Group Title: Research report (North Florida Research and Education Center (Quincy, Fla.))
Title: Induced stress on pearl millet vs. head length
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 Material Information
Title: Induced stress on pearl millet vs. head length
Series Title: Research report (North Florida Research and Education Center (Quincy, Fla.))
Physical Description: 18 p. : ill. ; 28 cm.
Language: English
Creator: Pudelko, J. A
Teare, I. D ( Iwan Dale ), 1931-
Wright, D. L ( David L )
North Florida Research and Education Center (Quincy, Fla.)
Publisher: North Florida Research and Education Center
Place of Publication: Quincy Fla
Publication Date: 1993
 Subjects
Subject: Pearl millet   ( lcsh )
Genre: non-fiction   ( marcgt )
 Notes
Statement of Responsibility: J. A. Pudelko, I. D. Teare, and D. L. Wright.
General Note: Caption title.
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Bibliographic ID: UF00066115
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 71173967

Full Text


/Vies


? 3-A- INDUCED STRESS ON PEARL MILLET vs. HEAD LENGTH /'c'S



J.A. Pudelko, I.D. Teare*, and D.L. Wright7i//4. 3


ABSTRACT A /

Pearl Millet [Pennisetum rlaucum (L.)] is a potentially-,.

productive, high-quality grain or silage crop with a panicle grain.

head whose head length is highly correlated with grain yield. Our

objective was to relate pearl millet head length with three induced

stressors: 1. date of planting/soil water stress, 2. herbicide

stress, and 3. plant density stress (row width/seeding rate).

This research was conducted on a Norfolk sandy loam located on the

* North Florida Res. and Educ. Ctr., Quincy FL with HGM-100 (W.W.

Hanna, Tifton, GA) pearl millet hybrid. Head lengths for 5 May, 15

May, and 15 June plantings accurately predicted grain head yields,

but 15 July planting produced less seed and smaller- seeds

(weight/1000 seeds) with moderately long heads. Tillage systems

(no-till and till) had no significant effect on head length.

Preplant applications of Dual with 2,4-D or Atrazine, Ramrod alone

or with Atrazine significantly (P = 0.05) increased head length in

till and no-till treatment. Prowl and Atrazine increased head


J.A. Pudelko; Agric. Univ. Inst.of Soil Cult. and Plant
Prod.,Mazowiecka 45/46, 60-623 Poznan', Poland:
D.L. Wright, I.D. Teare; North Florida Res. and Educ. Ctr. Quincy,
FL 32351 (Dept of Agronomy, Inst. of Food and Agric. Sci., Univ. of
Florida, FL 32611) Florida Agric Exp. Stn. Res. Rep. No. NF 93-13.
*Corresponding author.









length in till treatment only. The mean head length across row

widths for the 6 lb/A seeding rate was significantly shorter than

the 2 and 4 lb/A seeding rate. The mean head length across seeding

rates for the 5 inch row width was significantly greater than the

15 and 30 inch row width.

INTRODUCTION

Pearl millet is a potentially-productive high-quality grain or

silage crop (Burton et al.,1986 and Kumar et al., 1983). It is

grown under low-input management conditions (noncrusting sandy

soils) with little fertilizer and limited water (Payne et al.,

1990).

Hattendorf et al. (1988) report that pearl millet had the

greatest daily water use rate of all the crops studied. This and

the knowledge that pearl millet also had the greatest leaf area

index for the same crops suggest that pearl millet has the capacity

for deep rootedness, a greater number of roots and/or the attribute

for increased rooting density (Davis-Carter, 1989). Timing,

intensity and duration of water stress accounted for 70 to 85 % of

the variation in pearl millet grain yields within and across years

(Mahalakshmi et al., 1985, 1987, and 1988). Critical growth stages

receiving water stress were flowering and grain filling.

Two preplant herbicides, Pursuit and Accent, were reported to

reduce grain yield of pearl millet (HGM-100) 60 and 100 percent of

the handweeded check (Wright et al., 1993), but the effect of

herbicide stress has not been reported in relation to head length

measurements.









The objective of this study was to relate pearl millet induced

stress by date of planting/soil water stress, herbicide stress, and

plant density stress (row width/seedling rate) to head length which

has been used for predicting pearl millet head yields (Pudelko et

al., 1993).

MATERIALS AND METHODS

These studies were conducted in 1993 on a Norfolk sandy loam

(fine, loamy siliceous, thermic Typic Kandiudult) located on the

North Florida Research and Education Center, Quincy, Florida. The

soil has a compacted layer located 8 to 14 inches below the

surface.

