Mango

Training And Pruning

  • Mango being and evergreen plant requires very little training and pruning.
  • Training of young plant is done in early years of planting by removing side branches upto the height of one metre from the ground level and side branches are allowed to grow beyond 1 metre height.
  • Such type of initial training provides good architecture of the plant and it is helpful in good fruit production.
  • Most of the cultivars of mango grow erect, from a natural dome shape canopy and having symmetrical branching need only occasional pruning.
  • Generally dead, diseased or criss-cross branches are pruned.
  • Severe pruning is needed only in high density of Dashehari mango.
  • This pruning is done just after crop harvest and it is also called as summer pruning. In this pruning every shoot is cut back 2-3cm from growing point followed by spray of 1% urea and 0.1% copper pruning mango.

Effects of Pruning and Thinning

  • An experiment was conducted at Coimbatore on two large healthy Mulgoa trees more than 45 years old, but with poor and erratic cropping.
  • During August-September 1972, pruning was done firstly by removing some of the big, criss-cross branches so as to permit full sunlight penetration inside the tree and secondly by thinning out the shoots to retain only one or two vigorous shoots out of the 3-5 in a cluster.
  • The thinning out of shoot clusters was continued during the subsequent years also.
  • Soon after, each tree basin was opened and irrigated after application of 200 Kg well rotted farmyard manure and 5kg each of ammonium sulphate, super phosphate and muriate of potash.

Yield and Cropping

  • It could be seen that, prior, to pruning, fruit yield from the two Mulgoa trees was not only erratic but never exceeded 214 kg and after pruning in 1972, it slowly increased every year reaching 1194 kg in 1977, remained above 400 Kg until 1984 and declined later but was never below 108 Kg.
  • During 1981, at Madurai, pruning 13 year old erratic bearing cultivars Himayuddin, Rumani, Kalepad and Pottalma also registered significantly higher yield compared to that in unpruned trees.
  • In Himayuddin, the yield increased to 195 Kg in 1983 from only 13Kg prior to pruning, in Rumani to 62Kg, in Kalepad to 55.5 Kg from 21.5 Kg and in Pottalma to 42.77 Kg from 19.42 KG.
  • Interestingly, in addition to the crop at the terminal ends of the shoots, fruits were also produced from old branches.
  • It, therefore, appears that the apparently quiescent fruit bearing buds were activated by the treatment owing to the redistribution of the nedogenous hormnal substances, to favour flowering and fruiting.
  • In pruning studies to rejuvenate 55 years old mango trees, yield of 298.4 Kg in the on years and 158.1 kg in the off years was obtained by removal of secondary branches keeping the leader intact and application of 1.5 Kg N, 0.75 Kg P2O5 and 1.5 Kg K2O per tree.

Dry Matter and C/N Ratio

  • As a result of pruning, the dry matter content in leaf and stem reached the maximum by October-November so that the C/N ratio was the highest during November-December in Neelum, Banglora, Mulgoa and Peter cultivars.
  • This seems to be owing to increased photosynthetic efficiency as a result of improved light penetration in the trees.
  • High C/N ratio, however, did not always govern the fruit bud formation but the accumulation of starch at critical period was of special significance for fruit bud formation.

Ribonucleic Acid (RNA)

  • As a result of pruning, the RNA content of leaf, which attained the maximum level at the time of flower bud formation, was significantly higher during the second normal year than in the first learn year.
  • The treatments did not affect the RNA content in all the cultivars or in both the years.
  • The RNA content gradually declined after October-November.
  • A higher RNA content at pre-flower bud formation stage and declining trend with the progress of flower bud formation, were also demonstrated in the mango cultivars Langra and Fazil.
  • Increased RNA contents coinciding with flower bud formation in Mulgoa, Banglora, Neelum and Banganapalli have also been reported.

Ascoribic Acid

  • The second peak in ascorbic acid content in leaves during November after the first in September synchronized with the time of flower bud formation.
  • The treatments of pruning and thinning or thinning alone increased the ascrobic acid content from September onwards with a varying response in different cultivars the ascrobic acid content of mango leaves reached a major peak in November coinciding with flower bud formation.

Total Phenolics

  • Pruning and thinning or thinning alone increased the total phenolics content as a result of improved light conditions of trees.
  • Phenolic acids have been shown to act as inhibitors similar to abscisic acid to be favourable to flower bud formation in mango.
  • The total phenolics content in the leaves of a flowering shoot was higher than in a vegetative shoot.

