F 3
3 7-/ PHYSIOLOGICAL STAGES OF PEARL MILLET IN RELATION TO
PLANTING DATE AND AVAILABLE WATER
4 I.D. Teare, D.L. Wright, and J.A. Pudelk&rstof 5cence
5 LbrarY
7 ABSTRACT WR 0 9
8
9 Water status in plants is dynamic with soigatr and
10 atmospheric conditions, but also with plant physiology that is
11 indicated by stage of growth. Pearl Millet [Pennisetum qlaucum
12 (L.) R. Br., hybrid HGM-100] is a new crop in the Southeast
13 suitable for grain or silage. Our objective was to describe stage
14 of development of HGM-100 in relation to date of event and
15 available water for four planting dates through the summer growing
16 season. This research was conducted on a Norfolk sandy loam
17 located on the North Florida Res. and Educ. Ctr., Quincy FL with
0 HGM-100. Stage of development and rainfall/irrigation events and
19 amounts are described for four planting dates in 1993 for HGM-100.
20 Seed and predicted grain yields were related to amount of available
21 water (19.1 inches) and planting date. The 17 May planting date
22 produced the highest predicted grain yield and the 15 June planting
23 date produced the lowest grain yield. The low yield may have been
24 due to lack of pollinators (bumble bees) and not lack of water
25 (18.2 inches). The 5 May planting recieved the least water (16.4
26 inches).
27
28
29 North Fla. Res. & Educ. Ctr., Quincy, FL 32351 (Dept of Agronomy,
30 IFAS, Univ. of Fla., FL 32611): Agric. Univ. Inst.of Soil Cult. &
31 Plant Prod., Mazowiecka 45/46, 60-623 Poznan', Poland. North Fla.
Res. & Educ. Ctr. Res. Rep. No. NF-94-11:1-9.
1
1 INTRODUCTION
2 Knowledge of plant, insect and disease ontogeny in relation to
3 date of planting date as a function of growth stages and physiology
4 and environmental parameters make it possible to compare or to
5 combine limited bits of knowledge from all over the world to
6 explain yield phenomena.
7 HGM-100 pearl millet synchrony of date of planting with
8 expected environmental changes ,such as, available water, day
9 length and temperature; and the interactions with insect and
10 disease cycles must be understood to obtain successful crop yields
11 and has been defined as Systems Agriculture (Teare et al., 1992).
12 Pearl millet is a potentially-productive high-quality grain or
13 silage crop (Burton et al.,1986 and Kumar et al., 1983). It is
* grown under low-input management conditions (noncrusting sandy
15 soils) with little fertilizer and limited water (Payne et al.,
16 1990).
17 Hattendorf et al. (1988) report that pearl millet had the
18 greatest daily water use rate of the crops studied {pearl millet,
19 sunflower [Helianthus annuus L.], sorghum [Sorghum bicolor
20 (Moench), corn [Zea mays L.], and soybean [Glycine max (Merr.)]}.
21 This and the knowledge that pearl millet also had the greatest leaf
22 area index of these crops suggest that pearl millet has the
23 capacity for deep rootedness, a greater number of roots and/or the
24 attribute for increased rooting density (Davis-Carter, 1989).
25 Timing, intensity and duration of water stress accounted for
26 70 to 85 % of the variation in pearl millet grain yields within and
*
'2 across years in other studies (Mahalakshmi et al., 1985, 1987, and
2 1988). Critical growth stages identified as being sensitive to
3 water stress were flowering and grain filling.
4 The objective of this study was to determine the impact of
5 date of planting on HGM-100 pearl millet phenological events in
6 relation to insect activity and available water during the 1993
7 summer growing season.
8 MATERIALS AND METHODS
9 These studies were conducted in 1993 on a Norfolk sandy loam
10 (fine, loamy siliceous, thermic Typic Kandiudult) located on the
11 North Florida Research and Education Center, Quincy, Florida. The
12 soil has a compacted layer located 8 to 14 inches below the
13 surface.
The pearl millet hybrid used in this series of experiments was
15 HGM-100, developed as a grain pearl millet by W.W. Hanna (1991),
16 Tifton, Georgia. Pearl millet seed was no-till planted (in-row
17 subsoiled strip tillage) with a Brown Ro-Til implement with KMC
18 planters.
19 The pearl millet date of planting study was a split plot
20 design with planting dates as whole plots and stages of development
21 determined for six replications in relation to calendar date,
22 development period, and total water for each plot. Planting dates,
23 stages of development, and date of irrigation are shown in Table 1.
24 Plots were eight rows wide (rows were 36 inches apart) and 30 feet
25 long. Seed of pearl millet were planted 3/4" deep at 4 Ibs/A (302
26 667 seeds/A). This resulted in approximately 166 467 plants/A, or
*
1 55 % emergence.
2 Fertilizer (5-10-15 at 500 lbs/A) was applied three days
3 before planting. Nitrogen was sidedressed to the side of the row
4 at 120 lbs/A at boot stage. Prowl @ 1 qt/A + Atrazine @ 2 qt/A was
5 used for weed control (Wright et al.,1993). Prowl and Atrazine
6 were applied between stage 1 and 2 (Table 1, 10 to 15 days after
7 planting when pearl millet was 3 to 5 inches tall).
