Amroha is the land of mangoes and carps… it looks mysterious because we couldn’t understand the relation between mangoes and carps at first instance. Although Amroha is an ancient place and has rich history but its cultural revolution taken place in medieval times when Hazrat Syed Sharfuddin Shahwilayat (ra) reached Amroha. He came from Middle East (Iraq) and instructed (as per folks) that you should go to the place and reside there where you will find mangoes and carps (rohu fish). No doubt that he came across many towns and cities before reaching Amroha which surely have carps and mangoes because in north India you can find mango and rohu fish at almost every place from Lahore to Punjab to Amroha. Aam and rohu is very common to most of the towns if not all. So why he choose only Amroha to live?. Surely there might be some other reasons against this common belief to reside in Amroha but this is still a mystery and we will speculate it in future inshallah . Whatever is the reason but now Amroha is famous for mangoes. So this article is written for mango cultivators of Amroha (recommendations are general which can be follow at any place in northern India). About carps we will discuss in some other articles.
Centuries old culture of mango cultivation in Amroha
Amroha has more than 100 types of descripted and non-descripted varieties of mangoes, so its diversity is very high which make Amroha unique place for mangoes. There are so many fruits in the world but no other fruit has same value as that of mango. Some people called it King of Fruits (phalo ka raja). As per my opinion it is absolutely true and it has some uniqueness and that uniqueness is hidden in its diversity. Now see this, you eat apple it has same taste whether it is Himachali, Kashmiri or from United Kingdom, same is true for litchi, chiku or grapes. But when you eat dusseri you will have absolutely different taste sensation than landga or chaunsa. Although all are mangoes having same physiology but taste is different and no mango is superior to other on the basis of taste. All are equally well and I love this variation. Let us have a look for its commercial value and how we can improve the productivity.
Why I am sharing this knowledge – saving mango orchards – a tribute to my father
My farther also loved mangoes and he had taken orchards on rent during mango blossoming seasons. I loved to went those orchards along with him on cycle (not less than 15 Km from my home). He had passion for mangoes, although he hardly made any profits out of it but even then he always taken mango orchards on rent and use to live there in the nights. He taught me many practical things about mangoes like how to recognize variety by looking its shape and size. I was hardly 9 or 10 years old. He suffered huge losses and my mother scolded him for wasting money year after year. I wish I could help him to increase the productivity and help him to save his money with my knowledge, but he is not present today to take my help. But I want to reduce sufferings of farmers who are passing through same situations.
Mangoes – Brief account on its present status in India
Mango (Mangifera indica L.) is the choicest fruit of India in terms of not only production but also economic importance and acceptability by the consumers. It is grown in around 87 countries in the world but nowhere it is as greatly valued as in India where it covers around 36 per cent of total fruits growing area. Owing to delicious taste, succulence type and exotic flavour it enjoys the same popularity in the tropics as apple in the temperate region. India is the largest producer of choice table varieties of mango in the world. More than 1000 mango varieties are under cultivation in India, each differing in shape, size and taste. But the production share of mango in India is quite low (20.3%) with total annual production of only 15.19 million tons due to low productivity (6.6 tonnes/ha). Despite India has got excellent export mango varieties (Dashehari, grown in northern India, Alphonso and Kesar in western India and krishnabhog, Gulabkhas and Himsagar in eastern India) it occupies just fourth position in mango export market of the world with Philippines being the first.
Among the different factors responsible for low productivity and low export potentiality,physiological disorders associated with mango is one of the main factor which affects mango cultivation at all stages, right from the plants in the nursery to the fruits in storage or transit. These physiological disorders not only reduce the production efficiency of the tree but also hamper the fruit quality which is the key factor for export, resulting huge economic losses to the growers every year. Therefore, to obtain higher mango production with better quality, utmost attention must be given to solve the problems of physiological disorders.
Details of different physiological disorders along with their management strategies are as follows:
Alternate Bearing: it means trees give fruits every third year (first, third, fifth like this) This is one of the most burning problems of mango cultivation as it renders mango cultivation less remunerative to growers. It causes huge economic burden over farmers and they suffer losses in the form of land depreciation and product stagnancy.
It signifies the tendency of mango trees to bear a heavy crop in one year (on year) and very little or no crop in the succeeding year (off year). Most of the commercial varieties of north India, namely, Dashehari, Langra and Chausa are alternate bearers.
Reason: Generally mango trees when laden with fruits, they do not produce new shoots. Even after harvesting, if new shoots are produced, they are negligible in number and do not flower in the coming year because new vegetative flush of mango required a certain amount of maturity (8-10 months) for flower bud differentiation.