IAA-Oxodase Activity

  • Lower IAA Oxidase activity was observed as a result of pruning and thinning which possibly made optimum levels of auxin available to favour flowering.
  • However, higher auxin level at the time of flower bud formation has been reported but its precise role in mango is still unclear.

Respiration Rate

  • The respiration rate of leaves showing two peaks in September and during November-December, coinciding with flower bud formation and flowering, increased as a result of pruning and thinning.

Gibberellin-like Substances

  • The gibberellin-like substances in the leaves of pruned trees were found to be lower than those of unpruned trees except in the yound Mulgoa trees during the normal year.
  • Lower contents were associated with normal flowering in mango.

Cytokinin-like Substances

  • The levels of cytokinins which have been reported to favour flowering were found to increase as a result of pruning treatments in mango cultivars.
  • Higher levels of cytokinins in the bark samples from the region where inflorescence is induced as a result of pruning indicates that its increased flow in the xylem sap seems to have released the latent buds from their innate dormancy resulting in cauline flowering.
  • Application of N6 benzyladenine to lateral buds after partial defoliation retaining the fifth nodal leaf for the production of floral stimulus and to the decapitated shot tips stimulated flowering in the lateral buds of cultivar Mulgoa.
  • Removal of the competing sinks, leaves and shoot tips is likely to have improved the sink capacity of the lateral buds.

ABA-like Substances and Ethylene

  • The presence of presence of an inhibitor, similar to abscisic acid, which was antagonistic to GA3 and auxin.
  • Pruning treatments increased the inhibitor levels at the time of flower bud formation in the four cultivars during both the years.
  • The increase in inhibitor levels due to pruning and thinning may be ethylene mediated since ethylene production following injury by pruning treatments was increased.
  • The inhibitor and ethylene levels were found to be higher in bark samples from the region where inflorescence were produced as a result of pruning than in the region of a vegetative shoot or dormant bud.
  • Exogenous application of ethereal has been reported to inhibit vegetative growth of shoots and promote flowering in mango.

Top-Working Inferior Seedling Trees

  • One of the main handicaps that has led to slow pace of evolution of the mango industry in India is the preponderance of seedling trees which are mostly of inferior type:
  • In a pilot sample survey to study yield and cultivation practices of mango conducted by the Institute of Agricultural Research Statistics in the Varanasi and Saharanpur districts of Uttar Pradesh, it was reported that a substantial proportion (76 and 57% respectively) of mango trees in both the districts is of seedling (desi) type.
  • Thus a majority of the mango plantings in the countryside comprise inferior seedling trees.
  • Although commercially of little value, these trees could have been exploited for other suitable characters of value.
  • However, no organized effort has been made so far in this direction.
  • It is estimated that about 20,500 ha (50,000 acres) of the total area under mango is likely to be under seedling trees, of under 30 years.
  • The seedling trees in the countryside are mostly close plantings.
  • Manuring of such orchards is rare.
  • Thus due to bad sanitation the trees are generally affected by mango hopper, stem borer, shoot borer, die- back, gummosis, powdery mildew, black tip and mango malformation.
  • Of these, the first 2 are the most serious pests affecting mango trees.
  • Unless proper care is taken to control them, heavy loss in yield occurs.
  • Besides, the trees are erratic in their bearing habit and the fruits produced are mostly of inferior quality, fetching little price in the market.
  • Because of their large stature, it is difficult to apply insecticidal and fungicidal sprays.
  • Thus such plantings are more a liability than an asset
  • Young seedling trees below 20 years can conveniently be top- worked with scion woods of commercial varieties.
  • It is here that the technique of veneer grafting can be put to a maximum use.
  • Hence the importance of veneer grafting to mango industry is tremendous, provided adequate efforts are made all over the country to utilise this innovation properly.
  • At this Institute, a number of seedling trees under 16 years have been veneer grafted with the varieties 'Dashehari', 'Chausa' and Langra', after being headed back early in the spring season.
  • After heading back new shoots arise in the spring, which are ready to be veneer grafted during the rainy season.
  • If the tree is older, it is better not to head back all the main branches simultaneously, to avoid a sudden shock to the tree, which could result in the splitting of the bark of the main stem.
  • The tree can be converted into a commercial variety in stages.
  • The main trunk of this tree should be wrapped with hessian cloth or gunny bag during winter to avoid bark splitting.
  • Such top- worked trees start giving commercial crop in the third year of the top- working.

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Andhra Pradesh