8 Little rainfall occurred throughout the early growing season
9 for this experiment. One half inch applications of irrigation were
10 scheduled in response to paucity of rainfall (Table 1). Rainfall
11 events and amounts are shown in Fig. 1.
12
13 RESULTS AND DISCUSSION
0 Four pearl millet planting dates are shown in Fig. 1 in
15 relation to maturity dates and water (rainfall/irrigation) events
16 in relation to time. Note the lack of rainfall throughout the
17 season. Total water available from planting to maturity for each
18 planting date (PD) was: PDI = 16.4 inches, PD2 = 19.1 inches, PD3 =
19 18.7 inches, and PD4 = 18.2 inches (Table 1). Physiological stage
20 of development for each planting date is shown in relation to
21 calendar date and day of year (Table 1). Days between stages 0 to
22 3 were 20, 23, 14, and 15; stages 3 to 6 were 26, 30, 32, and 22;
23 and stages 6 to 9 were 35, 31, 28, 32 for PD1, PD2, PD3, and PD4,
24 respectively (Table 1).
25 Pearl millet head lengths; shown to be related to grain yield
26 by Pudelko et al., 1994; are shown for each planting date (Fig. 2)
*
1 (columns topped with the same letter are not significant at the 5
% level of significance). Head lengths for 5 May, 17 May, and 15
3 June plantings accurately predicted grain head yields P < 0.0001)
4 by the equation: Y = 0.0317 + 0.0048 X (Pudelko et al., 1993).
5 However, the 15 July planting date produced very little seed. The
6 average number of seeds per 20 non-bird damaged heads was only 105.
7 This may have been related to environmental changes, i.e., reduced
8 length of day, or paucity of pollinators. Bumble bees, the primary
9 pollinators for the first three planting dates, were essentially
10 absent during flowering of PD4. It probably wasn't lack of
11 available water (18.2 inches compared to 16.4 inches for PD,).
12 Contrary to Mahalakshmi et al. (1988), we found differences in
13 seed size (lb/1000 seed) due to planting date (Fig. 3). Seed size
S in relation to planting date indicates that environment affected
15 grain yield. One would expect that the 15 July planting date, with
16 only 105 seeds per 20 heads, should have large seeds like PD2 or at
17 least seeds the same size as PD1 and PD3. Figures 1 and 2 indicate
18 that grain yield (predicted by head length) and seed size (lb/1000
19 seed) are increased by increased water (19.1 inches for PD2, Table
20 1) (Mahalakshmi et al., 1987 and 1988). Thus, PD2 (17 May) may be
21 the optimum planting time for pearl millet in the Southern Coastal
22 Plain.
23
CONCLUSIONS
S1. Physiological growth from planting to black layer formation
3 are shown in relation to calendar date and date of year for
4 four planting dates.
5 2. The 17 May planting date recieved the most rainfall (19.1
6 inches) and produced the highest grain yields.
7 3. Head lengths for 5 May, 17 May, and 15 June plantings
8 accurately predicted pearl millet head yields (P < 0.05) with
9 equation Y = 0.0317 + 0.0048 X.
10 4. The 15 July planting date produced very little seed although
11 head lengths averaged over 30-cm long.
12 5. Bumble bee pollinators were essentially absent during
13 flowering of the 15 July planting date.
S 6. The 17 May planting produced grain with the largest seed size
15 and 15 July, the smallest seed size.
16
17 ACKNOWLEDGEMENTS
18 Our thanks to E. Brown Agricultural Technician IV; North Fla.
19 Res. and Educ. Ctr. Univ. of Fla., Quincy, FL; for plot
20 preparation and management, data collection, computer processing,
21 and data illustration.
22
23
2 REFERENCES
2 Burton, G.W., A.T. Primo, and R.S. Lowrey. 1986. Effect of
3 clipping frequency and maturity on the yield and quality of
4 four pearl millet. Crop Sci. 26:79-81.
5 Davis-Carter, J.G. 1989. Influence of spatial variability of soil
6 physical and chemical properties on the rooting patterns of
7 pearl millet and sorghum. Ph.D. diss. Texas A&M University,
8 College Station.
9 Hattendorf, M.J., M.S. Dedelfs, B. Amos, L.R. Stone, and R.E.
10 Given, Jr. 1988. Comparative water use characteristics of
11 six row crops. Agron. J. 80:80-85.
12 Hanna, W.W. 1991. Pearl millet-a potentially new crop for the
13 U.S. In Abstracts of Technical Papers, No. 18, Southern
Branch ASA, 2-6 Feb 1991, Ft. Worth, TX.
15 Kumar, K.A., S.C. Gupta, and D.J. Andrews. 1983. Relationship
16 between nutritional quality characters and grain yield in
17 pearl millet. Crop Sci. 23:232-234.
18 Mahalakshmi, V., and F.R. Bidinger. 1985. Water stress and time of
19 floral initiation in pearl millet. J. Agric. Sci.105:437-445.
