MODULE 6 Flashcards
plant growth and development (23 cards)
Plant growth regulators
Organic compounds other than nutrients which in minute amount promote, inhibit or modify plant growth and development. Either synthetic or natural
Phytohormones
naturally occurring plant growth regulator.
Classes of PGR:
Auxins, gibberellins, cytokinins, abscisic acid, ethylene
Training
techniques that direct or modify the growth of plants in terms of canopy size, shape and direction
Trellising
provision of support to viny crops and other crops that could not stand without support
Types of trellises
Fence, Overhead, A-type, T-type, Single, Teepee
Pruning
judicious removal of plant parts to achieve specific objectives
Pinching
removing terminal shoot of young plant to encourage spreading canopy growth and/or keep the tree dwarf e.g. coffee, lanzones
Bending
Coffee – to produce multiple vertical shoots, thus increase the number of bearing lateral branches
Preventive pruning
removal of dead, insect-infested and diseased plant parts
Formative pruning
to modify shape of canopy e.g.
Topiary
Corrective pruning
removing excess shoots that interfere with light penetration and aeration within the tree canopy
Rejuvenative pruning
removing most of the shoots in order to reinvigorate an old or unproductive tree
Desuckering
Done in bananas to remove excess suckers
Cutting out
removal of entire branch or shoot such as in corrective and preventive pruning
Cutting back
removal of portion of branch or shoot such as in formative pruning
Stubbing
a severe form of cutting back such as in rejuvenative pruning
Why is rejuvenation required?
Unproductive trees can’t be induced to flower because of canopy overlapping
How are windbreak trees planted?
In single or double rows near the fence line and within the orchard
Important role of windbreak
to reduce windspeed and to protect the crop from damage
Dense canopy of windbreak trees
a dense canopy provides more protection against strong winds
Height of windbreak trees
tall windbreaks protects a larger area and can reduce wind speed up to 20x its height
Pointers in windbreak establishment
- Rows must be oriented perpendicular to wind direction
- The first and last rows should be short to medium; tall ones at the middle row
