Flowering Habits of Fruit and Nut Crops
HORT 319 Temperate Fruit and Nut Production
Plant Development Stages
Juvenile phase
Not inducible to flower Basal portion remains juvenile Rooting ease
Adult phase
Minimum size, delayed by slow growth Apple, 16-20 nodes Non flowering adult phase varies with spp/cv
HORT 319 - Temperate Fruit and Nut Production
Plant Development Stages
Juvenile phase Adult phase Effect of budding
Use adult bud Flower more rapidly than seedling
HORT 319 - Temperate Fruit and Nut Production
Flowering Habits
Summer before
Same year
Quince Strawberry
Most initiate the summer before flowering
Stone fruit Apple and pear Blackberry Blueberry Grape Kiwi Fig Pecan - male Walnut Pistachio Persimmon
HORT 319 - Temperate Fruit and Nut Production
Fig Pecan - female
Flowering Habits
May coincide with fruit development Crop load, culture, and climate at this time affects next years crop
Bloom
Fruit bud development Fruit development Leaf fall -2C to -8 C Deacclimation -21C to -28C Endodormancy or Rest
Chilling
Bloom Heat Accum.
Endodormancy
Growth begins
Spring
Summer
Fall
HORT 319 - Temperate Fruit and Nut Production
Winter
Spring
Age of Fruiting Wood
Current Season
Quince Strawberry Fig
One-year Old
Peach Almond Persimmon Blackberry Blueberry Grape Kiwi Pistachio Pecan-male
Two-year Both 1&2Old Spurs year
Cherry Apple Pear Plum Apricot
Pecan-female
HORT 319 - Temperate Fruit and Nut Production
Alternate Bearing
Cycle of alternating heavy and light cropping years
Apples, pecans, plums, apricots, pistachios
Due to poor flower initiation during heavy cropping year
Response to developing embryo GA inhibits flower bud initiation Nutrients do not appear deficient
Management: control the crop load
HORT 319 - Temperate Fruit and Nut Production
Factors Affecting Fruit Bud Initiation
Precocity: Scion and rootstock Pruning
On young trees encourage vigorous growth
Bending
Encourages fruit bud initiation
Girdling
May increase if done early spring
HORT 319 - Temperate Fruit and Nut Production
Effect of bending on flowering
HORT 319 - Temperate Fruit and Nut Production
Factors Affecting Fruit Bud Initiation
Chemicals
Thinning agents Hormones - auxin and GA
Tree Growth Rate Crop Load Environmental Factors
Good nutrition Excessive heat/drought Insufficient chill
HORT 319 - Temperate Fruit and Nut Production
Pollination
Pollinator
vs. Pollinizer
Pollinator is the agent of pollen transfer (e.g., a bee) Pollinizer is the source of pollen
HORT 319 - Temperate Fruit and Nut Production
Pollination
Importance of Pollination
Needed for fruit set Seed development affects fruit growth
Fruit shape Fruit size
Cross pollination can enhance set over self pollination
HORT 319 - Temperate Fruit and Nut Production
Pollination
Wind pollination
Pecans, walnuts, pistachios, filberts
Insect pollination
Pome fruit Stone fruit Small fruit
Parthenocarpic set
Persimmons, common figs, and some pears
HORT 319 - Temperate Fruit and Nut Production
Pollination: Terminology
Self compatible or self incompatible Self fertile or self sterile Self fruitful or self unfruitful
Monoecious Dichogamous Protogynous Protandrous Dioecious
Staminate plant Pistillate plant
HORT 319 - Temperate Fruit and Nut Production
Wind Pollination Pecans and Walnuts
Dichogamous Monecious Self fertile
HORT 319 - Temperate Fruit and Nut Production
Wind Pollination Pecans and Walnuts
Types of varieties
Protandrous = male 1st Protogynous = female 1st
HORT 319 - Temperate Fruit and Nut Production
Wind Pollination Pecans and Walnuts
Pawnee Cheyenne Wichita Choctaw
Protandrous
Protandrous Protogynous Protogynous
Catkins shedding pollen Female flowers receptive
Pollen shed best
Low humidity (< 85% relative humidity) Slight breeze
HORT 319 - Temperate Fruit and Nut Production
Wind Pollination Pecans and Walnuts
Timing of pollen shed and female receptivity varies with the climate
Cool climate Hot climate Catkins shedding pollen Female flowers receptive
Protandrous
Thus in pecans orchards, 3 complementary cultivars are recommended
HORT 319 - Temperate Fruit and Nut Production
Wind Pollination Pistachios
Dioecious One staminate plant per 10 pistillate plants recommended
HORT 319 - Temperate Fruit and Nut Production
Insect Pollination: Pollinizer Need of Crops
Self fruitful
Peach Apricots* European plums* Tart cherry Strawberry Blackberry Highbush blueberry Grapes Walnuts+ Pecans+
Self unfruitful
Apple Pear Asian plums Sweet cherry* Almonds* Rabbiteye blueberry Lowbush blueberry
* also self fruitful/unfruitful types, + dichogamous so need pollinizers
HORT 319 - Temperate Fruit and Nut Production
Insect Pollination: Pollinizer Choice
Cross
compatibility of varieties Bloom overlap Pollen production Culturally compatibility Comparable pest/disease management needs Produce good fruit if possible
HORT 319 - Temperate Fruit and Nut Production
Pollinizers for Asian Plums
Range from self fertile to self incompatible
Laroda Laroda Mariposa Queen Rosa Santa Rosa Mariposa
Queen Rosa Santa Rosa
O F G G
F O F F
G F G G
G F G F
O = Self unfruitful; F = Fair fruit set most years; G = Good fruit set most years.