The pearl millet hybrid used in this series of experiments was

HGM-100, developed as a grain pearl millet by W.W. Hanna (1991),

Tifton, Georgia. Pearl millet seed was no-till planted in a weed

fallow field with a Brown Ro-Til implement with KMC planters.


Date of Planting/Soil Water Differences

The pearl millet date of planting study was a split plot

design with planting dates as whole plots and components of yield

selected within each whole plot as sub-plots (six replications).

Planting dates, stages of development, and date of irrigation are

shown in Table 1. Plots were eight rows wide (rows were 36 inches

apart) and 30 feet long. Seed of pearl millet were planted 3/4"

deep at 4 lbs/A (302 667 seeds/A). This resulted in approximately

166 467 plants/A, or 55 % emergence.

Fertilizer (5-10-15 at 500 Ibs/A) was applied three days









before planting. Nitrogen was sidedressed to the side of the row

at 120 lbs/A at boot stage. Prowl @ 1 qt/A + Atrazine @ 2 qt/A was

used for weed control (Wright et al.,1993). Prowl and Atrazine

were applied between stage 1 and 2 (10 to 15 days after planting

when pearl millet was 3 to 5 inches tall).

Twenty pearl millet heads were carefully selected at random

for each replication after black layer formation with concomitant

measurements of grain yields, head lengths, and counts of heads per

length of row harvested. Pearl millet heads were dried in a

greenhouse, and threshed with a clover threshing machine that

required 20 pearl millet heads per sample for the threshing

operation. Pearl millet heads were measured from top to bottom of

panicle (Pedulko et al., 1993).

Little rainfall occurred throughout the early growing season

for this experiment. One half inch applications of irrigation were

scheduled in response to paucity of rainfall. Rainfall events and

amounts are shown in Fig. 1.

Herbicide Study

A herbicide study on pearl millet was conducted on a field

where weeds had not been controlled for a year. The field was very

weedy. Before it was planted, the field was mowed and divided into

two equal parts. One part for conventional tillage-planting and

the other for no-tillage-planting. The conventional part was

subsoiled at 12 inch depth on 12 May and s-tine harrowed 2 June.

The no-till part was sprayed with Gramoxone on 2 June at the rate

of 3.0 pt/A primarily for nutsedge control.









Cultural practices common to both tillage systems were: 1. the

application of 500 lb/A of 5-10-15 fertilizer 21 June, 2. pearl

millet seed treatment with Concep to "safen" herbicide application

(particularly Dual), 3. planting on 23 June followed by irrigation

with 3/4 inch of water on the day of planting, 4. seeding rate of

4 lb/A in plots 12 feet by 25 feet in 36" rows (plant density of

166,000 plants per acre), 4. band application of 80 lb ammonium

nitrate/A two inches to the side of row on 21 July, 5. spraying

with Lannate for control of corn earworm on 8 July, and 6. all

plots were sprayed with 2,4-D for broad leaf weed control on 16

July.

Seventeen pre-emerge herbicide treatments were applied in

different herbicide combinations (Dual, Ramrod, Prowl, Atrazine,

and 2,4,-D) on 25 June (Table 2). Two postemergence treatments of

prowl were applied following pre-emerge applications of Atrazine,

Ramrod and Prowl in the no-till system only. One hand weeded

treatment and two treatments without weed control completed'the 22

treatments used in this study (Table 2).

The experiment was a split plot design with tillage systems as

whole plots and herbicide treatments as sub-plots. All treatments

were replicated four times. Results were subjected to analysis of

variance and means were separated using Fishers Least Significant

Difference Test at the 5 % level of probability.

Row Width/Seeding Rate Study

The row width-seeding rate study was planted on 28 June. Row

widths and seeding rates used in the study are shown in Table 3.









Plot size was 5 feet wide X 25 feet long.

Cultural practices common across all row widths and seeding

rates were: 1. application of 500 lb/A of 5-10-15 before planting

on 25 June; 2. three applications of ammonium nitrate banded

beside row at 50 lb N/A at 5th leaf stage (10 July), boot stage (31

July), and milk stage (27 Aug); and application of Prowl +,Atrazine

at 1.0 and 1.5 Ib/A, respectively on 30 June after planting and

before emergence (3 July).

