

Harvesting

Mango fruits should be harvested at optimum stage of maturity as immature fruits have inferior quality and over mature fruits have poor shelf life. Mangoes should be harvested at mature green stage, which can be judged, depending on the variety, by fully developed cheeks with outgrown shoulders, formation of a depression at the stalk end, visibility of lenticels, change in skin color from dark-green to light-green, change in pulp color from white to yellowish, when specific gravity of the fruit ranges between 1.01 and 1.02 or when one or two ripe fruits fall from the plant naturally. 

The method of harvesting mango in many growing areas is primitive, by shaking the branches, which cause injury to fruits. If harvesting is not done properly, it will injure the fruits which may be visible or not, but becomes entry point for microorganisms causing spoilage during ripening. So, mangoes should never be knocked from the tree, dropped or thrown to the ground. Where possible, mangoes should be harvested by hand with a certain length of the stalk. Where this is not possible, mango harvesters having long pole with a cutting blade and a small bag beneath to catch the fruit should be used.  Keep the harvested fruits in a cool place away from direct sunlight and heat to avoid accelerated metabolic activities and ripening that reduces the shelf life, and in case of Alphonso, promote spongy tissue incidence. After harvest, latex should be allowed to drain away from the fruit by placing them in inverted position over bamboo or gunny thread netting for 20 to 30 minutes or until the sap flow is stopped, with the stalk clipped short (1 cm), while holding the fruit with stem end down. The sap if fallen on the fruits will burn the fruit skin, leaving a blemish (sap burn) during ripening.  Fruits should not be allowed to come in contact with the soil at any stage as soil sticks to the latex and scratches the peel and microorganisms may enter from the soil through stalk or injuries. The fruits can be placed in plastic crates for handling and transportation and the use of bags, sacks and baskets should be avoided as these generally result in mechanical damage and bruising. Uniform ripening of mature mangoes could be hastened by exposure for 18-24 hours to ethylene gas, either direct from cylinders, ethylene generators or as liberated from ethephon/ethrel using alkali, in an air tight chamber or room. Optimum temperature for storage of mango is 13°C and 85 - 95% relative humidity, while that for ripening is 20° - 25°C.

Fruit yield

The yield depends on variety, growing conditions and management practices. Grafted plants start bearing at the age of 3 - 4 years (15-20 fruits / tree) and start to give optimum yield from 10^th to 15^th year (400 -600 fruits / tree) which continues to increase up to the age of about 40 years (about 2500 fruits / tree) under ideal growing conditions and good orchard management.