10-Alternate Bearing.ppt

21 de Mar de 2023

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10-Alternate Bearing.ppt

  1. Alternate bearing
  2. Alternate Bearing Habit of bearing heavy crop in one year (On year), followed by a little or no crop in the subsequent year (off-year). It exist in the history ( 1590) some mango varieties produced rich harvest one year and no fruit at all in the following year. Mango, Apple, Citrus, Plums, Pistachio and loquat
  3. Alternate bearing • Mango do not produce uniform crop • If crop is 40:60 instead of 50: 50 • But If 20:80 or 10:90 • This is not common in all orchards
  4. Factors Contributing Alternate Bearing Environmental factors Physiological factors Genetic factors A- Environmental factors (temperature, humidity and pests/diseases) 1. Heavy frost at bud opening in spring 2. Rain and high humidity at Blooming 3. Hails at fruit setting 4. Disease attack at fruit setting 5. Attack of insect pest (Mango hopper or mealy bug)
  5. Environment factors • Due to these factors flower shedding, fruit shedding in early stages leads to poor harvest • May be more vegetative growth and bumper crops in next year
  6. If above factors severe; may damage the opening of buds, flowers or young fruit and reduce crop load, with little crop of mature fruit in that year secondly too much growth (early shoot growth) bear heavy crop in following year and set biennial cycle of fruit production. 2-Physiological factors 1. Carbohydrate nitrogen ratio 2. Shoot or spur growth 3. Intensity of blossoming 4. Age of tree
  7. High C:N ratio in Langra and Dusheri accompanies the fruit bud differentiation period of the 0n-year crop while low ratio is found in the off-year Regular bearing varieties often have balance C:N ratio to coincide the time of fruit bud differentiation 1- Carbohydrate nitrogen ratio 2- Shoot or flush growth In Mango flushes appearing early in season bear higher percent of flowers in the following years than that emerging later; allowing long period of physiological maturity of shoot growth favour accumulation of photosynthesis materials result in heavy crop in the following year and start biennial cycle
  8. Shoot growth • April flush 36.7 % • May flush 29.4% • June flush 19.8% • July flush 11.0% • August flush 7.0 %
  9. B Physiological • Intensity of blooming • (excessive blooming retards the vegetative growth early in the season which provide the favorable condition for alternate bearing
  10. B Physiological • Age of the tree • Young tree bear regular crop • Older tree do not • Because aging factor by it self reduced the vigor thus they can not maintain balance between the vegetative and fruiting so plants deteriorate in health and vigor
  11. C- Genetic factors Alternate bearing vrs. Mango: Langra, Fajiri, Summar Bahisht, Sanghlakhi, Dusehri, Totapari, Romani, Fazli Apple: Delicious, Grimes Golden Regular bearing vrs. Mango: Neelum, Benglore.hybrid varieties Apple: McIntoash, Rome Beauty
  12. Factors involved in the control of alternate bearing Most of the cases the alternate bearing is of physiological nature. If the tree is physiologically so balanced as to produce enough new growth early in season along with fruit in on-year it could be possible to differentiate fruit bud annually. 1- Cultural Practices Ploughing, manuring, irrigation, nutrition maintain good health. In on-year good fertilization would induce more shoot or spur growth and help shoots to mature with in a short period of time so that they might bloom next flowering season.
  13. Cultural Practices • Proper cultivation, • balanced nutrition, • proper irrigation • Effective weed control • Pruning for sunlight
  14. 2. De-blossoming • Thinning usually reduces the total yield but when properly carried out increase the economic yield • Reduction of flowering intensity •
  15. 2- Thinning of flowers and young fruits Removal of certain portion of crop during on-year S No Material Dose Time 1 DNOC (dinitro-orthocresol) ⅔ kg 100 /Gall. water Full bloom 2 Sevin ½ kg 100 /Gall. water 14-21 DAFB 3 NAA 10-20 ppm 14-21 DAFB 4 TIBA (triiodobenzoic acid) 50-75 ppm 21 DAFB 5 Ethaphon 50-100 ppm Full bloom
  16. Nutrients spray • KNO3 12.5 g/liter produce uniform flowering • Urea 2-4% also minimize the alternate problem
  17. 3- Ringing and girdling To bring balanced C:N ratio Ringing/girdling treatment in August just before flower differentiation 4- Time of harvest Early harvest during on-year Late/delayed harvest during off-year 5- Pest and disease control Pre-blossom spray of insecticides to control, hoppers, mealy bugs etc Multiple sprays of Bordeaux mixture in Feb., April and September in mango to control anthracnose
  18. 6- Protection against frost Smoking Wind mills Sprinkler irrigation 7- Regular bearing varieties Selection of regular bearing varieties Hybrid varieties in mango in india