temperate fruit crops Flashcards
how do plants use light
- growth
- signalling
carbon dioxide + water = glucose + oxygen
difference between c3 and c4 plants
and the benefits of C4
c3 have a photosynthetic pathway which is less efficient in hot and dry environments
C4 plants have a much more efficient photosynthetic pathway in which the reactions happen in wreaths around closely spaced veins
in rice, if it was able to use a c4 pathway productivity could be increased by 50%
what is yield
quality vs quantity
economic, harvestable, marketable yeild
it encompasses many factors
what are some yield factors considerations
size
target fruit load per tree
pest and disease
nutrient and irrigation status
tree/vine growth habit
where do quality issues stem from
many limiting factors trace back to early season issues such as
pollination
bruising
sunburn
pest and diseases
the benefit of intensive plantings (apples)
smaller trees
2 years to cash flow rather than 5
4 years to full productivity instead of 7
what tree structure drives good yield?
dominant vertical centre leader that supports well-spaced tiers of scaffold limbs bearing fruiting laterals
there are innovations that now have
v-trellis
or 2D
export requirements (apple)
phytosanitary and food safety requirements differ between countries
commercial standards are more stringent than regulatory standards
regulations conflict, EU - residues VS Asia - Phytosanitary
require specific export inspections
often used as trade barriers
phytosanitary requirements of countries
Asia - very long lists of actionable pests
USA - long list of actionable pests
EU/UK very limited actionable pests
why prune (apples)
it is done to create a maximum fruit-bearing surface,
to create access for workers to thin and harvest fruit,
to promote good spray penetration,
to renew fruiting wood, and to maintain growth or vigour in all parts of the tree.
pruning should allow sunlight to enter and air to circulate through the tree
thinning,
benefits?
methods?
when?
benefits: increase fruit size, better leaf number per fruit, no runts, harvest ease, the trade-off for excessive size
methods: hand ($$$), mechanical, chemical
when: soon as possible, flowers, bud thinning
what triggers dormancy
declining day length is the key signal but the temperature may be important in pipfruit
the leaves are sensitive to the day length and consequently, the signal is transported to responding tissue
as a result plants enter dormancy or rest
how do deciduous trees respond to cold temperatures before dormancy
plants respond with cellular and morphological adjustments that enable them to survive the low winter temperatures
hot to calculate chilling hours
if temperature is above 7 degrees then it is too warm for the planet to accumulate chilling
if the temperature is below 7 degrees then the plant is affected by the cold temperatures with colder temperatures producing bigger effects
by summing these hourly amounts of chilling over the winter we have a measure of how cold the winter formed the plants perspective
what happens in the juvenility stage of a deciduous tree
starts with seed germination
intense vegetative development
strong apical dominance
higher rooting availability
big constraints in breeding programs focused to improve fruit quality traits.
ends when apical meristem reaches physiological maturity
