Lecture 7
Blueberries & cranberries are in the family Ericaceae. What are the general characteristics? What are the characteristics of cranberry?
-Favours acidic soils
-No root hair > get nutrients from ericoid mycorrhizae (fungal association)
-Pollen shed from terminal pores
Cranberry:
-creeping evergreen shrub with fibrous, shallow root system (2.5-7.5 cm, susceptible to drought)
-Favours wet, boggy area
-Horizontal stems (1st yr), then uprights (2nd yr) which bears fruit only once
-Apical bud on uprights Feb ~ July
-Flowering ~30 days after spring budbreak
Explain the genetic background of strawberry
Strawberry:
Family Rosaceae
Fragaria x ananassa (F. chiloensis x F. virginiana)
Polyploidy: 2n = 14 ~ 8n = 56
Explain the root, vegetative, and reproductive growth of blueberry.
Roots:
-fine, shallow roots with no root hair
-2 peaks of root growth in the year
-minimal lateral transport
Vegetative:
-vegetative buds (smaller, lower) & flower buds (bigger, upper)
-Most shoots from dormant buds from last year
-Apical meristem grows periodically with 2-3 flushes in a year (southern originated varieties have more & later flushes)
Reproductive:
-Flower bud initiation from the shoot tip basipetally in the fall (# of flower buds affects the yield next year)
-More light, more flower buds
-Chilling hours = 800-1200 hr at temp 0-7 oC
* In Lower Mainland, there is not enough time for flower bud initiation with shorter photoperiod varieties (e.g. PP 10 hours = Halloween in LM) before dormancy.
Explain the genetic background of the raspberry
Originated in E Europe & N Asia; cold, temperate
Rubus idaeus & Rubus strigosus
Explain the flowering development of blueberry and how it is related to the cold temperature.
-Flower bud dormancy & initiation co-occur
-Spring bloom tied to chill requirement to break dormancy & base temp for development
-Inflorescences at tips of 1 yo wood emerge first
-Terminal flower matures first at each cluster
-Cold hardiness of bluberries vary at different growth stages (e.g. flower bud development can tolerate colder temp (-12 ~ -4oC); as flower development proceeds, cold hardiness decreases (-5 ~ 0oC))
Compare & contrast the general anatomy of the strawberry & raspberry.
Strawberry: perennial herb with short, thickened stem (crown); mostly propagated vegetatively
Leaves: trifoliate with long petioles, arranged spirally along the crown
Inflorescence: cyme, leafless peduncle
Stolons = runners, vegetatively propagated
Root: primary & secondary roots for nutrient uptake & carb storage
Raspberry:
Perennial root, extensive root systems
Biennial shoots (canes) = primocane (vegetative) + floricane (fruit); adventitious, can be vegetatively propagated
Crown + root buds
Fruit borne laterals from the central cane
Compare & contrast fruit abscission of blueberry & cranberry
Blueberry:
-abscission btw pedicel & peduncle (main flower stem)
-no abscission btw pedicel & fruit > where stem scar occurs, rotting & dehydration happen
Cranberry:
-ripen fruit does not fall off plant
-In wet harvest, machine beats plants to detach fruit in a flooded bog > harvest when fruits float (higher bouyancy than water due to big locules filled with air)
Compare & contrast the floral/fruit anatomy of the strawberry & raspberry.
Strawberry
Flower: mostly white flowers, petals + sepals, self-fertile, enlarged receptacle
Fruit: aggregate of achenes, accessory fruit (receptacle)
Raspberry
Flower: a large receptacle left behind
Fruit: aggregate of drupelets (receptacle intact)
Explain the 3 phases in blueberry fruiting development.
(After bloom)
Phase 1 (25-35 days) Rapid cell division, grow 50% total volume, berry = green & hard
Phase 2 (30-40 days) development of embryo, little change in berry size
Phase 3 (30-60 days) rapid increase in berry volume due to cell expansion, berries turn blue
Compare & contrast the development of the strawberry & raspberry.
Strawberry: Top growth dies back in winter, crowns stop shoot growth. Growth resumes in spring as temp increases
Short-day vs long-day vs day-neutral
Floral initiation: low temp + short days
Vegetative: High temp + long days
Raspberry:
Primocane vs floricane cycles in production