Plant population density (plants per acre and plants per

linear foot of row) are shown in Table 3 for each seedling rate and

row width. Note the uniform plant population density across row

wisths (columns) and the increased number of plants within the row

as row width increased for each seeding rate.

RESULTS AND DISCUSSION

Four pearl millet planting dates are shown in Fig. 1 in

relation to maturity dates and rainfall/irrigation events in

relation to time. Note the lack of rainfall throughout the season.

Total water available from planting to maturity for each planting

date (PD) was: PD, = 16.4 inches, PD2 = 19.1 inches, PD3 = 18.7

inches, and PD4 = 18.2 inches (Table 1). Physiological stage of

development for each planting date is shown in relation to calendar

date and day of year.

Pearl millet head lengths are shown for each planting date

(Fig. 2) (columns topped with the same letter are not significant

at the 5 % level of significance). Head lengths for 5 May, 17 May,

and 15 June plantings accurately predicted grain head yields P <









* 0.001) by the equation: Y = 6.98 + 191.22 X (Pedulko et al., 1993).

However, the 15 July planting date produced very little seed. The

average number of seeds per 20 non-bird damaged heads was only 105.

This may have been related to environmental changes, i.e. reduced

length of day, or paucity of pollinators. Bumble bees which were

the primary pollinators for the first three planting dates were

essentially absent during flowering of PD4. It probably wasn't lack

of available water (18.2 inches) compared to 16.4 inches for PD,.

Contrary to Mahalakshmi et al. (1988), we found differences in seed

size (weight/1000 seed) (Fig. 3). Seed size in relation to

planting date gives an indication that environment had something to

do with grain yield. One would expect that the 15 July planting

date with only 105 seeds per 20 heads should have large seeds like

* PD2 or at least seeds the same size as PD, and PD3. Figures 1 and

2 indicate that grain yield (predicted by head length) and seed

size (seed weight/1000 seed) are increased by increased water (19.1

inches for PD2, Table 1) (Mahalakshmi et al., 1987 and 1988).' Thus,

PD2 (17 May) may be the optimum planting time during the pearl

millet growing season.

Herbicide Study

Tillage systems had no effect on pearl millet head length (P

=0.05) (Table 2). Number of heads/A is an indication of herbicide

treatment stress. Figure 4 with herbicide treatments ordered in

relation to Number of heads/A shows the lowest number of heads/A or

greatest herbicide stress at the left of the X axis and least

herbicide stress at the right of the X axis. Herbicide treatments









and their numerical codes are shown in Table 2. In the till system

(Fig. 4A), seed head lengths were significantly longer (E = 0.05)

with Dual and 2,4-D treatment (trt) at the two lower rates (trt 6

and 7), Ramrod and 2,4-D (trt 8 and 9), Dual and Atrazine (trt 12

and 13), Ramrod and Atrazine at the lower rates (trt 13), Prowl and

Atrazine (trt 17) than no herbicide application trt (18, 19, 20).

In the no-till stem (Fig. 4B) seed head lengths were significantly

(P = 0.05) longer for Dual and 2,4-D at all rates (trt 5, 6, and

7), Ramrod at all rates (trt 8 and 9), Dual and Atrazine (trt 13

and 14), and Ramrod and Atrazine (trt 15) than no herbicide

application in the no-till system. With the exception of trt 14

(Ramrod @ 4 qt/A and Atrazine with oil @ 1 lb/A), Dual and Ramrod

increased head lengths and reduced number of heads/A.

The two post emergence treatments of Ramrod and Atrazine (trt

21) and Prowl and Atrazine (trt 22) had no effect on pearl millet

head length (P = 0.05).

Row Width/Seeding Rate Study

The effect of pearl millet population density (plants/A and

plants/linear foot of row) for each combination row width/seeding

rate are shown in Table 3. Population density increased in rows

from left to right according to seeding rate, but population

density in columns from top to bottom across row widths remained

constant. Plants/linear foot of row increased for each row width

from left to right and from top to bottom for all seeding rates

across row widths (Table 4). Population density effects on pearl

millet head lengths are shown in Table 4. The mean head length









across row widths (Table 4) for the 6 Ib/A seeding rate was

significantly shorter than the 2 and 4 lb/A seeding rate (P =

0.05). The mean head length across seeding rates (Table 4) for the

5 inch row width was significantly greater than the 15 and 30 inch

row widths (P = 0.05).