It can be understand; first year it flowers and gives fruits à in second year new shoots will be seen in march April à then in third years it fruits again.
Moreover, when a tree produces heavy crop in one season, it gets nutritionally exhausted failing to yield in following season. Besides climatic factors, C/N (carbohydrate/nitrogen) ratio and hormonal imbalance also play vital role to cause alteration in bearing in mango.
· Paclobutrazol (PP333) @ 4 g/tree as soil and foliar spray in September results early maturation of vegetative flush and commencement of flowering in the following year.
· Deblossoming of some ‘on year’ flowers and pruning (selective removal of parts of a plant, such as branches, buds,) of the tree just after harvesting will maintain proper physiological balance between vegetative and reproductive growth and permit ample amount of sunlight to reach the inner area of the orchard resulting in better performance of the tree every year. Moreover pruning also helps to produce some new shoots just after harvesting which may mature in the next flowering season.
· Flowering in ‘off’ year’ can also be induced by smudging. Smudging in mango is carried out by building slow fires, emitting smoke under mango tree. Similarly, application of Ethrel can also induce flowering.
· Growers who are in primitive stage of mango cultivation can select cultivars like Amrapali, Mallika, Ratna, Dashehari-51, Pusa Arunima, Pusa Shrestha, Pusa Pitambar, Pusa Lalima, Pusa Pratibha, Arka Anmol, Arka Aruna, Arka Puneet, Arka Neelkiran for commercial cultivation as they are regular bearing in nature. Rejuvenation of old mango tree by grafting or budding with regular bearing varieties are also recommended to convert the alternate bearing habit into regular one.
Mango Malformation: It means improper shape and size of mango which render it less attractive and poor economic value. During last few decades farmers particularly in northern India facing huge problem due to this disorder. Although, it was first observed in 1891 in Bihar but now it is an alarming threat in Punjab, Delhi and Uttar Pradesh.
It is mainly of two types: vegetative and floral.
Vegetative malformation is more common in nursery seedling and in young plants. Malformed vegetative shoots assume the appearance of bunchy top with narrow scaly leaves. Vegetative buds growing in cluster, swells and losses the apical dominance. Almost all the commercial mango cultivars like Bombay Green, Dashehari, Lucknow Safeda and Chausa show huge susceptibility to this malady, however the cultivar Baramasi is less affected. Cultivars like Ellaichi, Alib and Bhadauran are totally free from this disorder but their fruit quality being not superior; their use is limited to only for resistant breeding not for commercial cultivation. Scientist from different part of the country reported that a fungi- Fusarium moniliformae var. subglutinans is highly associated with this disorder. Temperature range of 21-27°C (max.) and 8°C (min.) along with relative humidity of 85% during late winter or early spring is conducive for the growth of the fungi, resulting severe incidence of malformation on newly emerged panicles.
· Application of NAA/ Planofix (200ppm) during October, prior to fruit bud differentiation followed by de-bloosming of newly emerged panicles or bud during January- February is beneficial to control the disorder.
· Spraying of different phenolic compounds like catecal, cynamic acid, tannic acid during 1st week ofOctober at 2000 ppm is equally effective in reducing floral malformation.
· Several anti-malformins have been suggested for beneficial results when sprayed on panicles just after emergence (4-6 cm). Sprays of glutathione at 2250 ppm, ascorbic acid at 2110 ppm, AgNO3 at 600 ppm have also been found effective to control the malformation.
· Application of nutrients likes P & K and micronutrients especially Zn & B just after harvesting are quite effective in reducing the incidence of malformation. Application of moderate amount of N helped to minimize the vegetative malformation while Zn and B helped in biosynthesis of auxins which ultimately helps to reduce the incidence of mango malformation.
· Removal of just emerged malformed panicles or vegetative shoots at a distance of 15-20 cm below the point of occurrence is beneficial to minimize the spread of disorder further.
Black Tip: This malady is widely prevalent in Punjab, Uttar Pradesh, Bihar and West Bengal. It causes considerable economic losses to the growers. Among the commercial cultivars, Dashehari is the highly susceptible one, while Lucknow Safeda is the least. This disorder has mainly detected in orchards located in the vicinity of brick kilns. Gases like carbon dioxide, sulphur dioxide and ethylene constituting the fumes of brick kiln, damage growing tip of fruits and give rise to the symptoms of black tip.
· Establishment of the orchards away from brick kiln by at least 1.6 km in east to west and 0.8 km in north to south direction and increasing the chimney height to at least 15- 18 metres can be preventive measures for this malady.
