2.4 Pollination of Crops Flashcards
Pollination of top fruit
Pollination is required to achieve fertilisation and fruit set.
Fruit will not remain on tree if not fertilised.
Fertilised ovules attract food to developing fruitlets.
Fruit will be irregularly shaped if fertilisation is poor.
Even self fertile top fruit benefit from cross pollination.
Peaches, nectarines & certain plums and gages are self fertile.
Flowering periods must overlap.
Cultivars must be compatible.
Improving pollination chances for top fruit.
Most fruit pollinate by honey bee.
Bumble bees and wild bees are more effective in cold, windy weather.
Air temperatures affects pollen tube growth.
Nitrogen nutrition affects pollen tube growth.
Higher temp and less wind improves insect activity, better pollen tube growth and pollination and fertilisation.
Shelter reduces risk of frost damage to stigma and style.
Techniques for orchards to improve cross pollination.
Use if grafted pollinator shoots - especially apples.
Dwarf stock Malus ‘Hornet’ inserted in between trees in main row, or grafted into crown of every third tree.
Small pillar trees can be inserted at close spacing between main cultivar.
Bouquets of flowering branches can be hung from trees.
Bark ringing- keeps manufactured carbs in canopy. Increases carb/nitrogen ratio. Tree switches from vegetative growth to fruit production.
Number of pollinators needed for Triploids
Two pollinators needed.
Two diploids pollinate each other and both the triploid.
Eg Bramley, Cox, Discovery.
Cross- pollination, definition
Transfer of pollen between two different species or varieties.
Self pollination
Transfer of pollen within a single plant or among several plants of the same variety.
Self -unfruitful or self-sterile (self incompatible)
Plants in which very little fruit sets when pollinated with own pollen.
Self fruitful
Varieties that set fruit with their own pollen.
Cross-unfruitful
Varieties that will not set even when cross pollinated.
Inter-sterile
Neither if two varieties will fertilise the other.
Plums, gages and Damsons -details
Self fertile plums- Victoria AGM, Blue Tit AGM
Partly self fertile gage - Cambridge Gage
Self incompatible gage - Jefferson AGM
Self fertile Damson - Prune Damson
Generally self fertile.
Self fertile trees have improved fruit when cross pollinated.
Self incompatible or partly self fertile require cross pollination.
Pears - details
Pear blossom has a short season.
Nectar produced by pear blossom is not attractive to bees.
Pears need a large number of pollinators; generally honey bees.
All pears need pollinators.
Concorde and conference will produce some fruit by themselves.
Where there are a large number if pear tree it may be necessary to pant a pollinator.
All pear trees are pollinated by insects.
Pollination of Zea mays
Wind pollinated.
Grow in blocks not rows. 45 cm apart.
Sheltered sunny position, strong wind causes damage.
Fertile, well drained soil.
Each individual kernel requires pollination.
Pollen must encounter numerous strands if silk from each ear to pollinate.
Hand pollination will optimise harvest.
Pollination of cucumbers.
Honey bees are main pollinator.
Without pollination older cucumber cultivars do not form fruit.
Hand pollination may be necessary.
Make flowers do not produce fruit.
Modern cultivars produce all female flowers (gynoecious) and do not require pollination.
In poor light and low temperatures male flowers may be produced.
If pollen is transferred to female flowers it will be bitter and spoiled.
Pollinators must be excluded from modern cultivars.
Greenhouse cucumbers
Do not need pollinating.
Male flowers should be removed to avoid pollination which produces bitter fruit.
Eg. Cucumber ‘Flamingo’ it is gynoecious (only produces female flowers)