20 Mahalakshmi, V., and F.R. Bidinger, and D.S. Raju. 1987. Effect
21 of timing of water deficit on pearl millet (Pennisetum
22 americanum). Field Crop Res. 15:327-339.
23 Mahalakshmi, V., F.R. Bidinger, and G.D.P. Rao. 1988. Timing and
24 intensity of water deficits during flowering and grain-filling
25 in pearl millet. Agron. J. 80:130-135.
26
*
1 Payne, W.A., C.W. Wendt, and R. J. Lascano. 1990. Root zone water
2 balance of three low-input millet fields in Niger, West
3 Africa. Agron. J. 82:813-819.
4 Pudelko, J.A., D.L. Wright, and I.D. Teare. 1993. A method for
5 salvaging bird damaged pearl millet research. Fla.
6 Agric. Exp. Stn. Res. Rep. No. NF 93-12:1-11.
7 Teare, I.D., R. Manam, R.P. Waldren, and D.G. Naylor. 1992.
8 Physiological indicators of water stress vs. growth stages in
9 soybean. Fla. Agric. Exp. Stn. Res. Rep. No. NF-92-5:1-17.
10 Teare, I.D., and Hodges. 1994. Soybean physiology. pp. 10-14.
11 In Leon Higley and David Boethle (ed.). ESA Handbook of
12 Soybean Insect Pests.
Table 1. Planting date, stage of development, and 1/2" irrigation for calendar date and day of year at Quincy, FL, 1993.
Stage Description
Amount Amount Amount Amount
Calendar Day of Irrigation Calendar Day of Irrigation Calendar Day of Irrigation Calendar Day of Irrigation
date year (inches) Stage date year (Inches) Stage date year (inches) Stage date year (inches)
PI Preirrigation
PD, Planting date
I Irrigation
O 50% Emergence
I Irrigation
1 Third leaf visible
I Irrigation
2 Fifth leaf visible
I Irrigation
3 Panicle initiation'
4 Flag leaf visible
5 Boot stage
I Irrigation
I Irrigation
6 50% stigma emerged
7 Milk stage,1/2 length
8 Dough stage,1/2 length
9 Black layer,1/2 length
TR Total rainfall
30 April 120 1/2
5 May 125
7 May 127 1/2
10 May 130
14 May 134 1/2
15 May 135
17 May 137 1/2
21 May 141
27 May 147 1/2
30 May 150
5 June 156
8 June 159 1/2
12 June 163
17 June 168 1/2
22 June 173 1/2
25 June 176
10 July 191
19 July 200
30 July 211
86' 4.0'
12.4'
16.4'
PI 14 May 134 1/2
PD,+I 17 May 137 1/2
0 22 May 142
I 27 May 147 1/2
1 30 May 150
I 8 June 159 1/2
2 9 June 160
3 14 June 165
I 17 June 168 1/2
4 21 June 172
I 22 June 173 1/2
5 25 June 175
6 14 July 195
7 3 Aug 215
8 12 Aug 224
9 16 Aug 226
892 3.0'
TR 16.1'4
19.11
PI 8 June 159 1/2
PD, 15 June 166
O 20 June 171
I 22 June 173 1/2
1 26 June 177
2 30 June 181
3 4 July 185
4 14 July 195
5 20 July 201
6 5 Aug 217
7 17 Aug 229
8&I 24 Aug 236 1/2
9 2 Sept 245
862 1.5'
TR 17.2'
18.7'
PD, 15 July 196
O 21 July 202
1 26 July 207
2 30 July 211
3 5 Aug 217
4 12 Aug 224
5 19 Aug 231
I 24 Aug 236 1/2
6 27 Aug 239
7 15 Sept 258
8 21 Sept 264
9 28 Sept 271
792 0.5'
TR 17.7'
18.2'
'Panicle initiation occurs when fifth leaf fully extended.
'Days from planting to black layer formation at 1/2 length.
'Total irrigation.
otal rainfall during growing period: PD, (1 May to 30 July), PD2 (14 May to 16 Aug), PD, (11 June to 5 Sept.), PD4 (12 July to 30 Sept.)
'Total water during growing period.
C 1= C C
L. L.
- .- .. ..... -..... E .... ................. .......................... -............. .. ...... ........ .^ .. ...,.- -^ -...................- .. ............................ : ......
f f t t t t t
4
-3
C
2
0'
4-
lI
Tri
136 151 166 181 196 211
Day of Year
. .......1.
.I, III
. I f i 111 1 11
226 241 256
Figure 1. Rainfall during the 1993 pearl millet growing season for
four planting dates in relation to rainfall amounts and
dates of events.
ST. T. .
L.
3
....... I........ .
. .
"~ I
"'
L I ... I .
201
015
4-.-
C
a, 10
1o
0
Figure 2.
0 5
Figure 2.
AB
BC
H..--
May 5 May 17 June 15 July 15
Date of Planting
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.
-D
0
"o
0 0.03
0
O
0
0 0.02
O
0.01
ioo
"--
May 17 June 15 July 15
Date of Planting
Figure 3.
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.
0.04
---- ---------CG --- ---
0 ---.
May 5
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