Pre bloom growth and development Pre-bloom growth and development determines the yield potential› At first bloom 80-90% of the crop that will › At first bloom 80-90% of the crop that will be harvested is on the plant
Post bloom plant activity determines the Post bloom plant activity determines the yield and quality
The size of the plant (number of i t d ) t fi t bl mainstem nodes), at first bloom
determines the yield potential Fi t bl 8 d b l th First bloom -- 8 nodes below the terminal
7 l l t t› 7 or less -- early cutout› 9 or more -- rank growth
Elongation rate - change in internodeElongation rate change in internodelength - measure of top 5 nodes & first mature internodef m- Stress vs vigorous
Boll load - Carbohydrate supply in Boll load - Carbohydrate supply in the plant - the boll load drives the development of the plantdevelopment of the plantMoisture, Nitrogen, Light
Plant A Plant heightNumber f n d
Average = InternodeLength
of nodes g
9 Nodes
2615 = 1.7” AIL 15
AIL at first bloomf mDryland – > 1.1 Irrigated - 1.5” -1.75”
6 Nodes
Cotyledon nodes
Always try to make cotton Always try to make cotton on the front end of the
growing season
rather than on the back end
E l S Fi t FlEarly Square – First Flower
Stress from square initiation to first flower is the most critical first flower is the most critical period of yield determination
Stress during this period will limit the potential number of fruit
Fruit sensitivityHigh Small boll y
to shed
Small squaresquare
14 days 14 days after bloom
Low Bloom
CROP SET CROP SET 1-2 BALE YIELD POTENTIAL
AT EARLY BLOOM 1 2 BALE YIELD POTENTIAL
AT EARLY BLOOM 80-95% OF THE CROP TO BE HARVESTED IS
ALREADY ON THE ALREADY ON THE PLANTPLANT.
Anti-giberillinReduces internode length Restricts vegetative growth Increases leaf thickness and concentrates chlorophyllE h li i Enhances earliness in some cases Will not shrink cottonShould not be applied for yield Should not be applied for yield enhancement – increased yield is a bonusMC is a plant growth management tool MC is a plant growth management tool
Benefits Risks
Reduces Plant Size› Equipment operation
May cause early cutoutq pm p
› Less lodging and boll rot
Can increase li
cutoutIncreases drought stress
earliness› harvest and defoliation
scheduling
May reduce yieldGreatest risk is to g
› can help early retention
Sometimes increases i ld
pre-bloom cotton at high rates
yield
Internode growth or cell expansion is Internode growth or cell expansion is a very sensitive indicator of stress or luxuriant growth conditionsgWhen planting date is the same, the differences in plant height are due to
i i i i d l h variations in internode length - not the number of nodes and internodes. I t d th b d Internode growth can be used as a measure of plant vigor in the past, present and predict future growthpresent and predict future growth
Indication of boll load Indication of cutoutVigor of the plantIndication of water stressIndication of nitrogen stressnd cat on of n trogen stress
Nodes Above White FlowerNAWF
1. Water and nitrogenmanagement
2. Indication of boll load 3. Indication of cutout4. Vigor of the plant
A declining NAWF is indicative of a d i h t th ti ti it decrease in photosynthetic activity An increased carbohydrate demand by th b ll l dthe boll loadWater stress
Early BloomCarbohydrate
production
Early Bloom
production
Seed and lint demand
Vegetative DemandDemand
Late BloomCarbohydrate
production
Late Bloom
Seed and production Seed and lint demand
Seed and li d d
Vegetative lint demand
gDemand
8 NAWF
6 NAWF 6 NAWF
5 NAWF
3 NAWF
MepiquatMepiquat ChlorideChloride Use StrategyUse StrategyMepiquatMepiquat ChlorideChloride Use StrategyUse StrategyMepiquatMepiquat Chloride Chloride Use StrategyUse StrategyMepiquatMepiquat Chloride Chloride Use StrategyUse Strategy
P bl h h / d P bl h h / d P bl h h / d P bl h h / d •• Prior to bloom, use height/node ratio Prior to bloom, use height/node ratio (average (average internodeinternode length)length)
•• Prior to bloom, use height/node ratio Prior to bloom, use height/node ratio (average (average internodeinternode length)length)•• If average If average internodeinternode length is 1.2 length is 1.2
inches or greater, use 3inches or greater, use 3--4 ounces of 4 ounces of M i tM i t t i h d t t h h d t i h d t t h h d