CONCLUSIONS
1. Head lengths for 5 May, 17 May, 15 May, and 15 June plantings

accurately predicted pearl millet grain head yields (P = 0.05)

with equation Y = 6.98 + 191.22 X.

2. Fifteen July planting date produced very little seed and the

seed was small although head lengths averaged over 30 cm long.

3. Tillage systems had no significant effect on head length.

4. Dual and 2,4-D; Ramrod; Dual and Atrazine; Ramrod and Atrazine

increased head length in till and no-till systems. The Prowl

and Atrazine trt increased head length in the till system

only.

5. Post emergence treatments of Ramrod and Atrazine and Prowl and

Atrazine had no effect on head length (E = 0.05).

6. The mean head length across row widths for the 6 Ib/A seeding

rate was significantly shorter than the 2 and 4 Ib/A seeding

rates (P = 0.05).

7. The mean head lengths across seeding rates for the 5 inch row

width was significantly greater than the 15 and 30 inch row

widths (E = 0.05).









ACKNOWLEDGEMENTS

Our thanks to E. Brown Agricultural Technician IV; North Fla.

Res. and Educ. Ctr. Univ. of .Fla., Quincy, FL; for plot

preparation and management, data collection, computer processing,

and data illustration.



REFERENCES

Burton, G.W., A.T.Primo, and R.S. Lowrey. 1986. Effect of

clipping frequency and maturity on the yield and quality of

four pearl millets. Crop Sci. 26:79-81.

Davis-Carter, J.G. 1989. Influence of spatial variability of soil

physical and chemical properties on the rooting patterns of

pearl millet and sorghum. Ph.D. diss. Texas A&M University,

College Station.

Hattendorf, M.J., M.S. Dedelfs, B. Amos, L.R. Stone, and R.E.

Given, Jr. 1988. Comparative water use characteristics of

six row crops. Agron. J. 80:80-85.

Hanna, W.W. 1991. Pearl millet-a potentially new crop for the

U.S. In Abstracts of Technical Papers, No. 18, Southern

Branch ASA, 2-6 Feb 1991, Ft. Worth, TX.

Kumar, K.A., S.C. Gupta, and D.J. Andrews. 1983. Relationship

between nutritional quality characters and grain yield in

pearl millet. Crop Sci. 23:232-234.

Mahalakshmi, V., and F.R. Bidinger. 1985. Water stress and time of

floral initiation in pearl millet. J. Agric. Sci.105:437-445.









Mahalakshmi, V., and F., and D.S. Raju. 1987. Effect of timing of

water deficit on pearl millet (Pennisetum americanum). Field

Crop Res. 15:327-339.

Mahalakshmi, V., F.R. Bidinger, and G.D.P. Rao. 1988. Timing and

intensity of water deficits during flowering and grain-filling

in pearl millet. Agron. J. 80:130-135.

Payne, W.A., C.W. Wendt, and R. J. Lascano. 1990. Root zone water

balance of three low-input millet fields in Niger, West

Africa. Agron. J. 82:813-819.

Pudelko, J.A., D.L. Wright, and I.D. Teare. 1993. A method for

salvaging bird damaged pearl millet research. Fla.

Agric. Exp. Stn. Res. Rep. No. NF 93-12:1-11.

Wright, D.L., I.D. Teare, F.M. Rhoads, and R.K. Sprenkel. 1993.

Pearl millet production in a no-tillage system. p. 152-159.

In P. Bollich (Ed.) 1993 Southern Conservation Tillage

Conference for Sustainable Agriculture. June 15-17, Monroe,

LA. SB 93-1.












100

0)
80 ..


E 60L
4 0 ....... .......



.E. 40 ---- -



2 0 -- .. .....


0 [. I I" ..... ... ..... .
121 136 151 166 181 196 211
Day of Year


Figure 1.


226 241 256 271


Rainfall during the 1993 pearl millet growing season for

four planting dates in relation to rainfall amounts and

dates of events.













40


E
30



-J
0


ri
.20
(D
I

= 10


C


0 -__ -NE
May 5 May 17 June 15 July 15
Date of Planting

Figure 2. Pearl millet head lengths in relation to date of

planting. Columns topped by the same letter are not

different at the 5 % level of significance.


-- -----

















9-


6 --


3 --.


0 -----y
May 5


Figure 3.


May 17 June 15 July 15
Date of Planting


Pearl millet seed size (weight of 1000 seeds) in

relation to date of planting. Columns topped by the

same letter are not significantly different at the 5 %

level of significance.









