Lecture 6: SPECIAL PRACTICES TO CONTROL GROWTH AND DEVELOPMENT Flashcards
D objEctivEs In CConTrolling growth
*control direction of growth
*to restrict plant size in the case of ornamentals
*easier cultural management practices
*earlier flowering
*control timing and synchrony of flower or fruit
*induce rooting or shoot
*delay senescence or inhibit germination
APPROACHES TO CONTROLLING PLANT GROWTH AND DEVELOPMENT
- use of chemicals like Plant Growth Regulators (PGRs)
- physical methods
-training
-pruning
-girding
-smudging
organic compounds other than nutrients which in minute amount promote, inhibit, or modify plant growth development
Plant Growth Regulators (PGRs)
naturally occurring PGR’s
phytohormones
(PGR) auxins promote what?
rooting of stem cuttings
used to promote rooting of stem cuttings in mussaenda, guava, bougainvillea, and rose
Indole-3-butyric acid (IBA)
used to promote rooting of stem cuttings in black pepper
naphthaleneacetic acid (NAA)
a combination of IBA and NAA mixed with talcum powder, the powder mixtures adhere to the stem cuttings when dipped
quick root
stands for alpha-napthaleneacetic acid; a synthetic auxin
ANAA solution
(PGR) promote seed germi in mussaenda seeds
gibberellic acid (GA)
(PGR) increase fruit set in citrus
2,4-dichlorophenoxyacetic acid (2,4-D)
(PGR) reduce stem elongation in chrysanthemum
paclobutrazol
(PGR) induce/modify flowering of pineapple
ethrel, calcium carbide
(PGR) induce/modify flowering of mango
ethepon
special practice for mango using foliar spray
1- 3% KNO3
(PGR) induce flowering of crop by substituting for envi reqs in cabbage and gladiolus
gibberellic acid (GA)
(PGR) modify flowering in cucumber
gibberellic acid (GA) or ethepon
(PGR) stimulate latex flow in rubber and papaya
ethephon
(PGR) accelerate priming of uniform ripening for easier/synch harvesting in coffee
ethephon
use of PGR in postharvest
- hasten/acce ripening
- inihibit sprouting
to maintain a high level of reliability, commercial products must be registered with the ______________
Fertilizer and Pesticide Authority
product registration involves _________ and _________ as to guaranteed analysis of active ingredients
bioefficacy testing and correct labelling
techniques that direct/modify the growth of plant in terms of canopy size, shape, and direction
PHYSICAL METHOD OF CONTROLLING GROWTH
training
objectives in training
- To improve yield and quality
- To facilitate cultural practices
one technique of training
trellising (staking)
provision of support to viny crops and other crops and other crops that could not stand without support
trellising
types of trellis
a-type
t-type
fence type
teepee type
overhead
singular pole
judicious removal of plant parts to achieve specific objectives
PHYSICAL METHOD OF CONTROLLING GROWTH
pruning
pruning benefits
-control the size of the plant
-control the form (structural make-up of the plant)
-better quality fruits by better light distribution
-remove diseased & broken branches
-remove the non-productive parts
-proper proportion of root-shoot ratio
techniques in pruning
A. topping/cutting back/pinching
B. bending
TECHNIQUE IN PRUNING
removing terminal shoot of young plant to encourage spreading canopy growth and/or keep the tree dwarf
topping/cutting back/pinching
TECHNIQUE IN PRUNING
to produce multiple vertical shoots, thus increase the number of bearing lateral branches
bending
KINDS OF PRUNING
- preventive – removal of DEAD plant parts
- formative – to MODIFY SHAPE of canopy
- corrective – removing EXCESS shoots
- rejuvenative – removing most of the shoots to
reinvigorate an old or unproductive tree
special kind of pruning done in banana to remove excess suckers
desuckering
tips in pruning
-use sharp and proper tools
-cut as close to the stem as possible
-prune after harvest
-disinfect the tools when transferring from plant to plant
-for large wound ( >1 inch diameter), apply fungicide prevent the entry of microorganisms
TYPES OF PRUNING BASED ON PRUNING CUT
removal of entire branch or shoot such as in corrective and preventive pruning
cutting out
TYPES OF PRUNING BASED ON PRUNING CUT
removal of portion of branch or shoot such as in formative pruning
cutting back
TYPES OF PRUNING BASED ON PRUNING CUT
a severe form of cutting back such as in rejuvenative pruning
stubbing
why is rejuvenation required?
-unproductive
-wasted investment
cause of unproductivity in overlapping canopy
growers did not follow the concept of “Allotted
Space”
how to solve overlapping canopy
- thin out by eliminating the trees in the middle
- prune by heading-back
ANOTHER SPECIAL PRACTICE TO CONTROL GROWTH AND DEVELOPMENT (except PGR and physical methods)
windbreak establishment
Adverse effect of strong wind (typhoon)
- Damages among leaves, shoot and fruits
- Defoliation
- Breakage of branches
- Blow down of whole tree
effectiveness of windbreak depends on
- height
- canopy density
most important role of windbreak
to reduce windspeed and to protect the crop from damage