HORT 319 - Temperate Fruit and Nut Production
Triploids, self fertility, sports, late blooming
Pollinated variety
Mac spur Mc Intosh Golden Delicious Mutsu Northern Spy
Pollinizers for Apples
Macspur McIntosh G. Delicious Mutsu Northern Spy
P P G P P
P P G P P
G G F P G
G G G P G
P P G P P
HORT 319 - Temperate Fruit and Nut Production
Pollinizers for Apples
HORT 319 - Temperate Fruit and Nut Production
Pollinizers for cherries
HORT 319 - Temperate Fruit and Nut Production
Pollinizers for Sweet Cherries
Gametophytic incompatibility
HORT 319 - Temperate Fruit and Nut Production
Fruit Set Needed for a Full Crop
Pollination:
Small fruited crops
Range is 40% to 100% Commonly 60% to 70%
Large fruited crops
Range 2% to 25% Commonly 3% to 10%
HORT 319 - Temperate Fruit and Nut Production
Factors affecting Fruit Set
Competing blooms attract pollinators Temperature
Pollination:
Pollen tube growth Egg viability
HORT 319 - Temperate Fruit and Nut Production
Effective Pollination Period in Pear
Temp. C (F) 10-15 (50-59) 8-9 (46-48) 5-7 (41-45) Pollen tube growth to ovule 4 Ovule viability Effective Fertilization pollination probability period 6 High
Pollination:
10
10
13
Medium
13
13
None
HORT 319 - Temperate Fruit and Nut Production
HORT 319 - Temperate Fruit and Nut Production
Pollinators Pollen Transporters
Most common: European honey bee
Hives are rented to orchardists
Others bees
Wild bees: both honey and bumblebees Difficult to manage Normally adequate for small orchard
Africanized bees or KILLER BEES
HORT 319 - Temperate Fruit and Nut Production
Africanized Honey Bee
Hybrid bee between
African bee European honey bee
European honey bee on left, African honey bee, right.
Stings are equally venomous Behaviors very different
HORT 319 - Temperate Fruit and Nut Production
Pollinators Africanized Honey Bees
1957 into Brazil Very defensive of nest
Only attack if provoked
Swarm more often
4-8x vs. 1/5x per year
Less selective about nesting sites Produce more offspring Store less honey
HORT 319 - Temperate Fruit and Nut Production
HORT 319 - Temperate Fruit and Nut Production
Factors Affecting Bee Activity
Pollinators
Pesticide applications
Very susceptible to many insecticides Sevin, Diazinon, Parathion
Weather conditions
Wind (10-20 mph) Rain Temperature (10C or 50F)
HORT 319 - Temperate Fruit and Nut Production
Pollination Management
Hive density
1-4 per acre More hives
In poor weather With small fruited crops
Hive position
Normally hives are clustered Face south - warm up quicker Protected from wind
HORT 319 - Temperate Fruit and Nut Production
Pollination Management
Pollinizer distribution
Entire row every 4th row Every 3rd tree per 3rd row
Alternate pollen sources if low pollen production
Graft pollinizer branches Bouquets Beehive inserts Spray, puff, or by hand
HORT 319 - Temperate Fruit and Nut Production
Any Questions?
