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
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