•• If average If average internodeinternode length is 1.2 length is 1.2 inches or greater, use 3inches or greater, use 3--4 ounces of 4 ounces of M i tM i t t i h d t t h h d t i h d t t h h d MepiquatMepiquat at pin head to match head at pin head to match head squaresquare
•• If average If average internodeinternode length is less than length is less than
MepiquatMepiquat at pin head to match head at pin head to match head squaresquare
•• If average If average internodeinternode length is less than length is less than •• If average If average internodeinternode length is less than length is less than 1 inch, application is probably not 1 inch, application is probably not necessarynecessary
•• If average If average internodeinternode length is less than length is less than 1 inch, application is probably not 1 inch, application is probably not necessarynecessarynecessarynecessarynecessarynecessary
F ll bl d b h Following bloom, use nodes above white flower› Nodes above white flower should be hi hest › Nodes above white flower should be highest at first bloom, and decrease approximately one node per week until cutout
› If NAWF is 8 or higher, mepiquat should be used at 8-12 ounces at first bloom if cotton is not (or likely will not be) water cotton is not, (or likely will not be) water stressed in the next seven days
› More mepiquat is required for the same l li i i d l dresults as application is delayed
Also during blooming, a good technique is determination of the internode length between the fourth and fifth node from between the fourth and fifth node from the top of the plant› If this internode length is greater than 2.5
inches the plant should be evaluated for inches, the plant should be evaluated for another application
If the plant is well fruited, the fruit load will soon stress the plant and decrease vegetative soon stress the plant and decrease vegetative growthIf the plant is not well fruited, a heavy rate of mepiquat chloride will likely be needed to help p q y ppartition growth from vegetative to reproductive
12 The only internodes expanding
t 5 E thi b l it
4
3are top 5. Everything below ithas hardened.
5
internodelength
Do not usemepiquat chloride m p quat ch or
on drought on drought stressed cotton stressed cotton
The Performance of Growth Regulators in Oklahoma CottonVariety: FM 9063 B2F Planted: May 16, 2007
Fertility, Rainfall & Irrigation-300 lbs actual N preplant- Over 8 inches rain between planting & Matchhead app. (13” May-Sept.)- Furrow irrigation began 7/24 continuing weekly thru August (18” total)
The Performance of Growth Regulators in Oklahoma Cotton
The Performance of Growth Regulators in Oklahoma CottonTotal # Mainstem Nodes
18
19
20
16
17 abcc
abc abc abc abc
13
14
15Trt 1Trt 2Trt 3Trt 4Trt 5T t 6
ct 2 +
3
10
11
12Trt 6Trt 7
Gin
out
e 1.
5 +
2
e 2
+ 3
e 2
+ 3
+
ated
8
9
10
Mep
ex
Mep
ex
Stan
ce
Stan
ce
Pent
ia
Stan
ce
Unt
rea
7Total # Mainstem Nodes
M
The Performance of Growth Regulators in Oklahoma Cotton
NAWF-essentially no difference between treatments(Mepex slightly less than untreated)( p g y )
NACB – Mepex, Mepex Ginout & Stance significantly different from untreated (1.08-1.6 vs. 3.15)
The Performance of Growth Regulators in Oklahoma Cotton
nout
5 +
2
+ 3
+ 3
+ 3
pex
pex
Gin
nce
1.5
nce
2 +
ntia nce
2 +
trea
ted
Mep
Mep
Stan
Stan
Pen
Stan
Unt
No treatment lint yield was different from untreatedPentia treatment did produce more lint than Mepextreatment
The Performance of Growth Regulators in Oklahoma Cotton
3
Gin
out
1.5
+ 2
2 +
3
2 +
3 +
3
ed
Mep
ex
Mep
exG
tanc
e 1
tanc
e 2
entia
tanc
e 2
ntre
ate
M M S S P S U
The Performance of Growth Regulators in Oklahoma Cotton
nout
5 +
2
+ 3
+ 3
+ 3
d
pex
pex
Gin
ance
1.5
ance
2 +
ntia
ance
2 +
ntre
ated
Mep Me
Sta
Sta
Pen
Sta
Un
The Performance of Growth Regulators in Oklahoma Cotton
3
.5 +
2
+ 3
+ 3
+ 3
ed
epex
.Gin
tanc
e 1.
tanc
e 2
entia
tanc
e 2
ntre
ate
Me M.
St St Pe St U
The Performance of Growth Regulators in Oklahoma Cotton
3
inou
t
.5 +
2
+ 3
+ 3
+ 3
ed
epex
epex
G
tanc
e 1.
tanc
e 2
entia
tanc
e 2
ntre
ate
Me Me
St St Pe St U
When plant growth regulators are used correctly, the crop normally shows
li f i i if d il earlier fruiting, more uniform and easily managed plants, earlier application of h t id nd i h tin harvest aids, and easier harvesting conditionsHi h i ld b b b t i t Higher yield may be a bonus, but is not to be expected under all conditions