· Spray 1 per cent borax (10g/lit) thrice first before flowering, second during flowering and third at fruit set stage is very effective. Moreover, spraying of other alkaline solutions like caustic soda (0.8%) orwashing soda (0.5%) at pea stage followed by two more sprays at 15 days interval may neutralize the acidic fumes of brick kilns, precipitating on the tip of the fruits.
Spongy Tissue: This is caused because ripening enzymes during fruit maturation stage become inactive due to high temperature, convective heat and post harvest exposure of fruit to sunlight which results in the development of non-edible, sour, yellowish and sponge like patch with or without air pocket in the mesocarp of the fruit during ripening. In extreme cases, the whole fleshy portion becomes too soft resembling bacterial rot.
· Harvesting of fruits at 3/4th maturity stage and post harvest exposure to low temperatures between 10-150C for 10-18 hrs has been beneficial in reducing the disorder.
· Sod culture with Eragrostis (Spartina) cynosuroides, cover cropping etc. should be used in the orchard to reduce direct heat radiation from soil which ultimately minimizes the raise of convective heat from the ground.
· Use of black poly-ethylene mulch is recommended for spongy tissue prone orchards.
· Resistant varieties for new cultivators like Ratna, Arka Puneet, Arka Aruna which have Alphonso like character should be planted in the orchard.
Fruit Drop: Despite initial high fruit set, the ultimate retention is quite low in mango (only 0.1% perfect flowers develop fruit to maturity). The intensity of fruit drop varies from variety to variety. Among the commercially grown varieties, Langra is more susceptible to drop while Dashehari is the least. Fruit drop in mango is classified into three groups: (i) Pinhead drop, (ii) Post setting drop and (iii) pre-harvest drop (May drop).
The first two drops causes less economic losses to the growers but the third group is most destructive and cause huge economic losses to the growers as the fruits totally drop down at pre-harvesting stage.
· The extent of fruit drop in mango can be significantly reduced by regular and frequent irrigationsduring the entire fruit developmental period.
· Orchards should be protected from desiccating winds (Andhi) by planting wind breaks.
· Timely and effective control measures against major pests and diseases should be adopted.
· Growth regulators like NAA and 2,4-D in varying concentration depending upon the variety and time of application can be sprayed. The optimum concentration lies between 10- 15 ppm during the month of April-May.
Clustering (Jhumka): It implies the development of fruits in clusters at the tip of the panicles (A panicle is a much-branched inflorescence). Such fruits do not grow beyond pea or marble stage and drop down after a month of fruit set. Mainly it is due to lack of pollination / fertilizationwhich may be attributed to many reasons such as the absence of sufficient population of pollinators in the orchards (lower bee and butterfly population), indiscriminate spray of pesticides during flowering,spraying of synthetic pyrethroids, monoculture and bad weather during flowering.
· Spraying of pesticides during flowering should be avoided. Apart from this, monoculture in the orchard should be avoided by planting at least 5-6 per cent of other cultivars in new plantations.
· Introduction of beehives in the orchards during flowering season for increasing the number of pollinators.
Internal Fruit Necrosis: It is characterized by the appearance of dark green colour in lower half of the fruit followed by browning of the seed and mesocarp which ultimately turned into brown black necrotic lesion. It is mainly due to boron deficiency.
This disorder can be corrected by soil or foliar application of boron. For soil application, Borax @ 500 g per tree should be incorporated at the time of October fertilization. Foliar application of 1 % borax is recommended at the time of fruit set (pea size stage) followed by two more sprays at 10-15 days interval which will minimize the disorder to a great extent.
Leaf scorching in mango: The characteristic symptom is akin to that of potash deficiency i.e.scorching of old leaves at the tips or margins. The leaves fall down and consequently, the tree vigour and yield is reduced. It is mainly due to excess of chloride ions which render potash unavailability. This disorder is more common in saline soils or where brackish water is available for irrigation or where muriate of potash is used as a fertilizer to meet the potash requirement of the plants.
· It can be checked effectively by collecting and burning the fallen leaves and using potassium sulphate instead of muriate of potash.
· Acute condition can be cured by 4-5 foliar applications of potassium sulphate on newly emerged flushes at fortnightly intervals.
Conclusion: Among all the physiological disorders associated with mango, none is due to a single factor but all are due to the amalgamation of several factors like genetic factors, environmental factors, nutritional imbalance, poor cultural practices in the orchard, etc. So, it is very difficult bring a affected orchard into a healthy orchard in a single step within one or two years. But proper cultural and management practices like application of required fertilizers at proper stage, pruning of some old branches just after harvesting, debloosming of some flower buds during February-March,application of recommended plant growth regulators at proper stage etc. can prevent the disorders to a large extent.