Almonds

• Almonds have complete and perfect flowers
• Almonds have very low chill requirements, being about 200-300 hours
• Vegetative growth occurs on lateral buds, stems, terminal buds, and on spurs
• Vegetative growth is directly behind bloom and very early
• Flowering occurs in Febuary
• Vegetative growth occurs in Spring (march and april)
• Vegetative growth can happen as late as June depending on the management used
• Vegetative growth can be affected by lack of N or water
• Most vegetative growth stops before June
• Almonds have a heat-induced dormancy because the vegetative growth will stop in summer
• Flower bud initiation for the next year occurs in late summer to early fall
• Too much drought stress can cause a negative impact on next year's growth
• Most of the reproductive growth happens on the long-lived spurs
• The spurs alternate bare, but the tree and orchard does not
• Reproductive growth mainly occurs on developing spurs with a little bit on 1-year old growth
• The productivity of a spur is determined by the leaf area of a spur from last year
• It is necessary to promote and support vegetative growth and spur health
• Potassium plays a big role in reproductive growth
• 20% of spurs typically set fruit in a year due to self thinning
• The flower will produce pollen and nectar which is helpful to attract bees
• Almonds are an early flowering crop
• There are 3 waves of nut drop
• The first wave of nut drop occurs days after bloom which is before the ovule enlarges and is the drop of all fruits that were unsuccessfully pollinated
• The second wave of nut drop happens weeks into bloom and drops all crop that was not properly fertilized
• If nuts are not properly fertilized there will be slight ovary enlargement but then it stops and drops
• The third wave of nut drop is June Drop
• June Drop occurs in April to May
• June Drop causes fertilized fruit to stop growing and abscise at the pedunckle
• June Drop can be influenced by climate and cultivar
• Post June Drop most of the remaining flowers will set fruit
• Almonds have gametophytic self incompataibility
• Almonds have compatible and incompatible pollen tubes
• Almonds are incompatible to pollen from other cultivars that have a similar genetic makeup
• The pollen tubes won't grow properly when there is self incompatibility
• If the pollen grain has the same genetic makeup then the plant will stop the pollen tube growth
• The plant has a gene that is able to recognize and codes for self incompatibility
• Self incompatibility promotes genetic diversity
• If you grow a self incompatible cultivar you will need at least 2 other cultivars, usually more
• An allele us an alternate version of a gene. The plant gets one copy from each parent
• Even if the pollen is only half compatible then it can still be fertilized but it is recommended that the plant is fully compatible