Till No. Heads 0 Head Lenght


180 20

160-
140- 18
140-

120 *** 16
0
100-
80- 14
^" 80- -
) 0D o a 0
0 60- O O -12
C" 40 0 0 0 D D 0D CO
Cd 40- aD
0 0 0 0 0 -10
S 20- / -"
< 0
O o r"
0 0 I ic:
,C 12 6 13 7 5 15 9 17 8 14 4 20 19 18 2 16 3 11 1 10


Cc--


W W
"0-r



)_j

No-Till No. Heads 0 Head Lenght 0
O 180 20

0 160- 1
Z 140- 4 -18

120- -16
100-
80 14
80 0 1
O 00F00
60- O 0 -12
40- D o0 D D 0 o O O o
[ -10
20- *
0 I I I I I I I I I
7 13 6 12 9 5 15 8 14 17 16 20 4 2 19 18 3 1 11 10
Herbicide Treatment
Stress Non-Stress


Figure 4. Herbicide stress indicated by number of heads/A in

relation to herbicide treatment and length (inches) of

till and no-till systems.

15






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able 2. Pearl millet head len

Treatment Rat

1. Atrazine without oil 1.5
2. Atrazine without oil 2.0
3. Atrazine with oil 1.0
4. Atrazine with oil 1.5
5. Dual + 2,4 D 1.0
0
6. Dual + 2,4 D 1.5
0
7. Dual + 2,4 D 2.0
0
8. Ramrod (42%) + 2,4 D 3.0
0
9. Ramrod (42%) + 2,4 D 4.5
0
10. Prowl + 2,4 D 1.0
0
11. Prowl + 2,4 D 1.5
0
12. Dual +
Atrazine with oil 1.0
9. Dual +
Atrazine with oil 1.5
14. Ramrod +
Atrazine with oil 3.0
15. Ramrod +
Atrazine with oil 4.5
16. Prowl +
Atrazine with oil 1.0
17. Prowl +
Atrazine with oil 1.5
18. Check hand weed control
19. Check without weed control
20. Check without weed control

Mean'

21. On till only Ramrod + Atra


igth in relation to


e per A

lbs
Spt
I Ib + 1 qt
lbs + 1 pt
i pt +
.5 lb (a.i.)
pts +
i.5 lb (a.i.)
pts +
.5 lb (a.i.)
qt +
.5 lb (a.i.)
qt +
.5 lb (a.i.)
pt +
.5 lb (a.i.)
+
.5 Ib (a.i.)

pt + 1.0 lb

pt + 1.0 lb

qt + 1.0 lb

qt + 1.0 lb

pt + 1.0 lb

pt + 1.0 lb


zine


with oil and Prowl postemer
4.5 qt + 1.0 Ib 0.895 GHI
22. On till only Prowl + Atrazine
with oil and Prowl postemer
1.0 pt + 1.0 lb 0.898 GHI


SMean values in columns followed by the same letter are not significantly different at
the 5% level of significance.

Mean values in row followed by the same letter are not significantly different at the
5% level of significance.

17


weed control on Till

Till System
Head Lenqth'

0.918 FGHI
0.930 FGH
0.870 HI
0.870 HI

1.072 BC

1.070 BC

0.948 EFG

1.010 CDE

1.017 CD

0.910 GHI

0.880 HI

1.253 A

1.058 BC

1.102 B

0.948 EFG

0.918 FGHI

0.975 DEF
0.858 I
0.900 GHI
0.908 GHI

0.971 z


and No-till system.

No-Till System
Head Lenqth'

0.875 FG
0.900 FG
0.878 FG
0.945 EF

1.100 AB

1.120 AB

1.085 B

0.990 DE

1.005 CDE

0.882 FG

0.938 EFG

1.075 BC

1.173 A

0.888 FG

1.058 BCD

0.865 G

0.900 FG
0.889 FG
0.897 FG
0.905 FG

0.968 z


I I *









Table 3. Plant population density (plants/A) and plants/linear
foot of row' are shown for each combination seeding rate and row
width.


Seeding Rate2 (Ib/A)


Row width


5


15


30


89,000
(0.85)

'88,000
(2.54)

88,000
(5.08)


172,000
(1.65)

176,000
(5.06)

177,000
(10.16)


264,000
(2.53)

266,000
(7.64)

265,000
(15.23)


'Plants/linear foot of row in brackets


2Emergence rate approximately 55% of seeding rate


4 1 I*




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